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Sample records for acid-inducible gene-i-like receptors

  1. Retinoic acid-inducible gene-I-like receptor (RLR)-mediated antiviral innate immune responses in the lower respiratory tract: Roles of TRAF3 and TRAF5.

    PubMed

    Chiba, Yuki; Matsumiya, Tomoh; Satoh, Tsugumi; Hayakari, Ryo; Furudate, Ken; Xing, Fei; Yoshida, Hidemi; Tanji, Kunikazu; Mizukami, Hiroki; Imaizumi, Tadaatsu; Ito, Etsuro

    2015-11-13

    Upon viral infection, the cytoplasmic viral sensor retinoic acid-inducible gene-I (RIG-I) recognizes viral RNA to activate antiviral signaling to induce type I interferon (IFN). RIG-I-like receptors (RLRs) activate antiviral signaling in a tissue-specific manner. The molecular mechanism underlying antiviral signaling in the respiratory system remains unclear. We studied antiviral signaling in the lower respiratory tract (LRT), which is the site of many harmful viral infections. Epithelial cells of the LRT can be roughly divided into two groups: bronchial epithelial cells (BECs) and pulmonary alveolar epithelial cells (AECs). These two cell types exhibit different phenotypes; therefore, we hypothesized that these cells may play different roles in antiviral innate immunity. We found that BECs exhibited higher antiviral activity than AECs. TNF receptor-associated factor 3 (TRAF3) has been shown to be a crucial molecule in RLR signaling. The expression levels of TRAF3 and TRAF5, which have conserved domains that are nearly identical, in the LRT were examined. We found that the bronchus exhibited the highest expression levels of TRAF3 and TRAF5 in the LRT. These findings suggest the importance of the bronchus in antiviral innate immunity in the LRT and indicate that TRAF3 and TRAF5 may contribute to RLR signaling. PMID:26454171

  2. Comparative analysis of transcriptional profiles of retinoic-acid-induced gene I-like receptors and interferons in seven tissues from ducks infected with avian Tembusu virus.

    PubMed

    Fu, Guanghua; Chen, Cuiteng; Huang, Yu; Cheng, Longfei; Fu, Qiuling; Wan, Chunhe; Shi, Shaohua; Chen, Hongmei; Liu, Wei

    2016-01-01

    Avian Tembusu virus (ATV), an emerging virus that mainly infects laying and breeding ducks in China, has caused severe economic loss in duck industry. However, there have been no reports about host innate immune responses during ATV infection and its correlation with clinical signs or pathology. To identify the roles of these immune factors in the innate host response to ATV infection, quantitative real-time PCR (qPCR) was used to analyze the transcriptional profiles on the genes encoding two retinoic-acid-induced gene I (RIG-I)-like receptors (RLRs) and two interferons (INF-α and INF-γ) in seven tissues of an ATV-infected shelduck. After infection with ATV, both RLR genes were significantly upregulated (P < 0.05) in all seven tissues. The peak expression levels of the two RLR genes were observed at 24 hours postinfection (hpi) and were higher in non-lymphoid tissues (liver, lung, kidney, and ovary) than in lymphoid tissues (thymus, spleen and bursa). Although the transcription levels of both IFN genes were also upregulated, they showed different time-dependent expression patterns compared with those of the RLR genes. In addition, the highest mRNA expression of the two IFN genes was observed in the ovary at 6 hpi. This observation suggests that the ovary is the primary target tissue in ATV infection and explains the clinical characteristics of the primary pathological changes in the ovaries of ATV-infected ducks. Our results, for the first time, elucidate the differential and coordinated expression profiles of two RLRs and two IFNs in an ATV-infected shelduck.

  3. Human sweet taste receptor mediates acid-induced sweetness of miraculin.

    PubMed

    Koizumi, Ayako; Tsuchiya, Asami; Nakajima, Ken-ichiro; Ito, Keisuke; Terada, Tohru; Shimizu-Ibuka, Akiko; Briand, Loïc; Asakura, Tomiko; Misaka, Takumi; Abe, Keiko

    2011-10-01

    Miraculin (MCL) is a homodimeric protein isolated from the red berries of Richadella dulcifica. MCL, although flat in taste at neutral pH, has taste-modifying activity to convert sour stimuli to sweetness. Once MCL is held on the tongue, strong sweetness is sensed over 1 h each time we taste a sour solution. Nevertheless, no molecular mechanism underlying the taste-modifying activity has been clarified. In this study, we succeeded in quantitatively evaluating the acid-induced sweetness of MCL using a cell-based assay system and found that MCL activated hT1R2-hT1R3 pH-dependently as the pH decreased from 6.5 to 4.8, and that the receptor activation occurred every time an acid solution was applied. Although MCL per se is sensory-inactive at pH 6.7 or higher, it suppressed the response of hT1R2-hT1R3 to other sweeteners at neutral pH and enhanced the response at weakly acidic pH. Using human/mouse chimeric receptors and molecular modeling, we revealed that the amino-terminal domain of hT1R2 is required for the response to MCL. Our data suggest that MCL binds hT1R2-hT1R3 as an antagonist at neutral pH and functionally changes into an agonist at acidic pH, and we conclude this may cause its taste-modifying activity. PMID:21949380

  4. Human sweet taste receptor mediates acid-induced sweetness of miraculin

    PubMed Central

    Koizumi, Ayako; Tsuchiya, Asami; Nakajima, Ken-ichiro; Ito, Keisuke; Terada, Tohru; Shimizu-Ibuka, Akiko; Briand, Loïc; Asakura, Tomiko; Misaka, Takumi; Abe, Keiko

    2011-01-01

    Miraculin (MCL) is a homodimeric protein isolated from the red berries of Richadella dulcifica. MCL, although flat in taste at neutral pH, has taste-modifying activity to convert sour stimuli to sweetness. Once MCL is held on the tongue, strong sweetness is sensed over 1 h each time we taste a sour solution. Nevertheless, no molecular mechanism underlying the taste-modifying activity has been clarified. In this study, we succeeded in quantitatively evaluating the acid-induced sweetness of MCL using a cell-based assay system and found that MCL activated hT1R2-hT1R3 pH-dependently as the pH decreased from 6.5 to 4.8, and that the receptor activation occurred every time an acid solution was applied. Although MCL per se is sensory-inactive at pH 6.7 or higher, it suppressed the response of hT1R2-hT1R3 to other sweeteners at neutral pH and enhanced the response at weakly acidic pH. Using human/mouse chimeric receptors and molecular modeling, we revealed that the amino-terminal domain of hT1R2 is required for the response to MCL. Our data suggest that MCL binds hT1R2-hT1R3 as an antagonist at neutral pH and functionally changes into an agonist at acidic pH, and we conclude this may cause its taste-modifying activity. PMID:21949380

  5. Effect of a novel NK1 receptor selective antagonist (NKP608) on citric acid induced cough and airway obstruction.

    PubMed

    El-Hashim, A Z; Wyss, D; Lewis, C

    2004-01-01

    The effects of an orally administered novel and selective NK1 antagonist, NKP608, on cough and airway obstruction, induced by citric acid in guinea pigs, were investigated. Guinea pigs were pre-treated with 0.03, 0.3 and 1 mg kg(-1) of NKP608, the NK2 antagonist, SR48968 or both 2 h prior to challenge with citric acid (0.6 M) for a 10 min period. Guinea pigs pre-treated with 0.03, 0.3 and 1mgkg(-1) of NKP608 exhibited a significant reduction of 77, 74 and 79%, respectively, in the numbers of cough compared to vehicle pre-treated animals (P<0.05). SR48968, 10 mg kg(-1), alone did not significantly affect the citric acid-induced cough but when co-administered with 1 mg kg(-1) of NKP608, there was a significant 90% reduction in cough. NKP608 did not significantly reduce the citric acid-induced increase in Penh at any of the doses used. SR48968 significantly reduced the citric acid induced airway obstruction by about 50%. However, when SR48968 was co-administered with NKP608, there was a greater (73%) decrease in the airway obstruction compared with SR48968 alone. These data show that NKP608, a selective NK1 receptor antagonist, is a potent inhibitor of citric acid induced cough in guinea pigs and may therefore have value in the therapy of clinical cough.

  6. Lysophosphatidic acid induces anxiety-like behavior via its receptors in mice.

    PubMed

    Yamada, Misa; Tsukagoshi, Mai; Hashimoto, Tomio; Oka, Jun-Ichiro; Saitoh, Akiyoshi; Yamada, Mitsuhiko

    2015-03-01

    Lysophosphatidic acid (LPA) is a potent bioactive lipid mediator with diverse biological properties. We previously found altered expression of the LPA-related genes in rodents after treatment with sertraline, which is widely used to treat anxiety disorders and depression. However, little is known about the behavioral effects of LPA. In the present study, we investigated the behavioral effects of intracerebroventricular injection of LPA in adult mice. LPA did not significantly affect spontaneous locomotor activity, suggesting that LPA does not induce hyperactivity, ataxia, or sedation. We next investigated the emotional effects of LPA via the hole-board test. LPA significantly increased the number of head-dips in a dose- and time-related manner. A significant induction of head-dip counts occurred 15 and 30 min after LPA administration. To clarify the involvement of LPA receptors, we examined the effect of the non-selective LPA1-4 receptor antagonist, 1-bromo-3(S)-hydroxy-4-(palmitoyloxy)butyl-phosphonate (BrP-LPA) co-administered with LPA. BrP-LPA dose-dependently inhibited LPA-induced head-dip counts. We next investigated anxiety-like behavior via the elevated plus-maze test. LPA significantly reduced the percentage of time spent in the open arms and BrP-LPA dose-dependently inhibited this anxiety-like behavior. In conclusion, LPA induced anxiety-like behavior in mice via LPA receptors. Our results suggest that LPA signaling plays an important role in regulating anxiety in mice.

  7. Human myeloblastic leukemia cells (HL-60) express a membrane receptor for estrogen that signals and modulates retinoic acid-induced cell differentiation

    SciTech Connect

    Kauss, M. Ariel; Reiterer, Gudrun; Bunaciu, Rodica P.; Yen, Andrew

    2008-10-01

    Estrogen receptors are historically perceived as nuclear ligand activated transcription factors. An estrogen receptor has now been found localized to the plasma membrane of human myeloblastic leukemia cells (HL-60). Its expression occurs throughout the cell cycle, progressively increasing as cells mature from G{sub 1} to S to G{sub 2}/M. To ascertain that the receptor functioned, the effect of ligands, including a non-internalizable estradiol-BSA conjugate and tamoxifen, an antagonist of nuclear estrogen receptor function, were tested. The ligands caused activation of the ERK MAPK pathway. They also modulated the effect of retinoic acid, an inducer of MAPK dependent terminal differentiation along the myeloid lineage in these cells. In particular the ligands inhibited retinoic acid-induced inducible oxidative metabolism, a functional marker of terminal myeloid cell differentiation. To a lesser degree they also diminished retinoic acid-induced earlier markers of cell differentiation, namely CD38 and CD11b. However, they did not regulate retinoic acid-induced G{sub 0} cell cycle arrest. There is thus a membrane localized estrogen receptor in HL-60 myeloblastic leukemia cells that can cause ERK activation and modulates the response of these cells to retinoic acid, indicating crosstalk between the membrane estrogen and retinoic acid evoked pathways relevant to propulsion of cell differentiation.

  8. TRIP6 Enhances Lysophosphatidic Acid-induced Cell Migration by Interacting with the Lysophosphatidic Acid 2 Receptor*

    PubMed Central

    Xu, Jun; Lai, Yun-Ju; Lin, Weei-Chin; Lin, Fang-Tsyr

    2014-01-01

    Lysophosphatidic acid (LPA) induces actin rearrangement, focal adhesion assembly, and cell migration through the activation of small G protein Rho and its downstream effectors. These diverse cellular responses are mediated by its associated G protein-coupled receptors. However, the mechanisms and specificity by which these LPA receptors mediate LPA actions are still poorly understood. Here we show that LPA stimulation promotes the interaction of the LPA2 receptor with a focal adhesion molecule, TRIP6 (thyroid receptor interacting protein 6)/ZRP-1 (zyxin-related protein 1). TRIP6 directly binds to the carboxyl-terminal tail of the LPA2 receptor through its LIM domains. LPA-dependent recruitment of TRIP6 to the plasma membrane promotes its targeting to focal adhesions and co-localization with actin stress fibers. In addition, TRIP6 associates with the components of focal complexes including paxillin, focal adhesion kinase, c-Src, and p130cas in an agonist-dependent manner. Overexpression of TRIP6 augments LPA-induced cell migration; in contrast, suppression of endogenous TRIP6 expression by a TRIP6-specific small interfering RNA reduces it in SKOV3 ovarian cancer cells. Strikingly, the association with TRIP6 is specific to the LPA2 receptor but not LPA1 or LPA3 receptor, indicating a specific role for TRIP6 in regulating LPA2 receptor-mediated signaling. Taken together, our results suggest that TRIP6 functions at a point of convergence between the activated LPA2 receptor and downstream signals involved in cell adhesion and migration. PMID:14688263

  9. Genetic variation in pattern recognition receptors: functional consequences and susceptibility to infectious disease.

    PubMed

    Jaeger, Martin; Stappers, Mark H T; Joosten, Leo A B; Gyssens, Inge C; Netea, Mihai G

    2015-01-01

    Cells of the innate immune system are equipped with surface and cytoplasmic receptors for microorganisms called pattern recognition receptors (PRRs). PRRs recognize specific pathogen-associated molecular patterns and as such are crucial for the activation of the immune system. Currently, five different classes of PRRs have been described: Toll-like receptors, C-type lectin receptors, nucleotide-binding oligomerization domain-like receptors, retinoic acid-inducible gene I-like receptors and absent in melanoma 2-like receptors. Following their discovery, many sequence variants in PRR genes have been uncovered and shown to be implicated in human infectious diseases. In this review, we will discuss the effect of genetic variation in PRRs and their signaling pathways on susceptibility to infectious diseases in humans.

  10. Farnesoid X receptor signal is involved in deoxycholic acid-induced intestinal metaplasia of normal human gastric epithelial cells.

    PubMed

    Li, Shu; Chen, Xin; Zhou, Lu; Wang, Bang-Mao

    2015-11-01

    The farnesoid X receptor (FXR) signaling pathway is known to be involved in the metabolism of bile acid, glucose and lipid. In the present study, we demonstrated that 400 µmol/l deoxycholic acid (DCA) stimulation promotes the proliferation of normal human gastric epithelial cells (GES-1). In addition, DCA activated FXR and increased the expression of intestinal metaplasia genes, including caudal-related homeobox transcription factor 2 (Cdx2) and mucin 2 (MUC2). The treatment of FXR agonist GW4064/antagonist guggulsterone (Gug.) significantly increased/decreased the expression levels of FXR, Cdx2 and MUC2 protein in DCA-induced GES-1 cells. GW4064/Gug. also enhanced/reduced the nuclear factor-κB (NF-κB) activity and binding of the Cdx2 promoter region and NF-κB, the most common subunit p50 protein. Taken together, the results indicated that DCA is capable of modulating the expression of Cdx2 and the downstream MUC2 via the nuclear receptor FXR-NF-κB activity in normal gastric epithelial cells. FXR signaling pathway may therefore be involved in the intestinal metaplasia of human gastric mucosa.

  11. Purple sweet potato color attenuates domoic acid-induced cognitive deficits by promoting estrogen receptor-α-mediated mitochondrial biogenesis signaling in mice.

    PubMed

    Lu, Jun; Wu, Dong-mei; Zheng, Yuan-lin; Hu, Bin; Cheng, Wei; Zhang, Zi-feng

    2012-02-01

    Recent findings suggest that endoplasmic reticulum stress may be involved in the pathogenesis of domoic acid-induced neurodegeneration. Purple sweet potato color, a class of naturally occurring anthocyanins, has beneficial health and biological effects. Recent studies have also shown that anthocyanins have estrogenic activity and can enhance estrogen receptor-α expression. In this study, we evaluated the effect of purple sweet potato color on cognitive deficits induced by hippocampal mitochondrial dysfunction in domoic acid-treated mice and explored the potential mechanisms underlying this effect. Our results showed that the oral administration of purple sweet potato color to domoic acid-treated mice significantly improved their behavioral performance in a step-through passive avoidance task and a Morris water maze task. These improvements were mediated, at least in part, by a stimulation of estrogen receptor-α-mediated mitochondrial biogenesis signaling and by decreases in the expression of p47phox and gp91phox. Decreases in reactive oxygen species and protein carbonylation were also observed, along with a blockade of the endoplasmic reticulum stress pathway. Furthermore, purple sweet potato color significantly suppressed endoplasmic reticulum stress-induced apoptosis, which prevented neuron loss and restored the expression of memory-related proteins. However, knockdown of estrogen receptor-α using short hairpin RNA only partially blocked the neuroprotective effects of purple sweet potato color in the hippocampus of mice cotreated with purple sweet potato color and domoic acid, indicating that purple sweet potato color acts through multiple pathways. These results suggest that purple sweet potato color could be a possible candidate for the prevention and treatment of cognitive deficits in excitotoxic and other brain disorders.

  12. Agathisflavone enhances retinoic acid-induced neurogenesis and its receptors α and β in pluripotent stem cells.

    PubMed

    Paulsen, Bruna S; Souza, Cleide S; Chicaybam, Leonardo; Bonamino, Martin Hernán; Bahia, Marcus; Costa, Silvia Lima; Borges, Helena L; Rehen, Stevens K

    2011-10-01

    Flavonoids have key functions in the regulation of multiple cellular processes; however, their effects have been poorly examined in pluripotent stem cells. Here, we tested the hypothesis that neurogenesis induced by all-trans retinoic acid (RA) is enhanced by agathisflavone (FAB, Caesalpinia pyramidalis Tull). Mouse embryonic stem (mES) cells and induced pluripotent stem (miPS) cells growing as embryoid bodies (EBs) for 4 days were treated with FAB (60 μM) and/or RA (2 μM) for additional 4 days. FAB did not interfere with the EB mitotic rate of mES cells, as evidenced by similar percentages of mitotic figures labeled by phospho-histone H3 in control (3.4% ± 0.4%) and FAB-treated groups (3.5% ± 1.1%). Nevertheless, the biflavonoid reduced cell death in both control and RA-treated EBs from mES cells by almost 2-fold compared with untreated EBs. FAB was unable, by itself, to induce neuronal differentiation in EBs after 4 days of treatment. On the other hand, FAB enhanced neuronal differentiation induced by RA in both EBs of mES and miPS. FAB increased the percentage of nestin-labeled cells by 2.7-fold (mES) and 2.4 (miPS) and β-tubulin III-positive cells by 2-fold (mES) and 2.7 (miPS) in comparison to RA-treated EBs only. FAB increased the expression of RA receptors α and β in mES EBs, suggesting that the availability of RA receptors is limiting RA-induced neurogenesis in pluripotent stem cells. This is the first report to describe that naturally occurring biflavonoids regulate apoptosis and neuronal differentiation in pluripotent stem cells.

  13. Receptor for advanced glycation end products plays a more important role in cellular survival than in neurite outgrowth during retinoic acid-induced differentiation of neuroblastoma cells.

    PubMed

    Sajithlal, Gangadharan; Huttunen, Henri; Rauvala, Heikki; Munch, Gerald

    2002-03-01

    The receptor for advanced glycation end products (RAGE), a member of the immunoglobulin superfamily, is known to interact with amphoterin. This interaction has been proposed to play a role in neurite outgrowth and process elongation during neurodifferentiation. However, there is as yet no direct evidence of the relevance of this pathway to neurodifferentiation under physiological conditions. In this study we have investigated a possible role of RAGE and amphoterin in the retinoic acid-induced differentiation of neuroblastoma cells. The functional inactivation of RAGE by dominant negative and antisense strategies showed that RAGE is not required for process outgrowth or differentiation, although overexpression of RAGE accelerates the elongation of neuritic processes. Using the antisense strategy, amphoterin was shown to be essential for process outgrowth and differentiation, suggesting that amphoterin may interact with other molecules to exert its effect in this context. Interestingly, the survival of the neuroblastoma cells treated with retinoic acid was partly dependent on the expression of RAGE, and inhibition of RAGE function partially blocked the increase in anti-apoptotic protein Bcl-2 following retinoic acid treatment. Based on these results we propose that a combination therapy using RAGE blockers and retinoic acid may prove as a useful approach for chemotherapy for the treatment of neuroblastoma.

  14. Lipoteichoic Acid-Induced Nitric Oxide Production Depends on the Activation of Platelet-Activating Factor Receptor and Jak21

    PubMed Central

    Han, Seung Hyun; Kim, Je Hak; Seo, Ho Seong; Martin, Michael H.; Chung, Gook-Hyun; Michalek, Suzanne M.; Nahm, Moon H.

    2006-01-01

    NO production by macrophages in response to lipoteichoic acid (LTA) and a synthetic lipopeptide (Pam3CSK4) was investigated. LTA and Pam3CSK4 induced the production of both TNF-α and NO. Inhibitors of platelet-activating factor receptor (PAFR) blocked LTA- or Pam3CSK4-induced production of NO but not TNF-α. Jak2 tyrosine kinase blocked LTA-induced production of NO but not TNF-α. PAFR inhibition blocked phosphorylation of Jak2 and STAT1, a key factor for expressing inducible NO synthase. In addition, LTA did not induce IFN-β expression, and p38 mitogen-activated protein serine kinase was necessary for LTA-induced NO production but not for TNF-α production. These findings suggest that Gram-positive bacteria induce NO production using a PAFR signaling pathway to activate STAT1 via Jak2. This PAFR/Jak2/STAT1 signaling pathway resembles the IFN-β, type I IFNR/Jak/STAT1 pathway described for LPS. Consequently, Gram-positive and Gram-negative bacteria appear to have different but analogous mechanisms for NO production. PMID:16365452

  15. Inhibitory effects of imidazoline receptor ligands on basal and kainic acid-induced neurotoxic signalling in mice.

    PubMed

    Keller, Benjamin; García-Sevilla, Jesús A

    2016-09-01

    This in vivo study assessed the potential of the imidazoline receptor (IR) ligands moxonidine (selective I1-IR), BU224 (selective I2-IR) and LSL61122 (mixed I1/I2-IR) to dampen excitotoxic signalling induced by kainic acid (KA; 45 mg/kg) in the mouse brain (hippocampus and cerebral cortex). KA triggered a strong behavioural syndrome (seizures; maximal at 60-90 minutes) and sustained stimulation (at 72 hours with otherwise normal mouse behaviour) of pro-apoptotic c-Jun-N-terminal kinases (JNK) and calpain with increased cleavage of p35 into neurotoxic p25 (cyclin-dependent kinase 5 [Cdk5] activators) in mouse hippocampus. Pretreatment (five days) with LSL61122 (10 mg/kg), but not moxonidine (1 mg/kg) or BU224 (20 mg/kg), attenuated the KA-induced behavioural syndrome, and all three IR ligands inhibited JNK and calpain activation, as well as p35/p25 cleavage after KA in the hippocampus (effects also observed after acute IR drug treatments). Efaroxan (I1-IR, 10 mg/kg) and idazoxan (I2-IR, 10 mg/kg), postulated IR antagonists, did not antagonise the effects of moxonidine and LSL61122 on KA targets (these IR ligands showed agonistic properties inhibiting pro-apoptotic JNK). Brain subcellular preparations revealed reduced synaptosomal postsynaptic density-95 protein contents (a mediator of JNK activation) and indicated increased p35/Cdk5 complexes (with pro-survival functions) after treatment with moxonidine, BU224 and LSL61122. These results showed that I1- and I2-IR ligands (moxonidine and BU224), and especially the mixed I1/I2-IR ligand LSL61122, are partly neuroprotective against KA-induced excitotoxic signalling. These findings suggest a therapeutic potential of IR drugs in disorders associated with glutamate-mediated neurodegeneration. PMID:27302941

  16. Inhibitory effects of imidazoline receptor ligands on basal and kainic acid-induced neurotoxic signalling in mice.

    PubMed

    Keller, Benjamin; García-Sevilla, Jesús A

    2016-09-01

    This in vivo study assessed the potential of the imidazoline receptor (IR) ligands moxonidine (selective I1-IR), BU224 (selective I2-IR) and LSL61122 (mixed I1/I2-IR) to dampen excitotoxic signalling induced by kainic acid (KA; 45 mg/kg) in the mouse brain (hippocampus and cerebral cortex). KA triggered a strong behavioural syndrome (seizures; maximal at 60-90 minutes) and sustained stimulation (at 72 hours with otherwise normal mouse behaviour) of pro-apoptotic c-Jun-N-terminal kinases (JNK) and calpain with increased cleavage of p35 into neurotoxic p25 (cyclin-dependent kinase 5 [Cdk5] activators) in mouse hippocampus. Pretreatment (five days) with LSL61122 (10 mg/kg), but not moxonidine (1 mg/kg) or BU224 (20 mg/kg), attenuated the KA-induced behavioural syndrome, and all three IR ligands inhibited JNK and calpain activation, as well as p35/p25 cleavage after KA in the hippocampus (effects also observed after acute IR drug treatments). Efaroxan (I1-IR, 10 mg/kg) and idazoxan (I2-IR, 10 mg/kg), postulated IR antagonists, did not antagonise the effects of moxonidine and LSL61122 on KA targets (these IR ligands showed agonistic properties inhibiting pro-apoptotic JNK). Brain subcellular preparations revealed reduced synaptosomal postsynaptic density-95 protein contents (a mediator of JNK activation) and indicated increased p35/Cdk5 complexes (with pro-survival functions) after treatment with moxonidine, BU224 and LSL61122. These results showed that I1- and I2-IR ligands (moxonidine and BU224), and especially the mixed I1/I2-IR ligand LSL61122, are partly neuroprotective against KA-induced excitotoxic signalling. These findings suggest a therapeutic potential of IR drugs in disorders associated with glutamate-mediated neurodegeneration.

  17. Acid-induced sweetness of neoculin is ascribed to its pH-dependent agonistic-antagonistic interaction with human sweet taste receptor.

    PubMed

    Nakajima, Ken-ichiro; Morita, Yuji; Koizumi, Ayako; Asakura, Tomiko; Terada, Tohru; Ito, Keisuke; Shimizu-Ibuka, Akiko; Maruyama, Jun-ichi; Kitamoto, Katsuhiko; Misaka, Takumi; Abe, Keiko

    2008-07-01

    Neoculin (NCL) is a sweet protein that also has taste-modifying activity to convert sourness to sweetness. However, it has been unclear how NCL induces this unique sensation. Here we quantitatively evaluated the pH-dependent acid-induced sweetness of NCL using a cell-based assay system. The human sweet taste receptor, hT1R2-hT1R3, was functionally expressed in HEK293T cells together with G alpha protein. When NCL was applied to the cells under different pH conditions, it activated hT1R2-hT1R3 in a pH-dependent manner as the condition changed from pH 8 to 5. The pH-response sigmoidal curve resembled the imidazole titration curve, suggesting that His residues were involved in the taste-modifying activity. We then constructed an NCL variant in which all His residues were replaced with Ala and found that the variant elicited strong sweetness at neutral pH as well as at acidic pH. Since NCL and the variant elicited weak and strong sweetness at the same neutral pH, respectively, we applied different proportions of NCL-variant mixtures to the cells at this pH. As a result, NCL competitively inhibits the variant-induced receptor activation. All these data suggest that NCL acts as an hT1R2-hT1R3 agonist at acidic pH but functionally changes into its antagonist at neutral pH.

  18. Toll-like Receptor 3, RIG-I-like Receptors and the NLRP3 Inflammasome: Key Modulators of Innate Immune Responses to Double-stranded RNA Viruses

    PubMed Central

    Yu, Man; Levine, Stewart J.

    2011-01-01

    Double-stranded RNA (dsRNA), the genetic material for many RNA viruses, induces robust host immune responses via pattern recognition receptors, which include Toll-like receptor 3 (TLR3), retinoic acid-inducible gene-I-like receptors (RLRs) and the multi-protein NLRP3 inflammasome complex. The engagement of dsRNA receptors or inflammasome activation by viral dsRNA initiates complex intracellular signaling cascades that play essential roles in inflammation and innate immune responses, as well as the resultant development of adaptive immunity. This review focuses on signaling pathways mediated by TLR3, RLRs and the NLRP3 inflammasome, as well as the potential use of agonists and antagonists that target these pathways to treat disease. PMID:21466970

  19. Hepatitis C Virus Frameshift/Alternate Reading Frame Protein Suppresses Interferon Responses Mediated by Pattern Recognition Receptor Retinoic-Acid-Inducible Gene-I

    PubMed Central

    Park, Seung Bum; Seronello, Scott; Mayer, Wasima; Ojcius, David M.

    2016-01-01

    Hepatitis C virus (HCV) actively evades host interferon (IFN) responses but the mechanisms of how it does so are not completely understood. In this study, we present evidence for an HCV factor that contributes to the suppression of retinoic-acid-inducible gene-I (RIG-I)-mediated IFN induction. Expression of frameshift/alternate reading frame protein (F/ARFP) from HCV -2/+1 frame in Huh7 hepatoma cells suppressed type I IFN responses stimulated by HCV RNA pathogen-associated molecular pattern (PAMP) and poly(IC). The suppression occurred independently of other HCV factors; and activation of interferon stimulated genes, TNFα, IFN-λ1, and IFN-λ2/3 was likewise suppressed by HCV F/ARFP. Point mutations in the full-length HCV sequence (JFH1 genotype 2a strain) were made to introduce premature termination codons in the -2/+1 reading frame coding for F/ARFP while preserving the original reading frame, which enhanced IFNα and IFNβ induction by HCV. The potentiation of IFN response by the F/ARFP mutations was diminished in Huh7.5 cells, which already have a defective RIG-I, and by decreasing RIG-I expression in Huh7 cells. Furthermore, adding F/ARFP back via trans-complementation suppressed IFN induction in the F/ARFP mutant. The F/ARFP mutants, on the other hand, were not resistant to exogenous IFNα. Finally, HCV-infected human liver samples showed significant F/ARFP antibody reactivity, compared to HCV-uninfected control livers. Therefore, HCV F/ARFP likely cooperates with other viral factors to suppress type I and III IFN induction occurring through the RIG-I signaling pathway. This study identifies a novel mechanism of pattern recognition receptor modulation by HCV and suggests a biological function of the HCV alternate reading frame in the modulation of host innate immunity. PMID:27404108

  20. The histone deacetylase inhibitor suberoylanilide hydroxamic acid induces apoptosis, down-regulates the CXCR4 chemokine receptor and impairs migration of chronic lymphocytic leukemia cells

    PubMed Central

    Stamatopoulos, Basile; Meuleman, Nathalie; De Bruyn, Cécile; Delforge, Alain; Bron, Dominique; Lagneaux, Laurence

    2010-01-01

    Background Chronic lymphocytic leukemia is a neoplastic disorder that arises largely as a result of defective apoptosis leading to chemoresistance. Stromal cell-derived factor-1 and its receptor, CXCR4, have been shown to play an important role in chronic lymphocytic leukemia cell trafficking and survival. Design and Methods Since histone acetylation is involved in the modulation of gene expression, we evaluated the effects of suberoylanilide hydroxamic acid, a histone deacetylase inhibitor, on chronic lymphocytic leukemia cells and in particular on cell survival, CXCR4 expression, migration, and drug sensitization. Results Here, we showed that treatment with suberoylanilide hydroxamic acid (20 μM) for 48 hours induced a decrease in chronic lymphocytic leukemia cell viability via apoptosis (n=20, P=0.0032). Using specific caspase inhibitors, we demonstrated the participation of caspases-3, -6 and -8, suggesting an activation of the extrinsic pathway. Additionally, suberoylanilide hydroxamic acid significantly decreased CXCR4 mRNA (n=10, P=0.0010) and protein expression (n=40, P<0.0001). As a result, chronic lymphocytic leukemia cell migration in response to stromal cell-derived factor-1 (n=23, P<0.0001) or through bone marrow stromal cells was dramatically impaired. Consequently, suberoylanilide hydroxamic acid reduced the protective effect of the microenvironment and thus sensitized chronic lymphocytic leukemia cells to chemotherapy such as fludarabine. Conclusions In conclusion, suberoylanilide hydroxamic acid induces apoptosis in chronic lymphocytic leukemia cells via the extrinsic pathway and down-regulates CXCR4 expression leading to decreased cell migration. Suberoylanilide hydroxamic acid in combination with other drugs represents a promising therapeutic approach to inhibiting migration, chronic lymphocytic leukemia cell survival and potentially overcoming drug resistance. PMID:20145270

  1. Hepatitis C Virus Frameshift/Alternate Reading Frame Protein Suppresses Interferon Responses Mediated by Pattern Recognition Receptor Retinoic-Acid-Inducible Gene-I.

    PubMed

    Park, Seung Bum; Seronello, Scott; Mayer, Wasima; Ojcius, David M

    2016-01-01

    Hepatitis C virus (HCV) actively evades host interferon (IFN) responses but the mechanisms of how it does so are not completely understood. In this study, we present evidence for an HCV factor that contributes to the suppression of retinoic-acid-inducible gene-I (RIG-I)-mediated IFN induction. Expression of frameshift/alternate reading frame protein (F/ARFP) from HCV -2/+1 frame in Huh7 hepatoma cells suppressed type I IFN responses stimulated by HCV RNA pathogen-associated molecular pattern (PAMP) and poly(IC). The suppression occurred independently of other HCV factors; and activation of interferon stimulated genes, TNFα, IFN-λ1, and IFN-λ2/3 was likewise suppressed by HCV F/ARFP. Point mutations in the full-length HCV sequence (JFH1 genotype 2a strain) were made to introduce premature termination codons in the -2/+1 reading frame coding for F/ARFP while preserving the original reading frame, which enhanced IFNα and IFNβ induction by HCV. The potentiation of IFN response by the F/ARFP mutations was diminished in Huh7.5 cells, which already have a defective RIG-I, and by decreasing RIG-I expression in Huh7 cells. Furthermore, adding F/ARFP back via trans-complementation suppressed IFN induction in the F/ARFP mutant. The F/ARFP mutants, on the other hand, were not resistant to exogenous IFNα. Finally, HCV-infected human liver samples showed significant F/ARFP antibody reactivity, compared to HCV-uninfected control livers. Therefore, HCV F/ARFP likely cooperates with other viral factors to suppress type I and III IFN induction occurring through the RIG-I signaling pathway. This study identifies a novel mechanism of pattern recognition receptor modulation by HCV and suggests a biological function of the HCV alternate reading frame in the modulation of host innate immunity. PMID:27404108

  2. A putative G-protein-coupled receptor, H218, is down-regulated during the retinoic acid-induced differentiation of F9 embryonal carcinoma cells.

    PubMed

    Li, Y; MacLennan, A J; Rogers, M B

    1998-03-15

    We have previously cloned a novel guanine nucleotide-binding protein (G-protein)-coupled receptor, H218, that has sequence similarity to a lysophosphatidic acid receptor, edg2. We present here Northern analysis indicating that the H218 mRNA is expressed in undifferentiated F9 embryonal carcinoma cells. The H218 message is down-regulated and its stability is decreased during retinoic acid- and dibutyryl cAMP-induced differentiation. Treatment by various receptor-selective retinoids indicated that retinoic acid receptor beta or gamma signaling, but not retinoid X receptor activation, is required for the down-regulation of H218 mRNA. Activation of the H218 receptor may contribute to the phenotype of undifferentiated F9 embryonal carcinoma cells.

  3. Dominant negative mutant of retinoic acid receptor alpha inhibits retinoic acid-induced P19 cell differentiation by binding to DNA.

    PubMed

    Costa, S L; McBurney, M W

    1996-05-25

    Retinoic acid (RA) is a potent inducer of P19 cell differentiation. RA activity is thought to be mediated by nuclear RA receptors (RARs), transcription factors whose activity is dependent on RA. There are three RARs called alpha, beta, and gamma. We created truncated versions of the three RARs and compared their activities as inhibitors of RA-mediated gene transcription and of P19 cell differentiation. Only mutants of the RAR alpha were inhibitory in these assays. A mutant of RAR alpha carrying a 10-amino-acid insert was able to heterodimerize with RXRbeta or with the normal RAR alpha and the inhibitory activity of this mutant was dependent on an intact DNA binding domain. We conclude that dominant negative mutants of RAR alpha act by heterodimerizing with RXRs or RARs and binding to RA response elements on DNA, thereby preventing binding of the normal receptors to those sites. PMID:8635515

  4. Lysophosphatidic Acid-induced ERK Activation and Chemotaxis in MC3T3-E1 Preosteoblasts are Independent of EGF Receptor Transactivation

    SciTech Connect

    Karagiosis, Sue A.; Chrisler, William B.; Bollinger, Nikki; Karin, Norman J.

    2009-06-01

    Growing evidence indicates that bone-forming osteoblasts and their progenitors are target cells for the lipid growth factor lysophosphatidic acid (LPA) which is produced by degranulating platelets at sites of injury. LPA is a potent inducer of bone cell migration, proliferation and survival in vitro and an attractive candidate to facilitate preosteoblast chemotaxis during skeletal regeneration in vivo, but the intracellular signaling pathways mediating the effects of this lipid on bone cells are not defined. In this study we measured the ability of LPA to stimulate extracellular signal-related kinase (ERK1/2) in MC3T3-E1 preosteoblastic cells and determined the contribution of this pathway to LPA-stimulated chemotaxis. LPA-treated cells exhibited a bimodal activation of ERK1/2 with maximal phosphorylation at 5 and 60 minutes. The kinetics of ERK1/2 phosphorylation were not coupled to Ras activation or LPA-induced elevations in cytosolic Ca2+. While LPA is coupled to the transactivation of the EGF receptor in many cell types, LPA-stimulated ERK1/2 activation in MC3T3-E1 cells was unaffected by inhibition of EGF receptor function. ERK isoforms rapidly accumulated at nuclear sites in LPA-treated cells, a process that was blocked if ERK1/2 phosphorylation was prevented with the MEK1 inhibitor U0126. Blocking ERK1/2 phosphorylation with U0126 also diminished MC3T3-E1 cell migration and altered the normal disassembly of LPA-induced stress fibers, while the inhibition of EGF receptor function had no effect on LPA-coupled preosteoblast motility. Our results identify ERK1/2 activation as a mediatora mediator of LPA-stimulated MC3T3-E1 cell migration that may be relevant to preosteoblast motility during bone repair in vivo.

  5. Aromatic hydrocarbon receptor inhibits lysophosphatidic acid-induced vascular endothelial growth factor-A expression in PC-3 prostate cancer cells

    SciTech Connect

    Wu, Pei-Yi; Lin, Yueh-Chien; Lan, Shun-Yan; Huang, Yuan-Li; Lee, Hsinyu

    2013-08-02

    Highlights: •LPA-induced VEGF-A expression was regulated by HIF-1α and ARNT. •PI3K mediated LPA-induced VEGF-A expression. •AHR signaling inhibited LPA-induced VEGF-A expression in PC-3 cells. -- Abstract: Lysophosphatidic acid (LPA) is a lipid growth factor with multiple biological functions and has been shown to stimulate cancer cell secretion of vascular endothelial growth factor-A (VEGF-A) and trigger angiogenesis. Hypoxia-inducible factor-1 (HIF-1), a heterodimer consisting of HIF-1α and HIF-1β (also known as aromatic hydrocarbon receptor nuclear translocator (ARNT)) subunits, is an important regulator of angiogenesis in prostate cancer (PC) through the enhancement of VEGF-A expression. In this study, we first confirmed the ability of LPA to induce VEGF-A expression in PC-3 cells and then validated that LPA-induced VEGF-A expression was regulated by HIF-1α and ARNT through phosphatidylinositol 3-kinase activation. Aromatic hydrocarbon receptor (AHR), a receptor for dioxin-like compounds, functions as a transcription factor through dimerization with ARNT and was found to inhibit prostate carcinogenesis and vanadate-induced VEGF-A production. Since ARNT is a common dimerization partner of AHR and HIF-1α, we hypothesized that AHR might suppress LPA-induced VEGF-A expression in PC-3 cells by competing with HIF-1α for ARNT. Here we demonstrated that overexpression and ligand activation of AHR inhibited HIF-1-mediated VEGF-A induction by LPA treatment of PC-3 cells. In conclusion, our results suggested that AHR activation may inhibit LPA-induced VEGF-A expression in PC-3 cells by attenuating HIF-1α signaling, and subsequently, suppressing angiogenesis and metastasis of PC. These results suggested that AHR presents a potential therapeutic target for the prevention of PC metastasis.

  6. Catalase potentiates retinoic acid-induced THP-1 monocyte differentiation into macrophage through inhibition of peroxisome proliferator-activated receptor gamma.

    PubMed

    Ding, Qiurong; Jin, Ting; Wang, Zhenzhen; Chen, Yan

    2007-06-01

    Macrophage differentiation plays a pivotal role in cardiovascular diseases and many other physiological processes. However, the role of reaction oxygen species in macrophage differentiation has not been elucidated. Here, we report functional characterization of catalase, an enzyme that degrades hydrogen peroxide (H(2)O(2)), in THP-1 monocyte differentiation. Treatment of THP-1 cells with catalase was able to synergize with all-trans retinoic acid (ATRA) to enhance macrophage differentiation, demonstrated by changes of cell adherence, cell cycle arrest, nitroblue tetrazolium reduction, and expression of differentiation markers including CD68, CD11b, and matrix metalloproteinase 9 (MMP9). ATRA could stimulate retinoic acid (RA) receptor-mediated transcription, but this was not affected by catalase. However, ATRA and catalase were capable of reducing transcriptional activity mediated by peroxisome proliferator-activated receptor gamma (PPARgamma). Consistently, PPARgamma antagonists enhanced, and PPARgamma agonists inhibited MMP9 expression stimulated by ATRA and catalase in THP-1 cells. Therefore, these data indicate that catalase is able to potentiate ATRA-induced macrophage differentiation by inhibition of PPARgamma activity, underscoring an important interplay between H(2)O(2), RA, and PPARgamma in macrophages.

  7. Netupitant, a Potent and Highly Selective NK1 Receptor Antagonist, Alleviates Acetic Acid-Induced Bladder Overactivity in Anesthetized Guinea-Pigs.

    PubMed

    Palea, Stefano; Guilloteau, Véronique; Rekik, Moéz; Lovati, Emanuela; Guerard, Marc; Guardia, Maria-Alba; Lluel, Philippe; Pietra, Claudio; Yoshiyama, Mitsuharu

    2016-01-01

    Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1-3 mg/kg, i.v.) or L-733,060 (3-10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex circuit

  8. Netupitant, a Potent and Highly Selective NK1 Receptor Antagonist, Alleviates Acetic Acid-Induced Bladder Overactivity in Anesthetized Guinea-Pigs

    PubMed Central

    Palea, Stefano; Guilloteau, Véronique; Rekik, Moéz; Lovati, Emanuela; Guerard, Marc; Guardia, Maria-Alba; Lluel, Philippe; Pietra, Claudio; Yoshiyama, Mitsuharu

    2016-01-01

    Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1–3 mg/kg, i.v.) or L-733,060 (3–10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex

  9. PK 11195 attenuates kainic acid-induced seizures and alterations in peripheral-type benzodiazepine receptor (PBR) protein components in the rat brain.

    PubMed

    Veenman, L; Leschiner, S; Spanier, I; Weisinger, G; Weizman, A; Gavish, M

    2002-03-01

    Peripheral-type benzodiazepine receptors (PBR) are located in glial cells in the brain and in peripheral tissues. Mitochondria form the primary location for PBR. Functional PBR appear to require at least three components: an isoquinoline binding protein, a voltage-dependent anion channel, and an adenine nucleotide carrier. In the present study, rats received intraperitoneal kainic acid injections, which are known to cause seizures, neurodegeneration, hyperactivity, gliosis, and a fivefold increase in PBR ligand binding density in the hippocampus. In the forebrain of control rats, hippocampal voltage-dependent anion channel and adenine nucleotide carrier abundance was relatively low, while isoquinoline binding protein abundance did not differ between hippocampus and the rest of the forebrain. One week after kainic acid injection, isoquinoline binding protein abundance was increased more than 20-fold in the hippocampal mitochondrial fraction. No significant changes were detected regarding hippocampal voltage-dependent anion channel and adenine nucleotide carrier abundance. Pre-treatment with the isoquinoline PK11195, a specific PBR ligand, attenuated the occurrence of seizures, hyperactivity, and increases in isoquinoline binding protein levels in the hippocampus, which usually follow kainic acid application. These data suggest that isoquinoline binding protein may be involved in these effects of kainic acid injections.

  10. An Overview of Pathogen Recognition Receptors for Innate Immunity in Dental Pulp

    PubMed Central

    Jang, Ji-Hyun; Shin, Hee Woong; Lee, Jung Min; Lee, Hyeon-Woo; Kim, Eun-Cheol; Park, Sang Hyuk

    2015-01-01

    Pathogen recognition receptors (PRRs) are a class of germ line-encoded receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed. PRRs differ in the signaling cascades and host responses activated by their engagement and in their tissue distribution. Currently identified PRR families are the Toll-like receptors (TLRs), the C-type lectin receptors (CLRs), the nucleotide-binding oligomerization domain-like receptors (NLRs), the retinoic acid-inducible gene-I-like receptors (RLRs), and the AIM2-like receptor (ALR). The environment of the dental pulp is substantially different from that of other tissues of the body. Dental pulp resides in a low compliance root canal system that limits the expansion of pulpal tissues during inflammatory processes. An understanding of the PRRs in dental pulp is important for immunomodulation and hence for developing therapeutic targets in the field of endodontics. Here we comprehensively review recent finding on the PRRs and the mechanisms by which innate immunity is activated. We focus on the PRRs expressed on dental pulp and periapical tissues and their role in dental pulp inflammation. PMID:26576076

  11. An Overview of Pathogen Recognition Receptors for Innate Immunity in Dental Pulp.

    PubMed

    Jang, Ji-Hyun; Shin, Hee Woong; Lee, Jung Min; Lee, Hyeon-Woo; Kim, Eun-Cheol; Park, Sang Hyuk

    2015-01-01

    Pathogen recognition receptors (PRRs) are a class of germ line-encoded receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed. PRRs differ in the signaling cascades and host responses activated by their engagement and in their tissue distribution. Currently identified PRR families are the Toll-like receptors (TLRs), the C-type lectin receptors (CLRs), the nucleotide-binding oligomerization domain-like receptors (NLRs), the retinoic acid-inducible gene-I-like receptors (RLRs), and the AIM2-like receptor (ALR). The environment of the dental pulp is substantially different from that of other tissues of the body. Dental pulp resides in a low compliance root canal system that limits the expansion of pulpal tissues during inflammatory processes. An understanding of the PRRs in dental pulp is important for immunomodulation and hence for developing therapeutic targets in the field of endodontics. Here we comprehensively review recent finding on the PRRs and the mechanisms by which innate immunity is activated. We focus on the PRRs expressed on dental pulp and periapical tissues and their role in dental pulp inflammation.

  12. Retinoic acid-induced expression of apolipoprotein D and concomitant growth arrest in human breast cancer cells are mediated through a retinoic acid receptor RARalpha-dependent signaling pathway.

    PubMed

    López-Boado, Y S; Klaus, M; Dawson, M I; López-Otín, C

    1996-12-13

    Apolipoprotein D (apoD) is a human plasma protein, belonging to the lipocalin superfamily, that is produced by a specific subtype of highly differentiated breast carcinomas and that is strongly up-regulated by retinoic acid (RA) in breast cancer cells. In this work, we have examined the molecular mechanisms mediating the induction of apoD gene expression by retinoids in T-47D human breast cancer cells. Northern blot analysis revealed that Ro40-6055, a synthetic retinoid that selectively binds and activates the retinoic acid receptor RARalpha, induced the accumulation of apoD mRNA in breast cancer cells in a time- and dose-dependent manner. The time course analysis demonstrated that apoD mRNA was induced 14-fold over control cells after 48 h of incubation with 10(-8) M Ro40-6055. As little as 10(-11) M of this retinoid induced apoD mRNA 5-fold over the control, whereas incubation with 10(-7) M Ro40-6055 induced maximally 15-fold over control cells. RARalpha-selective antagonists counteracted the inductive effects of all-trans-RA, 9-cis-RA, and Ro40-6055 on the expression of apoD, when present at the same concentration as the retinoid agonists. By contrast, RARbeta-, RARgamma-, and RXR-selective retinoids did not affect apoD gene expression. The retinoid agonist Ro40-6055 had an antiproliferative effect on T-47D cells, with maximal growth inhibition of approximately 60% obtained after 7 days of incubation with 10(-7) M. This antiproliferative effect could be counteracted by a 100-fold excess of the antagonist Ro41-5253. Treatment of the cells with retinoids that do not bind the nuclear retinoic acid receptors did not affect apoD expression, despite the fact that they did have a strong antiproliferative effect on T-47D cells. On the basis of these results, a role for RARalpha on apoD gene expression induction by retinoids in breast cancer cells is proposed.

  13. Hepatoprotective Effects of Schisandra sphenanthera Extract against Lithocholic Acid-Induced Cholestasis in Male Mice Are Associated with Activation of the Pregnane X Receptor Pathway and Promotion of Liver Regeneration.

    PubMed

    Zeng, Hang; Li, Dongshun; Qin, Xiaoling; Chen, Pan; Tan, Huasen; Zeng, Xuezhen; Li, Xi; Fan, Xiaomei; Jiang, Yiming; Zhou, Yawen; Chen, Yixin; Wang, Ying; Huang, Min; Bi, Huichang

    2016-03-01

    We previously reported that the ethanol extract of Schisandra sphenanthera [Wuzhi (WZ) tablet] significantly protects against acetaminophen-induced hepatoxicity. However, whether WZ exerts a protective effect against cholestasis remains unclear. In this study, the protective effect of WZ on lithocholic acid (LCA)-induced intrahepatic cholestasis in mice was characterized and the involved mechanisms were investigated. WZ pretreatment (350 mg/kg) with LCA significantly reversed liver necrosis and decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activity. More importantly, serum total bile acids and total bilirubin were also remarkably reduced. Quantitative reverse-transcription polymerase chain reaction and Western blot analysis showed that hepatic expression of pregnane X receptor (PXR) target genes such as CYP3A11 and UDP-glucuronosyltransferase (UGT) 1A1 were significantly increased by WZ treatment. Luciferase assays performed in LS174T cells illustrated that WZ extract and its six bioactive lignans could all activate human PXR. In addition, WZ treatment significantly promoted liver regeneration via inhibition of p53/p21 to induce cell proliferation-associated proteins such as cyclin D1 and proliferating cell nuclear antigen. In conclusion, WZ has a protective effect against LCA-induced intrahepatic cholestasis, partially owing to activation of the PXR pathway and promotion of liver regeneration.

  14. Transcriptomic analysis of Mandarin fish brain cells infected with infectious spleen and kidney necrosis virus with an emphasis on retinoic acid-inducible gene 1-like receptors and apoptosis pathways.

    PubMed

    Hu, Xianqin; Fu, Xiaozhe; Li, Ningqiu; Dong, Xingxing; Zhao, Lijuan; Lan, Jiangfeng; Ji, Wei; Zhou, Weidong; Ai, Taoshan; Wu, Shuqin; Lin, Li

    2015-08-01

    Infectious spleen and kidney necrosis virus (ISKNV) has caused significant economic losses in the cultured Mandarin fish (Siniperca chuatsi) industry. The molecular mechanisms that underlie the pathogenesis of the viral infection remain poorly understood. In this study, deep RNA sequencing technique was used to analyze the transcriptomic profiles of Mandarin fish brain cells (CPB) at progressive time points after ISKNV infection. A total of 96,206,040 clean data from 98,235,240 sequence reads were obtained. These raw data were assembled into 66,787 unigenes. Among these unigenes, 33,225 and 29,210 had significant hit the Nr and SwissProt databases where they matched 27,537and 19,638 unique protein accessions, respectively. In the samples harvested at 24 or 72 h post of the infection, a total of 10,834 or 7584 genes were differentially expressed in infected CPB cells compared to non-infected cells, including 5445 or 3766 up-regulated genes and 5389 or 3818 down-regulated genes, respectively. In addition, 12 differentially expressed genes (DEGs) were validated by quantitative PCR. These DEGs were involved in many pathways of viral pathogenesis. Further analysis of the major DEGs genes involved in the RLRs and apoptosis pathways revealed some interesting findings. In the RLRs pathway, ISKNV infection inhibited the activation of NF-κB via over expression of the IKKB-α and IKKB-β and lessened expression of interleukin-1 receptor-associated kinase 4 (IRAK4). In the apoptosis pathway, ISKNV infection could induce apoptosis mainly via tumor necrosis factor (TNF) mediated extrinsic pathway. The cellular apoptosis induced by ISKNV infection was confirmed using annexinV-FITC/PI and DAPI staining methods.

  15. Transcriptomic analysis of Mandarin fish brain cells infected with infectious spleen and kidney necrosis virus with an emphasis on retinoic acid-inducible gene 1-like receptors and apoptosis pathways.

    PubMed

    Hu, Xianqin; Fu, Xiaozhe; Li, Ningqiu; Dong, Xingxing; Zhao, Lijuan; Lan, Jiangfeng; Ji, Wei; Zhou, Weidong; Ai, Taoshan; Wu, Shuqin; Lin, Li

    2015-08-01

    Infectious spleen and kidney necrosis virus (ISKNV) has caused significant economic losses in the cultured Mandarin fish (Siniperca chuatsi) industry. The molecular mechanisms that underlie the pathogenesis of the viral infection remain poorly understood. In this study, deep RNA sequencing technique was used to analyze the transcriptomic profiles of Mandarin fish brain cells (CPB) at progressive time points after ISKNV infection. A total of 96,206,040 clean data from 98,235,240 sequence reads were obtained. These raw data were assembled into 66,787 unigenes. Among these unigenes, 33,225 and 29,210 had significant hit the Nr and SwissProt databases where they matched 27,537and 19,638 unique protein accessions, respectively. In the samples harvested at 24 or 72 h post of the infection, a total of 10,834 or 7584 genes were differentially expressed in infected CPB cells compared to non-infected cells, including 5445 or 3766 up-regulated genes and 5389 or 3818 down-regulated genes, respectively. In addition, 12 differentially expressed genes (DEGs) were validated by quantitative PCR. These DEGs were involved in many pathways of viral pathogenesis. Further analysis of the major DEGs genes involved in the RLRs and apoptosis pathways revealed some interesting findings. In the RLRs pathway, ISKNV infection inhibited the activation of NF-κB via over expression of the IKKB-α and IKKB-β and lessened expression of interleukin-1 receptor-associated kinase 4 (IRAK4). In the apoptosis pathway, ISKNV infection could induce apoptosis mainly via tumor necrosis factor (TNF) mediated extrinsic pathway. The cellular apoptosis induced by ISKNV infection was confirmed using annexinV-FITC/PI and DAPI staining methods. PMID:25982401

  16. Farnesoid X receptor activation by chenodeoxycholic acid induces detoxifying enzymes through AMP-activated protein kinase and extracellular signal-regulated kinase 1/2-mediated phosphorylation of CCAAT/enhancer binding protein β.

    PubMed

    Noh, Kyoung; Kim, Young Mi; Kim, Young Woo; Kim, Sang Geon

    2011-08-01

    Farnesoid X receptor (FXR) regulates redox homeostasis and elicits a cytoprotective effect. CCAAT/enhancer binding protein-β (C/EBPβ) plays a role in regulating the expression of hepatocyte-specific genes and contributes to hepatocyte protection and liver regeneration. In view of the role of FXR in xenobiotic metabolism and hepatocyte survival, this study investigated the potential of FXR to activate C/EBPβ for the induction of detoxifying enzymes and the responsible regulatory pathway. Chenodeoxycholic acid (CDCA), a major component in bile acids, activates FXR. In HepG2 cells, CDCA treatment activated C/EBPβ, as shown by increases in its phosphorylation, nuclear accumulation, and expression. 3-(2,6-Dichlorophenyl)-4-(3'-carboxy-2-chlorostilben-4-yl-)oxymethyl-5-isopropyl-isoxazole (GW4064), a synthetic FXR ligand, had similar effects. In addition, CDCA enhanced luciferase gene transcription from the construct containing -1.65-kb GSTA2 promoter, which contained C/EBP response element (pGL-1651). Moreover, CDCA treatment activated AMP-activated protein kinase (AMPK), which led to extracellular signal-regulated kinase 1/2 (ERK1/2) activation, as evidenced by the results of experiments using a dominant-negative mutant of AMPKα and chemical inhibitor. The activation of ERK1/2 was responsible for the activating phosphorylation of C/EBPβ. FXR knockdown attenuated the ability of CDCA to activate AMPK and ERK1/2 and phosphorylate C/EBPβ. Consistently, enforced expression of FXR promoted the phosphorylation of AMPKα, ERK1/2, and C/EBPβ, verifying that C/EBPβ phosphorylation elicited by CDCA results from the activation of AMPK and ERK1/2 by FXR. In mice, CDCA treatment activated C/EBPβ with the induction of detoxifying enzymes in the liver. Our results demonstrate that CDCA induces antioxidant and xenobiotic-metabolizing enzymes by activating C/EBPβ through AMPK-dependent ERK1/2 pathway downstream of FXR.

  17. Clavulanic acid induces penile erection and yawning in male rats: comparison with apomorphine.

    PubMed

    Sanna, Fabrizio; Melis, Maria Rosaria; Angioni, Laura; Argiolas, Antonio

    2013-02-01

    The beta-lactamase inhibitor clavulanic acid induced penile erection and yawning in a dose dependent manner when given intraperitoneally (IP, 0.05-5mg/kg), perorally (OS, 0.1-5mg/kg) and intracereboventricularly (ICV, 0.01-5 μg/rat) to male rats. The effect resembles that of the dopamine receptor agonist apomorphine given subcutaneously (SC) (0.02-0.25mg/kg), although the responses of the latter followed a U inverted dose-response curve, disappearing at doses higher than 0.1mg/kg. Clavulanic acid responses were reduced by about 55% by haloperidol, a dopamine D2 receptor antagonist (0.1mg/kg IP), and by d(CH(2))(5)Tyr(Me)(2)-Orn(8)-vasotocin, an oxytocin receptor antagonist (2 μg/rat ICV), both given 15 min before clavulanic acid. A higher reduction of clavulanic acid responses (more than 80%) was also found with morphine, an opioid receptor agonist (5mg/kg IP), and with mianserin, a serotonin 5HT(2c) receptor antagonist (0.2mg/kg SC). In contrast, no reduction was found with naloxone, an opioid receptor antagonist (1mg/kg IP). The ability of haloperidol, d(CH(2))(5)Tyr(Me)(2)-Orn(8)-vasotocin and morphine to reduce clavulanic acid induced penile erection and yawning suggests that clavulanic acid induces these responses, at least in part, by increasing central dopaminergic neurotransmission. Dopamine in turn activates oxytocinergic neurotransmission and centrally released oxytocin induces penile erection and yawning. However, since both penile erection and yawning episodes were reduced not only by the blockade of central dopamine and oxytocin receptors and by the stimulation of opioid receptors, which inhibits oxytocinergic neurotransmission, but also by mianserin, an increase of central serotonin neurotransmission is also likely to participate in these clavulanic acid responses.

  18. Nucleic acid-induced antiviral immunity in invertebrates: an evolutionary perspective.

    PubMed

    Wang, Pei-Hui; Weng, Shao-Ping; He, Jian-Guo

    2015-02-01

    Nucleic acids derived from viral pathogens are typical pathogen associated molecular patterns (PAMPs). In mammals, the recognition of viral nucleic acids by pattern recognition receptors (PRRs), which include Toll-like receptors (TLRs) and retinoic acid-inducible gene (RIG)-I-like receptors (RLRs), induces the release of inflammatory cytokines and type I interferons (IFNs) through the activation of nuclear factor κB (NF-κB) and interferon regulatory factor (IRF) 3/7 pathways, triggering the host antiviral state. However, whether nucleic acids can induce similar antiviral immunity in invertebrates remains ambiguous. Several studies have reported that nucleic acid mimics, especially dsRNA mimic poly(I:C), can strongly induce non-specific antiviral immune responses in insects, shrimp, and oyster. This behavior shows multiple similarities to the hallmarks of mammalian IFN responses. In this review, we highlight the current understanding of nucleic acid-induced antiviral immunity in invertebrates. We also discuss the potential recognition and regulatory mechanisms that confer non-specific antiviral immunity on invertebrate hosts.

  19. Esophageal Submucosal Injection of Capsaicin but Not Acid Induces Symptoms in Normal Subjects

    PubMed Central

    Lee, Robert H; Korsapati, Hariprasad; Bhalla, Vikas; Varki, Nissi; Mittal, Ravinder K

    2016-01-01

    Background/Aims Transient receptor potential vanilloid-1 (TRPV1) is a candidate for mediating acid-induced symptoms in the esophagus. We conducted studies to determine if the presence of acid in the mucosa/submucosa and direct activation of TRPV1 by capsaicin elicited symptoms in normal healthy subjects. We also studied the presence of TRPV1 receptors in the esophagus. Methods Unsedated endoscopy was performed on healthy subjects with no symptoms. Using a sclerotherapy needle, normal saline (pH 2.0–7.5) was injected into the mucosa/submucosa, 5 cm above the Z line. In a separate group of healthy subjects, injection of capsaicin and vehicle was also studied. Quality of symptoms was reported using the McGill Pain Questionnaire, and symptom intensity using the visual analogue scale (VAS). Immunohistochemistry was performed on 8 surgical esophagus specimens using TRPV1 antibody. Results Acid injection either did not elicit or elicited mild symptoms in subjects at all pH solutions. Capsaicin but not the vehicle elicited severe heartburn/chest pain in all subjects. Mean VAS for capsaicin was 91 ± 3 and symptoms lasted for 25 ± 1 minutes. Immunohistochemistry revealed a linear TRPV1 staining pattern between the epithelial layer and the submucosa that extended into the papillae. Eighty-five percent of papillae stained positive for TRPV1 with a mean 1.1 positive papillae per high-powered field. Conclusions The mechanism of acid-induced heartburn and chest pain is not the simple interaction of hydrogen ions with afferents located in the esophageal mucosa and submucosa. TRPV1 receptors are present in the lamina propria and their activation induces heartburn and chest pain. PMID:26932896

  20. Amoxicillin/clavulanic acid-induced pemphigus vulgaris: case report.

    PubMed

    Baroni, Adone; Russo, Teresa; Faccenda, Franco; Piccolo, Vincenzo

    2012-01-01

    Drug-induced pemphigus is a well-established variety of pemphigus, presenting with clinical and histopathologic features identical to idiopathic form. Medical history plays a fundamental role in the diagnosis of drug-induced pemphigus. A large variety of drugs have been implicated in its pathogenesis and they may induce acantholysis via biochemical and/or immune mechanism. We present a case of a 69-year-old woman affected by amoxicillin/clavulanic acid-induced pemphigus and discuss its pathogenetic mechanism.

  1. γ-Hydroxybutyric Acid-Induced Electrographic Seizures

    PubMed Central

    Cheung, Joseph; Lucey, Brendan P.; Duntley, Stephen P.; Darken, Rachel S.

    2014-01-01

    We describe a case of absence-like electrographic seizures during NREM sleep in a patient who was taking sodium oxybate, a sodium salt of γ-hydroxybutyric acid (GHB). An overnight full montage electroencephalography (EEG) study revealed numerous frontally predominant rhythmic 1.5-2 Hz sharp waves and spike-wave activity during stage N2 and N3 sleep at the peak dose time for sodium oxybate, resembling atypical absence-like electrographic seizures. The patient was later weaned off sodium oxybate, and a repeat study did not show any such electrographic seizures. Absence-like seizures induced by GHB had previously been described in experimental animal models. We present the first reported human case of absence-like electrographic seizure associated with sodium oxybate. Citation: Cheung J, Lucey BP, Duntley SP, Darken RS. γ-hydroxybutyric acid-induced electrographic seizures. J Clin Sleep Med 2014;10(7):811-812. PMID:25024661

  2. Increased isoprostane levels in oleic acid-induced lung injury

    SciTech Connect

    Ono, Koichi; Koizumi, Tomonobu; Tsushima, Kenji; Yoshikawa, Sumiko; Yokoyama, Toshiki; Nakagawa, Rikimaru; Obata, Toru

    2009-10-16

    The present study was performed to examine a role of oxidative stress in oleic acid-induced lung injury model. Fifteen anesthetized sheep were ventilated and instrumented with a lung lymph fistula and vascular catheters for blood gas analysis and measurement of isoprostanes (8-epi prostaglandin F2{alpha}). Following stable baseline measurements, oleic acid (0.08 ml/kg) was administered and observed 4 h. Isoprostane was measured by gas chromatography mass spectrometry with the isotope dilution method. Isoprostane levels in plasma and lung lymph were significantly increased 2 h after oleic acid administration and then decreased at 4 h. The percent increases in isoprostane levels in plasma and lung lymph at 2 h were significantly correlated with deteriorated oxygenation at the same time point, respectively. These findings suggest that oxidative stress is involved in the pathogenesis of the pulmonary fat embolism-induced acute lung injury model in sheep and that the increase relates with the deteriorated oxygenation.

  3. Proteomic study on usnic-acid-induced hepatotoxicity in rats.

    PubMed

    Liu, Qian; Zhao, Xiaoping; Lu, Xiaoyan; Fan, Xiaohui; Wang, Yi

    2012-07-25

    Usnic acid, a lichen metabolite, is used as a dietary supplement for weight loss. However, clinical studies have shown that usnic acid causes hepatotoxicity. The present study aims to investigate the mechanism of usnic acid hepatotoxicity in vivo. Two-dimensional gel electrophoresis coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to analyze the expression profiles of differentially regulated and expressed proteins in rat liver after usnic acid administration. The results reveal the differential expression of 10 proteins in usnic-acid-treated rats compared to the normal controls. These proteins are associated with oxidative stress, lipid metabolism, and several other molecular pathways. The endoplasmic reticulum and mitochondria may be the primary targets of usnic-acid-induced hepatotoxicity.

  4. Tachykinin inhibition of acid-induced gastric hyperaemia in the rat.

    PubMed Central

    Heinemann, A.; Jocic, M.; Herzeg, G.; Holzer, P.

    1996-01-01

    1. Primary afferent neurones releasing the vasodilator, calcitonin gene-related peptide, mediate the gastric hyperaemic response to acid back-diffusion. The tachykinins neurokinin A (NKA) and substance P (SP) are located in the same neurones and are co-released with calcitonin gene-related peptide. In this study we investigated the effect and possible role of tachykinins in the acid-evoked gastric vasodilatation in urethane-anaesthetized rats. 2. Gastric acid back-diffusion, induced by perfusing the stomach with 15% ethanol in the presence of 0.05 M HCl, increased gastric mucosal blood flow by 60-90%, as determined by the hydrogen clearance technique. NKA and SP (0.14-3.78 nmol min-1 kg-1, infused intra-aortically) inhibited the gastric mucosal hyperaemic response to acid back-diffusion in a dose-dependent manner, an effect that was accompanied by aggravation of ethanol/acid-induced macroscopic haemorrhagic lesions. 3. The inhibitory effect of NKA (1.26 nmol min-1 kg-1) on the acid-induced gastric mucosal vasodilatation was prevented by the tachykinin NK2 receptor antagonists, MEN 10,627 (200 nmol kg-1) but left unaltered by the NK1 receptor antagonist, SR 140,333 (300 nmol kg-1) and the mast-cell stabilizer, ketotifen (4.6 mumol kg-1). 4. Under basal conditions, with 0.05 M HCl being perfused through the stomach, NKA (1.26 nmol min-1 kg-1) reduced gastric mucosal blood flow by about 25%, an effect that was abolished by SR 140,333 but not MEN 10,627 or ketotifen. 5. SR 140,333, MEN 10,627 or ketotifen had no significant effect on basal gastric mucosal blood flow nor did they modify the gastric mucosal hyperaemic reaction to acid back-diffusion. 6. The effect of NKA (1.26 nmol min-1 kg-1) in causing vasoconstriction and inhibiting the vasodilator response to acid back-diffusion was also seen when blood flow in the left gastric artery was measured with the ultrasonic transit time shift technique. 7. Arginine vasopressin (AVP, 0.1 nmol min-1 kg-1) induced gastric

  5. Unsaturated fatty acids induce non-canonical autophagy

    PubMed Central

    Niso-Santano, Mireia; Malik, Shoaib Ahmad; Pietrocola, Federico; Bravo-San Pedro, José Manuel; Mariño, Guillermo; Cianfanelli, Valentina; Ben-Younès, Amena; Troncoso, Rodrigo; Markaki, Maria; Sica, Valentina; Izzo, Valentina; Chaba, Kariman; Bauvy, Chantal; Dupont, Nicolas; Kepp, Oliver; Rockenfeller, Patrick; Wolinski, Heimo; Madeo, Frank; Lavandero, Sergio; Codogno, Patrice; Harper, Francis; Pierron, Gérard; Tavernarakis, Nektarios; Cecconi, Francesco; Maiuri, Maria Chiara; Galluzzi, Lorenzo; Kroemer, Guido

    2015-01-01

    To obtain mechanistic insights into the cross talk between lipolysis and autophagy, two key metabolic responses to starvation, we screened the autophagy-inducing potential of a panel of fatty acids in human cancer cells. Both saturated and unsaturated fatty acids such as palmitate and oleate, respectively, triggered autophagy, but the underlying molecular mechanisms differed. Oleate, but not palmitate, stimulated an autophagic response that required an intact Golgi apparatus. Conversely, autophagy triggered by palmitate, but not oleate, required AMPK, PKR and JNK1 and involved the activation of the BECN1/PIK3C3 lipid kinase complex. Accordingly, the downregulation of BECN1 and PIK3C3 abolished palmitate-induced, but not oleate-induced, autophagy in human cancer cells. Moreover, Becn1+/− mice as well as yeast cells and nematodes lacking the ortholog of human BECN1 mounted an autophagic response to oleate, but not palmitate. Thus, unsaturated fatty acids induce a non-canonical, phylogenetically conserved, autophagic response that in mammalian cells relies on the Golgi apparatus. PMID:25586377

  6. Characterization of salicylic acid-induced genes in Chinese cabbage.

    PubMed

    Park, Y-S; Min, H-J; Ryang, S-H; Oh, K-J; Cha, J-S; Kim, H Y; Cho, T-J

    2003-06-01

    Salicylic acid is a messenger molecule in the activation of defense responses in plants. In this study, we isolated four cDNA clones representing salicylic acid-induced genes in Chinese cabbage (Brassica rapa subsp. pekinensis) by subtractive hybridization. Of the four clones, the BC5-2 clone encodes a putative glucosyltransferase protein. The BC5-3 clone is highly similar to an Arabidopsis gene encoding a putative metal-binding farnesylated protein. The BC6-1 clone is a chitinase gene with similarities to a rapeseed class IV chitinase. Class IV chitinases have deletions in the chitin-binding and catalytic domains and the BC6-1 chitinase has an additional deletion in the catalytic domain. The BCP8-1 clone is most homologous to an Arabidopsis gene that contains a tandem array of two thiJ-like sequences. These four cabbage genes were barely expressed in healthy leaves, but were strongly induced by salicylic acid and benzothiadiazole. Expression of the three genes represented by the BC5-2, BC5-3 and BCP8-1 clones were also induced by Pseudomonas syringae pv. tomato, a nonhost pathogen that elicits a hypersensitive response in Chinese cabbage. None of these four genes, however, was strongly induced by methyl jasmonate or by ethylene.

  7. Sulfuric acid-induced corrosion of aluminum surfaces

    SciTech Connect

    Dai, Q.; Freedman, A.; Robinson, G.N.

    1995-12-01

    The sulfuric acid-induced corrosion of smooth (2 nm average roughness) aluminum surfaces has been studied in real times using an in situ Fourier transform infrared reflection absorption spectrometer and a quartz crystal microbalance. Submicron thick, 35 to 55 weight percent (5 to 12 molal), sulfuric acid films were formed on room temperature metal surfaces by the reaction of gas-phase SO{sub 3} and H{sub 2}O vapor in a flowing gas system at a total pressure of {approximately}200 Torr. The deposition of the acid films and subsequent changes in their chemical composition resulting from corrosion of the aluminum substrate could be monitored using characteristic infrared absorption features. The corrosion process always significantly perturbed the spectral signature of the films from that which was observed on inert gold surfaces. Using changes in spectral features that are linked to the production of Al{sup 3+} as indicators of corrosion, the authors conclude the rate of corrosion of the metal is strongly enhanced by both higher relative humidities and increased rates of sulfuric acid deposition.

  8. Computerized image analysis for acetic acid induced intraepithelial lesions

    NASA Astrophysics Data System (ADS)

    Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

    2008-03-01

    Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

  9. Sphingoid bases inhibit acid-induced demineralization of hydroxyapatite.

    PubMed

    Valentijn-Benz, Marianne; van 't Hof, Wim; Bikker, Floris J; Nazmi, Kamran; Brand, Henk S; Sotres, Javier; Lindh, Liselott; Arnebrant, Thomas; Veerman, Enno C I

    2015-01-01

    Calcium hydroxyapatite (HAp), the main constituent of dental enamel, is inherently susceptible to the etching and dissolving action of acids, resulting in tooth decay such as dental caries and dental erosion. Since the prevalence of erosive wear is gradually increasing, there is urgent need for agents that protect the enamel against erosive attacks. In the present study we studied in vitro the anti-erosive effects of a number of sphingolipids and sphingoid bases, which form the backbone of sphingolipids. Pretreatment of HAp discs with sphingosine, phytosphingosine (PHS), PHS phosphate and sphinganine significantly protected these against acid-induced demineralization by 80 ± 17%, 78 ± 17%, 78 ± 7% and 81 ± 8%, respectively (p < 0.001). On the other hand, sphingomyelin, acetyl PHS, octanoyl PHS and stearoyl PHS had no anti-erosive effects. Atomic force measurement revealed that HAp discs treated with PHS were almost completely and homogeneously covered by patches of PHS. This suggests that PHS and other sphingoid bases form layers on the surface of HAp, which act as diffusion barriers against H(+) ions. In principle, these anti-erosive properties make PHS and related sphingosines promising and attractive candidates as ingredients in oral care products.

  10. Neuroprotective effects of MK-801 on L-2-chloropropionic acid-induced neurotoxicity.

    PubMed

    Williams, R E; Lock, E A; Bachelard, H S

    2001-02-01

    L-2-Chloropropionic acid is selectively toxic to the cerebellum in rats; the granule cell necrosis observed within 48 h can be prevented by prior administration of MK-801. Short-term treatment (2 h) with L-2-chloropropionic acid has also been shown to activate the mitochondrial pyruvate dehydrogenase complex in fasted adult rats. This study aimed to investigate the effect of prior exposure to MK-801 on the biochemical and neurotoxicological effects of L-2-chloropropionic acid. Extracts were prepared from the forebrain and cerebellum of animals that had been treated with L-2-chloropropionic acid, with and without prior treatment with MK-801, and were analysed using magnetic resonance spectroscopy and amino acid analysis. Glucose metabolism was studied by monitoring the metabolism of [1-(13)C]-glucose using GC/MS. L-2-Chloropropionic acid caused increased glucose metabolism in both brain regions 6 h after administration, confirming activation of the pyruvate dehydrogenase complex, which was not prevented by MK-801. After 48 h an increase in lactate and a decrease in N-acetylaspartate was observed only in the cerebellum, whereas phosphocreatine and ATP decreased in both tissues. MK-801 prevented the changes in lactate and N:-acetylaspartate, but not those on the energy state. These studies suggest that L-2-chloropropionic acid-induced neurotoxicity is only partly mediated by the NMDA subtype of glutamate receptor.

  11. Role of neurosteroids in experimental 3-nitropropionic acid induced neurotoxicity in rats.

    PubMed

    Kumar, Pushpender; Kumar, Puneet; Khan, Aamir; Deshmukh, Rahul; Lal Sharma, Pyare

    2014-01-15

    Huntington's disease is an autosomal dominant, progressive, and fatal neurodegenerative disease characterized by motor and non-motor symptoms. Systemic administration of 3-nitropropionic acid, a complex II inhibitor of the electron transport chain induces selective striatal lesions in rodents. Neurosteroids are synthesized in central nervous system, able to modulate GABAA receptor function and has been reported to have neuroprotective action. The present study has been designed to investigate the role of neurosteroids such as progesterone and pregnenolone which are positive and negative modulators of GABA respectively against 3-nitropropionic acid induced experimental Huntington's disease. Systemic administration of 3-nitropropionic acid (10mg/kg i.p.) for 14 days significantly reduced body weight, locomotor activity, motor coordination, balance beam walk performance, antioxidant defense enzymes (reduced glutathione and catalase) and significantly increase oxidative stress markers (lipid peroxidation and nitrite level) in striatum and cortex. 3-Nitropropionic acid treatment also increases pro-inflammatory cytokines (TNF-α and IL-1β) level in striatum. Progesterone (10, 20mg/kg/day i.p.) treatments for 14 days significantly reversed the behavioral, antioxidant defense enzymes, oxidative stress marker and pro-inflammatory cytokines as compared to the 3-Nitropropionic acid treated group. Pregnenolone (1 and 2mg/kg i.p.), a negative modulator of GABAA pretreatment significantly reversed the protective effect of progesterone on behavioral and biochemical parameters. The results of the present study suggest that the positive GABAergic modulation may be beneficial for the treatment of motor disorder. PMID:24333475

  12. [Elucidation of mechanisms underlying docosahexaenoic acid-induced antinociception].

    PubMed

    Nishinaka, Takashi; Matsumoto, Kengo; Nakamoto, Kazuo; Anbo, Akihiro; Mankura, Mitsumasa; Koyama, Yutaka; Tokuyama, Shogo

    2013-01-01

    Docosahexaenoic acid (DHA), a predominant of n-3 polyunsaturated fatty acids (n-3 PUFA), has numerous beneficial physiological effects, including neuroprotection and cardiovascular protection. Recently, a possible involvement of n-3 PUFA in pain control has gathered considerable attention because numerous studies have reported a regulatory role of n-3 PUFAs. However, the mechanisms underlying how DHA exerts antinociceptive effect remain unknown. Here, we performed elucidation of mechanisms underlying DHA-induced antinociception. DHA administration dose-dependently exerted an antinociceptive effect. This effect was abolished by pretreated with the β-funaltrexamine (β-FNA), a μ-opioid receptor antagonist, and the nartrindole (NTI), a δ-opioid receptor antagonist, but not by the nor-binaltorphimine (nor-BNI), a κ-opioid receptor antagonist. In the radioligand binding assay, DHA itself did not have the affinity for μ-, δ- and κ- opioid receptor. Furthermore, the pretreatment of anti β-endorphin antiserum inhibited DHA-induced antinociception. The plasma levels of β-endorphin increased 30 min after DHA administration. The β-endorphin immunoreactivity in the brain increased at 30 min after DHA treatment. Expression of GPR40 protein was widely observed in the brain as well as the spinal cord. The intracerebroventricular but not intrathecal injection of DHA and GW9508, a GPR40/GPR120 agonist, significantly reduced formalin-induced pain behavior. The β-endorphin immunoreactivity in the brain increased at 10 and 20 min after intracerebroventricular injection of DHA and GW9508. These findings suggest that DHA-induced antinociception via β-endorphin release may be mediated through GPR40 signaling in the supraspinal area. PMID:23649389

  13. Chrysophanic Acid Induces Necrosis but not Necroptosis in Human Renal Cell Carcinoma Caki-2 Cells

    PubMed Central

    Choi, Joon-Seok

    2016-01-01

    Background: Chrysophanic acid, also known as chrysophanol, has a number of biological activities. It enhances memory and learning abilities, raises superoxide dismutase activity, and has anti-cancer effects in several model systems. According to previous reports, chrysophanic acid-induced cell death shares features of necrotic cell death. However, the molecular and cellular processes underlying chrysophanic acid-induced cell death remain poorly understood. Methods: Chrysophanic acid-induced cell death was monitored by cell viability assay and Annexin V-propidium iodide (PI) staining of renal cell carcinoma Caki-2 cells. The induction of intracellular reactive oxygen species (ROS) by chrysophanic acid and the suppression of ROS by anti-oxidants were evaluated by 2′,7′-dichlorofluorescin diacetate staining. The expression and phosphorylation of proteins that are involved in apoptosis and necroptosis were detected by immunoblotting. Results: The extent of chrysophanic acid-induced cell death was concentration and time dependent, and dead cells mainly appeared in the PI-positive population, which is a major feature of necrosis, upon fluorescence-activated cell sorting analysis. Chrysophanic acid-induced cell death was associated with the generation of intracellular ROS, and this effect was reversed by pretreatment with N-acetyl cysteine. Chrysophanic acid-induced cell death was not associated with changes in apoptotic or necroptotic marker proteins. Conclusions: The cell death induced by chrysophanic acid resembled neither apoptotic nor necroptotic cell death in human renal cell carcinoma Caki-2 cells. PMID:27390736

  14. Loss of n-6 fatty acid induced pediatric obesity protects against acute murine colitis

    PubMed Central

    Nagy-Szakal, Dorottya; Mir, Sabina A. V.; Harris, R. Alan; Dowd, Scot E.; Yamada, Takeshi; Lacorazza, H. Daniel; Tatevian, Nina; Smith, C. Wayne; de Zoeten, Edwin F.; Klein, John; Kellermayer, Richard

    2015-01-01

    Dietary influences may affect microbiome composition and host immune responses, thereby modulating propensity toward inflammatory bowel diseases (IBDs): Crohn disease (CD) and ulcerative colitis (UC). Dietary n-6 fatty acids have been associated with UC in prospective studies. However, the critical developmental period when (n-6) consumption may induce UC is not known. We examined the effects of transiently increased n-6 consumption during pediatric development on subsequent dextran-sulfate-sodium (DSS)-induced acute murine colitis. The animals transiently became obese then rapidly lost this phenotype. Interestingly, mice were protected against DSS colitis 40 days after n-6 consumption. The transient high n-6-induced protection against colitis was fat type- and dietary reversal-dependent and could be transferred to germ-free mice by fecal microbiota transplantation. We also detected decreased numbers of chemokine receptor (Cxcr)5+ CD4+ T cells in the mesenteric lymph nodes (MLNs) of transiently n-6-fed mice. Further experiments revealed that anti-chemokine ligand (Cxcl)13 (the ligand of Cxcr5) antibody treatment decreased DSS colitis severity, implicating the importance of the Cxcr5-Cxcl13 pathway in mammalian colitis. Consecutively, we found elevated CXCL13 concentrations (CD: 1.8-fold, P = 0.0077; UC: 1.9-fold, P = 0.056) in the serum of untreated pediatric IBD patients. The human serologic observations supported the translational relevance of our findings.—Nagy-Szakal, D., Mir, S. A. V., Harris, R. A., Dowd, S. E., Yamada, T., Lacorazza, H. D., Tatevian, N., Smith, C. W., de Zoeten, E. F., Klein, J., Kellermayer, R. Loss of n-6 fatty acid induced pediatric obesity protects against acute murine colitis. PMID:25903104

  15. Intrarenal renin-angiotensin system mediates fatty acid-induced ER stress in the kidney.

    PubMed

    Li, Chunling; Lin, Yu; Luo, Renfei; Chen, Shaoming; Wang, Feifei; Zheng, Peili; Levi, Moshe; Yang, Tianxin; Wang, Weidong

    2016-03-01

    Obesity-related kidney disease is related to caloric excess promoting deleterious cellular responses. Accumulation of saturated free fatty acids in tubular cells produces lipotoxicity involving significant cellular dysfunction and injury. The objectives of this study were to elucidate the role of renin-angiotensin system (RAS) activation in saturated fatty acid-induced endoplasmic reticulum (ER) stress in cultured human proximal tubule epithelial cells (HK2) and in mice fed with a high-fat diet. Treatment with saturated fatty acid palmitic acid (PA; 0.8 mM) for 24 h induced ER stress in HK2, leading to an unfolded protein response as reflected by increased expressions of the ER chaperone binding immunoglobulin protein (BiP) and proapoptotic transcription factor C/EBP homologous protein (CHOP) protein as evaluated by immunoblotting. PA treatment also induced increased protein expression of inositol requiring protein 1α (IRE1α), phosphorylated eukaryotic initiation factor-α (eIF2α), and activating transcription factor 4 (ATF4) as well as activation of caspase-3. PA treatment was associated with increased angiotensin II levels in cultured medium. The angiotensin II type 1 receptor (AT1R) blocker valsartan or renin inhibitor aliskiren dramatically suppressed PA-induced upregulation of BiP, CHOP, IRE1α, p-eIF2α, and ATF4 in HK2 cells. In contrast, valsartan or aliskiren did not prevent ER stress induced by tunicamycin. C57BL/6 mice fed with a high-fat diet for 14 wk exhibited increased protein expressions of BiP and CHOP compared with control mice, which were significantly attenuated by the valsartan treatment. Increased angiotensin II levels in serum and urine were observed in mice fed with a high-fat diet when compared with controls. It is suggested that the intrarenal RAS activation may play an important role in diabetic kidney injury via mediating ER stress induced by saturated fatty acid. PMID:26672616

  16. Lysophosphatidic acid-induced chemotaxis of bone cells.

    SciTech Connect

    Karagiosis, Sue A.; Masiello, Lisa M.; Bollinger, Nikki; Karin, Norm J.

    2006-07-01

    Lysophosphatidic acid (LPA) is a platelet-derived bioactive lipid that is postulated to regulate wound healing. LPA activates G protein-coupled receptors to induce Ca2+ signaling in MC3T3-E1 pre-osteoblasts, and is a potent chemotactic stimulus for these cells. Since bone fracture healing requires the migration of osteoblast progenitors, we postulate that LPA is among the factors that stimulate bone repair. UMR 106-01 cells, which express a more mature osteoblastic phenotype than MC3T3-E1 cells, did not migrate in response to LPA, although they express LPA receptors and exhibit LPA-induced Ca2+ signals. This suggests that LPA differentially induces pre-osteoblast chemotaxis, consistent with our hypothesis that LPA stimulates the motility of osteoblast progenitors during bone healing. LPA-stimulated MC3T3-E1 cells exhibit striking changes in morphology and F-actin architecture, and phosphatidylinositol-3 kinase (PI3K) is required for motility-associated cytoskeletal rearrangements in many cell types. We found a dose-dependent reduction in LPA-induced osteoblast migration when cells also were treated with the PI3K inhibitor, LY294002. Treatment of many cell types with LPA is associated with an autocrine/paracrine transactivation of the EGF receptor (EGFR) via shedding of surface-tethered EGFR ligands, a phenomenon often required for LPA-induced chemotaxis. MC3T3-E1 cells express multiple EGFR ligands (epigen, epiregulin, HB-EGF and amphiregulin) and migrated in response to EGF. However, while EGF-stimulated motility in MC3T3-E1 cells was blocked by an EGFR inhibitor, there was no significant effect on LPA-induced chemotaxis. Activation of MAP kinases is a hallmark of EGFR-mediated signaling, and EGF treatment of MC3T3-E1 cells led to a strong stimulation of ERK1/2 kinase. In contrast, LPA induced only a minor elevation in ERK activity. Thus, it is likely that the increase in ERK activity by LPA is related to cell proliferation associated with lipid treatment. We

  17. Lysophosphatidic acid induces necrosis and apoptosis in hippocampal neurons.

    PubMed

    Holtsberg, F W; Steiner, M R; Keller, J N; Mark, R J; Mattson, M P; Steiner, S M

    1998-01-01

    A diverse body of evidence indicates a role for the lipid biomediator lysophosphatidic acid (LPA) in the CNS. This study identifies and characterizes the induction of neuronal death by LPA. Treatment of cultured hippocampal neurons from embryonic rat brains with 50 microM LPA resulted in neuronal necrosis, as determined morphologically and by the release of lactate dehydrogenase. A concentration of LPA as low as 10 microM led to the release of lactate dehydrogenase. In contrast, treatment of neurons with 0.1 or 1.0 microM LPA resulted in apoptosis, as determined by chromatin condensation. In addition, neuronal death induced by 1 microM LPA was characterized as apoptotic on the basis of terminal dUTP nick end-labeling (TUNEL) staining, externalization of phosphatidylserine, and protection against chromatin condensation, TUNEL staining, and phosphatidylserine externalization by treatment with N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone, a broad-spectrum inhibitor of caspases, i.e., members of the interleukin-1beta converting enzyme family. Studies with antagonists of ionotropic glutamate receptors did not indicate a significant role for these receptors in apoptosis induced by 1 microM LPA. LPA (1 microM) also induced a decrease in mitochondrial membrane potential. Moreover, pretreatment of neurons with cyclosporin A protected against the LPA-induced decrease in mitochondrial membrane potential and neuronal apoptosis. Thus, LPA, at pathophysiological levels, can induce neuronal apoptosis and could thereby participate in neurodegenerative disorders. PMID:9422348

  18. Bile acids induce hepatic differentiation of mesenchymal stem cells

    PubMed Central

    Sawitza, Iris; Kordes, Claus; Götze, Silke; Herebian, Diran; Häussinger, Dieter

    2015-01-01

    Mesenchymal stem cells (MSC) have the potential to differentiate into multiple cell lineages and their therapeutic potential has become obvious. In the liver, MSC are represented by stellate cells which have the potential to differentiate into hepatocytes after stimulation with growth factors. Since bile acids can promote liver regeneration, their influence on liver-resident and bone marrow-derived MSC was investigated. Physiological concentrations of bile acids such as tauroursodeoxycholic acid were able to initiate hepatic differentiation of MSC via the farnesoid X receptor and transmembrane G-protein-coupled bile acid receptor 5 as investigated with knockout mice. Notch, hedgehog, transforming growth factor-β/bone morphogenic protein family and non-canonical Wnt signalling were also essential for bile acid-mediated differentiation, whereas β-catenin-dependent Wnt signalling was able to attenuate this process. Our findings reveal bile acid-mediated signalling as an alternative way to induce hepatic differentiaion of stem cells and highlight bile acids as important signalling molecules during liver regeneration. PMID:26304833

  19. Retinoic acid-induced neural differentiation of embryonal carcinoma cells.

    PubMed Central

    Jones-Villeneuve, E M; Rudnicki, M A; Harris, J F; McBurney, M W

    1983-01-01

    We have previously shown that the P19 line of embryonal carcinoma cells develops into neurons, astroglia, and fibroblasts after aggregation and exposure to retinoic acid. The neurons were initially identified by their morphology and by the presence of neurofilaments within their cytoplasm. We have more fully documented the neuronal nature of these cells by showing that their cell surfaces display tetanus toxin receptors, a neuronal cell marker, and that choline acetyl-transferase and acetyl cholinesterase activities appear coordinately in neuron-containing cultures. Several days before the appearance of neurons, there is a marked decrease in the amount of an embryonal carcinoma surface antigen, and at the same time there is a substantial decrease in the volumes of individual cells. Various retinoids were able to induce the development of neurons in cultures of aggregated P19 cells, but it did not appear that polyamine metabolism was involved in the effect. We have isolated a mutant clone which does not differentiate in the presence of any of the drugs which are normally effective in inducing differentiation of P19 cells. This mutant and others may help to elucidate the chain of events triggered by retinoic acid and other differentiation-inducing drugs. Images PMID:6656766

  20. Dynamic changes during acid-induced activation of influenza hemagglutinin

    PubMed Central

    Garcia, Natalie K.; Guttman, Miklos; Ebner, Jamie L.; Lee, Kelly K.

    2015-01-01

    SUMMARY Influenza hemagglutinin (HA) mediates virus attachment to host cells and fusion of the viral and endosomal membranes during entry. While high-resolution structures are available for the pre-fusion HA ectodomain and the post-fusion HA2 subunit, the sequence of conformational changes during HA activation has eluded structural characterization. Here we apply hydrogen-deuterium exchange with mass spectrometry to examine changes in structural dynamics of the HA ectodomain at various stages of activation, as well as to compare the soluble ectodomain with intact HA on virions. At pH conditions approaching activation (pH 6.0–5.5) HA exhibits increased dynamics at the fusion peptide and neighboring regions, while the interface between receptor-binding subunits (HA1) becomes stabilized. In contrast to many activation models, these data suggest that HA responds to endosomal acidification by releasing the fusion peptide prior to HA1 uncaging and the spring-loaded refolding of HA2. This staged process may facilitate efficient HA-mediated fusion. PMID:25773144

  1. Albumin-associated free fatty acids induce macropinocytosis in podocytes

    PubMed Central

    Chung, Jun-Jae; Huber, Tobias B.; Gödel, Markus; Jarad, George; Hartleben, Björn; Kwoh, Christopher; Keil, Alexander; Karpitskiy, Aleksey; Hu, Jiancheng; Huh, Christine J.; Cella, Marina; Gross, Richard W.; Miner, Jeffrey H.; Shaw, Andrey S.

    2015-01-01

    Podocytes are specialized epithelial cells in the kidney glomerulus that play important structural and functional roles in maintaining the filtration barrier. Nephrotic syndrome results from a breakdown of the kidney filtration barrier and is associated with proteinuria, hyperlipidemia, and edema. Additionally, podocytes undergo changes in morphology and internalize plasma proteins in response to this disorder. Here, we used fluid-phase tracers in murine models and determined that podocytes actively internalize fluid from the plasma and that the rate of internalization is increased when the filtration barrier is disrupted. In cultured podocytes, the presence of free fatty acids (FFAs) associated with serum albumin stimulated macropinocytosis through a pathway that involves FFA receptors, the Gβ/Gγ complex, and RAC1. Moreover, mice with elevated levels of plasma FFAs as the result of a high-fat diet were more susceptible to Adriamycin-induced proteinuria than were animals on standard chow. Together, these results support a model in which podocytes sense the disruption of the filtration barrier via FFAs bound to albumin and respond by enhancing fluid-phase uptake. The response to FFAs may function in the development of nephrotic syndrome by amplifying the effects of proteinuria. PMID:25915582

  2. Bile-acid-induced cell injury and protection

    PubMed Central

    Perez, Maria J; Briz, Oscar

    2009-01-01

    Several studies have characterized the cellular and molecular mechanisms of hepatocyte injury caused by the retention of hydrophobic bile acids (BAs) in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial injury in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced injury in hepatocytes. The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyl-N-methylglycine or cholylsarcosine, have also aroused pharmacological interest owing to their protective properties. PMID:19360911

  3. Olodaterol attenuates citric acid-induced cough in naïve and ovalbumin-sensitized and challenged guinea pigs.

    PubMed

    Wex, Eva; Bouyssou, Thierry

    2015-01-01

    Excessive coughing is a common feature of airway diseases. Different G-protein coupled receptors, including β2-adrenergic receptors (β2-AR), have been implicated in the molecular mechanisms underlying the cough reflex. However, the potential antitussive property of β2-AR agonists in patients with respiratory disease is a matter of ongoing debate. The aim of our study was to test the efficacy of the long-acting β2-AR agonist olodaterol with regard to its antitussive property in a pre-clinical model of citric acid-induced cough in guinea pigs and to compare the results to different clinically relevant β2-AR agonists. In our study β2-AR agonists were intratracheally administered, as dry powder, into the lungs of naïve or ovalbumin-sensitized guinea pigs 15 minutes prior to induction of cough by exposure to citric acid. Cough events were counted over 15 minutes during the citric acid exposure. Olodaterol dose-dependently inhibited the number of cough events in naïve and even more potently and with a greater maximal efficacy in ovalbumin-sensitized guinea pigs (p < 0.01). Formoterol and salmeterol showed a trend towards reducing cough. On the contrary, indacaterol demonstrated pro-tussive properties as it significantly increased the number of coughs, both in naïve and ovalbumin-sensitized animals (p < 0.001). In conclusion, olodaterol, at doses eliciting bronchodilation, showed antitussive properties in a model of citric acid-induced cough in naïve and ovalbumin-sensitized guinea pigs. This is in agreement with pre-clinical and clinical studies showing antitussive efficacy of β2-AR agonists. Indacaterol increased the number of coughs in this model, which concurs with clinical data where a transient cough has been observed after indacaterol inhalation. While the antitussive properties of β2-AR agonists can be explained by their ability to lead to the cAMP-induced hyperpolarization of the neuron membrane thereby inhibiting sensory nerve activation and the

  4. Olodaterol Attenuates Citric Acid-Induced Cough in Naïve and Ovalbumin-Sensitized and Challenged Guinea Pigs

    PubMed Central

    Wex, Eva; Bouyssou, Thierry

    2015-01-01

    Excessive coughing is a common feature of airway diseases. Different G-protein coupled receptors, including β2-adrenergic receptors (β2-AR), have been implicated in the molecular mechanisms underlying the cough reflex. However, the potential antitussive property of β2-AR agonists in patients with respiratory disease is a matter of ongoing debate. The aim of our study was to test the efficacy of the long-acting β2-AR agonist olodaterol with regard to its antitussive property in a pre-clinical model of citric acid-induced cough in guinea pigs and to compare the results to different clinically relevant β2-AR agonists. In our study β2-AR agonists were intratracheally administered, as dry powder, into the lungs of naïve or ovalbumin-sensitized guinea pigs 15 minutes prior to induction of cough by exposure to citric acid. Cough events were counted over 15 minutes during the citric acid exposure. Olodaterol dose-dependently inhibited the number of cough events in naïve and even more potently and with a greater maximal efficacy in ovalbumin-sensitized guinea pigs (p < 0.01). Formoterol and salmeterol showed a trend towards reducing cough. On the contrary, indacaterol demonstrated pro-tussive properties as it significantly increased the number of coughs, both in naïve and ovalbumin-sensitized animals (p < 0.001). In conclusion, olodaterol, at doses eliciting bronchodilation, showed antitussive properties in a model of citric acid-induced cough in naïve and ovalbumin-sensitized guinea pigs. This is in agreement with pre-clinical and clinical studies showing antitussive efficacy of β2-AR agonists. Indacaterol increased the number of coughs in this model, which concurs with clinical data where a transient cough has been observed after indacaterol inhalation. While the antitussive properties of β2-AR agonists can be explained by their ability to lead to the cAMP-induced hyperpolarization of the neuron membrane thereby inhibiting sensory nerve activation and the

  5. Acid-induced aggregation propensity of nivolumab is dependent on the Fc.

    PubMed

    Liu, Boning; Guo, Huaizu; Xu, Jin; Qin, Ting; Xu, Lu; Zhang, Junjie; Guo, Qingcheng; Zhang, Dapeng; Qian, Weizhu; Li, Bohua; Dai, Jianxin; Hou, Sheng; Guo, Yajun; Wang, Hao

    2016-01-01

    Nivolumab, an anti-programmed death (PD)1 IgG4 antibody, has shown notable success as a cancer treatment. Here, we report that nivolumab was susceptible to aggregation during manufacturing, particularly in routine purification steps. Our experimental results showed that exposure to low pH caused aggregation of nivolumab, and the Fc was primarily responsible for an acid-induced unfolding phenomenon. To compare the intrinsic propensity of acid-induced aggregation for other IgGs subclasses, tocilizumab (IgG1), panitumumab (IgG2) and atezolizumab (aglyco-IgG1) were also investigated. The accurate pH threshold of acid-induced aggregation for individual IgG Fc subclasses was identified and ranked as: IgG1 < aglyco-IgG1 < IgG2 < IgG4. This result was cross-validated by thermostability and conformation analysis. We also assessed the effect of several protein stabilizers on nivolumab, and found mannitol ameliorated the acid-induced aggregation of the molecule. Our results provide valuable insight into downstream manufacturing process development, especially for immune checkpoint modulating molecules with a human IgG4 backbone. PMID:27310175

  6. MICROARRAY ANALYSIS OF DICHLOROACETIC ACID-INDUCED CHANGES IN GENE EXPRESSION

    EPA Science Inventory


    MICROARRAY ANALYSIS OF DICHLOROACETIC ACID-INDUCED CHANGES IN GENE EXPRESSION

    Dichloroacetic acid (DCA) is a major by-product of water disinfection by chlorination. Several studies have demonstrated the hepatocarcinogenicity of DCA in rodents when administered in dri...

  7. Luteolin prevents uric acid-induced pancreatic β-cell dysfunction

    PubMed Central

    Ding, Ying; Shi, Xuhui; Shuai, Xuanyu; Xu, Yuemei; Liu, Yun; Liang, Xiubin; Wei, Dong; Su, Dongming

    2014-01-01

    Abstract Elevated uric acid causes direct injury to pancreatic β-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced β-cell dysfunction. We first evaluated the effect of luteolin on nitric oxide (NO) formation in uric acid-stimulated Min6 cells using the Griess method. Next, we performed transient transfection and reporter assays to measure transcriptional activity of nuclear factor (NF)-κB. Western blotting assays were also performed to assess the effect of luteolin on the expression of MafA and inducible NO synthase (iNOS) in uric acid-treated cells. Finally, we evaluated the effect of luteolin on uric acid-induced inhibition of glucose-stimulated insulin secretion (GSIS) in Min6 cells and freshly isolated mouse pancreatic islets. We found that luteolin significantly inhibited uric acid-induced NO production, which was well correlated with reduced expression of iNOS mRNA and protein. Furthermore, decreased activity of NF-κB was implicated in inhibition by luteolin of increased iNOS expression induced by uric acid. Besides, luteolin significantly increased MafA expression in Min6 cells exposed to uric acid, which was reversed by overexpression of iNOS. Moreover, luteolin prevented uric acid-induced inhibition of GSIS in both Min6 cells and mouse islets. In conclusion, luteolin protects pancreatic β-cells from uric acid-induced dysfunction and may confer benefit on the protection of pancreatic β-cells in hyperuricemia-associated diabetes. PMID:25050113

  8. Anti-inflammatory effects of nesfatin-1 in rats with acetic acid - induced colitis and underlying mechanisms.

    PubMed

    Ozturk, C C; Oktay, S; Yuksel, M; Akakin, D; Yarat, A; Kasimay Cakir, O

    2015-10-01

    Mucosal balance impairment, bacterial over-proliferation, cytokines, inflammatory mediators are known as responsible for inflammatory bowel disease. Besides known anorexigenic, neuroprotective, and anti-apoptotic effects, the major effect of nesfatin-1 on colitis is unknown. Our aim was to investigate the possible anti-inflammatory effects of nesfatin-1 in acetic acid induced colitis model and potential underlying mechanisms. Male Spraque-Dawley rats were anesthetized by intraperitoneal ketamine (100 mg/kg) and chlorpromazine (0.75 mg/kg). For nesfatin-1 and antagonist applications some of the rats were intracerebroventricularly (i.c.v.) cannulated. In colitis group, intrarectally (i.r.) 4% acetic acid solution (1 ml) and 10 minutes later i.c.v. nesfatin-1 (0.05 μg/5 μl) or vehicle (5 μl) were administered. Treatments continued for 3 days. In control group, physiological saline solution was used intrarectally. To identify the underlying effective mechanism of nesfatin-1, rats were divided into 3 subgroups, 5 minutes following colitis induction; i.c.v. atosiban (oxytocin receptor antagonist), SHU9119 (melanocortin receptor antagonist) or GHSR-1a antagonist (ghrelin receptor antagonist) were administered, 5 minutes later nesfatin-1 was administered for 3 days. On the fourth day, rats were decapitated, and colon tissues were sampled. Macroscopic and microscopic damage scores of distal colon, and colonic tissue malondialdehyde, glutathione, myeloperoxidase, superoxide dismutase, catalase, luminol and lucigenin chemiluminescence measurements were analysed. The increased myeloperoxidase activity, malondialdehyde levels, luminol and lucigenin chemiluminescence measurements, macroscopic and microscopic damage scores with colitis induction (P < 0.05 - 0.001) were decreased with nesfatin-1 treatment (P < 0.05 - 0.001). Nesfatin-1 may show this effect by inhibiting neutrophil infiltration through tissues and by decreasing formation of free oxygen radicals. Atosiban and

  9. Protective Effect of Ocimum basilicum Essential Oil Against Acetic Acid-Induced Colitis in Rats.

    PubMed

    Rashidian, Amir; Roohi, Parnia; Mehrzadi, Saeed; Ghannadi, Ali Reza; Minaiyan, Mohsen

    2016-10-01

    Ocimum basilicum L has been traditionally used for the treatment of inflammatory bowel disease in Iran. This study investigates the ameliorative effect of Ocimum basilicum essential oil on an acetic acid-induced colitis model in rats. Ocimum basilicum essential oil with 2 doses (200 and 400 μL/kg) significantly ameliorated wet weight/length ratio of colonic tissue compared to the control group. Higher doses of essential oil (200 and 400 μL/kg) significantly reduced ulcer severity, ulcer area, and ulcer index. On the other hand, histological examination revealed the diminution of total colitis index as a marker for inflammatory cell infiltration in the colonic segments of rats treated with Ocimum basilicum essential oil (200 and 400 μL/kg). The increased level of myeloperoxidase was significantly decreased after the treatment with the essential oil (200 and 400 μL/kg). These results suggest that Ocimum basilicum exhibits protective effect against acetic acid-induced colitis.

  10. Minocycline ameliorates prenatal valproic acid induced autistic behaviour, biochemistry and blood brain barrier impairments in rats.

    PubMed

    Kumar, Hariom; Sharma, Bhupesh

    2016-01-01

    Autism is a neurodevelopment disorder. One percent worldwide population suffers with autism and males suffer more than females. Microglia plays an important role in neurodevelopment, neuropsychiatric and neurodegenerative disorders. The present study has been designed to investigate the role of minocycline in prenatal valproic acid induced autism in rats. Animals with prenatal valproic acid have reduced social interaction (three chamber social behaviour apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (both in prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complexes I, II, IV). Furthermore, prenatal valproic acid treated animals have shown an increase in locomotion (actophotometer), anxiety (elevated plus maze), brain oxidative stress (thiobarbituric acid reactive species, glutathione, catalase), nitrosative stress (nitrite/nitrate), inflammation (both in brain and ileum myeloperoxidase activity), calcium and blood brain barrier permeability. Treatment with minocycline significantly attenuated prenatal valproic acid induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, minocycline has also attenuated prenatal valproic acid induced increase in locomotion, anxiety, brain oxidative and nitrosative stress, inflammation, calcium and blood brain barrier permeability. Thus, it may be concluded that prenatal valproic acid has induced autistic behaviour, biochemistry and blood brain barrier impairment in animals, which were significantly attenuated by minocycline. Minocycline should be explored further for its therapeutic benefits in autism.

  11. Protective effect of hispidulin on kainic acid-induced seizures and neurotoxicity in rats.

    PubMed

    Lin, Tzu Yu; Lu, Cheng Wei; Wang, Su Jane; Huang, Shu Kuei

    2015-05-15

    Hispidulin is a flavonoid compound which is an active ingredient in a number of traditional Chinese medicinal herbs, and it has been reported to inhibit glutamate release. The purpose of this study was to investigate whether hispidulin protects against seizures induced by kainic acid, a glutamate analog with excitotoxic properties. The results indicated that intraperitoneally administering hispidulin (10 or 50mg/kg) to rats 30 min before intraperitoneally injecting kainic acid (15 mg/kg) increased seizure latency and decreased seizure score. In addition, hispidulin substantially attenuated kainic acid-induced hippocampal neuronal cell death, and this protective effect was accompanied by the suppression of microglial activation and the production of proinflammatory cytokines such as interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampus. Moreover, hispidulin reduced kainic acid-induced c-Fos expression and the activation of mitogen-activated protein kinases in the hippocampus. These data suggest that hispidulin has considerable antiepileptic, neuroprotective, and antiinflammatory effects on kainic acid-induced seizures in rats. PMID:25746462

  12. Houttuyniae Herba Attenuates Kainic Acid-Induced Neurotoxicity via Calcium Response Modulation in the Mouse Hippocampus.

    PubMed

    Kim, Hyo Geun; Jeong, Hyun Uk; Hong, Sung In; Oh, Myung Sook

    2015-12-01

    Epilepsy is a complex neurological disorder characterized by the repeated occurrence of electrical activity known as seizures. This activity induces increased intracellular calcium, which ultimately leads to neuronal damage. Houttuyniae Herba, the aerial part of Houttuynia cordata, has various pharmacological effects and is widely used as a traditional herb. In the present study, we evaluated the protective effects of Houttuyniae Herba water extract on kainic acid-induced neurotoxicity. Kainic acid directly acts on calcium release, resulting in seizure behavior, neuronal damage, and cognitive impairment. In a rat primary hippocampal culture system, Houttuyniae Herba water extract significantly protected neuronal cells from kainic acid toxicity. In a seizure model where mice received intracerebellar kainic acid injections, Houttuyniae Herba water extract treatment resulted in a lower seizure stage score, ameliorated cognitive impairment, protected neuronal cells against kainic acid-induced toxicity, and suppressed neuronal degeneration in the hippocampus. In addition, Houttuyniae Herba water extract regulated increases in the intracellular calcium level, its related downstream pathways (reactive oxygen species production and mitochondrial dysfunction), and calcium/calmodulin complex kinase type II immunoreactivity in the mouse hippocampus, which resulted from calcium influx stimulation induced by kainic acid. These results demonstrate the neuroprotective effects of Houttuyniae Herba water extract through inhibition of calcium generation in a kainic acid-induced epileptic model. PMID:26366753

  13. Minocycline ameliorates prenatal valproic acid induced autistic behaviour, biochemistry and blood brain barrier impairments in rats.

    PubMed

    Kumar, Hariom; Sharma, Bhupesh

    2016-01-01

    Autism is a neurodevelopment disorder. One percent worldwide population suffers with autism and males suffer more than females. Microglia plays an important role in neurodevelopment, neuropsychiatric and neurodegenerative disorders. The present study has been designed to investigate the role of minocycline in prenatal valproic acid induced autism in rats. Animals with prenatal valproic acid have reduced social interaction (three chamber social behaviour apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (both in prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complexes I, II, IV). Furthermore, prenatal valproic acid treated animals have shown an increase in locomotion (actophotometer), anxiety (elevated plus maze), brain oxidative stress (thiobarbituric acid reactive species, glutathione, catalase), nitrosative stress (nitrite/nitrate), inflammation (both in brain and ileum myeloperoxidase activity), calcium and blood brain barrier permeability. Treatment with minocycline significantly attenuated prenatal valproic acid induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, minocycline has also attenuated prenatal valproic acid induced increase in locomotion, anxiety, brain oxidative and nitrosative stress, inflammation, calcium and blood brain barrier permeability. Thus, it may be concluded that prenatal valproic acid has induced autistic behaviour, biochemistry and blood brain barrier impairment in animals, which were significantly attenuated by minocycline. Minocycline should be explored further for its therapeutic benefits in autism. PMID:26551768

  14. Dietary interesterified fat enriched with palmitic acid induces atherosclerosis by impairing macrophage cholesterol efflux and eliciting inflammation.

    PubMed

    Afonso, Milessa Silva; Lavrador, Maria Silvia Ferrari; Koike, Marcia Kiyomi; Cintra, Dennys Esper; Ferreira, Fabiana Dias; Nunes, Valeria Sutti; Castilho, Gabriela; Gioielli, Luiz Antonio; Paula Bombo, Renata; Catanozi, Sergio; Caldini, Elia Garcia; Damaceno-Rodrigues, Nilsa Regina; Passarelli, Marisa; Nakandakare, Edna Regina; Lottenberg, Ana Maria

    2016-06-01

    Interesterified fats are currently being used to replace trans fatty acids. However, their impact on biological pathways involved in the atherosclerosis development was not investigated. Weaning male LDLr-KO mice were fed for 16weeks on a high-fat diet (40% energy as fat) containing polyunsaturated (PUFA), TRANS, palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR) or stearic interesterified (STEAR INTER). Plasma lipids, lipoprotein profile, arterial lesion area, macrophage infiltration, collagen content and inflammatory response modulation were determined. Macrophage cholesterol efflux and the arterial expression of cholesterol uptake and efflux receptors were also performed. The interesterification process did not alter plasma lipid concentrations. Although PALM INTER did not increase plasma cholesterol concentration as much as TRANS, the cholesterol enrichment in the LDL particle was similar in both groups. Moreover, PALM INTER induced the highest IL-1β, MCP-1 and IL-6 secretion from peritoneal macrophages as compared to others. This inflammatory response elicited by PALM INTER was confirmed in arterial wall, as compared to PALM. These deleterious effects of PALM INTER culminate in higher atherosclerotic lesion, macrophage infiltration and collagen content than PALM, STEAR, STEAR INTER and PUFA. These events can partially be attributed to a macrophage cholesterol accumulation, promoted by apoAI and HDL2-mediated cholesterol efflux impairment and increased Olr-1 and decreased Abca1 and Nr1h3 expressions in the arterial wall. Interesterified fats containing palmitic acid induce atherosclerosis development by promoting cholesterol accumulation in LDL particles and macrophagic cells, activating the inflammatory process in LDLr-KO mice.

  15. Adipokines enhance oleic acid-induced proliferation of vascular smooth muscle cells by inducing CD36 expression.

    PubMed

    Schlich, Raphaela; Lamers, Daniela; Eckel, Jürgen; Sell, Henrike

    2015-01-01

    Adipose tissue is not only releasing lipids but also various adipokines that are both dysregulated in the obese state and may contribute to obesity-associated vascular dysfunction and cardiovascular risk. We have previously shown that the combination of adipocyte-conditioned medium (CM) and oleic acid (OA) increases proliferation of human vascular smooth muscle cells (VSMC) in a synergistic way. We identified vascular endothelial growth factor (VEGF) as a component within CM that is responsible for most of the observed effects. In this study, we investigate novel mechanisms that underlie the combined effects of adipokine and oleic acid-induced proliferation of VSMC. Oleic acid leads to significant lipid accumulation in VSMC that is further enhanced by the combined treatment with CM. Accordingly CM stimulates CD36 expression in VSMC while OA is not affecting CD36. Silencing of CD36 was established and prevents lipid accumulation in all tested conditions. CD36 silencing also abrogates CM- and OA-induced proliferation and considerably reduces proliferation induced by the combination of CM and OA. At the same time, VEGF secretion and VEGF-receptor 1 (VEGF-R1) by VSMC was not affected by CD36 silencing. However, VEGF was not able to induce any proliferation in VSMC after CD36 silencing that also blunted VEGF-induced extracellular signal-regulated kinase (ERK) activation. Finally, combined silencing of CD36 together with a blocking antibody against VEGF prevented most of CMOA-induced proliferation. In conclusion, our results demonstrate that CD36 is mediating CM-induced proliferation of VSMC. Induction of CD36 by adipokines enhances the response of VSMC towards VEGF and OA.

  16. Benfotiamine attenuates nicotine and uric acid-induced vascular endothelial dysfunction in the rat.

    PubMed

    Balakumar, Pitchai; Sharma, Ramica; Singh, Manjeet

    2008-01-01

    The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nicotine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2 mg kg(-1)day(-1), i.p., 4 weeks) and uric acid (150 mg kg(-1)day(-1), i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and aortic concentration of nitrite/nitrate. Further, the integrity of vascular endothelium was assessed using the scanning electron microscopy (SEM) of thoracic aorta. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS) and aortic superoxide anion generation. The administration of nicotine and uric acid produced VED by impairing the integrity of vascular endothelium and subsequently decreasing serum and aortic concentration of nitrite/nitrate and attenuating acetylcholine-induced endothelium dependent relaxation. Further, nicotine and uric acid produced oxidative stress, which was assessed in terms of increase in serum TBARS and aortic superoxide generation. However, treatment with benfotiamine (70 mg kg(-1)day(-1), p.o.) or atorvastatin (30 mg kg(-1)day(-1) p.o., a standard agent) markedly prevented nicotine and uric acid-induced VED and oxidative stress by improving the integrity of vascular endothelium, increasing the concentration of serum and aortic nitrite/nitrate, enhancing the acetylcholine-induced endothelium dependent relaxation and decreasing serum TBARS and aortic superoxide anion generation. Thus, it may be concluded that benfotiamine reduces the oxidative stress and consequently improves the integrity of vascular endothelium and enhances the generation of nitric oxide to prevent nicotine and uric acid-induced experimental VED. PMID:18951979

  17. Lipopolysaccharide Stimulates Butyric Acid-Induced Apoptosis in Human Peripheral Blood Mononuclear Cells

    PubMed Central

    Kurita-Ochiai, Tomoko; Fukushima, Kazuo; Ochiai, Kuniyasu

    1999-01-01

    We previously reported that butyric acid, an extracellular metabolite from periodontopathic bacteria, induced apoptosis in murine thymocytes, splenic T cells, and human Jurkat T cells. In this study, we examined the ability of butyric acid to induce apoptosis in peripheral blood mononuclear cells (PBMC) and the effect of bacterial lipopolysaccharide (LPS) on this apoptosis. Butyric acid significantly inhibited the anti-CD3 monoclonal antibody- and concanavalin A-induced proliferative responses in a dose-dependent fashion. This inhibition of PBMC growth by butyric acid depended on apoptosis in vitro. It was characterized by internucleosomal DNA digestion and revealed by gel electrophoresis followed by a colorimetric DNA fragmentation assay to occur in a concentration-dependent fashion. Butyric acid-induced PBMC apoptosis was accompanied by caspase-3 protease activity but not by caspase-1 protease activity. LPS potentiated butyric acid-induced PBMC apoptosis in a dose-dependent manner. Flow-cytometric analysis revealed that LPS increased the proportion of sub-G1 cells and the number of late-stage apoptotic cells induced by butyric acid. Annexin V binding experiments with fractionated subpopulations of PBMC in flow cytometory revealed that LPS accelerated the butyric acid-induced CD3+-T-cell apoptosis followed by similar levels of both CD4+- and CD8+-T-cell apoptosis. The addition of LPS to PBMC cultures did not cause DNA fragmentation, suggesting that LPS was unable to induce PBMC apoptosis directly. These data suggest that LPS, in combination with butyric acid, potentiates CD3+ PBMC T-cell apoptosis and plays a role in the apoptotic depletion of CD4+ and CD8+ cells. PMID:9864191

  18. The acid-induced folded state of Sac7d is the native state.

    PubMed Central

    Bedell, J. L.; McCrary, B. S.; Edmondson, S. P.; Shriver, J. W.

    2000-01-01

    Sac7d unfolds at low pH in the absence of salt, with the greatest extent of unfolding obtained at pH 2. We have previously shown that the acid unfolded protein is induced to refold by decreasing the pH to 0 or by addition of salt (McCrary BS, Bedell J. Edmondson SP, Shriver JW, 1998, J Mol Biol 276:203-224). Both near-ultraviolet circular dichroism spectra and ANS fluorescence enhancements indicate that the acid- and salt-induced folded states have a native fold and are not molten globular. 1H,15N heteronuclear single quantum coherence NMR spectra confirm that the native, acid-, and salt-induced folded states are essentially identical. The most significant differences in amide 1H and 15N chemical shifts are attributed to hydrogen bonding to titrating carboxyl side chains and through-bond inductive effects. The 1H NMR chemical shifts of protons affected by ring currents in the hydrophobic core of the acid- and salt-induced folded states are identical to those observed in the native. The radius of gyration of the acid-induced folded state at pH 0 is shown to be identical to that of the native state at pH 7 by small angle X-ray scattering. We conclude that acid-induced collapse of Sac7d does not lead to a molten globule but proceeds directly to the native state. The folding of Sac7d as a function of pH and anion concentration is summarized with a phase diagram that is similar to those observed for other proteins that undergo acid-induced folding except that the A-state is encompassed by the native state. These results demonstrate that formation of a molten globule is not a general property of proteins that are refolded by acid. PMID:11106160

  19. Unsaturated fatty acid-induced non-canonical autophagy: unusual? or unappreciated?

    PubMed Central

    Bankaitis, Vytas A

    2015-01-01

    The breakdown of cellular components via autophagy is crucial for cellular homeostasis. In this issue of The EMBO Journal, Niso-Santano et al (2015) report the important observation that feeding cells with saturated or unsaturated fatty acids triggers mechanistically distinct autophagic responses. Feeding cells saturated fatty acid induced the canonical, BECN1/PI3K-dependent autophagy pathway. Conversely, the unsaturated fatty acid oleate triggered autophagic responses that were independent of the BECN1/PI3K complex, but that required a functional Golgi system. PMID:25762589

  20. Role of hepatocyte S6K1 in palmitic acid-induced endoplasmic reticulum stress, lipotoxicity, insulin resistance and in oleic acid-induced protection.

    PubMed

    Pardo, Virginia; González-Rodríguez, Águeda; Muntané, Jordi; Kozma, Sara C; Valverde, Ángela M

    2015-06-01

    The excess of saturated free fatty acids, such as palmitic acid, that induces lipotoxicity in hepatocytes, has been implicated in the development of non-alcoholic fatty liver disease also associated with insulin resistance. By contrast, oleic acid, a monounsaturated fatty acid, attenuates the effects of palmitic acid. We evaluated whether palmitic acid is directly associated with both insulin resistance and lipoapoptosis in mouse and human hepatocytes and the impact of oleic acid in the molecular mechanisms that mediate both processes. In human and mouse hepatocytes palmitic acid at a lipotoxic concentration triggered early activation of endoplasmic reticulum (ER) stress-related kinases, induced the apoptotic transcription factor CHOP, activated caspase 3 and increased the percentage of apoptotic cells. These effects concurred with decreased IR/IRS1/Akt insulin pathway. Oleic acid suppressed the toxic effects of palmitic acid on ER stress activation, lipoapoptosis and insulin resistance. Besides, oleic acid suppressed palmitic acid-induced activation of S6K1. This protection was mimicked by pharmacological or genetic inhibition of S6K1 in hepatocytes. In conclusion, this is the first study highlighting the activation of S6K1 by palmitic acid as a common and novel mechanism by which its inhibition by oleic acid prevents ER stress, lipoapoptosis and insulin resistance in hepatocytes.

  1. Obestatin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats.

    PubMed

    Matuszyk, Aleksandra; Ceranowicz, Piotr; Warzecha, Zygmunt; Cieszkowski, Jakub; Bonior, Joanna; Jaworek, Jolanta; Kuśnierz-Cabala, Beata; Konturek, Peter; Ambroży, Tadeusz; Dembiński, Artur

    2016-01-01

    Obestatin, a 23-amino acid peptide derived from the proghrelin, has been shown to exhibit some protective and therapeutic effects in the gut. The aim of present study was to determine the effect of obestatin administration on the course of acetic acid-induced colitis in rats. Materials and Methods. Studies have been performed on male Wistar rats. Colitis was induced by a rectal enema with 3.5% acetic acid solution. Obestatin was administered intraperitoneally twice a day at a dose of 8 nmol/kg, starting 24 h after the induction of colitis. Seven or 14 days after the induction of colitis, the healing rate of the colon was evaluated. Results. Treatment with obestatin after induction of colitis accelerated the healing of colonic wall damage and this effect was associated with a decrease in the colitis-evoked increase in mucosal activity of myeloperoxidase and content of interleukin-1β. Moreover, obestatin administration significantly reversed the colitis-evoked decrease in mucosal blood flow and DNA synthesis. Conclusion. Administration of exogenous obestatin exhibits therapeutic effects in the course of acetic acid-induced colitis and this effect is related, at least in part, to the obestatin-evoked anti-inflammatory effect, an improvement of local blood flow, and an increase in cell proliferation in colonic mucosa.

  2. Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats

    PubMed Central

    Matuszyk, Aleksandra; Ceranowicz, Piotr; Warzecha, Zygmunt; Cieszkowski, Jakub; Ceranowicz, Dagmara; Gałązka, Krystyna; Bonior, Joanna; Jaworek, Jolanta; Bartuś, Krzysztof; Gil, Krzysztof; Olszanecki, Rafał; Dembiński, Artur

    2016-01-01

    Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis. PMID:27598133

  3. Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats.

    PubMed

    Matuszyk, Aleksandra; Ceranowicz, Piotr; Warzecha, Zygmunt; Cieszkowski, Jakub; Ceranowicz, Dagmara; Gałązka, Krystyna; Bonior, Joanna; Jaworek, Jolanta; Bartuś, Krzysztof; Gil, Krzysztof; Olszanecki, Rafał; Dembiński, Artur

    2016-01-01

    Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis. PMID:27598133

  4. Icariin, a major constituent from Epimedium brevicornum, attenuates ibotenic acid-induced excitotoxicity in rat hippocampus.

    PubMed

    Zong, Nan; Li, Fei; Deng, Yuanyuan; Shi, Jingshan; Jin, Feng; Gong, Qihai

    2016-10-15

    Excitotoxicity is one of the most extensively studied causes of neuronal death and plays an important role in Alzheimer's disease (AD). Icariin is a flavonoid component of a traditional Chinese medicine reported to possess a broad spectrum of pharmacological effects. The present study was designed to investigate the effects of icariin against learning and memory impairment induced by excitotoxicity. Here, we demonstrated that rats receiving intracerebroventricular injection of excitatory neurotoxin ibotenic acid exhibited impaired learning and memory. Oral administration of icariin at doses of 20 and 40mg/kg rescued behavioral performance and protected against neurotoxicity in rat hippocampus by suppressing ibotenic acid induced pro-apoptosis. Furthermore, Western blott of hippocampal specimens revealed that icariin up-regulated the expression of calbindin-D28k protein following ibotenic acid administration. Additionally, icariin inhibited mitogen-activated protein kinase (MAPK) family phosphorylation and nuclear factor kappa B (NF-κB) signaling, implicating the MAPK signaling and NF-κB signaling pathways were involved in the mechanism underlying icariin-mediated neuroprotection against ibotenic acid-induced excitotoxicity. These data suggested that icariin could be a potential agent for treatment of excitotoxicity-related diseases, including AD. PMID:27368415

  5. Protective Effect of Ocimum basilicum Essential Oil Against Acetic Acid-Induced Colitis in Rats.

    PubMed

    Rashidian, Amir; Roohi, Parnia; Mehrzadi, Saeed; Ghannadi, Ali Reza; Minaiyan, Mohsen

    2016-10-01

    Ocimum basilicum L has been traditionally used for the treatment of inflammatory bowel disease in Iran. This study investigates the ameliorative effect of Ocimum basilicum essential oil on an acetic acid-induced colitis model in rats. Ocimum basilicum essential oil with 2 doses (200 and 400 μL/kg) significantly ameliorated wet weight/length ratio of colonic tissue compared to the control group. Higher doses of essential oil (200 and 400 μL/kg) significantly reduced ulcer severity, ulcer area, and ulcer index. On the other hand, histological examination revealed the diminution of total colitis index as a marker for inflammatory cell infiltration in the colonic segments of rats treated with Ocimum basilicum essential oil (200 and 400 μL/kg). The increased level of myeloperoxidase was significantly decreased after the treatment with the essential oil (200 and 400 μL/kg). These results suggest that Ocimum basilicum exhibits protective effect against acetic acid-induced colitis. PMID:26620574

  6. Comparative neuroprotective profile of statins in quinolinic acid induced neurotoxicity in rats.

    PubMed

    Kalonia, Harikesh; Kumar, Puneet; Kumar, Anil

    2011-01-01

    A possible neuroprotective role has been recently suggested for 3H3MGCoA reductase inhibitors (statins). Here, we sought to determine neuroprotective effect of statins in quinolinic acid induced neurotoxicity in rats. Rats were surgically administered quinolinic acid and treated with Atorvastatin (10, 20 mg/kg), simvastatin (15, 30 mg/kg) and fluvastatin (5, 10 mg/kg) once daily up to 3 weeks. Atorvastatin (10, 20 mg/kg), simvastatin (30 mg/kg) and fluvastatin (10 mg/kg) treatment significantly attenuated the quinolinic acid induced behavioral (locomotor activity, rotarod performance and beam walk test), biochemical (lipid peroxidation, nitrite concentration, SOD and catalase), mitochondrial enzyme complex alterations in rats suggesting their free radical scavenging potential. Additionally, atorvastatin (10, 20 mg/kg), simvastatin (30 mg/kg) and fluvastatin (10 mg/kg) significantly decrease the TNF-α level and striatal lesion volume in quinolinic acid treated animals indicating their anti-inflammatory effects. In comparing the protective effect of different statins, atorvastatin is effective at both the doses while simvastatin and fluvastatins at respective lower doses were not able to produce the protective effect in quinolinic acid treated animals. These modulations can account, at least partly, for the beneficial effect of statins in our rodent model of striatal degeneration. Our findings show that statins could be explored as possible neuroprotective agents for neurodegenerative disorders such as HD. PMID:20696189

  7. Licofelone attenuates quinolinic acid induced Huntington like symptoms: possible behavioral, biochemical and cellular alterations.

    PubMed

    Kalonia, Harikesh; Kumar, Puneet; Kumar, Anil

    2011-03-30

    Cyclo-oxygenase and lipoxygenase enzymes are involved in arachidonic acid metabolism. Emerging evidence indicates that cyclo-oxygenase and lipoxygenase inhibitors prevent neurodegenerative processes and related complications. Therefore, the present study has been designed to explore the neuroprotective potential of licofelone (dual COX-2/5-LOX inhibitor) against quinolinic acid induced Huntington like symptom in rats. Intrastriatal administration of quinolinic acid significantly caused reduction in body weight and motor function (locomotor activity, rotarod performance and beam walk test), oxidative defense (as evidenced by increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidant enzymes), alteration in mitochondrial enzyme complex (I, II and IV) activities, raised TNF-α level and striatal lesion volume as compared to sham treated animals. Licofelone (2.5, 5 and 10 mg/kg) treatment significantly improved body weight, locomotor activity, rotarod performance, balance beam walk performance, oxidative defense, mitochondrial enzyme complex activities and attenuated TNF-α level and striatal lesion as compared to control (quinolinic acid). The present study highlights that licofelone attenuates behavioral, biochemical and cellular alterations against quinolinic acid induced neurotoxicity and this could be an important therapeutic avenue to ameliorate the Huntington like symptoms. PMID:21237233

  8. Icariin, a major constituent from Epimedium brevicornum, attenuates ibotenic acid-induced excitotoxicity in rat hippocampus.

    PubMed

    Zong, Nan; Li, Fei; Deng, Yuanyuan; Shi, Jingshan; Jin, Feng; Gong, Qihai

    2016-10-15

    Excitotoxicity is one of the most extensively studied causes of neuronal death and plays an important role in Alzheimer's disease (AD). Icariin is a flavonoid component of a traditional Chinese medicine reported to possess a broad spectrum of pharmacological effects. The present study was designed to investigate the effects of icariin against learning and memory impairment induced by excitotoxicity. Here, we demonstrated that rats receiving intracerebroventricular injection of excitatory neurotoxin ibotenic acid exhibited impaired learning and memory. Oral administration of icariin at doses of 20 and 40mg/kg rescued behavioral performance and protected against neurotoxicity in rat hippocampus by suppressing ibotenic acid induced pro-apoptosis. Furthermore, Western blott of hippocampal specimens revealed that icariin up-regulated the expression of calbindin-D28k protein following ibotenic acid administration. Additionally, icariin inhibited mitogen-activated protein kinase (MAPK) family phosphorylation and nuclear factor kappa B (NF-κB) signaling, implicating the MAPK signaling and NF-κB signaling pathways were involved in the mechanism underlying icariin-mediated neuroprotection against ibotenic acid-induced excitotoxicity. These data suggested that icariin could be a potential agent for treatment of excitotoxicity-related diseases, including AD.

  9. Salicylic acid induces mitochondrial injury by inhibiting ferrochelatase heme biosynthesis activity.

    PubMed

    Gupta, Vipul; Liu, Shujie; Ando, Hideki; Ishii, Ryohei; Tateno, Shumpei; Kaneko, Yuki; Yugami, Masato; Sakamoto, Satoshi; Yamaguchi, Yuki; Nureki, Osamu; Handa, Hiroshi

    2013-12-01

    Salicylic acid is a classic nonsteroidal anti-inflammatory drug. Although salicylic acid also induces mitochondrial injury, the mechanism of its antimitochondrial activity is not well understood. In this study, by using a one-step affinity purification scheme with salicylic acid-immobilized beads, ferrochelatase (FECH), a homodimeric enzyme involved in heme biosynthesis in mitochondria, was identified as a new molecular target of salicylic acid. Moreover, the cocrystal structure of the FECH-salicylic acid complex was determined. Structural and biochemical studies showed that salicylic acid binds to the dimer interface of FECH in two possible orientations and inhibits its enzymatic activity. Mutational analysis confirmed that Trp301 and Leu311, hydrophobic amino acid residues located at the dimer interface, are directly involved in salicylic acid binding. On a gel filtration column, salicylic acid caused a shift in the elution profile of FECH, indicating that its conformational change is induced by salicylic acid binding. In cultured human cells, salicylic acid treatment or FECH knockdown inhibited heme synthesis, whereas salicylic acid did not exert its inhibitory effect in FECH knockdown cells. Concordantly, salicylic acid treatment or FECH knockdown inhibited heme synthesis in zebrafish embryos. Strikingly, the salicylic acid-induced effect in zebrafish was partially rescued by FECH overexpression. Taken together, these findings illustrate that FECH is responsible for salicylic acid-induced inhibition of heme synthesis, which may contribute to its antimitochondrial and anti-inflammatory function. This study establishes a novel aspect of the complex pharmacological effects of salicylic acid.

  10. Bovine chromosomal regions affecting rheological traits in acid-induced skim milk gels.

    PubMed

    Glantz, M; Gustavsson, F; Bertelsen, H P; Stålhammar, H; Lindmark-Månsson, H; Paulsson, M; Bendixen, C; Gregersen, V R

    2015-02-01

    The production of fermented milk products has increased worldwide during the last decade and is expected to continue to increase during the coming decade. The quality of these products may be optimized through breeding practices; however, the relations between cow genetics and technological properties of acid milk gels are not fully known. Therefore, the aim of this study was to identify chromosomal regions affecting acid-induced coagulation properties and possible candidate genes. Skim milk samples from 377 Swedish Red cows were rheologically analyzed for acid-induced coagulation properties using low-amplitude oscillation measurements. The resulting traits, including gel strength, coagulation time, and yield stress, were used to conduct a genome-wide association study. Single nucleotide polymorphisms (SNP) were identified using the BovineHD SNPChip (Illumina Inc., San Diego, CA), resulting in almost 621,000 segregating markers. The genome was scanned for putative quantitative trait loci (QTL) regions, haplotypes based on highly associated SNP were inferred, and the additive genetic effects of haplotypes within each QTL region were analyzed using mixed models. A total of 8 genomic regions were identified, with large effects of the significant haplotype explaining between 4.8 and 9.8% of the phenotypic variance of the studied traits. One major QTL was identified to overlap between gel strength and yield stress, the QTL identified with the most significant SNP closest to the gene coding for κ-casein (CSN3). In addition, a chromosome-wide significant region affecting yield stress on BTA 11 was identified to be colocated with PAEP, coding for β-lactoglobulin. Furthermore, the coagulation properties of the genetic variants within the 2 genes were compared with the coagulation properties identified by the patterns of the haplotypes within the regions, and it was discovered that the haplotypes were more diverse and in one case slightly better at explaining the

  11. Valproic Acid-Induced Severe Acute Pancreatitis with Pseudocyst Formation: Report of a Case

    PubMed Central

    Khamrui, Sujan; Kataria, Mohnish; Biswas, Jayanta; Saha, Suman

    2015-01-01

    Valproic acid is the most widely used anti-epilep­tic drug in children, and it is probably the most frequent cause of drug-induced acute pancreatitis. Outcomes for patients with valproic acid-associated pancreatitis vary from full recovery after discontinuation of the drug to severe acute pancreatitis and death. Here, we present a case of valproic acid-induced severe acute pancreatitis with pseudocyst formation in a 10-year-old girl with cerebral palsy and generalized tonic-clonic seizure. There was no resolution of the pseudocyst after discontinuation of valproic acid. The patient became symptomatic with a progressive increase in the size of the pseudocyst. She was successfully treated with cystogastrostomy and was well at 12-month follow-up. PMID:26366333

  12. Effect of zinc sulphate on acetic acid-induced gastric ulceration in rats.

    PubMed

    Li, K M

    1990-09-01

    The effects of zinc sulphate on gastric ulcer healing rate and mucosal mucus content of acetic acid-induced ulceration in rats have been assessed. Daily treatment with zinc sulphate progressively accelerated ulcer healing in a dose-dependent manner with a significant increase observed on day 15 after ulcer induction in rats treated with 44 and 88 mg kg-1 zinc sulphate. A significant increase in gastric mucosal adherent mucus was also observed in those animals treated with 88 mg kg-1 zinc sulphate. The results suggest that a minimum treatment period of 15 days is needed for the zinc sulphate to be effective, and that zinc ions may promote gastric ulcer healing by enhancing mucus formation to prevent acid back-diffusion into the gastric mucosa.

  13. Proteomic investigation into betulinic acid-induced apoptosis of human cervical cancer HeLa cells.

    PubMed

    Xu, Tao; Pang, Qiuying; Zhou, Dong; Zhang, Aiqin; Luo, Shaman; Wang, Yang; Yan, Xiufeng

    2014-01-01

    Betulinic acid is a pentacyclic triterpenoid that exhibits anticancer functions in human cancer cells. This study provides evidence that betulinic acid is highly effective against the human cervical cancer cell line HeLa by inducing dose- and time-dependent apoptosis. The apoptotic process was further investigated using a proteomics approach to reveal protein expression changes in HeLa cells following betulinic acid treatment. Proteomic analysis revealed that there were six up- and thirty down-regulated proteins in betulinic acid-induced HeLa cells, and these proteins were then subjected to functional pathway analysis using multiple analysis software. UDP-glucose 6-dehydrogenase, 6-phosphogluconate dehydrogenase decarboxylating, chain A Horf6-a novel human peroxidase enzyme that involved in redox process, was found to be down-regulated during the apoptosis process of the oxidative stress response pathway. Consistent with our results at the protein level, an increase in intracellular reactive oxygen species was observed in betulinic acid-treated cells. The proteins glucose-regulated protein and cargo-selection protein TIP47, which are involved in the endoplasmic reticulum pathway, were up-regulated by betulinic acid treatment. Meanwhile, 14-3-3 family proteins, including 14-3-3β and 14-3-3ε, were down-regulated in response to betulinic acid treatment, which is consistent with the decrease in expression of the target genes 14-3-3β and 14-3-3ε. Furthermore, it was found that the antiapoptotic bcl-2 gene was down-regulated while the proapoptotic bax gene was up-regulated after betulinic acid treatment in HeLa cells. These results suggest that betulinic acid induces apoptosis of HeLa cells by triggering both the endoplasmic reticulum pathway and the ROS-mediated mitochondrial pathway.

  14. Neuroprotective effects of butterbur and rough aster against kainic Acid-induced oxidative stress in mice.

    PubMed

    Oh, Sang Hee; Sok, Dai-Eun; Kim, Mee Ree

    2005-01-01

    The separate and combined neuroprotective effects of rough aster (Aster scaber) and butterbur (Petasite japonicus) extracts against oxidative damage in the brain of mice challenged with kainic acid were examined by comparing behavioral changes and biochemical parameters of oxidative stress. Rough aster butanol extract (400 mg/kg) and/or butterbur butanol extract (150 or 400 mg/kg) were administered to male ICR mice, 6-8 weeks old, through a gavage for 4 days consecutively, and on day 4, kainic acid (50 mg/kg) was administered intraperitoneally. Compared with the vehicle-treated control, no significant changes in body and brain weight were observed in mice administered rough aster or butterbur butanol extract. Administration of kainic acid only, causing a lethality of approximately 54%, resulted in a significant decrease of total glutathione level and increase of thiobarbituric acid-reactive substances (TBARS) value in brain tissue. The administration of butterbur or rough aster extract (400 mg/kg) decreased the lethality (50%) of kainic acid to 25%, alleviated the behavioral signs of neurotoxicity, restored the cytosolic glutathione level of brain homogenate to approximately 80% (P < .05), and reduced kainic acid-induced increases in TBARS values. In contrast to no significant neuroprotection by butterbur extract at a low dose (150 mg/kg), the combination of rough aster extract and butterbur extract reduced the lethality to 12.5%. Moreover, the combination delayed the onset time of behavioral signs by twofold, and significantly preserved the level of cytosolic glutathione peroxidase and glutathione reductase activities. However, the other biochemical parameters were not altered significantly by the combination. Thus, the combination of two vegetable extracts significantly increased the neuroprotective action against kainic acid-induced neurotoxicity. Based on these findings, the combination of butterbur extract and rough aster extract contains a functional agent or

  15. Short Chain Fatty Acids Induce Pro-Inflammatory Cytokine Production Alone And In Combination With Toll-like Receptor Ligands

    PubMed Central

    Mirmonsef, Paria; Zariffard, M Reza; Gilbert, Douglas; Makinde, Hadijat; Landay, Alan L.; Spear, Greg T.

    2011-01-01

    Problem Short chain fatty acids (SCFAs), produced at relatively high levels by anaerobic bacteria in bacterial vaginosis (BV), are believed to be anti-inflammatory. BV, a common alteration of the genital microbiota associated with increased susceptibility to HIV infection, is characterized by increased levels of both pro-inflammatory cytokines and SCFAs. We investigated how SCFAs alone or together with TLR-ligands affected pro-inflammatory cytokine secretion. Method of study Cytokines were measured by ELISA. Flow was used for phenotyping and reactive oxygen species (ROS) measurement. Results SCFAs, at 20mM, induced IL-8, IL-6, and IL-1β release while lower levels (0.02–2mM) did not induce cytokine secretion. Levels >20mM were toxic to cells. Interestingly, lower levels of SCFAs significantly enhanced TLR2 ligand- and TLR7 ligand-induced production of IL-8 and TNFα in a time- and dose-dependent manner, but had little effect on LPS-induced cytokine release. SCFAs mediated their effects on pro-inflammatory cytokine production at least in part by inducing generation of reactive oxygen species. Conclusions Our data suggest that SCFAs, especially when combined with specific TLR ligands, contribute to a pro-inflammatory milieu in the lower genital tract and help further our understanding of how BV affects susceptibility to microbial infections. PMID:22059850

  16. Dose Dependent Activation of Retinoic Acid-Inducible Gene-I Promotes Both Proliferation and Apoptosis Signals in Human Head and Neck Squamous Cell Carcinoma

    PubMed Central

    Yan, Ming; Zhu, Chao; Ye, Weimin; Zhu, Hanguang; Chen, Wantao; Zhang, Chenping; Zhang, Zhiyuan

    2013-01-01

    The retinoic-acid-inducible gene (RIG)-like receptor (RLR) family proteins are major pathogen reorganization receptors (PRR) responsible for detection of viral RNA, which initiates antiviral response. Here, we evaluated the functional role of one RLR family member, RIG-I, in human head and neck squamous cell carcinoma (HNSCC). RIG-I is abundantly expressed both in poorly-differentiated primary cancer and lymph node metastasis, but not in normal adjacent tissues. Activation of RIG-I by transfection with low dose of 5′-triphosphate RNA (3p-RNA) induces low levels of interferon and proinflammatory cytokines and promotes NF-κB- and Akt-dependent cell proliferation, migration and invasion. In contrast, activation of RIG-I by a high dose of 3p-RNA induces robust mitochondria-derived apoptosis accompanied by decreased activation of Akt, which is independent of the interferon and TNFα receptor, but can be rescued by over-expression of constitutively active Akt. Furthermore, co-immunoprecipitation experiments indicate that the CARD domain of RIG-I is essential for inducing apoptosis by interacting with caspase-9. Together, our results reveal a dual role of RIG-I in HNSCC through regulating activation of Akt, in which RIG-I activation by low-dose viral dsRNA increases host cell surviral, whereas higher level of RIG-I activation leads to apopotosis. These findings highlight the therapeutic potential of dsRNA mediated RIG-I activation in the treatment of HNSCC. PMID:23484008

  17. DIBROMOACETIC ACID-INDUCED ELEVATIONS IN CIRCULATING ESTRADIOL: EFFECTS IN BOTH CYCLING AND OVARIECTOMIZED/STEROID-PRIMED FEMALE RATS

    EPA Science Inventory

    RTD-03-031
    Goldman, JM and Murr, AS. Dibromoacetic Acid-induced Elevations in Circulating Estradiol: Effects in Both Cycling and Ovariectomized/Steroid-primed Female Rats. Reproductive Toxicology (in press).

    Abstract

    Oral exposures to high concentrations of th...

  18. Gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancers by accelerating EGFR turnover.

    PubMed

    Nam, Boas; Rho, Jin Kyung; Shin, Dong-Myung; Son, Jaekyoung

    2016-10-01

    Gallic acid is a common botanic phenolic compound, which is present in plants and foods worldwide. Gallic acid is implicated in various biological processes such as cell growth and apoptosis. Indeed, gallic acid has been shown to induce apoptosis in many cancer types. However, the molecular mechanisms of gallic acid-induced apoptosis in cancer, particularly lung cancer, are still unclear. Here, we report that gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancer (NSCLC) cells, but not in EGFR-WT NSCLC cells. Treatment with gallic acid resulted in a significant reduction in proliferation and induction of apoptosis, only in EGFR-mutant NSCLC cells. Interestingly, treatment with gallic acid led to a robust decrease in EGFR levels, which is critical for NSCLC survival. Treatment with gallic acid had no significant effect on transcription, but induced EGFR turnover. Indeed, treatment with a proteasome inhibitor dramatically reversed gallic acid-induced EGFR downregulation. Moreover, treatment with gallic acid induced EGFR turnover leading to apoptosis in EGFR-TKI (tyrosine kinase inhibitor)-resistant cell lines, which are dependent on EGFR signaling for survival. Thus, these studies suggest that gallic acid can induce apoptosis in EGFR-dependent lung cancers that are dependent on EGFR for growth and survival via acceleration of EGFR turnover.

  19. Gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancers by accelerating EGFR turnover.

    PubMed

    Nam, Boas; Rho, Jin Kyung; Shin, Dong-Myung; Son, Jaekyoung

    2016-10-01

    Gallic acid is a common botanic phenolic compound, which is present in plants and foods worldwide. Gallic acid is implicated in various biological processes such as cell growth and apoptosis. Indeed, gallic acid has been shown to induce apoptosis in many cancer types. However, the molecular mechanisms of gallic acid-induced apoptosis in cancer, particularly lung cancer, are still unclear. Here, we report that gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancer (NSCLC) cells, but not in EGFR-WT NSCLC cells. Treatment with gallic acid resulted in a significant reduction in proliferation and induction of apoptosis, only in EGFR-mutant NSCLC cells. Interestingly, treatment with gallic acid led to a robust decrease in EGFR levels, which is critical for NSCLC survival. Treatment with gallic acid had no significant effect on transcription, but induced EGFR turnover. Indeed, treatment with a proteasome inhibitor dramatically reversed gallic acid-induced EGFR downregulation. Moreover, treatment with gallic acid induced EGFR turnover leading to apoptosis in EGFR-TKI (tyrosine kinase inhibitor)-resistant cell lines, which are dependent on EGFR signaling for survival. Thus, these studies suggest that gallic acid can induce apoptosis in EGFR-dependent lung cancers that are dependent on EGFR for growth and survival via acceleration of EGFR turnover. PMID:27597244

  20. DIBROMOACETIC ACID-INDUCED ELEVATIONS OF ESTRADIOL IN THE CYCLING AND OVARIECTOMOZED/ESTRADIOL-IMPLANTED FEMALE RAT

    EPA Science Inventory

    Goldman, JM and Murr, AS. Dibromoacetic Acid-induced Elevations of Estradiol in Both Cycling and Ovariectomized / Estradiol-implanted Female Rats

    ABSTRACT
    Haloacetic acids are one of the principal classes of disinfection by-products generated by the chlorination of mun...

  1. Phenylethanoids in the herb of Plantago lanceolata and inhibitory effect on arachidonic acid-induced mouse ear edema.

    PubMed

    Murai, M; Tamayama, Y; Nishibe, S

    1995-10-01

    The five phenylethanoids, acteoside (1), cistanoside F (2), lavandulifolioside (3), plantamajoside (4) and isoacteoside (5) were isolated from the herb of Plantago lanceolata L. (Plantaginaceae). Compounds 1, the major phenylethanoid in the herb of P. lanceolata L., and 4, the major phenylethanoid in the herb of P. asiatica L., showed inhibitory effects on arachidonic acid-induced mouse ear edema. PMID:7480214

  2. Phenylethanoids in the herb of Plantago lanceolata and inhibitory effect on arachidonic acid-induced mouse ear edema.

    PubMed

    Murai, M; Tamayama, Y; Nishibe, S

    1995-10-01

    The five phenylethanoids, acteoside (1), cistanoside F (2), lavandulifolioside (3), plantamajoside (4) and isoacteoside (5) were isolated from the herb of Plantago lanceolata L. (Plantaginaceae). Compounds 1, the major phenylethanoid in the herb of P. lanceolata L., and 4, the major phenylethanoid in the herb of P. asiatica L., showed inhibitory effects on arachidonic acid-induced mouse ear edema.

  3. Multiple copies of a bile acid-inducible gene in Eubacterium sp. strain VPI 12708.

    PubMed Central

    Gopal-Srivastava, R; Mallonee, D H; White, W B; Hylemon, P B

    1990-01-01

    Eubacterium sp. strain VPI 12708 is an anaerobic intestinal bacterium which possesses inducible bile acid 7-dehydroxylation activity. Several new polypeptides are produced in this strain following induction with cholic acid. Genes coding for two copies of a bile acid-inducible 27,000-dalton polypeptide (baiA1 and baiA2) have been previously cloned and sequenced. We now report on a gene coding for a third copy of this 27,000-dalton polypeptide (baiA3). The baiA3 gene has been cloned in lambda DASH on an 11.2-kilobase DNA fragment from a partial Sau3A digest of the Eubacterium DNA. DNA sequence analysis of the baiA3 gene revealed 100% homology with the baiA1 gene within the coding region of the 27,000-dalton polypeptides. The baiA2 gene shares 81% sequence identity with the other two genes at the nucleotide level. The flanking nucleotide sequences associated with the baiA1 and baiA3 genes are identical for 930 bases in the 5' direction from the initiation codon and for at least 325 bases in the 3' direction from the stop codon, including the putative promoter regions for the genes. An additional open reading frame (occupying from 621 to 648 bases, depending on the correct start codon) was found in the identical 5' regions associated with the baiA1 and baiA3 clones. The 5' sequence 930 bases upstream from the baiA1 and baiA3 genes was totally divergent. The baiA2 gene, which is part of a large bile acid-inducible operon, showed no homology with the other two genes either in the 5' or 3' direction from the polypeptide coding region, except for a 15-base-pair presumed ribosome-binding site in the 5' region. These studies strongly suggest that a gene duplication (baiA1 and baiA3) has occurred and is stably maintained in this bacterium. Images PMID:2376563

  4. Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells

    PubMed Central

    Cao, Weibiao

    2016-01-01

    Mechanisms of the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK) inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA. PMID:26901778

  5. Unsaturated fatty acids induce calcium influx into keratinocytes and cause abnormal differentiation of epidermis.

    PubMed

    Katsuta, Yuji; Iida, Toshii; Inomata, Shinji; Denda, Mitsuhiro

    2005-05-01

    Abnormal follicular keratinization is involved in comedogenesis in acne vulgaris. We recently demonstrated that calcium influx into epidermal keratinocytes is associated with impaired skin barrier function and epidermal proliferation. Based on these results, we hypothesized that sebum components affect calcium dynamics in the keratinocyte and consequently induce abnormal keratinization. To test this idea, we first observed the effects of topical application of sebum components, triglycerides (triolein), saturated fatty acids (palmitic acid and stearic acid), and unsaturated fatty acids (oleic acid and palmitoleic acid) on hairless mouse skin. Neither triglyceride nor saturated fatty acids affected the skin surface morphology or epidermal proliferation. On the other hand, application of unsaturated fatty acids, oleic acid, and palmitoleic acid induced scaly skin, abnormal keratinization, and epidermal hyperplasia. Application of triglycerides and saturated fatty acids on cultured human keratinocytes did not affect the intracellular calcium concentration ([Ca(2+)](i)), whereas unsaturated fatty acids increased the [Ca(2+)](i) of the keratinocytes. Moreover, application of oleic acid on hairless mouse skin induced an abnormal calcium distribution in the epidermis. These results suggest that unsaturated fatty acids in sebum alter the calcium dynamics in epidermal keratinocytes and induce abnormal follicular keratinization.

  6. Primary and secondary genetic responses after folic acid-induced acute renal injury in the mouse.

    PubMed

    Calvet, J P; Chadwick, L J

    1994-12-01

    Folic acid-induced acute renal injury results in dramatic changes in gene expression. Among the genes affected by folic acid treatment are the primary response genes, c-fos and c-myc, which are thought to function to initiate cell cycle events. In this report, changes in the expression of three other genes in response to folic acid injury have been investigated: ornithine decarboxylase, epidermal growth factor (EGF), and sulfated glycoprotein-2 (SGP-2). Renal injury was found to cause a rapid decrease in EGF mRNA, which remained absent for several days after the initial injury, gradually returning to normal levels over an approximately 3-wk regeneration and recovery period. Ornithine decarboxylase mRNA showed a similar decrease. In contrast, folic acid caused a rapid increase in SGP-2 mRNA, which peaked several days after treatment, decreasing to normal levels over the 3-wk period. The mRNAs for the primary response genes were superinduced in the injured kidneys in the presence of the protein synthesis inhibitor cycloheximide. In contrast, the changes in EGF and SGP-2 mRNA levels were blocked by cycloheximide, indicating that these responses required new protein synthesis during the first few hours after folic acid injury. The opposite but parallel responses in the expression of the EGF and SGP-2 genes suggest that their regulation is coupled to the initial injury-induced dedifferentiation and subsequent return to the fully differentiated state.

  7. On the molecular mechanisms of the acid-induced dissociation of hydroxy-apatite in water.

    PubMed

    Hochrein, Oliver; Zahn, Dirk

    2011-06-01

    The enamel/saliva interface is mimicked by the comparably much simpler model of (001) surfaces of hydroxy-apatite ( Ca(10)(PO(4))(6)(OH)(2) ) in contact with aqueous solution. At neutral pH, the dissociation of ions is penalized by more than 150 kJ mol(-1) giving rise to very stable apatite-water interfaces. This picture changes drastically with decreasing pH, as the protonation of phosphate and hydroxide ions lowers the free energy of calcium ions dissociation. Our simulations suggest the mechanism of acid-induced apatite decomposition to i) require a considerable degree of protonation of the apatite surface. The first ion dissociation step ii) involves calcium ions which electrostatic binding has been locally destabilized through phosphate and hydroxide protonation. The depletion of calcium ions embedding the anions then allows iii) the dissociation of the anionic species. Along this line, the protective role of fluoride in caries prevention is related to the stabilization of the calcium triangles embedding the OH(-)/F(-) ions.

  8. PDIA3 Knockdown Exacerbates Free Fatty Acid-Induced Hepatocyte Steatosis and Apoptosis

    PubMed Central

    Yu, Chao-hui; Xu, Cheng-fu; Xu, Lei; Li, You-ming; Chen, Wei-xing

    2015-01-01

    Nonalcoholic fatty liver disease (NAFLD) has emerged as one of the most common chronic liver disease over the past decades. Endoplasmic reticulum stress (ERS) plays a pivotal role during the development of NAFLD. This study aims to analyze the potential role of protein disulfide isomerase A3 precursor (PDIA3), one of the ER chaperones, in free fatty acid-induced cell model of NAFLD. Human liver L02 cell line was treated with sodium palmitate for 24 hours, which developed severe intracellular lipid accumulation. The increased protein level of PDIA3 was detected via immunoblotting analysis in the fat loaded cell models of NAFLD. siRNA-mediated knockdown of PDIA3 in L02 cells not only increased the cellular lipid accumulation, but also exacerbated hepatocytes apoptosis induced by sodium palmitate. Further investigation revealed that knockdown of PDIA3 up-regulated protein expression of fatty acid synthase (FAS), a key enzyme involved in fatty acid synthesis. PDIA3 knockdown also up-regulated key molecules of ERS pathway, including glucose-regulated protein 78 (GRP78), phospho-PKR-like ER kinase (p-PERK), and C/EBP homologous protein (CHOP). Our results suggested that ER chaperone PDIA3 plays a pivotal role in FFA-induced hepatocyte steatosis and apoptosis. PMID:26214517

  9. Formic acid and acetic acid induce a programmed cell death in pathogenic Candida species.

    PubMed

    Lastauskienė, Eglė; Zinkevičienė, Auksė; Girkontaitė, Irutė; Kaunietis, Arnoldas; Kvedarienė, Violeta

    2014-09-01

    Cutaneous fungal infections are common and widespread. Antifungal agents used for the treatment of these infections often have undesirable side effects. Furthermore, increased resistance of the microorganisms to the antifungal drugs becomes the growing problem. Accordingly, the search for natural antifungal compounds continues to receive attention. Apoptosis is highly regulated programmed cell death. During yeast cell apoptosis, amino acids and peptides are released and can stimulate regeneration of human epithelium cells. Thus, detection of chemical compounds inducing apoptosis in yeast and nontoxic for humans is of great medical relevance. The aim of this study was to detect chemical compound inducing apoptosis in pathogenic Candida species with the lowest toxicity to the mammalian cells. Five chemical compounds--acetic acid, sodium bicarbonate, potassium carbonate, lithium acetate, and formic acid--were tested for evaluation of antifungal activity on C. albicans, C. guilliermondii, and C. lusitaniae. The results showed that acetic acid and formic acid at the lowest concentrations induced yeast cells death. Apoptosis analysis revealed that cells death was accompanied by activation of caspase. Minimal inhibitory concentrations of potassium carbonate and sodium bicarbonate induced Candida cells necrosis. Toxicity test with mammalian cell cultures showed that formic acid has the lowest effect on the growth of Jurkat and NIH 3T3 cells. In conclusion, our results show that a low concentration of formic acid induces apoptosis-like programmed cell death in the Candida yeast and has a minimal effect on the survivability of mammalian cells, suggesting potential applications in the treatment of these infections. PMID:24752490

  10. Anacardic acid induces apoptosis-like cell death in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Muzaffar, Suhail; Bose, Chinchu; Banerji, Ashok; Nair, Bipin G; Chattoo, Bharat B

    2016-01-01

    Anacardic acid (6-pentadecylsalicylic acid), extracted from cashew nut shell liquid, is a natural phenolic lipid well known for its strong antibacterial, antioxidant, and anticancer activities. Its effect has been well studied in bacterial and mammalian systems but remains largely unexplored in fungi. The present study identifies antifungal, cytotoxic, and antioxidant activities of anacardic acid in the rice blast fungus Magnaporthe oryzae. It was found that anacardic acid causes inhibition of conidial germination and mycelial growth in this ascomycetous fungus. Phosphatidylserine externalization, chromatin condensation, DNA degradation, and loss of mitochondrial membrane potential suggest that growth inhibition of fungus is mainly caused by apoptosis-like cell death. Broad-spectrum caspase inhibitor Z-VAD-FMK treatment indicated that anacardic acid induces caspase-independent apoptosis in M. oryzae. Expression of a predicted ortholog of apoptosis-inducing factor (AIF) was upregulated during the process of apoptosis, suggesting the possibility of mitochondria dependent apoptosis via activation of apoptosis-inducing factor. Anacardic acid treatment leads to decrease in reactive oxygen species rather than increase in reactive oxygen species (ROS) accumulation normally observed during apoptosis, confirming the antioxidant properties of anacardic acid as suggested by earlier reports. Our study also shows that anacardic acid renders the fungus highly sensitive to DNA damaging agents like ethyl methanesulfonate (EMS). Treatment of rice leaves with anacardic acid prevents M. oryzae from infecting the plant without affecting the leaf, suggesting that anacardic acid can be an effective antifungal agent. PMID:26381667

  11. Ethanol promotes saturated fatty acid-induced hepatoxicity through endoplasmic reticulum (ER) stress response.

    PubMed

    Yi, Hong-Wei; Ma, Yu-Xiang; Wang, Xiao-Ning; Wang, Cui-Fen; Lu, Jian; Cao, Wei; Wu, Xu-Dong

    2015-04-01

    Serum palmitic acid (PA), a type of saturated fatty acid, causes lipid accumulation and induces toxicity in hepatocytes. Ethanol (EtOH) is metabolized by the liver and induces hepatic injury and inflammation. Herein, we analyzed the effects of EtOH on PA-induced lipotoxicity in the liver. Our results indicated that EtOH aggravated PA-induced apoptosis and lipid accumulation in primary rat hepatocytes in dose-dependent manner. EtOH intensified PA-caused endoplasmic reticulum (ER) stress response in vitro and in vivo, and the expressions of CHOP, ATF4, and XBP-1 in nucleus were significantly increased. EtOH also increased PA-caused cleaved caspase-3 in cytoplasm. In wild type and CHOP(-/-) mice treated with EtOH and high fat diet (HFD), EtOH worsened the HFD-induced liver injury and dyslipidemia, while CHOP knockout blocked toxic effects of EtOH and PA. Our study suggested that targeting UPR-signaling pathways is a promising, novel approach to reducing EtOH and saturated fatty acid-induced metabolic complications.

  12. Saturated phosphatidic acids mediate saturated fatty acid-induced vascular calcification and lipotoxicity.

    PubMed

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M; Kuro-O, Makoto; Miyazaki, Makoto

    2015-12-01

    Recent evidence indicates that saturated fatty acid-induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification. PMID:26517697

  13. Phosphoenolpyruvate carboxykinase is an acid-induced, chromosomally encoded virulence factor in Agrobacterium tumefaciens.

    PubMed

    Liu, Pu; Wood, Derek; Nester, Eugene W

    2005-09-01

    The pckA gene, encoding phosphoenolpyruvate carboxykinase, catalyzes the reversible decarboxylation and phosphorylation of oxaloacetate to form phosphoenolpyruvate. Located on the circular chromosome of Agrobacterium, this locus is adjacent to the loci chvG and chvI, encoding a two-component regulatory system that has been shown to be important in virulence. Using a reporter gene fusion, studies showed that the pckA gene is induced by acidic pH but not by acetosyringone. This acid induction is regulated by the chvG-chvI regulatory system, which controls acid-inducible genes. A pckA mutant had no demonstrable PckA enzyme activity and grew on AB minimal medium with glucose but did not grow on the same medium with succinate as the sole carbon source and was more inhibited in its growth than the wild-type strain by an acidic environment. A pckA mutant was highly attenuated in tumor-inducing ability on tobacco leaf disks and was severely attenuated in vir gene expression. Although vir gene induction was completely restored when a constitutive virG gene was introduced into the mutant strain, virulence was only partially restored. These results suggest that avirulence may be due to a combination of the inhibition of this mutant in the acidic plant wound environment and the poor induction of the vir genes. PMID:16109945

  14. Anti-osteoporosis activity of naringin in the retinoic acid-induced osteoporosis model.

    PubMed

    Wei, Min; Yang, Zhonglin; Li, Ping; Zhang, Yabo; Sse, Wing Cho

    2007-01-01

    Isoflavonoids isolated from plants have been confirmed to fight osteoporosis and promote bone health. However, few studies have been conducted to describe the anti-osteoporosis activity of botanical flavonone. Based on the experimental outcomes, we demonstrated the ability of naringin to fight osteoporosis in vitro. We developed a retinoic acid-induced osteoporosis model of rats to assess whether naringin has similar bioactivity against osteoporosis in vitro. After a 14-day supplement of retinoic acid to induce osteoporosis, SD rats were administered naringin. A blood test showed that naringin-treated rats experienced significantly lower activity of serum alkaline phosphatase and had higher femur bone mineral density, compared to untreated rats. All three dosages of naringin improved the decrease in bone weight coefficient, the length and the diameter of the bone, the content of bone ash, calcium, and phosphorus content induced by retinoic acid. The data of histomorphological metrology of naringin groups showed no difference as compared to normal control rats. These outcomes suggest that naringin offer a potential in the management of osteoporosis in vitro. PMID:17708632

  15. SV40 enhancer activation during retinoic acid-induced differentiation of F9 embryonal carcinoma cells.

    PubMed Central

    Sleigh, M J; Lockett, T J

    1985-01-01

    The transient expression vector pSV2CAT, which carries the bacterial chloramphenicol acetyl transferase (CAT) gene under the control of the SV40 early promoter, was used to transfect the murine embryonal carcinoma cell line F9 at various times during the retinoic acid-induced differentiation of these cells. Expression of the CAT gene under SV40 promoter control was found to increase markedly on F9 cell differentiation, measured relative to expression from the thymidine kinase promoter in the same cells. A series of constructs was prepared to identify the features of the SV40 early promoter required for transcription in differentiated and undifferentiated cells, as well as the factors limiting transcription in each case. The increased transcription seen on F9 cell differentiation was not observed when cells were transfected with molecules lacking a functional enhancer. It appears that as embryonal carcinoma cells differentiate, increased SV40 transcription results from enhancer sequence activation. In both differentiated and undifferentiated cell types the level of transcription was found to be limited by the availability and/or activity of cellular factors necessary for enhancer function. Images Fig. 1. PMID:3004973

  16. Bile acid induced colonic irritation stimulates intracolonic nitric oxide release in humans.

    PubMed Central

    Casellas, F; Mourelle, M; Papo, M; Guarner, F; Antolin, M; Armengol, J R; Malagelada, J R

    1996-01-01

    AIM--To measure the intracolonic release of nitric oxide end products (nitrates plus nitrites) and eicosanoids in response to intraluminal irritation with deoxycholic acid (DCA). PATIENTS--Seven patients with irritable bowel syndrome. METHODS--The left colon was perfused with a solution with or without 3 mM deoxycholic acid. Aspirates were assayed for eicosanoids by specific radioimmuno-assay, and for nitrates plus nitrites by the Griess reaction. To confirm that stimulated colonic mucosa can produce nitric oxide (NO), ancillary studies were performed in vitro using samples of normal mucosa obtained from five surgically resected colons. Samples were incubated for 30 minutes in Kreb's solution, 3 mM DCA or DCA with 1 mM L-nitro-arginine-methyl-ester (L-NAME) to inhibit the NO synthase. Finally, NO synthase activity was measured in five samples of human colonic mucosa. RESULTS--Intracolonic release of nitrates plus nitrites was basally undetectable in six of seven patients. Bile acid considerably increased the release of prostaglandin E2 and nitrates plus nitrites (p < 0.01). By contrast, no increase in thromboxane and leukotriene was seen. In vitro mucosal incubation with DCA increased the production of NO synthase products, which was blocked by L-NAME. Activity of Ca+2 independent NO synthase was detectable in four of five samples of human colonic mucosa. CONCLUSION--The human colonic mucosa responds to bile acid induced irritation by a surge in NO generation via NO synthase. PMID:8707118

  17. A West Nile virus mutant with increased resistance to acid-induced inactivation.

    PubMed

    Martín-Acebes, Miguel A; Saiz, Juan-Carlos

    2011-04-01

    West Nile virus (WNV) is a mosquito-borne flavivirus responsible for epidemics of febrile illness, meningitis, encephalitis and flaccid paralysis. WNV gains entry into host cells through endocytosis. The acid pH inside endosomes triggers rapid conformational rearrangements of the flavivirus envelope (E) glycoprotein that result in fusion of the endosomal membrane with the virion envelope. Conformational rearrangements of the E glycoprotein can be induced by acid exposure in solution in the absence of target membranes, thus causing a loss of infectivity. Following a genetic approach to study this process, a WNV mutant with increased resistance to acid-induced inactivation was isolated and its complete genome was sequenced. A single amino acid substitution, T70I, in the E glycoprotein was found to be responsible for the increased acid resistance, which was linked to an increase in the sensitivity of infection to the chemical rise of endosomal pH, suggesting that the mutant required a more acid pH inside the endosomes for fusion. No alterations in viral infection kinetics, plaque size or induced mortality rates in mice of the mutant were noted. However, by means of virus competition assays, a reduction in viral fitness under standard culture conditions was observed for the mutant. These results provide new evidence of the adaptive flexibility to environmental factors--pH variation in this case--of WNV populations. Implications of the T70I replacement on the E glycoprotein structure-function relationship are discussed.

  18. Saturated phosphatidic acids mediate saturated fatty acid-induced vascular calcification and lipotoxicity.

    PubMed

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M; Kuro-O, Makoto; Miyazaki, Makoto

    2015-10-26

    Recent evidence indicates that saturated fatty acid-induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification.

  19. Folic acid induces salicylic acid-dependent immunity in Arabidopsis and enhances susceptibility to Alternaria brassicicola.

    PubMed

    Wittek, Finni; Kanawati, Basem; Wenig, Marion; Hoffmann, Thomas; Franz-Oberdorf, Katrin; Schwab, Wilfried; Schmitt-Kopplin, Philippe; Vlot, A Corina

    2015-08-01

    Folates are essential for one-carbon transfer reactions in all organisms and contribute, for example, to de novo DNA synthesis. Here, we detected the folate precursors 7,8-dihydropteroate (DHP) and 4-amino-4-deoxychorismate (ADC) in extracts from Arabidopsis thaliana plants by Fourier transform ion cyclotron resonance-mass spectrometry. The accumulation of DHP, but not ADC, was induced after infection of plants with Pseudomonas syringae delivering the effector protein AvrRpm1. Application of folic acid or the DHP precursor 7,8-dihydroneopterin (DHN) enhanced resistance in Arabidopsis to P. syringae and elevated the transcript accumulation of the salicylic acid (SA) marker gene pathogenesis-related1 in both the treated and systemic untreated leaves. DHN- and folic acid-induced systemic resistance was dependent on SA biosynthesis and signalling. Similar to SA, folic acid application locally enhanced Arabidopsis susceptibility to the necrotrophic fungus Alternaria brassicicola. Together, the data associate the folic acid pathway with innate immunity in Arabidopsis, simultaneously activating local and systemic SA-dependent resistance to P. syringae and suppressing local resistance to A. brassicicola.

  20. Inhibition of ascorbic acid-induced modifications in lens proteins by peptides.

    PubMed

    Argirova, Mariana; Argirov, Ognyan

    2003-03-01

    The effects of three dipeptides L-phenylalanyl-glybine, glycyl-L-phenylalanine,and aspartame (L-aspartyl-L-phenylalanine, methyl ester) as inhibitors of the ascorbic acid-induced modifications in lens proteins were studied. Their efficiency was compared to that of two known inhibitors--aminoguanidine and carnosine. The tested dipeptides diminished protein carbonyl content by 32-58% and most moderated the formation of chromophores, as measured by the absorbency at 325 nm of the glycated proteins. The appearance of non-tryptophan fluorescence (excitation 340 nm/emission 410 nm) was observed for proteins glycated with ascorbic acid. All of the dipeptides examined, as well as aminoguanidine, decreased this glycation-related fluorescence. The potential inhibitors prevented the intensive formation of very high molecular weight aggregates. A competitive mechanism of their inhibitory effect was proposed, based on the reactivity of individual substances toward ascorbic acid. These findings indicate that they have a potential for use as alternatives for aminoguanidine as an anti-glycation agent.

  1. Effect of galactose on acid induced molten globule state of Soybean Agglutinin: Biophysical approach

    NASA Astrophysics Data System (ADS)

    Alam, Parvez; Naseem, Farha; Abdelhameed, Ali Saber; Khan, Rizwan Hasan

    2015-11-01

    In the present study the formation of molten globule-like unfolding intermediate Soybean Agglutinin (SBA) in acidic pH range has been established with the help of acrylamide quenching, intrinsic fluorescence, ANS fluorescence measurement, far UV CD and dynamic light scattering measurement. A marked increase in ANS fluorescence was observed at pH 2.2. Ksv of acrylamide quenching was found to be higher at pH 2.2 than that of native SBA at pH 7. Far UV CD spectra of pH induced state suggest that SBA shows significant retention of secondary structure closure to native. Hydrodynamic radius of SBA at pH 2.2 was found be more as compared to native state and also in other pH induced states. Further we checked the effect of galactose on the molten globule state of SBA. This study suggests that SBA exist as molten globule at pH 2.2 and this study will help in acid induced molten globule state of other proteins.

  2. Evidence for genetic regulation of mRNA expression of the dosage-sensitive gene retinoic acid induced-1 (RAI1) in human brain

    PubMed Central

    Chen, Li; Tao, Yu; Song, Fan; Yuan, Xi; Wang, Jian; Saffen, David

    2016-01-01

    RAI1 (retinoic acid induced-1) is a dosage-sensitive gene that causes Smith-Magenis syndrome (SMS) when mutated or deleted and Potocki-Lupski Syndrome (PTLS) when duplicated, with psychiatric features commonly observed in both syndromes. How common genetic variants regulate this gene, however, is unknown. In this study, we found that RAI1 mRNA expression in Chinese prefrontal and temporal cortex correlate with genotypes of common single nucleotide polymorphisms (SNPs) located in the RAI1 5′-upstream region. Using genotype imputation, “R2-Δ2” analysis, and data from the RegulomeDB database, we identified SNPs rs4925102 and rs9907986 as possible regulatory variants, accounting for approximately 30–40% of the variance in RAI1 mRNA expression in both brain regions. Specifically, rs4925102 and rs9907986 are predicted to disrupt the binding of retinoic acid RXR-RAR receptors and the transcription factor DEAF1 (Deformed epidermal autoregulatory factor-1), respectively. Consistent with these predictions, we observed binding of RXRα and RARα to the predicted RAI1 target in chromatin immunoprecipitation assays. Retinoic acid is crucial for early development of the central neural system, and DEAF1 is associated with intellectual disability. The observation that a significant portion of RAI1 mRNA expression is genetically controlled raises the possibility that common RAI1 5′-region regulatory variants contribute more generally to psychiatric disorders. PMID:26743651

  3. Helicobacter pylori impedes acid-induced tightening of gastric epithelial junctions

    PubMed Central

    Marcus, Elizabeth A.; Vagin, Olga; Tokhtaeva, Elmira; Sachs, George

    2013-01-01

    Gastric infection by Helicobacter pylori is the most common cause of ulcer disease and gastric cancer. The mechanism of progression from gastritis and inflammation to ulcers and cancer in a fraction of those infected is not definitively known. Significant acidity is unique to the gastric environment and is required for ulcer development. The interplay between gastric acidity and H. pylori pathogenesis is important in progression to advanced disease. The aim of this study was to characterize the impact of acid on gastric epithelial integrity and cytokine release and how H. pylori infection alters these responses. Human gastric epithelial (HGE-20) cells were grown on porous inserts, and survival, barrier function, and cytokine release were studied at various apical pH levels in the presence and absence of H. pylori. With apical acidity, gastric epithelial cells demonstrate increased barrier function, as evidenced by increased transepithelial electrical resistance (TEER) and decreased paracellular permeability. This effect is reduced in the presence of wild-type, but not urease knockout, H. pylori. The epithelial inflammatory response is also modulated by acidity and H. pylori infection. Without H. pylori, epithelial IL-8 release decreases in acid, while IL-6 release increases. In the presence of H. pylori, acidic pH diminishes the magnitude of the previously reported increase in IL-8 and IL-6 release. H. pylori interferes with the gastric epithelial response to acid, contributing to altered barrier function and inflammatory response. H. pylori diminishes acid-induced tightening of cell junctions in a urease-dependent manner, suggesting that local pH elevation promotes barrier compromise and progression to mucosal damage. PMID:23989011

  4. Diets Rich in Saturated and Polyunsaturated Fatty Acids Induce Morphological Alterations in the Rat Ventral Prostate

    PubMed Central

    Furriel, Angélica; Campos-Silva, Pamella; Silva, Paola Cariello Guedes Picarote; Costa, Waldemar Silva; Sampaio, Francisco José Barcellos; Gregório, Bianca Martins

    2014-01-01

    Aim To evaluate the influence of dietary lipid quality on the body mass, carbohydrate metabolism and morphology of the rat ventral prostate. Materials and Methods Wistar rats were divided into four groups: SC (standard chow), HF-S (high-fat diet rich in saturated fatty acids), HF-P (high-fat diet rich in polyunsaturated fatty acids) and HF-SP (high-fat diet rich in saturated and polyunsaturated fatty acids). We analyzed body mass, fat mass deposits, plasma blood, insulin resistance and the ventral prostate structure. Results Groups that received high-fat diets were heavier and presented larger fat deposits than SC group. The HF-S and HF-SP groups had higher glucose, insulin and total cholesterol serum levels and insulin resistance compared with the SC. The acinar area, epithelium height and area density of the lumen were higher in the HF-SP than in the other groups. The epithelium area density and epithelial cell proliferation were greater in the HF-P and HF-SP than in the SC group. All of the groups that received high-fat diets had greater area density of the stroma, area density of smooth muscle cells and stromal cell proliferation compared with the SC group. Conclusion Diets rich in saturated and/or polyunsaturated fatty acids induced overweight. Independently of insulin resistance, polyunsaturated fatty acids increased prostate stromal and epithelial cell proliferation. Saturated fatty acids influenced only stromal cellular proliferation. These structural and morphometric alterations may be considered risk factors for the development of adverse remodeling process in the rat ventral prostate. PMID:25029463

  5. A dual inhibitor of cyclooxygenase and 5-lipoxygenase protects against kainic acid-induced brain injury.

    PubMed

    Minutoli, Letteria; Marini, Herbert; Rinaldi, Mariagrazia; Bitto, Alessandra; Irrera, Natasha; Pizzino, Gabriele; Pallio, Giovanni; Calò, Margherita; Adamo, Elena Bianca; Trichilo, Vincenzo; Interdonato, Monica; Galfo, Federica; Squadrito, Francesco; Altavilla, Domenica

    2015-06-01

    Systemic administration of kainic acid causes inflammation and apoptosis in the brain, resulting in neuronal loss. Dual cyclooxygenase/5-lipoxygenase (COX/5-LOX) inhibitors could represent a possible neuroprotective approach in preventing glutamate excitotoxicity. Consequently, we investigated the effects of a dual inhibitor of COX/5-LOX following intraperitoneal administration of kainic acid (KA, 10 mg/kg) in rats. Animals were randomized to receive either the dual inhibitor of COX/5-LOX (flavocoxid, 20 mg/kg i.p.) or its vehicle (1 ml/kg i.p.) 30 min after KA administration. Sham brain injury rats were used as controls. We evaluated protein expression of phosphorylated extracellular signal-regulated kinase (p-ERK1/2) and tumor necrosis factor alpha (TNF-α) as well as levels of malondialdehyde (MDA), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the hippocampus. Animals were also observed for monitoring behavioral changes according to Racine Scale. Finally, histological analysis and brain edema evaluation were carried out. Treatment with the dual inhibitor of COX/5-LOX decreased protein expression of p-ERK1/2 and TNF-α in hippocampus, markedly reduced MDA, LTB4 and PGE2 hippocampal levels, and also ameliorated brain edema. Histological analysis showed a reduction in cell damage in rats treated with the dual inhibitor of COX/5-LOX, particularly in hippocampal subregion CA3c. Moreover, flavocoxid significantly improved behavioral signs following kainic acid administration. Our results suggest that dual inhibition of COX/5-LOX by flavocoxid has neuroprotective effects during kainic acid-induced excitotoxicity. PMID:25893744

  6. Bile acid-induced necrosis in primary human hepatocytes and in patients with obstructive cholestasis

    SciTech Connect

    Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.; Clarke, Joanna I.; Gholami, Parviz; Li, Feng; Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson; Fan, Fang; Jenkins, Rosalind E.; Park, B. Kevin; Hagenbuch, Bruno; Olyaee, Mojtaba; Jaeschke, Hartmut

    2015-03-15

    Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with, or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box 1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models. - Highlights: • Cholestatic liver injury is due to cytoplasmic bile acid accumulation in hepatocytes. • Primary human hepatocytes are resistant to BA-induced injury

  7. Bile Acid-Induced Necrosis in Primary Human Hepatocytes and in Patients with Obstructive Cholestasis

    PubMed Central

    Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.; Clarke, Joanna I.; Gholami, Parviz; Li, Feng; Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson; Fan, Fang; Jenkins, Rosalind E.; Park, B. Kevin; Hagenbuch, Bruno; Olyaee, Mojtaba; Jaeschke, Hartmut

    2015-01-01

    Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with, or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models. PMID:25636263

  8. Role of ion transporters in the bile acid-induced esophageal injury.

    PubMed

    Laczkó, Dorottya; Rosztóczy, András; Birkás, Klaudia; Katona, Máté; Rakonczay, Zoltán; Tiszlavicz, László; Róka, Richárd; Wittmann, Tibor; Hegyi, Péter; Venglovecz, Viktória

    2016-07-01

    Barrett's esophagus (BE) is considered to be the most severe complication of gastro-esophageal reflux disease (GERD), in which the prolonged, repetitive episodes of combined acidic and biliary reflux result in the replacement of the squamous esophageal lining by columnar epithelium. Therefore, the acid-extruding mechanisms of esophageal epithelial cells (EECs) may play an important role in the defense. Our aim was to identify the presence of acid/base transporters on EECs and to investigate the effect of bile acids on their expressions and functions. Human EEC lines (CP-A and CP-D) were acutely exposed to bile acid cocktail (BAC) and the changes in intracellular pH (pHi) and Ca(2+) concentration ([Ca(2+)]i) were measured by microfluorometry. mRNA and protein expression of ion transporters was investigated by RT-PCR, Western blot, and immunohistochemistry. We have identified the presence of a Na(+)/H(+) exchanger (NHE), Na(+)/HCO3 (-) cotransporter (NBC), and a Cl(-)-dependent HCO3 (-) secretory mechanism in CP-A and CP-D cells. Acute administration of BAC stimulated HCO3 (-) secretion in both cell lines and the NHE activity in CP-D cells by an inositol triphosphate-dependent calcium release. Chronic administration of BAC to EECs increased the expression of ion transporters compared with nontreated cells. A similar expression pattern was observed in biopsy samples from BE compared with normal epithelium. We have shown that acute administration of bile acids differently alters ion transport mechanisms of EECs, whereas chronic exposure to bile acids increases the expression of acid/base transporters. We speculate that these adaptive processes of EECs represent an important mucosal defense against the bile acid-induced epithelial injury. PMID:27198194

  9. The influence of pretreatment with ghrelin on the development of acetic-acid-induced colitis in rats.

    PubMed

    Maduzia, D; Matuszyk, A; Ceranowicz, D; Warzecha, Z; Ceranowicz, P; Fyderek, K; Galazka, K; Dembinski, A

    2015-12-01

    Ghrelin has been primarily shown to exhibit protective and therapeutic effect in the gut. Pretreatment with ghrelin inhibits the development of acute pancreatitis and accelerates pancreatic recovery in the course of this disease. In the stomach, ghrelin reduces gastric mucosal damage induced by ethanol, stress or alendronate, as well as accelerates the healing of acetic acid-induced gastric and duodenal ulcer. The aim of present studies was to investigate the effect of pretreatment with ghrelin on the development of acetic acid-induced colitis. Studies have been performed on male Wistar rats. Animals were treated intraperitoneally with saline (control) or ghrelin (4, 8 or 16 nmol/kg/dose). Saline or ghrelin was given twice: 8 and 1 h before induction of colitis. Colitis was induced by a rectal enema with 1 ml of 4% solution of acetic acid and the severity of colitis was assessed 1 or 24 hours after induction of inflammation. Rectal administration of acetic acid induced colitis in all animals. Damage of colonic wall was seen at the macroscopic and microscopic level. This effect was accompanied by a reduction in colonic blood flow and mucosal DNA synthesis. Moreover, induction of colitis significantly increased mucosal concentration of pro-inflammatory interleukin-1β (IL-1β), activity of myeloperoxidase and concentration of malondialdehyde (MDA). Mucosal activity of superoxide dismutase (SOD) was reduced. Pretreatment with ghrelin reduced the area and grade of mucosal damage. This effect was accompanied by an improvement of blood flow, DNA synthesis and SOD activity in colonic mucosa. Moreover, ghrelin administration reduced mucosal concentration of IL-1β and MDA, as well as decreased mucosal activity of myeloperoxidase. Administration of ghrelin protects the large bowel against the development of the acetic acid-induced colitis and this effect seems to be related to the ghrelin-evoked anti-inflammatory and anti-oxidative effects.

  10. The influence of pretreatment with ghrelin on the development of acetic-acid-induced colitis in rats.

    PubMed

    Maduzia, D; Matuszyk, A; Ceranowicz, D; Warzecha, Z; Ceranowicz, P; Fyderek, K; Galazka, K; Dembinski, A

    2015-12-01

    Ghrelin has been primarily shown to exhibit protective and therapeutic effect in the gut. Pretreatment with ghrelin inhibits the development of acute pancreatitis and accelerates pancreatic recovery in the course of this disease. In the stomach, ghrelin reduces gastric mucosal damage induced by ethanol, stress or alendronate, as well as accelerates the healing of acetic acid-induced gastric and duodenal ulcer. The aim of present studies was to investigate the effect of pretreatment with ghrelin on the development of acetic acid-induced colitis. Studies have been performed on male Wistar rats. Animals were treated intraperitoneally with saline (control) or ghrelin (4, 8 or 16 nmol/kg/dose). Saline or ghrelin was given twice: 8 and 1 h before induction of colitis. Colitis was induced by a rectal enema with 1 ml of 4% solution of acetic acid and the severity of colitis was assessed 1 or 24 hours after induction of inflammation. Rectal administration of acetic acid induced colitis in all animals. Damage of colonic wall was seen at the macroscopic and microscopic level. This effect was accompanied by a reduction in colonic blood flow and mucosal DNA synthesis. Moreover, induction of colitis significantly increased mucosal concentration of pro-inflammatory interleukin-1β (IL-1β), activity of myeloperoxidase and concentration of malondialdehyde (MDA). Mucosal activity of superoxide dismutase (SOD) was reduced. Pretreatment with ghrelin reduced the area and grade of mucosal damage. This effect was accompanied by an improvement of blood flow, DNA synthesis and SOD activity in colonic mucosa. Moreover, ghrelin administration reduced mucosal concentration of IL-1β and MDA, as well as decreased mucosal activity of myeloperoxidase. Administration of ghrelin protects the large bowel against the development of the acetic acid-induced colitis and this effect seems to be related to the ghrelin-evoked anti-inflammatory and anti-oxidative effects. PMID:26769837

  11. Attenuation of proinflammatory cytokines and apoptotic process by verapamil and diltiazem against quinolinic acid induced Huntington like alterations in rats.

    PubMed

    Kalonia, Harikesh; Kumar, Puneet; Kumar, Anil

    2011-02-01

    Huntington disease is a neurodegenerative disease with complex pathophysiology. Recently, role of neuroinflammation and interplay between various other cellular cascades have been suggested to be involved in pathophysiology of Huntington disease. Involvement of calcium overload mediated oxidative damage and excitotoxicity have been suggested to play a central role in quinolinic acid induced Huntington like symptoms. The present study has been carried out to investigate the neuroprotective effect of calcium channel blockers (verapamil and diltiazem) against quinolinic acid induced dysfunction in motor, biochemical and neuroinflammatory signaling in rats. Intrastriatal quinolinic acid administration leads to significant motor [locomotor (72% reduction), rotarod (55% reduction), balance beam walk performance] dysfunction coupled with the marked oxidative damage and increased neuroinflammatory markers [TNF-α (140%), IL-6 (115%), caspase-3(75%)] levels in striatum as compared to the sham treatment. Verapamil (10 and 20mg/kg), diltiazem (10 and 20mg/kg) drug treatment for 21days resulted in a significant improvement in the motor function (improvement in locomotor activity, rotarod and balance beam walk performance). Further, verapamil (10 and 20mg/kg), diltiazem (10 and 20mg/kg) treatment significantly attenuated oxidative damage, level of proinflammatory mediators (TNF-α IL-6 and caspase-3) in quinolinic acid treated animals. Results of the present study demonstrate that protective effect of these calcium channel blockers (verapamil, diltiazem) might be due to their inhibitory action on different neuroinflammatory pathways against quinolinic acid induced Huntington disease like symptoms in rats. PMID:21112316

  12. Effect of CMC Molecular Weight on Acid-Induced Gelation of Heated WPI-CMC Soluble Complex.

    PubMed

    Huan, Yan; Zhang, Sha; Vardhanabhuti, Bongkosh

    2016-02-01

    Acid-induced gelation properties of heated whey protein isolate (WPI) and carboxymethylcellulose (CMC) soluble complex were investigated as a function of CMC molecular weight (270, 680, and 750 kDa) and concentrations (0% to 0.125%). Heated WPI-CMC soluble complex with 6% protein was made by heating biopolymers together at pH 7.0 and 85 °C for 30 min and diluted to 5% protein before acid-induced gelation. Acid-induced gel formed from heated WPI-CMC complexes exhibited increased hardness and decreased water holding capacity with increasing CMC concentrations but gel strength decreased at higher CMC content. The highest gel strength was observed with CMC 750 k at 0.05%. Gels with low CMC concentration showed homogenous microstructure which was independent of CMC molecular weight, while increasing CMC concentration led to microphase separation with higher CMC molecular weight showing more extensive phase separation. When heated WPI-CMC complexes were prepared at 9% protein the acid gels showed improved gel hardness and water holding capacity, which was supported by the more interconnected protein network with less porosity when compared to complexes heated at 6% protein. It is concluded that protein concentration and biopolymer ratio during complex formation are the major factors affecting gel properties while the effect of CMC molecular weight was less significant.

  13. Interactions between the Influenza A Virus RNA Polymerase Components and Retinoic Acid-Inducible Gene I

    PubMed Central

    Li, Weizhong; Chen, Hongjun; Sutton, Troy; Obadan, Adebimpe

    2014-01-01

    ABSTRACT The influenza A virus genome possesses eight negative-strand RNA segments in the form of viral ribonucleoprotein particles (vRNPs) in association with the three viral RNA polymerase subunits (PB2, PB1, and PA) and the nucleoprotein (NP). Through interactions with multiple host factors, the RNP subunits play vital roles in replication, host adaptation, interspecies transmission, and pathogenicity. In order to gain insight into the potential roles of RNP subunits in the modulation of the host's innate immune response, the interactions of each RNP subunit with retinoic acid-inducible gene I protein (RIG-I) from mammalian and avian species were investigated. Studies using coimmunoprecipitation (co-IP), bimolecular fluorescence complementation (BiFc), and colocalization using confocal microscopy provided direct evidence for the RNA-independent binding of PB2, PB1, and PA with RIG-I from various hosts (human, swine, mouse, and duck). In contrast, the binding of NP with RIG-I was found to be RNA dependent. Expression of the viral NS1 protein, which interacts with RIG-I, did not interfere with the association of RNA polymerase subunits with RIG-I. The association of each individual virus polymerase component with RIG-I failed to significantly affect the interferon (IFN) induction elicited by RIG-I and 5′ triphosphate (5′ppp) RNA in reporter assays, quantitative reverse transcription-PCR (RT-PCR), and IRF3 phosphorylation tests. Taken together, these findings indicate that viral RNA polymerase components PB2, PB1, and PA directly target RIG-I, but the exact biological significance of these interactions in the replication and pathogenicity of influenza A virus needs to be further clarified. IMPORTANCE RIG-I is an important RNA sensor to elicit the innate immune response in mammals and some bird species (such as duck) upon influenza A virus infection. Although the 5′-triphosphate double-stranded RNA (dsRNA) panhandle structure at the end of viral genome RNA is

  14. Involvement of ionotropic purinergic receptors in the histamine-induced enhancement of the cough reflex sensitivity in guinea pigs.

    PubMed

    Kamei, Junzo; Takahashi, Yoshiki

    2006-10-10

    We examined the effect of inhaled histamine on citric acid-induced coughs and clarified the role of ionotropic purinergic receptors in the resulting changes. Although the inhalation of 0.1 M citric acid by itself produced only a few coughs in guinea pigs, exposure to histamine, at concentrations of 0.3 to 1 mM, for 2 min concentration dependently increased the number of citric acid-induced coughs. This histamine-induced increase in the number of citric acid-induced coughs was dose dependently and significantly reduced when animals were pretreated with fexofenadine, a histamine H1 receptor antagonist. The histamine-induced increase in the number of citric acid-induced coughs was completely reduced when animals were co-pretreated with 2',3'-O-(2,4,6-trinitrophenyl) adenosine 5-triphosphate (TNP-ATP, 50 microM), a P2X receptor antagonist, and reactive blue 2, a P2Y receptor antagonist, for 2 min. Furthermore, the ATP-induced increase in the number of citric acid-induced coughs was dose dependently and significantly decreased when animals were pretreated with fexofenadine, at doses of 0.3, 1 and 3 mg/kg, p.o. These results suggest that histamine enhances the excitability of rapidly adapting receptors to tussive stimuli via modulation of ATP release in the airways. Furthermore, ATP might act not only on P2X receptors to directly activate rapidly adapting receptors, but also on P2Y receptors to increase histamine release, indirectly increasing the cough reflex sensitivity.

  15. Transient changes in the limbic histaminergic system after systemic kainic acid-induced seizures.

    PubMed

    Lintunen, Minnamaija; Sallmen, Tina; Karlstedt, Kaj; Panula, Pertti

    2005-10-01

    Increased brain histamine is reported to protect against convulsions. We used systemic kainic acid (KA) administration to study possible changes of the histaminergic system in rat brain in status epilepticus (SE). Robust increases in brain histamine concentrations and numbers of histamine-immunoreactive nerve fibers were detected in the piriform cortex (Pir) and amygdala after KA injection, suggesting a reactive increase, which is opposite to other published aminergic transmitter responses. These changes, lasting several weeks, might be coupled to a mechanism unrelated to the anticonvulsive function of histamine. Transient increases in mRNA expression of H(3) receptor isoforms with a full-length third intracellular loop, coupled to mitogen-activated protein kinase pathway, were detected first in the hippocampal CA3c area, followed by the Pir and amygdala and then the hippocampal CA1 area. These results suggest that histamine and H3 receptors, which also control the release of GABA and glutamate, might be involved in convulsive SE.

  16. Activation of the central histaminergic system mediates arachidonic-acid-induced cardiovascular effects.

    PubMed

    Altinbas, Burcin; Topuz, Bora Burak; İlhan, Tuncay; Yilmaz, Mustafa Sertac; Erdost, Hatice; Yalcin, Murat

    2014-08-01

    The aim of this study was to explain the involvement of the central histaminergic system in arachidonic acid (AA)-induced cardiovascular effects in normotensive rats using hemodynamic, immunohistochemistry, and microdialysis studies. Intracerebroventricularly (i.c.v.) administered AA (0.25, 0.5, and 1.0 μmol) induced dose- and time-dependent increases in mean arterial pressure and decreased heart rate in conscious normotensive Sprague-Dawley rats. Central injection of AA (0.5 μmol) also increased posterior hypothalamic extracellular histamine levels and produced strong COX-1 but not COX-2 immunoreactivity in the posterior hypothalamus of rats. Moreover, the cardiovascular effects and COX-1 immunoreactivity in the posterior hypothalamus induced by AA (0.5 μmol; i.c.v.) were almost completely blocked by the H2 receptor antagonist ranitidine (50 and 100 nmol; i.c.v.) and partially blocked by the H1 receptor blocker chlorpheniramine (100 nmol; i.c.v.) and the H3-H4 receptor antagonist thioperamide (50 and 100 nmol; i.c.v.). In conclusion, these results indicate that centrally administered AA induces pressor and bradycardic responses in conscious rats. Moreover, we suggest that AA may activate histaminergic neurons and increase extracellular histamine levels, particularly in the posterior hypothalamus. Acting as a neurotransmitter, histamine is potentially involved in AA-induced cardiovascular effects under normotensive conditions.

  17. Muscovy duck retinoic acid-induced gene I (MdRIG-I) functions in innate immunity against H9N2 avian influenza viruses (AIV) infections.

    PubMed

    Cheng, Yuqiang; Huang, Qingqing; Ji, Wenhui; Du, Bin; Fu, Qiang; An, Huiting; Li, Jing; Wang, Hengan; Yan, Yaxian; Ding, Chan; Sun, Jianhe

    2015-02-15

    Retinoic acid inducible gene I (RIG-I) is a cytosolic pattern recognition receptor that senses pathogen-associated molecular patterns (PAMPs). Muscovy duck (Cairina moschata) is a large duck different from other species of ducks, and is more susceptible to some microbial pathogens. In this study, the Muscovy duck RIG-I gene (MdRIG-I) was identified. Quantitative RT-PCR showed that MdRIG-I mRNA was widely expressed in different tissues, especially in those with mucosa. RIG-I null DF-1 cells transfected with DNA constructs encoding MdRIG-I or CARDs domain can activate IRF-3 and NF-κB to up-regulated activity of IFN-β promoter. The components of the signaling pathway downstream of RIG-I in mammalian cells including IRF-3, NF-κB, IFN-β and the IFN-stimulated genes Mx-1, PKR and MDA5 were significantly up-regulated in CARDs-overexpressing-DF-1 cells. Implicating RIG-I in the antiviral response to an infection in vivo, we found that RIG-I expression in brain, spleen, lung and bursa were up-regulated in ducks challenged with H9N2 avian influenza virus (AIV), whose six internal genes were closely related to the H7N9 and H10N8 AIV. In vitro, DF-1 cells transfected with MdRIG-I plasmid can respond significantly to H9N2 AIV, evident through enhancement of IFN-β promoter activity and decreased virus titer. Altogether, these results indicated that MdRIG-I is a novel member of RLR gene family, engaging in the early stage of antiviral innate immunity.

  18. Identification of a retinoic acid-inducible gene I from Japanese eel (Anguilla japonica) and expression analysis in vivo and in vitro.

    PubMed

    Feng, Jianjun; Guo, Songlin; Lin, Peng; Wang, Yilei; Zhang, Ziping; Zhang, Zaipeng; Yu, Lili

    2016-08-01

    RIG-I (retinoic acid inducible gene-I) is one of the key cytosolic pattern recognition receptors (PRRs) for the recognition of cytosolic viral nucleic acids and the production of type I interferons (IFNs). The full-length cDNA sequence of RIG-I (AjRIG-I) in Japanese eel (Anguilla japonica) was identified and characterized in this article. The full-length cDNA of AjRIG-I was 3468 bp, including a 5'-untranslated region (UTR) of 52 bp, a 3'-UTR of 617 bp and an open reading frame (ORF) of 2799 bp encoding a polypeptide of 933 amino acid residues with a calculated molecular mass of 106.2 kDa. NCBI CDD analysis showed that the AjRIG-I protein had the typical conserved domains, including two adjacent caspase activation and recruitment domains (CARDs), a DEXDc domain, a HELICc domain and a C-terminal regulatory domain (RD). Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed a broad expression for AjRIG-I in a wide range of tissues, with the predominant expression in liver, followed by the gills, spleen, kidney, intestine, skin, and the very low expression in muscle and heart. The AjRIG-I expressions in liver, spleen and kidney were significantly induced following injection with LPS, the viral mimic poly I:C, and Aeromonas hydrophila infection. In vitro, the AjRIG-I transcripts of Japanese eel liver cells were significantly enhanced by poly I:C and PGN stimulation, down-regulated with CpG-DNA treatment whereas no change of the expression level was found post LPS challenge. These results collectively suggested AjRIG-I transcripts expression possibly play an important role in fish defense against viral and bacterial infection.

  19. Citric acid induces cell-cycle arrest and apoptosis of human immortalized keratinocyte cell line (HaCaT) via caspase- and mitochondrial-dependent signaling pathways.

    PubMed

    Ying, Tsung-Ho; Chen, Chia-Wei; Hsiao, Yu-Ping; Hung, Sung-Jen; Chung, Jing-Gung; Yang, Jen-Hung

    2013-10-01

    Citric acid is an alpha-hydroxyacid (AHA) widely used in cosmetic dermatology and skincare products. However, there is concern regarding its safety for the skin. In this study, we investigated the cytotoxic effects of citric acid on the human keratinocyte cell line HaCaT. HaCaT cells were treated with citric acid at 2.5-12.5 mM for different time periods. Cell-cycle arrest and apoptosis were investigated by 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining, flow cytometry, western blot and confocal microscopy. Citric acid not only inhibited proliferation of HaCaT cells in a dose-dependent manner, but also induced apoptosis and cell cycle-arrest at the G2/M phase (before 24 h) and S phase (after 24 h). Citric acid increased the level of Bcl-2-associated X protein (BAX) and reduced the levels of B-cell lymphoma-2 (BCL-2), B-cell lymphoma-extra large (BCL-XL) and activated caspase-9 and caspase-3, which subsequently induced apoptosis via caspase-dependent and caspase-independent pathways. Citric acid also activated death receptors and increased the levels of caspase-8, activated BH3 interacting-domain death agonist (BID) protein, Apoptosis-inducing factor (AIF), and Endonuclease G (EndoG). Therefore, citric acid induces apoptosis through the mitochondrial pathway in the human keratinocyte cell line HaCaT. The study results suggest that citric acid is cytotoxic to HaCaT cells via induction of apoptosis and cell-cycle arrest in vitro.

  20. Increased expression of retinoic acid-induced gene 1 in the dorsolateral prefrontal cortex in schizophrenia, bipolar disorder, and major depression

    PubMed Central

    Haybaeck, Johannes; Postruznik, Magdalena; Miller, Christine L; Dulay, Jeannette R; Llenos, Ida C; Weis, Serge

    2015-01-01

    Background Retinoids regulate gene expression in different cells and tissues at the transcriptional level. Retinoic acid transcriptionally regulates downstream regulatory molecules, including enzymes, transcription factors, cytokines, and cytokine receptors. Animal models indicate an involvement of retinoid signaling pathways in the regulation of synaptic plasticity and learning, especially in the hippocampus. Retinoic acid-inducible or induced gene 1 (RAI-1) is induced during neuronal differentiation, and was associated with the severity of the phenotype and response to medication in schizophrenic patients. Methods In the present study, we used immunohistochemistry to investigate the expression of RAI-1 in 60 brains from the Stanley Neuropathology Consortium (15 cases each from controls and from patients with schizophrenia, bipolar disorder, and major depression). Rating scores for density and intensity were determined in the dorsolateral prefrontal cortex. Results All four groups showed high interindividual variation. RAI-1-positive cells were identified as neurons and astrocytes. Significantly increased intensities in cortical neurons were noted in all three major psychiatric groups compared with controls. The density of RAI-1-positive neurons was increased (P=0.06) in schizophrenia and bipolar disorder. In bipolar disorder, RAI-1-positive astrocytes in gray matter showed a significantly increased intensity and compound value. Thus, a significant increase in the parameters measured was found in schizophrenia, bipolar disorder, and major depression. Conclusion Our study shows a significant increase in expression of RAI-1 in the brains from patients with schizophrenia, bipolar disorder, or major depression. The increased expression might reflect altered signaling pathways, like that for retinoic acid. The underlying mechanisms leading to the increased expression and its functional consequences are so far unknown, and remain to be investigated in future studies

  1. Identification of a retinoic acid-inducible gene I from Japanese eel (Anguilla japonica) and expression analysis in vivo and in vitro.

    PubMed

    Feng, Jianjun; Guo, Songlin; Lin, Peng; Wang, Yilei; Zhang, Ziping; Zhang, Zaipeng; Yu, Lili

    2016-08-01

    RIG-I (retinoic acid inducible gene-I) is one of the key cytosolic pattern recognition receptors (PRRs) for the recognition of cytosolic viral nucleic acids and the production of type I interferons (IFNs). The full-length cDNA sequence of RIG-I (AjRIG-I) in Japanese eel (Anguilla japonica) was identified and characterized in this article. The full-length cDNA of AjRIG-I was 3468 bp, including a 5'-untranslated region (UTR) of 52 bp, a 3'-UTR of 617 bp and an open reading frame (ORF) of 2799 bp encoding a polypeptide of 933 amino acid residues with a calculated molecular mass of 106.2 kDa. NCBI CDD analysis showed that the AjRIG-I protein had the typical conserved domains, including two adjacent caspase activation and recruitment domains (CARDs), a DEXDc domain, a HELICc domain and a C-terminal regulatory domain (RD). Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed a broad expression for AjRIG-I in a wide range of tissues, with the predominant expression in liver, followed by the gills, spleen, kidney, intestine, skin, and the very low expression in muscle and heart. The AjRIG-I expressions in liver, spleen and kidney were significantly induced following injection with LPS, the viral mimic poly I:C, and Aeromonas hydrophila infection. In vitro, the AjRIG-I transcripts of Japanese eel liver cells were significantly enhanced by poly I:C and PGN stimulation, down-regulated with CpG-DNA treatment whereas no change of the expression level was found post LPS challenge. These results collectively suggested AjRIG-I transcripts expression possibly play an important role in fish defense against viral and bacterial infection. PMID:27238428

  2. Acid-induced off-response of PKD2L1 channel in Xenopus oocytes and its regulation by Ca(2.).

    PubMed

    Hussein, Shaimaa; Zheng, Wang; Dyte, Chris; Wang, Qian; Yang, JungWoo; Zhang, Fan; Tang, Jingfeng; Cao, Ying; Chen, Xing-Zhen

    2015-01-01

    Polycystic kidney disease (PKD) protein 2 Like 1 (PKD2L1), also called transient receptor potential polycystin-3 (TRPP3), regulates Ca(2+)-dependent hedgehog signalling in primary cilia, intestinal development and sour tasting but with an unclear mechanism. PKD2L1 is a Ca(2+)-permeable cation channel that is activated by extracellular Ca(2+) (on-response) in Xenopus oocytes. PKD2L1 co-expressed with PKD protein 1 Like 3 (PKD1L3) exhibits extracellular acid-induced activation (off-response, i.e., activation following acid removal) but whether PKD1L3 participates in acid sensing remains unclear. Here we used the two-microelectrode voltage-clamp, site directed mutagenesis, Western blotting, reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence, and showed that PKD2L1 expressed in oocytes exhibits sustained off-response currents in the absence of PKD1L3. PKD1L3 co-expression augmented the PKD2L1 plasma membrane localization but did not alter the observed properties of the off-response. PKD2L1 off-response was inhibited by an increase in intracellular Ca(2+). We also identified two intra-membrane residues aspartic acid 349 (D349) and glutamic acid 356 (E356) in the third transmembrane domain that are critical for PKD2L1 channel function. Our study suggests that PKD2L1 may itself sense acids and defines off-response properties in the absence of PKD1L3. PMID:26502994

  3. Retinoic acid inducible gene-I and melanoma differentiation-associated gene 5 are induced but not essential for dengue virus induced type I interferon response.

    PubMed

    Qin, Cheng-Feng; Zhao, Hui; Liu, Zhong-Yu; Jiang, Tao; Deng, Yong-Qiang; Yu, Xu-Dong; Yu, Man; Qin, E-De

    2011-08-01

    Dengue viruses (DENVs) are important human pathogens that cause mild dengue fever, and severe dengue hemorrhagic fever/dengue shock syndrome, and no vaccine or antiviral therapy are currently available. At the initial stage of DENV infection, host pattern recognition receptors are responsible for sensing viral proteins or nucleic acids and initiating innate antiviral responses, including the activation of type I interferon (IFN) and proinflammatory cytokines. Two RNA helicases, retinoic acid inducible gene-I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5), are recently identified as cytoplasmic PPRs for virus infection. Here, in this study the involvement of RIG-I and MDA5 in DENV-induced IFN-β response A549 cells were investigated. DENV infection readily up-regulated RIG-I expression, activated IRF-3 and RIG-I mRNA transcription, and induced the production of IFN-β in A549 cells in a strain- and serotype-independent manner. While gene silencing of RIG-I by small interfering RNAs failed to significantly inhibit IFN-β production induced by DENV infection. Further experiments demonstrated that MDA5 was also induced by DENV infection, and MDA5 knockout did not block DENV induced IFN-β production in A549 cells. Our results demonstrated that both RIG-I and MDA5 were induced but neither of the two was essential for DENV induced IFN IFN-β response in A549 cells. These findings suggest that innate immune pathway are involved in the recognition of DENV by human non-immune cells, and provide insights for the understanding of the molecular mechanism for DENV-induced antiviral response.

  4. Genetic parameters for rennet- and acid-induced coagulation properties in milk from Swedish Red dairy cows.

    PubMed

    Gustavsson, F; Glantz, M; Poulsen, N A; Wadsö, L; Stålhammar, H; Andrén, A; Lindmark Månsson, H; Larsen, L B; Paulsson, M; Fikse, W F

    2014-01-01

    Milk coagulation is an important processing trait, being the basis for production of both cheese and fermented products. There is interest in including technological properties of these products in the breeding goal for dairy cattle. The aim of the present study was therefore to estimate genetic parameters for milk coagulation properties, including both rennet- and acid-induced coagulation, in Swedish Red dairy cattle using genomic relationships. Morning milk samples and blood samples were collected from 395 Swedish Red cows that were selected to be as genetically unrelated as possible. Using a rheometer, milk samples were analyzed for rennet- and acid-induced coagulation properties, including gel strength (G'), coagulation time, and yield stress (YS). In addition to the technological traits, milk composition was analyzed. A binary trait was created to reflect that milk samples that had not coagulated 40min after rennet addition were considered noncoagulating milk. The cows were genotyped by using the Illumina BovineHD BeadChip (Illumina Inc., San Diego, CA). Almost 600,000 markers remained after quality control and were used to construct a matrix of genomic relationships among the cows. Multivariate models including fixed effects of herd, lactation stage, and parity were fitted using the ASReml software to obtain estimates of heritabilities and genetic and phenotypic correlations. Heritability estimates (h(2)) for G' and YS in rennet and acid gels were found to be high (h(2)=0.38-0.62) and the genetic correlations between rennet-induced and acid-induced coagulation properties were weak but favorable, with the exception of YSrennet with G'acid and YSacid, both of which were strong. The high heritability (h(2)=0.45) for milk coagulating ability expressed as a binary trait suggests that noncoagulation could be eliminated through breeding. Additionally, the results indicated that the current breeding objective could increase the frequency of noncoagulating milk and

  5. Lysophosphatidic acid induces chemotaxis in MC3T3-E1 osteoblastic cells

    SciTech Connect

    Masiello, Lisa M.; Fotos, Joseph S.; Galileo, Deni S.; Karin, Norm J.

    2006-07-01

    Lysophosphatidic acid (LPA) is a bioactive lipid that has pleiotropic effects on a variety of cell types and enhances the migration of endothelial and cancer cells, but it is not known if this lipid can alter osteoblast motility. We performed transwell migration assays using MC3T3-E1 osteoblastic cells and found LPA to be a potent chemotactic agent. Quantitative time-lapse video analysis of osteoblast migration after wounds were introduced into cell monolayers indicated that LPA stimulated both migration velocity and the average migration distance per cell. LPA also elicited substantial changes in cell shape and actin cytoskeletal structure; lipid-treated cells contained fewer stress fibers and displayed long membrane processes that were enriched in F-actin. Quantitative RT-PCR analysis showed that MC3T3-E1 cells express all four known LPA-specific G protein-coupled receptors (LPA1-LPA4) with a relative mRNA abundance of LPA1 > LPA4 > LPA2 >> LPA3. LPA-induced changes in osteoblast motility and morphology were antagonized by both pertussis toxin and Ki16425, a subtype-specific blocker of LPA1 and LPA3 receptor function. Cell migration in many cell types is linked to changes in intracellular Ca2+. Ki16425 also inhibited LPA-induced Ca2+ signaling in a dose-dependent manner, suggesting a link between LPA-induced Ca2+ transients and osteoblast chemotaxis. Our data show that LPA stimulates MC3T3-E1 osteoblast motility via a mechanism that is linked primarily to the G protein-coupled receptor LPA1.

  6. Retinoic acid induces nuclear accumulation of Raf1 during differentiation of HL-60 cells

    SciTech Connect

    Smith, James; Bunaciu, Rodica P.; Reiterer, Gudrun; Coder, David; George, Thaddeus; Asaly, Michael; Yen, Andrew

    2009-08-01

    All trans-retinoic acid (RA) is a standard therapeutic agent used in differentiation induction therapy treatment of acute promyelocytic leukemia (APL). RA and its metabolites use a diverse set of signal transduction pathways during the differentiation program. In addition to the direct transcriptional targets of the nuclear RAR and RXR receptors, signals derived from membrane receptors and the Raf-MEK-ERK pathway are required. Raf1 phosphorylation and the prolonged activation of Raf1 persisting during the entire differentiation process are required for RA-dependent differentiation of HL-60 cells. Here we identify a nuclear redistribution of Raf1 during the RA-induced differentiation of HL-60 cells. In addition, the nuclear accumulation of Raf1 correlates with an increase in Raf1 phosphorylated at serine 621. The serine 621 phosphorylated Raf1 is predominantly localized in the nucleus. The RA-dependent nuclear accumulation of Raf1 suggests a novel nuclear role for Raf1 during the differentiation process.

  7. Mitochondrial genome depletion in human liver cells abolishes bile acid-induced apoptosis: role of the Akt/mTOR survival pathway and Bcl-2 family proteins.

    PubMed

    Marin, Jose J G; Hernandez, Alicia; Revuelta, Isabel E; Gonzalez-Sanchez, Ester; Gonzalez-Buitrago, Jose M; Perez, Maria J

    2013-08-01

    Acute accumulation of bile acids in hepatocytes may cause cell death. However, during long-term exposure due to prolonged cholestasis, hepatocytes may develop a certain degree of chemoresistance to these compounds. Because mitochondrial adaptation to persistent oxidative stress may be involved in this process, here we have investigated the effects of complete mitochondrial genome depletion on the response to bile acid-induced hepatocellular injury. A subline (Rho) of human hepatoma SK-Hep-1 cells totally depleted of mitochondrial DNA (mtDNA) was obtained, and bile acid-induced concentration-dependent activation of apoptosis/necrosis and survival signaling pathways was studied. In the absence of changes in intracellular ATP content, Rho cells were highly resistant to bile acid-induced apoptosis and partially resistant to bile acid-induced necrosis. In Rho cells, both basal and bile acid-induced generation of reactive oxygen species (ROS), such as hydrogen peroxide and superoxide anion, was decreased. Bile acid-induced proapoptotic signals were also decreased, as evidenced by a reduction in the expression ratios Bax-α/Bcl-2, Bcl-xS/Bcl-2, and Bcl-xS/Bcl-xL. This was mainly due to a downregulation of Bax-α and Bcl-xS. Moreover, in these cells the Akt/mTOR pathway was constitutively activated in a ROS-independent manner and remained similarly activated in the presence of bile acid treatment. In contrast, ERK1/2 activation was constitutively reduced and was not activated by incubation with bile acids. In conclusion, these results suggest that impaired mitochondrial function associated with mtDNA alterations, which may occur in liver cells during prolonged cholestasis, may activate mechanisms of cell survival accounting for an enhanced resistance of hepatocytes to bile acid-induced apoptosis. PMID:23597504

  8. Nicotinic acid induces secretion of prostaglandin D2 in human macrophages: an in vitro model of the niacin flush.

    PubMed

    Meyers, C Daniel; Liu, Paul; Kamanna, Vaijinath S; Kashyap, Moti L

    2007-06-01

    Nicotinic acid is a safe, broad-spectrum lipid agent shown to prevent cardiovascular disease, yet its widespread use is limited by the prostaglandin D2 (PGD2) mediated niacin flush. Previous research suggests that nicotinic acid-induced PGD2 secretion is mediated by the skin, but the exact cell type remains unclear. We hypothesized that macrophages are a source of nicotinic acid-induced PGD2 secretion and performed a series of experiments to confirm this. Nicotinic acid (0.1-3 mM) induced PGD2 secretion in cultured human macrophages, but not monocytes or endothelial cells. The PGD2 secretion was dependent on the concentration of nicotinic acid and the time of exposure. Nicotinuric acid, but not nicotinamide, also induced PGD2 secretion. Pre-incubation of the cells with aspirin (100 microM) entirely prevented the nicotinic acid effects on PGD2 secretion. The PGD2 secreting effects of nicotinic acid were additive to the effects of the calcium ionophore A23187 (6 microM), but were independent of extra cellular calcium. These findings, combined with recent in vivo work, provide evidence that macrophages play a significant role in mediating the niacin flush and may lead to better strategies to eliminate this limiting side effect.

  9. Effects of tumour necrosis factor-alpha synthesis inhibitors on rat trinitrobenzene sulphonic acid-induced chronic colitis.

    PubMed

    Bobin-Dubigeon, C; Collin, X; Grimaud, N; Robert, J M; Le Baut, G; Petit, J Y

    2001-11-01

    The fact that tumour necrosis factor-alpha (TNF-alpha) is clearly involved in the pathogenesis of intestinal bowel disease, especially Crohn's disease, suggests that TNF-alpha synthesis inhibitors could be beneficial for treatment. The present study assessed the effect of chronic oral gavage of two in vitro TNF-alpha synthesis inhibitors, JM 34 maleate or [N-(4,6-dimethylpyridin-2-yl)-furane-2-carboxamide)] maleate and XC 21 or (N-betapicolyl-tetrafluorophtalimide), on colonic inflammation in trinitrobenzene sulphonic acid-induced colitis in rats. Rats received JM 34 maleate (100 mg/kg) and XC 21 (50 mg/kg) 1 h before colitis induction and then daily for 8 days by oral gavage. The colon was removed on day 8 and processed for clinical score, myeloperoxidase activity, and soluble TNF-alpha release. Treatment with XC 21, as well as dexamethasone and sulphasalazine, reduced colonic damage and decreased (except with dexamethasone) the incidence of diarrhoea. JM 34 maleate failed to improve the clinical signs of chronic colitis. After trinitrobenzene sulphonic acid-induced colitis, myeloperoxidase activity and TNF-alpha colonic mucosal production were substantially increased compared to the control (saline instillation). Both of these inflammatory indicators were then significantly decreased (P< or =0.05) after the four chronic treatments (JM 34 maleate, XC 21, sulphasalazine, and dexamethasone). XC 21 appeared to be as efficient as sulphasalazine in improving colonic inflammation. PMID:11716848

  10. Allicin alleviates inflammation of trinitrobenzenesulfonic acid-induced rats and suppresses P38 and JNK pathways in Caco-2 cells.

    PubMed

    Li, Chen; Lun, Weijian; Zhao, Xinmei; Lei, Shan; Guo, Yandong; Ma, Jiayi; Zhi, Fachao

    2015-01-01

    Background. Allicin has anti-inflammatory, antioxidative and proapoptotic properties. Aims. To evaluate the effects and investigate the mechanism of allicin on trinitrobenzenesulfonic acid-induced colitis, specifically with mesalazine or sulfasalazine. Methods. 80 rats were divided equally into 8 groups: control; trinitrobenzenesulfonic acid; allicin prevention; allicin; mesalazine; sulfasalazine; allicin + sulfasalazine, and mesalazine + allicin. Systemic and colonic inflammation parameters were analysed. In addition, protein and culture medium of Caco-2 cells treated with various concentrations of IL-1β or allicin were collected for investigation of IL-8, NF-κB p65 P38, ERK, and JNK. One-way ANOVA and Kruskal-Wallis H test were used for parametric and nonparametric tests, respectively. Results. Allicin reduced the body weight loss of trinitrobenzenesulfonic acid-induced rats, histological score, serum TNF-α and IL-1β levels, and colon IL-1β mRNA level and induced serum IL-4 level, particularly in combination with mesalazine. In addition, 1 ng/mL IL-1β stimulated the P38, ERK, and JNK pathways, whereas pretreatment with allicin depressed this phenomenon, except for the ERK pathway. Conclusions. The inflammation induced by trinitrobenzenesulfonic acid is mitigated significantly by allicin treatment, particularly combined with mesalazine. Allicin inhibits the P38 and JNK pathways and the expression of NF-κB which explained the potential anti-inflammatory mechanisms of allicin. PMID:25729217

  11. Retinoic acid induced growth arrest of human breast carcinoma cells requires protein kinase C alpha expression and activity.

    PubMed

    Cho, Y; Tighe, A P; Talmage, D A

    1997-09-01

    Retinoic acid inhibits proliferation of hormone-dependent, but not hormone-independent breast cancer cells. Retinoic acid-induced changes in cellular proliferation and differentiation are associated with disturbances in growth factor signaling and frequently with changes in protein kinase C expression. PKC delta, epsilon, and zeta are expressed in both hormone-dependent (T-47D) and hormone-independent (MDA-MB-231) cell lines. Retinoic acid arrested T-47D proliferation, induced PKC alpha expression and concomitantly repressed PKC zeta expression. The changes in PKC alpha and PKC zeta reflect retinoic acid-induced changes in mRNA. In contrast, retinoic acid had no effect on growth, or PKC expression in MDA-MB-231 cells. Growth arrest and the induction of PKC alpha, but not the reduction in PKC zeta, resulted from selective activation of RAR alpha. In total, these results support an important role for PKC alpha in mediating the anti-proliferative action of retinoids on human breast carcinoma cells.

  12. Protective effect of Agave americana Linn. leaf extract in acetic acid-induced ulcerative colitis in rats

    PubMed Central

    Mannasaheb, Basheerahmed A.A.; Kulkarni, Preeti V.; Sangreskopp, Mashood Ahmed; Savant, Chetan; Mohan, Anjana

    2015-01-01

    Introduction: Natural plants always provide core compounds for new drug development. In the present life and food style, inflammatory bowel disease has become common and needs a lead compound for its drug development. Aim: To evaluate the effect of Agave americana Linn. leaf extract in acetic acid-induced ulcerative colitis in rats based on its traditional anti-inflammatory use. Materials and Methods: Male Wistar rats were pretreated with A. americana leaf extract in the dose of 200 and 400 mg/kg p.o. daily for 7 days. On 8th day, 2 ml of 4% v/v acetic acid in saline was instilled into rats’ rectum. Prednisolone was used as standard drug and it was administered on the day of acetic acid instillation and continued for 3 days. Extract treatment was continued till 11th day. Body weight, ulcer score, colonic muscle contraction, antioxidant activity and histopathology were studied. Statistical analysis was performed using Parametric one-way analysis of variance followed by Tukey's posttest. Results: A. americana have retained total body weight significantly (P < 0.01) and decreased colon weight/length ratio. Extract have shown a significant decrease (P < 0.001) in ulcer scores, myeloperoxidase, lipid peroxidase activity. Further, extract have shown significant improvement in colonic muscle contraction, histopathology of colon etc., which is comparable with standard drug. Conclusion: A. americana possess protective effect against acetic acid-induced colitis in rats. PMID:26730148

  13. Modeling and analysis of retinoic acid induced differentiation of uncommitted precursor cells.

    PubMed

    Tasseff, Ryan; Nayak, Satyaprakash; Song, Sang Ok; Yen, Andrew; Varner, Jeffrey D

    2011-05-01

    Manipulation of differentiation programs has therapeutic potential in a spectrum of human cancers and neurodegenerative disorders. In this study, we integrated computational and experimental methods to unravel the response of a lineage uncommitted precursor cell-line, HL-60, to Retinoic Acid (RA). HL-60 is a human myeloblastic leukemia cell-line used extensively to study human differentiation programs. Initially, we focused on the role of the BLR1 receptor in RA-induced differentiation and G1/0-arrest in HL-60. BLR1, a putative G protein-coupled receptor expressed following RA exposure, is required for RA-induced cell-cycle arrest and differentiation and causes persistent MAPK signaling. A mathematical model of RA-induced cell-cycle arrest and differentiation was formulated and tested against BLR1 wild-type (wt) knock-out and knock-in HL-60 cell-lines with and without RA. The current model described the dynamics of 729 proteins and protein complexes interconnected by 1356 interactions. An ensemble strategy was used to compensate for uncertain model parameters. The ensemble of HL-60 models recapitulated the positive feedback between BLR1 and MAPK signaling. The ensemble of models also correctly predicted Rb and p47phox regulation and the correlation between p21-CDK4-cyclin D formation and G1/0-arrest following exposure to RA. Finally, we investigated the robustness of the HL-60 network architecture to structural perturbations and generated experimentally testable hypotheses for future study. Taken together, the model presented here was a first step toward a systematic framework for analysis of programmed differentiation. These studies also demonstrated that mechanistic network modeling can help prioritize experimental directions by generating falsifiable hypotheses despite uncertainty.

  14. Effects of L-carnitine pretreatment in methamphetamine and 3-nitropropionic acid-induced neurotoxicity.

    PubMed

    Binienda, Zbigniew K; Przybyla, Beata D; Robinson, Bonnie L; Salem, Nadia; Virmani, Ashraf; Amato, Antonino; Ali, Syed F

    2006-08-01

    Adult, male Sprague-Dawley rats were injected with 3-ni-tropropionic acid (3-NPA) at 30 mg/kg or methamphetamine (METH) at 20 mg/kg alone or following pretreatment with L-cartnitine (LC) at 100 mg/kg. Rectal temperature was measured before and 4 h following treatment. Animals were sacrificed at 4 h posttreatment. Monoamine neurotransmitters, dopamine (DA) and serotonin (5-HT), and their metabolites were analyzed in the striatum using high-performance liquid chromatography method coupled with electrochemical detection (HPLC/ED). Transcripts of several genes related to DA metabolism were quantified using real time reverse transciption polymerase chain reaction (RT-PCR). Core temperature decreased significantly after 3-NPA acid and increased in METH-treated rats (P < 0.05). Temperature change at 4 h exhibited a significant LC effect for 3-NPA, preventing hypothermia (P < 0.05) and no effect for METH. Concentration of DA and 5-HT, and their metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA), increased significantly in 3-NPA and decreased in METH-treated rats. An increase in DOPAC/DA turnover and serotonin observed after 3-NPA was abolished in LC-/3-NPA-treated rats. In both 3-NPA- and METH-treated rats, LC prevented an increase in DA receptor D(1) gene expression. It appears that carnitine effect preventing hypothermia after 3-NPA treatments may be related not only to its mitochondriotropic actions but also to inhibitory effect on the DA and 5-HT systems activated after the exposure to 3-NPA. The same effect observed at the transcriptional level, at least for the DA receptor D(1), may account for protection against METH toxicity.

  15. Mast cell mediators in citric acid-induced airway constriction of guinea pigs

    SciTech Connect

    Lin, C.-H.; Lai, Y.-L. . E-mail: tiger@ha.mc.ntu.edu.tw

    2005-08-15

    We demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. In this study, we further investigated the underlying mediator(s) for this type of airway constriction. At first, to examine effects caused by blocking agents, 67 young Hartley guinea pigs were divided into 7 groups: saline + CA; methysergide (serotonin receptor antagonist) + CA; MK-886 (leukotriene synthesis inhibitor) + CA; mepyramine (histamine H{sub 1} receptor antagonist) + CA; indomethacin (cyclooxygenase inhibitor) + CA; cromolyn sodium (mast cell stabilizer) + CA; and compound 48/80 (mast cell degranulating agent) + CA. Then, we tested whether leukotriene C{sub 4} (LTC{sub 4}) or histamine enhances CA-induced airway constriction in compound 48/80-pretreated guinea pigs. We measured dynamic respiratory compliance (Crs) and forced expiratory volume in 0.1 s (FEV{sub 0.1}) during either baseline or recovery period. In addition, we detected histamine level, an index of pulmonary mast cell degranulation, in bronchoalveolar lavage (BAL) samples. Citric acid aerosol inhalation caused decreases in Crs and FEV{sub 0.1}, indicating airway constriction in the control group. This airway constriction was significantly attenuated by MK-886, mepyramine, cromolyn sodium, and compound 48/80, but not by either methysergide or indomethacin. Both LTC{sub 4} and histamine infusion significantly increased the magnitude of CA-induced airway constriction in compound 48/80-pretreated guinea pigs. Citric acid inhalation caused significant increase in histamine level in the BAL sample, which was significantly suppressed by compound 48/80. These results suggest that leukotrienes and histamine originating from mast cells play an important role in CA inhalation-induced noncholinergic airway constriction.

  16. Mast cells in citric acid-induced cough of guinea pigs

    SciTech Connect

    Lai, Y.-L. . E-mail: tiger@ha.mc.ntu.edu.tw; Lin, T.-Y.

    2005-01-01

    It was demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. To investigate the role of mast cells in CA-induced cough, three experiments were carried out in this study. In the first experiment, 59 guinea pigs were employed and we used compound 48/80 to deplete mast cells, cromolyn sodium to stabilize mast cells, MK-886 to inhibit leukotriene synthesis, pyrilamine to antagonize histamine H{sub 1} receptor, methysergide to antagonize serotonin receptor, and indomethacin to inhibit cyclooxygenase. In the second experiment, 56 compound 48/80-pretreated animals were divided into two parts; the first one was used to test the role of exogenous leukotriene (LT) C{sub 4}, while the second one to test the role of exogenous histamine in CA-induced cough. Each animal with one of the above pretreatments was exposed sequentially to saline (baseline) and CA (0.6 M) aerosol, each for 3 min. Then, cough was recorded for 12 min using a barometric body plethysmograph. In the third experiment, the activation of mast cells upon CA inhalation was investigated by determining arterial plasma histamine concentration in 17 animals. Exposure to CA induced a marked increase in cough number. Compound 48/80, cromolyn sodium, MK-886 and pyrilamine, but not indomethacin or methysergide, significantly attenuated CA-induced cough. Injection of LTC{sub 4} or histamine caused a significant increase in CA-induced cough in compound 48/80-pretreated animals. In addition, CA inhalation caused significant increase in plasma histamine concentration, which was blocked by compound 48/80 pretreatment. These results suggest that mast cells play an important role in CA aerosol inhalation-induced cough via perhaps mediators LTs and histamine.

  17. Mechanisms of motility change on trinitrobenzenesulfonic Acid-induced colonic inflammation in mice.

    PubMed

    Cheon, Gab Jin; Cui, Yuan; Yeon, Dong-Soo; Kwon, Seong-Chun; Park, Byong-Gon

    2012-12-01

    Ulcerative colitis is an inflammatory bowel disease (IBD) characterized by recurrent episodes of colonic inflammation and tissue degeneration in human or animal models. The contractile force generated by the smooth muscle is significantly attenuated, resulting in altered motility leading to diarrhea or constipation in IBD. The aim of this study is to clarify the altered contractility of circular and longitudinal smooth muscle layers in proximal colon of trinitrobenzen sulfonic acid (TNBS)-induced colitis mouse. Colitis was induced by direct injection of TNBS (120 mg/kg, 50% ethanol) in proximal colon of ICR mouse using a 30 G needle anesthetized with ketamin (50 mg/kg), whereas animals in the control group were injected of 50% ethanol alone. In TNBS-induced colitis, the wall of the proximal colon is diffusely thickened with loss of haustration, and showed mucosal and mucular edema with inflammatory infiltration. The colonic inflammation is significantly induced the reduction of colonic contractile activity including spontaneous contractile activity, depolarization-induced contractility, and muscarinic acetylcholine receptor-mediated contractile response in circular muscle layer compared to the longitudinal muscle layer. The inward rectification of currents, especially, important to Ca(2+) and Na(+) influx-induced depolarization and contraction, was markedly reduced in the TNBS-induced colitis compared to the control. The muscarinic acetylcholine-mediated contractile responses were significantly attenuated in the circular and longitudinal smooth muscle strips induced by the reduction of membrane expression of canonical transient receptor potential (TRPC) channel isoforms from the proximal colon of the TNBS-induced colitis mouse than the control.

  18. Alleviating Effects of Bushen-Yizhi Formula on Ibotenic Acid-Induced Cholinergic Impairments in Rat

    PubMed Central

    Hou, Xue-Qin; Zhang, Lei; Yang, Cong; Rong, Cui-Ping; He, Wen-Qing; Zhang, Chun-Xia; Li, Shi; Su, Ru-Yu; Chang, Xiang; Qin, Ji-Huan; Chen, Yun-Bo

    2015-01-01

    Abstract This study explored the curative effect and underlying mechanisms of a traditional Chinese medicine compound prescription, Bushen-Yizhi formula (BSYZ), in ibotenic acid (IBO)-induced rats. Morris water maze and novel object recognition tests showed that BSYZ significantly improved spatial and object memory. Brain immunohistochemistry staining showed that BSYZ significantly up-regulated expression of choline acetyltransferase (ChAT) and nerve growth factor (NGF) in the hippocampus and cortex. The protein tyrosine kinase high-affinity receptor TrkA was slightly increased in the hippocampus and cortex, and significantly enhanced in the nucleus basalis of Meynert (NBM) after BSYZ intervention. The immunoreactivity of the p75 low-affinity receptor in BSYZ-treated rats was significantly strengthened in the cortex. Similar expression trends of nerve growth factor (NGF), TrkA, and p75 mRNA were observed in the hippocampus and cortex. Additionally, BSYZ reversed IBO-induced disorders of acetylcholine (ACh) levels, ChAT, and cholinesterase (ChE) in the cortex, which was consistent with the changes in mRNA levels of ChAT and acetylcholinesterase (AChE). Expression of ChAT and AChE proteins and mRNA in the hippocampus was up-regulated, whereas the apoptosis-relative protein cleaved caspase-3 was decreased after administration of BSYZ. Moreover, changes in cell death were confirmed by histological morphology. Thus, the results indicated that the BSYZ formula could ameliorate memory impairments in IBO-induced rats, and it exerted its therapeutic action probably by modulating cholinergic pathways, NGF signaling, and anti-apoptosis. Overall, it is suggested that the BSYZ formula might be a potential therapeutic approach for the treatment of Alzheimer's disease (AD) and other cholinergic impairment-related diseases. PMID:25482164

  19. n-3 Fatty Acids Induce Neurogenesis of Predominantly POMC-Expressing Cells in the Hypothalamus.

    PubMed

    Nascimento, Lucas F R; Souza, Gabriela F P; Morari, Joseane; Barbosa, Guilherme O; Solon, Carina; Moura, Rodrigo F; Victório, Sheila C; Ignácio-Souza, Letícia M; Razolli, Daniela S; Carvalho, Hernandes F; Velloso, Lício A

    2016-03-01

    Apoptosis of hypothalamic neurons is believed to play an important role in the development and perpetuation of obesity. Similar to the hippocampus, the hypothalamus presents constitutive and stimulated neurogenesis, suggesting that obesity-associated hypothalamic dysfunction can be repaired. Here, we explored the hypothesis that n-3 polyunsaturated fatty acids (PUFAs) induce hypothalamic neurogenesis. Both in the diet and injected directly into the hypothalamus, PUFAs were capable of increasing hypothalamic neurogenesis to levels similar or superior to the effect of brain-derived neurotrophic factor (BDNF). Most of the neurogenic activity induced by PUFAs resulted in increased numbers of proopiomelanocortin but not NPY neurons and was accompanied by increased expression of BDNF and G-protein-coupled receptor 40 (GPR40). The inhibition of GPR40 was capable of reducing the neurogenic effect of a PUFA, while the inhibition of BDNF resulted in the reduction of global hypothalamic cell. Thus, PUFAs emerge as a potential dietary approach to correct obesity-associated hypothalamic neuronal loss.

  20. Embryonic Gut Anomalies in a Mouse Model of Retinoic Acid-Induced Caudal Regression Syndrome

    PubMed Central

    Pitera, Jolanta E.; Smith, Virpi V.; Woolf, Adrian S.; Milla, Peter J.

    2001-01-01

    Vitamin A and its derivatives such as retinoic acid (RA) are important signaling molecules for morphogenesis of vertebrate embryos. Little is known, however, about morphogenetic factors controlling the development of the gastrointestinal tract and RA is likely to be involved. In the mouse, teratogenic doses of RA cause truncation of the embryonic caudal body axis that parallel the caudal regression syndrome as described in humans. These changes are often associated with anomalies of the lower digestive tract. Overlapping spatiotemporal expression of retinoic acid receptor-β (RARβ) and cellular retinol-binding protein I, CRBPI, with Hoxb5 and c-ret in the gut mesoderm imply possible cooperation required for proper neuromuscular development. To determine susceptibility and responsiveness of the developing gut and its neuromusculature to exogenous retinoids we used a mouse model of RA-induced caudal regression syndrome. The results showed that stage-specific RA treatment both in vivo and in vitro affected gut looping/rotation morphogenesis and growth of asymmetrical structures such as the cecum together with delayed differentiation of the gut mesoderm and colonization of the postcecal gut by neural crest-derived enteric neuronal precursors. These observations demonstrate that RA has a direct effect on gut morphogenesis and innervation. PMID:11733381

  1. Necrostatin-1 protects against oleic acid-induced acute respiratory distress syndrome in rats.

    PubMed

    Pan, Long; Yao, Dun-Chen; Yu, Yu-Zhong; Li, Sheng-Jie; Chen, Bing-Jun; Hu, Gui-He; Xi, Chang; Wang, Zi-Hui; Wang, Hong-Yan; Li, Jian-Hua; Tu, Yong-Sheng

    2016-09-30

    Necroptosis is a recently discovered necrotic cell death which is regulated by receptor interacting protein kinase 1 (RIPK1) and RIPK3 under the stimulus of death signal and can be inhibited by necrostatin-1 (Nec-1) specifically. Therefore, the aim was to investigate the role of necroptosis in a rat model of acute respiratory distress syndrome (ARDS) induced by oleic acid (OA) and assess the effect of Nec-1 on lung injury in ARDS. Our results found that RIPK1, RIPK3 and mixed lineage kinase domain-like protein (MLKL) were abundantly expressed in rat lung tissues of OA-induced ARDS. Nec-1 pretreatment improved pulmonary function and attenuated lung edema dramatically in OA-induced ARDS rats. Furthermore, Nec-1 reduced RIPK1-RIPK3 interaction and down-regulated RIPK1-RIPK3-MLKL signal pathway, and inhibited inflammatory response by reducing neutrophil infiltration and protein leakage into lung tissue in OA-induced ARDS. Collectively, our study proves the intervention of necroptosis in OA-induced ARDS. Moreover, our findings imply that Nec-1 plays an important role in the treatment of ARDS via inhibiting necroptosis and inflammation. PMID:27586277

  2. Lysophosphatidic acid induces cell migration through the selective activation of Akt1

    PubMed Central

    Kim, Eun Kyoung; Yun, Sung Ji; Do, Kee Hun; Kim, Min Sung; Cho, Mong; Suh, Dong-Soo; Kim, Chi Dae; Kim, Jae Ho; Birnbaum, Morris J.

    2008-01-01

    Akt plays pivotal roles in many physiological responses including growth, proliferation, survival, metabolism, and migration. In the current studies, we have evaluated the isoform-specific role of akt in lysophosphatidic acid (LPA)-induced cell migration. Ascites from ovarian cancer patients (AOCP) induced mouse embryo fibroblast (MEF) cell migration in a dose-dependent manner. On the other hand, ascites from liver cirrhosis patients (ALCP) did not induce MEF cell migration. AOCP-induced MEF cell migration was completely blocked by pre-treatment of cells with LPA receptor antagonist, Ki16425. Both LPA- and AOCP-induced MEF cell migration was completely attenuated by PI3K inhibitor, LY294002. Furthermore, cells lacking Akt1 displayed defect in LPA-induced cell migration. Re-expression of Akt1 in DKO (Akt1-/-Akt2-/-) cells restored LPA-induced cell migration, whereas re-expression of Akt2 in DKO cells could not restore the LPA-induced cell migration. Finally, Akt1 was selectively phosphorylated by LPA and AOCP stimulation. These results suggest that LPA is a major factor responsible for AOCP-induced cell migration and signaling specificity of Akt1 may dictate LPA-induced cell migration. PMID:18779657

  3. Combinatorial localized dissolution analysis: Application to acid-induced dissolution of dental enamel and the effect of surface treatments.

    PubMed

    Parker, Alexander S; Al Botros, Rehab; Kinnear, Sophie L; Snowden, Michael E; McKelvey, Kim; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo; Philpotts, Carol; Unwin, Patrick R

    2016-08-15

    A combination of scanning electrochemical cell microscopy (SECCM) and atomic force microscopy (AFM) is used to quantitatively study the acid-induced dissolution of dental enamel. A micron-scale liquid meniscus formed at the end of a dual barrelled pipette, which constitutes the SECCM probe, is brought into contact with the enamel surface for a defined period. Dissolution occurs at the interface of the meniscus and the enamel surface, under conditions of well-defined mass transport, creating etch pits that are then analysed via AFM. This technique is applied to bovine dental enamel, and the effect of various treatments of the enamel surface on acid dissolution (1mM HNO3) is studied. The treatments investigated are zinc ions, fluoride ions and the two combined. A finite element method (FEM) simulation of SECCM mass transport and interfacial reactivity, allows the intrinsic rate constant for acid-induced dissolution to be quantitatively determined. The dissolution of enamel, in terms of Ca(2+) flux ( [Formula: see text] ), is first order with respect to the interfacial proton concentration and given by the following rate law: [Formula: see text] , with k0=0.099±0.008cms(-1). Treating the enamel with either fluoride or zinc ions slows the dissolution rate, although in this model system the partly protective barrier only extends around 10-20nm into the enamel surface, so that after a period of a few seconds dissolution of modified surfaces tends towards that of native enamel. A combination of both treatments exhibits the greatest protection to the enamel surface, but the effect is again transient.

  4. Combinatorial localized dissolution analysis: Application to acid-induced dissolution of dental enamel and the effect of surface treatments.

    PubMed

    Parker, Alexander S; Al Botros, Rehab; Kinnear, Sophie L; Snowden, Michael E; McKelvey, Kim; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo; Philpotts, Carol; Unwin, Patrick R

    2016-08-15

    A combination of scanning electrochemical cell microscopy (SECCM) and atomic force microscopy (AFM) is used to quantitatively study the acid-induced dissolution of dental enamel. A micron-scale liquid meniscus formed at the end of a dual barrelled pipette, which constitutes the SECCM probe, is brought into contact with the enamel surface for a defined period. Dissolution occurs at the interface of the meniscus and the enamel surface, under conditions of well-defined mass transport, creating etch pits that are then analysed via AFM. This technique is applied to bovine dental enamel, and the effect of various treatments of the enamel surface on acid dissolution (1mM HNO3) is studied. The treatments investigated are zinc ions, fluoride ions and the two combined. A finite element method (FEM) simulation of SECCM mass transport and interfacial reactivity, allows the intrinsic rate constant for acid-induced dissolution to be quantitatively determined. The dissolution of enamel, in terms of Ca(2+) flux ( [Formula: see text] ), is first order with respect to the interfacial proton concentration and given by the following rate law: [Formula: see text] , with k0=0.099±0.008cms(-1). Treating the enamel with either fluoride or zinc ions slows the dissolution rate, although in this model system the partly protective barrier only extends around 10-20nm into the enamel surface, so that after a period of a few seconds dissolution of modified surfaces tends towards that of native enamel. A combination of both treatments exhibits the greatest protection to the enamel surface, but the effect is again transient. PMID:27209395

  5. L-arginine augments the antioxidant effect of garlic against acetic acid-induced ulcerative colitis in rats.

    PubMed

    Harisa, Gamal Eldin I; Abo-Salem, Osama M; El-Sayed, El-Sayed M; Taha, Ehab I; El-Halawany, Nermin

    2009-10-01

    Garlic contains many sulfhydryl compounds that act as antioxidants. However, the role of nitric oxide (NO) in inflammation is controversial. The aim of the present study is to investigate the possible protective effect of garlic against acetic acid-induced ulcerative colitis in rats, as well as the probable modulatory effect of L-arginine (NO precursor) on garlic activity. Intra-rectal inoculation of rats with 4% acetic acid for 3 consecutive days caused a significant increase in the colon weight and marked decrease in the colon length. In addition, acetic acid induced a significant increase in serum levels of nitrate as well as colonic tissue content of malondialdehyde (MDA). Moreover, colonic tissue contents of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were markedly reduced. On the other hand, pre-treatment of rats with garlic (0.25 g/kgbwt, orally) for 4 consecutive weeks and 3 days during induction of colitis significantly reduced the increase in the colon weight induced by acetic acid and ameliorated alterations in oxidant and antioxidant parameters. Interestingly, oral co-administration of garlic (0.25 g/kgbwt) and L-arginine (625 mg/kgbwt) for the same period of garlic administration mitigated the changes in both colon weight and length induced by acetic acid and increased garlic effect on colon tissue contents of MDA and GSH. In conclusion, L-arginine can augment the protective effect of garlic against ulcerative colitis; an effect that might be mainly attributed to its NO donating property resulting in enhancement of garlic antioxidant effect. Further studies will be needed to determine which one of the active ingredients of garlic has the main antioxidant effect to be used with L-arginine. PMID:19783514

  6. Acid-induced molten globule state of a prion protein: crucial role of Strand 1-Helix 1-Strand 2 segment.

    PubMed

    Honda, Ryo P; Yamaguchi, Kei-ichi; Kuwata, Kazuo

    2014-10-31

    The conversion of a cellular prion protein (PrP(C)) to its pathogenic isoform (PrP(Sc)) is a critical event in the pathogenesis of prion diseases. Pathogenic conversion is usually associated with the oligomerization process; therefore, the conformational characteristics of the pre-oligomer state may provide insights into the conversion process. Previous studies indicate that PrP(C) is prone to oligomer formation at low pH, but the conformation of the pre-oligomer state remains unknown. In this study, we systematically analyzed the acid-induced conformational changes of PrP(C) and discovered a unique acid-induced molten globule state at pH 2.0 termed the "A-state." We characterized the structure of the A-state using far/near-UV CD, 1-anilino-8-naphthalene sulfonate fluorescence, size exclusion chromatography, and NMR. Deuterium exchange experiments with NMR detection revealed its first unique structure ever reported thus far; i.e. the Strand 1-Helix 1-Strand 2 segment at the N terminus was preferentially unfolded, whereas the Helix 2-Helix 3 segment at the C terminus remained marginally stable. This conformational change could be triggered by the protonation of Asp(144), Asp(147), and Glu(196), followed by disruption of key salt bridges in PrP(C). Moreover, the initial population of the A-state at low pH (pH 2.0-5.0) was well correlated with the rate of the β-rich oligomer formation, suggesting that the A-state is the pre-oligomer state. Thus, the specific conformation of the A-state would provide crucial insights into the mechanisms of oligomerization and further pathogenic conversion as well as facilitating the design of novel medical chaperones for treating prion diseases. PMID:25217639

  7. Neuroprotective effect of curcumin on okadaic acid induced memory impairment in mice.

    PubMed

    Rajasekar, N; Dwivedi, Subhash; Tota, Santosh Kumar; Kamat, Pradeep Kumar; Hanif, Kashif; Nath, Chandishwar; Shukla, Rakesh

    2013-09-01

    Okadaic acid (OKA) has been observed to cause memory impairment in human subjects having seafood contaminated with dinoflagellate (Helicondria okadai). OKA induces tau hyperphosphorylation and oxidative stress leading to memory impairment as our previous study has shown. Curcumin a natural antioxidant has demonstrated neuroprotection in various models of neurodegeneration. However, the effect of curcumin has not been explored in OKA induced memory impairment. Therefore, present study evaluated the effect of curcumin on OKA (100ng, intracerebrally) induced memory impairment in male Swiss albino mice as evaluated in Morris water maze (MWM) and passive avoidance tests (PAT). OKA administration resulted in memory impairment with a decreased cerebral blood flow (CBF) (measured by laser doppler flowmetry), ATP level and increased mitochondrial (Ca(2+))i, neuroinflammation (increased TNF-α, IL-1β, COX-2 and GFAP), oxidative-nitrosative stress, increased Caspase-9 and cholinergic dysfunction (decreased AChE activity/expression and α7 nicotinic acetylcholine receptor expression) in cerebral cortex and hippocampus of mice brain. Oral administration of curcumin (50mg/kg) for 13 days significantly improved memory function in both MWM and PAT along with brain energy metabolism, CBF and cholinergic function. It decreased mitochondrial (Ca(2+))i, and ameliorated neuroinflammation and oxidative-nitrostative stress in different brain regions of OKA treated mice. Curcumin also inhibited astrocyte activation as evidenced by decreased GFAP expression. This neuroprotective effect of curcumin is due to its potent anti-oxidant action thus confirming previous studies. Therefore, use of curcumin should be encouraged in people consuming sea food (contaminated with dinoflagellates) to prevent cognitive impairment.

  8. Effects of laropiprant on nicotinic acid-induced flushing in patients with dyslipidemia.

    PubMed

    Paolini, John F; Mitchel, Yale B; Reyes, Robert; Kher, Uma; Lai, Eseng; Watson, Douglas J; Norquist, Josephine M; Meehan, Alan G; Bays, Harold E; Davidson, Michael; Ballantyne, Christie M

    2008-03-01

    Niacin (nicotinic acid) is not optimally used mainly because of flushing, a process mediated primarily by prostaglandin D(2), which leads to poor patient compliance and suboptimal dosing. This phase II dose-ranging study was designed to assess whether the prostaglandin D(2) receptor 1 antagonist laropiprant (LRPT; MK-0524) would (1) reduce extended-release niacin (ERN)-induced flushing in dyslipidemic patients and (2) support a novel accelerated ERN dosing paradigm: initiating ERN at 1 g and advancing rapidly to 2 g. In part A of the study, 154 dyslipidemic patients were randomized to LRPT 150 mg/day or placebo in a 9-week, 2-period crossover study. Patients who completed part A (n = 122) entered part B (after a 2-week washout), together with additional patients who entered part B directly (n = 290). Part B patients were randomized to placebo, ERN 1 g (Niaspan, no previous titration), or ERN 1 g coadministered with LRPT 18.75, 37.5, 75, or 150 mg for 4 weeks, with doubling of the respective doses for the remaining 4 weeks. Patients treated with LRPT plus ERN experienced significantly less ERN-induced flushing than those treated with ERN alone during the initiation of treatment (ERN 1 g, week 1) and the maintenance treatment (ERN 1 to 2 g, weeks 2 to 8). All doses of LRPT were maximally effective in inhibiting niacin-induced flushing. LRPT did not alter the beneficial lipid effects of ERN. LRPT plus ERN was well tolerated. In conclusion, the significant reduction in ERN-induced flushing provided by LRPT plus ERN supports an accelerated ERN dose-advancement paradigm to achieve rapidly a 2-g dose in dyslipidemic patients. PMID:18308010

  9. Gallic Acid Induces Necroptosis via TNF–α Signaling Pathway in Activated Hepatic Stellate Cells

    PubMed Central

    Chang, Ya Ju; Hsu, Shih Lan; Liu, Yi Ting; Lin, Yu Hsuan; Lin, Ming Hui; Huang, Shu Jung; Ho, Ja-an Annie; Wu, Li-Chen

    2015-01-01

    Gallic acid (3, 4, 5-trihydroxybenzoic acid, GA), a natural phenolic acid widely found in gallnuts, tea leaves and various fruits, possesses several bioactivities against inflammation, oxidation, and carcinogenicity. The beneficial effect of GA on the reduction of animal hepatofibrosis has been indicated due to its antioxidative property. However, the cytotoxicity of GA autoxidation causing cell death has also been reported. Herein, we postulated that GA might target activated hepatic stellate cells (aHSCs), the cell type responsible for hepatofibrosis, to mitigate the process of fibrosis. The molecular cytotoxic mechanisms that GA exerted on aHSCs were then analyzed. The results indicated that GA elicited aHSC programmed cell death through TNF–α–mediated necroptosis. GA induced significant oxidative stress through the suppression of catalase activity and the depletion of glutathione (GSH). Elevated oxidative stress triggered the production of TNF–α facilitating the undergoing of necroptosis through the up-regulation of key necroptotic regulatory proteins TRADD and receptor-interacting protein 3 (RIP3), and the inactivation of caspase–8. Calmodulin and calpain–1 activation were engaged, which promoted subsequent lysosomal membrane permeabilization (LMP). The TNF–α antagonist (SPD–304) and the RIP1 inhibitor (necrostatin–1, Nec–1) confirmed GA-induced TNFR1–mediated necroptosis. The inhibition of RIP1 by Nec–1 diverted the cell death from necroptosis to apoptosis, as the activation of caspase 3 and the increase of cytochrome c. Collectively, this is the first report indicating that GA induces TNF signaling–triggered necroptosis in aHSCs, which may offer an alternative strategy for the amelioration of liver fibrosis. PMID:25816210

  10. Quinolinic acid induces disrupts cytoskeletal homeostasis in striatal neurons. Protective role of astrocyte-neuron interaction.

    PubMed

    Pierozan, Paula; Ferreira, Fernanda; de Lima, Bárbara Ortiz; Pessoa-Pureur, Regina

    2015-02-01

    Quinolinic acid (QUIN) is an endogenous metabolite of the kynurenine pathway involved in several neurological disorders. Among the several mechanisms involved in QUIN-mediated toxicity, disruption of the cytoskeleton has been demonstrated in striatally injected rats and in striatal slices. The present work searched for the actions of QUIN in primary striatal neurons. Neurons exposed to 10 µM QUIN presented hyperphosphorylated neurofilament (NF) subunits (NFL, NFM, and NFH). Hyperphosphorylation was abrogated in the presence of protein kinase A and protein kinase C inhibitors H89 (20 μM) and staurosporine (10 nM), respectively, as well as by specific antagonists to N-methyl-D-aspartate (50 µM DL-AP5) and metabotropic glutamate receptor 1 (100 µM MPEP). Also, intra- and extracellular Ca(2+) chelators (10 µM BAPTA-AM and 1 mM EGTA, respectively) and Ca(2+) influx through L-type voltage-dependent Ca(2+) channel (10 µM verapamil) are implicated in QUIN-mediated effects. Cells immunostained for the neuronal markers βIII-tubulin and microtubule-associated protein 2 showed altered neurite/neuron ratios and neurite outgrowth. NF hyperphosphorylation and morphological alterations were totally prevented by conditioned medium from QUIN-treated astrocytes. Cocultured astrocytes and neurons interacted with one another reciprocally, protecting them against QUIN injury. Cocultured cells preserved their cytoskeletal organization and cell morphology together with unaltered activity of the phosphorylating system associated with the cytoskeleton. This article describes cytoskeletal disruption as one of the most relevant actions of QUIN toxicity in striatal neurons in culture with soluble factors secreted by astrocytes, with neuron-astrocyte interaction playing a role in neuroprotection.

  11. The bisphosphonate alendronate improves the damage associated with trinitrobenzenesulfonic acid-induced colitis in rats

    PubMed Central

    Ballester, I; Daddaoua, A; López-Posadas, R; Nieto, A; Suárez, M D; Zarzuelo, A; Martínez-Augustin, O; de Medina, F Sánchez

    2007-01-01

    Background and purpose: The nitrogen-containing bisphosphonates are drugs used successfully in the treatment of osteoporosis. They act inhibiting farnesyl diphosphate synthase. This mechanism may also produce anti-inflammatory effects. The therapeutic activity of alendronate was tested in vivo using a model of inflammatory bowel disease. Experimental approach: The trinitrobenzenesulfonic acid model of colitis in the rat was used. Rats were treated orally with alendronate and its efficacy compared with that of oral sulphasalazine or vehicle, starting 2 h after colitis induction. The status of the animals was assessed 5 days later. Key results: Alendronate treatment (25 or 75 mg kg-1 day-1) resulted in a decrease in the colonic damage score and loss of body weight (at 25 mg kg-1 day-1 only). This was associated to a dramatic reduction in the mRNA levels of interleukin 1β (IL-1β), monocyte chemoattractant protein 1 (MCP-1) and interleukin 1 receptor antagonist (IL-1ra). The magnitude of the beneficial effect was comparable to that of sulphasalazine (at a 6-20 fold higher dose). Thus sulphasalazine post-treatment reduced the mRNA levels of IL-1β/IL-1ra and MCP-1 to the same extent as alendronate and additionally lowered colonic alkaline phosphatase activity, but failed to affect body weight loss or colonic damage score. Alendronate failed to exert beneficial effects when administered intraperitoneally. Conclusions and Implications: Oral but not intraperitoneal alendronate significantly protected the colon in experimental rat colitis. Inflammatory bowel disease patients might benefit from exposure to oral alendronate. PMID:17375077

  12. Gambogic acid induces apoptosis and inhibits colorectal tumor growth via mitochondrial pathways

    PubMed Central

    Huang, Guang-Ming; Sun, Yu; Ge, Xin; Wan, Xin; Li, Chun-Bo

    2015-01-01

    of pro-caspase-8, -9 and -3 were significantly decreased (P < 0.05 for all). Furthermore, GA significantly and dose-dependently inhibited the growth of HT-29 tumors in a mouse xenograft model (P < 0.05). CONCLUSION: GA inhibits HT-29 proliferation via induction of apoptosis. The anti-cancer effects are likely mediated by death receptor (extrinsic) and mitochondrial (intrinsic) pathways. PMID:26034354

  13. Global analysis of the acid-induced and urea-induced unfolding of staphylococcal nuclease and two of its variants.

    PubMed

    Ionescu, R M; Eftink, M R

    1997-02-01

    We have studied the equilibrium unfolding staphylococcal nuclease and two of its variants, V66W and V66W', over two perturbation axes (acid-induced unfolding as a function of urea concentration and urea-induced unfolding as a function of pH). The transitions were monitored by simultaneous measurements of circular dichroism and fluorescence. With this multidimensional array of data (2 perturbation axes and 2 signals), we present a strategy of performing a global analysis, over as many as 12 individual data sets, to test various models for the unfolding process, to determine with greater confidence the pertinent thermodynamic parameters, and to characterize unfolding intermediates. For example, wildtype nuclease shows a cooperative two-state transition with either urea or pH as denaturant, but the global fits are improved when the model is expanded to include a pH dependence of the urea m value or when two distinct classes of protonic groups are considered. The best fit for wild-type nuclease is with delta G degree 0,UN = 6.4 kcal/mol at pH 7, with the acid-induced unfolding being triggered by protonation of three to five carboxylate groups (with possible contribution from His121), and with the urea m = 2.5 kcal mol-1 M-1. V66W' lacks the last 13 amino acids on the C-terminus, has a tryptophan at position 66, has a predominantly beta-sheet structure, and is less stable than the wild type. For V66W', delta G degree 0,UN = 1.6 kcal/mol, m = 1.2 kcal mol-1 M-1, and there are two or three groups responsible for acid unfolding. V66W, a full-length mutant with two tryptophan residues, unfolds via a three-state mechanism: native reversible intermediate reversible unfolded. It appears that its beta-barrel subdomain retains structure in the intermediate state. Assuming that the unfolding of V66W' and the beta-barrel subdomain of V66W can be described by the same thermodynamic parameters, a global analysis enabled a description of the alpha subdomain of V66W with delta G

  14. Pregnane X receptor is a target of farnesoid X receptor.

    PubMed

    Jung, Diana; Mangelsdorf, David J; Meyer, Urs A

    2006-07-14

    The pregnane X receptor (PXR) is an essential component of the body's detoxification system. PXR is activated by a broad spectrum of xenobiotics and endobiotics, including bile acids and their precursors. Bile acids in high concentrations are toxic; therefore, their synthesis is tightly regulated by the farnesoid X receptor, and their catabolism involves several enzymes regulated by PXR. Here we demonstrate that the expression of PXR is regulated by farnesoid X receptor. Feeding mice with cholic acid or the synthetic farnesoid X receptor (FXR) agonist GW4064 resulted in a robust PXR induction. This effect was abolished in FXR knock-out mice. Long time bile acid treatment resulted in an increase of PXR target genes in wild type mice. A region containing four FXR binding sites (IR1) was identified in the mouse Pxr gene. This region was able to trigger an 8-fold induction after GW4064 treatment in transactivation studies. Deletion or mutation of single IR1 sites caused a weakened response. The importance of each individual IR1 element was assessed by cloning a triple or a single copy and was tested in transactivation studies. Two elements were able to trigger a strong response, one a moderate response, and one no response to GW4064 treatment. Mobility shift assays demonstrated that the two stronger responding elements were able to bind FXR protein. This result was confirmed by chromatin immunoprecipitation. These results strongly suggest that PXR is regulated by FXR. Bile acids activate FXR, which blocks synthesis of bile acids and also leads to the transcriptional activation of PXR, promoting breakdown of bile acids. The combination of the two mechanisms leads to an efficient protection of the liver against bile acid induced toxicity.

  15. Biocontrol agents-mediated suppression of oxalic acid induced cell death during Sclerotinia sclerotiorum-pea interaction.

    PubMed

    Jain, Akansha; Singh, Akanksha; Singh, Surendra; Sarma, Birinchi Kumar; Singh, Harikesh Bahadur

    2015-05-01

    Oxalic acid (OA) is an important pathogenic factor during early Sclerotinia sclerotiorum-host interaction and might work by reducing hydrogen peroxide production (H2 O2 ). In the present investigation, oxalic acid-induced cell death in pea was studied. Pea plants treated with biocontrol agents (BCAs) viz., Pseudomonas aeruginosa PJHU15, Bacillus subtilis BHHU100, and Trichoderma harzianum TNHU27 either singly and/or in consortium acted on S. sclerotiorum indirectly by enabling plants to inhibit the OA-mediated suppression of oxidative burst via induction of H2 O2 . Our results showed that BCA treated plants upon treatment with culture filtrate of the pathogen, conferred the resistance via. significantly decreasing relative cell death of pea against S. sclerotiorum compared to control plants without BCA treatment but treated with the culture filtrate of the pathogen. The results obtained from the present study indicate that the microbes especially in consortia play significant role in protection against S. sclerotiorum by modulating oxidative burst and partially enhancing tolerance by increasing the H2 O2 generation, which is otherwise suppressed by OA produced by the pathogen.

  16. Stearic acid induces proinflammatory cytokine production partly through activation of lactate-HIF1α pathway in chondrocytes.

    PubMed

    Miao, Hongming; Chen, Liang; Hao, Lijun; Zhang, Xuan; Chen, Yujuan; Ruan, Zhihua; Liang, Houjie

    2015-01-01

    The biomechanics stress and chronic inflammation in obesity are causally linked to osteoarthritis. However, the metabolic factors mediating obesity-related osteoarthritis are still obscure. Here we scanned and identified at least two elevated metabolites (stearic acid and lactate) from the plasma of diet-induced obese mice. We found that stearic acid potentiated LDH-a-dependent production of lactate, which further stabilized HIF1α protein and increased VEGF and proinflammatory cytokine expression in primary mouse chondrocytes. Treatment with LDH-a and HIF1α inhibitors notably attenuated stearic acid-or high fat diet-stimulated proinflammatory cytokine production in vitro and in vivo. Furthermore, positive correlation of plasma lactate, cartilage HIF1α and cytokine levels with the body mass index was observed in subjects with osteoarthritis. In conclusion, saturated free fatty acid induced proinflammatory cytokine production partly through activation of a novel lactate-HIF1α pathway in chondrocytes. Our findings hold promise of developing novel clinical strategies for the management of obesity-related diseases such as osteoarthritis.

  17. Possible protective role of pregnenolone-16 alpha-carbonitrile in lithocholic acid-induced hepatotoxicity through enhanced hepatic lipogenesis.

    PubMed

    Miyata, Masaaki; Nomoto, Masahiro; Sotodate, Fumiaki; Mizuki, Tomohiro; Hori, Wataru; Nagayasu, Miho; Yokokawa, Shinya; Ninomiya, Shin-ichi; Yamazoe, Yasushi

    2010-06-25

    Lithocholic acid (LCA) feeding causes both liver parenchymal and cholestatic damages in experimental animals. Although pregnenolone-16 alpha-carbonitrile (PCN)-mediated protection against LCA-induced hepatocyte injury may be explained by induction of drug metabolizing enzymes, the protection from the delayed cholestasis remains incompletely understood. Thus, the PCN-mediated protective mechanism has been studied from the point of modification of lipid metabolism. At an early stage of LCA feeding, an imbalance of biliary bile acid and phospholipid excretion was observed. Co-treatment with PCN reversed the increase in serum alanine aminotransferase (ALT) as well as alkaline phosphatase (ALP) activities and hepatic hydrophobic bile acid levels. LCA feeding decreased hepatic mRNA levels of several fatty acid- and phospholipid-related genes before elevation of serum ALT and ALP activities. On the other hand, PCN co-treatment reversed the decrease in the mRNA levels and hepatic levels of phospholipids, triglycerides and free fatty acids. PCN co-treatment also reversed the decrease in biliary phospholipid output in LCA-fed mice. Treatment with PCN alone increased hepatic phospholipid, triglyceride and free fatty acid concentrations. Hepatic fatty acid and phosphatidylcholine synthetic activities increased in mice treated with PCN alone or PCN and LCA, compared to control mice, whereas these activities decreased in LCA-fed mice. These results suggest the possibility that PCN-mediated stimulation of lipogenesis contributes to the protection from lithocholic acid-induced hepatotoxicity.

  18. Protective Effect of Cod (Gadus macrocephalus) Skin Collagen Peptides on Acetic Acid-Induced Gastric Ulcer in Rats.

    PubMed

    Niu, Huina; Wang, Zhicong; Hou, Hu; Zhang, Zhaohui; Li, Bafang

    2016-07-01

    This research was performed to explore the protective effect of cod skin collagen peptides (CCP) on gastric ulcer induced by acetic acid. The CCP were fractionated into low molecular CCP (LMCCP, Mw < 3 kDa) and high molecular CCP (HMCCP, Mw > 3 kDa). In HMCCP and LMCCP, glycine of accounted for about one-third of the total amino acids without cysteine and tryptophan, and hydrophobic amino acids accounted for about 50%. After 21 d CCP treatment (60 or 300 mg/kg, p.o./daily), the healing effects on acetic acid-induced gastric ulcers were evaluated by macroscopic measure, microscopic measure, and immune histochemistry. Moreover, the expression levels of the growth factors, such as vascular endothelial growth factor, epidermal growth factor, transforming growth factor β1 (TGFβ1), and the heat shock protein 70 (HSP70) was detected. The results showed that both LMCCP and HMCCP could significantly decrease the ulcer areas and promote the healing of the lesions. They also could improve the levels of hexosamine, glutathione, superoxide dismutase, and glutathione peroxidase, and reduce the content of malondialdehyde and inducible nitric oxide synthase. In addition, the expression level of TGFβ1 gene and HSP70 mRNA was significantly improved by the treatment. It suggested that CCP could be able to improve symptoms of gastric ulcer and probably be used in the treatment of gastric ulcer. PMID:27219644

  19. Phenylbutyric acid induces the cellular senescence through an Akt/p21{sup WAF1} signaling pathway

    SciTech Connect

    Kim, Hag Dong; Jang, Chang-Young; Choe, Jeong Min; Sohn, Jeongwon; Kim, Joon

    2012-06-01

    Highlights: Black-Right-Pointing-Pointer Phenylbutyric acid induces cellular senescence. Black-Right-Pointing-Pointer Phenylbutyric acid activates Akt kinase. Black-Right-Pointing-Pointer The knockdown of PERK also can induce cellular senescence. Black-Right-Pointing-Pointer Akt/p21{sup WAF1} pathway activates in PERK knockdown induced cellular senescence. -- Abstract: It has been well known that three sentinel proteins - PERK, ATF6 and IRE1 - initiate the unfolded protein response (UPR) in the presence of misfolded or unfolded proteins in the ER. Recent studies have demonstrated that upregulation of UPR in cancer cells is required to survive and proliferate. Here, we showed that long exposure to 4-phenylbutyric acid (PBA), a chemical chaperone that can reduce retention of unfolded and misfolded proteins in ER, induced cellular senescence in cancer cells such as MCF7 and HT1080. In addition, we found that treatment with PBA activates Akt, which results in p21{sup WAF1} induction. Interestingly, the depletion of PERK but not ATF6 and IRE1 also induces cellular senescence, which was rescued by additional depletion of Akt. This suggests that Akt pathway is downstream of PERK in PBA induced cellular senescence. Taken together, these results show that PBA induces cellular senescence via activation of the Akt/p21{sup WAF1} pathway by PERK inhibition.

  20. Neuroprotective effects of trans-caryophyllene against kainic acid induced seizure activity and oxidative stress in mice.

    PubMed

    Liu, Hao; Song, Zhi; Liao, Daguang; Zhang, Tianyi; Liu, Feng; Zhuang, Kai; Luo, Kui; Yang, Liang

    2015-01-01

    Trans-caryophyllene (TC), a component of essential oil found in many flowering plants, has shown its neuroprotective effects in various neurological disorders. However, the effects of TC on epilepsy haven't been reported before. In this study, we investigated the effect of TC on kainic acid-induced seizure activity caused by oxidative stress and pro-inflammation. We found that TC pretreatment significantly decreased seizure activity score compared to kainic acid treated group. Importantly, TC pretreatment leads to lowering the mortality in kainic acid treated mice. In addition, TC was found to significantly inhibit KA-induced generation of malondialdehyde. TC pretreatment also preserved the activity of GPx, SOD, and CAT. Notably, our data shows that an important property of TC is its capacity to exert cerebral anti-inflammatory effects by mitigating the expression of proinflammatory cytokines, such as TNF-α and IL-1β. These data suggest that TC has a potential protective effect on chemical induced seizure and brain damage. PMID:25417010

  1. Standardized Extract of Bacopa monniera Attenuates Okadaic Acid Induced Memory Dysfunction in Rats: Effect on Nrf2 Pathway

    PubMed Central

    Nagarajan, Rajasekar; Hanif, Kashif; Siddiqui, Hefazat Husain; Nath, Chandishwar

    2013-01-01

    The aim of the present study is to investigate the effect of standardized extract of Bacopa monnieri (memory enhancer) and Melatonin (an antioxidant) on nuclear factor erythroid 2 related factor 2 (Nrf2) pathway in Okadaic acid induced memory impaired rats. OKA (200 ng) was administered intracerebroventricularly (ICV) to induce memory impairment in rats. Bacopa monnieri (BM-40 and 80 mg/kg) and Melatonin (20 mg/kg) were administered 1 hr before OKA injection and continued daily up to day 13. Memory functions were assessed by Morris water maze test on days 13–15. Rats were sacrificed for biochemical estimations of oxidative stress, neuroinflammation, apoptosis, and molecular studies of Nrf2, HO1, and GCLC expressions in cerebral cortex and hippocampus brain regions. OKA caused a significant memory deficit with oxidative stress, neuroinflammation, and neuronal loss which was concomitant with attenuated expression of Nrf2, HO1, and GCLC. Treatment with BM and Melatonin significantly improved memory dysfunction in OKA rats as shown by decreased latency time and path length. The treatments also restored Nrf2, HO1, and GCLC expressions and decreased oxidative stress, neuroinflammation, and neuronal loss. Thus strengthening the endogenous defense through Nrf2 modulation plays a key role in the protective effect of BM and Melatonin in OKA induced memory impairment in rats. PMID:24078822

  2. Platelet-Rich Plasma in Treatment of Zoledronic Acid-Induced Bisphosphonate-related Osteonecrosis of the Jaws

    PubMed Central

    Sarkarat, Farzin; Kalantar Motamedi, Mohammad Hosein; Jahanbani, Jahanfar; Sepehri, Dena; Kahali, Roozbeh; Nematollahi, Zahra

    2014-01-01

    Background: Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a well-known challenging entity warranting management. Platelet-Rich Plasma (PRP) plays an important role in bone biology by enhancing bone repair and regeneration. Objectives: The aim of this animal study was to evaluate the effects of PRP on zoledronic acid-induced BRONJ. Materials and Methods: Seven rats were given 0.04 mg Zoledronic acid intravenously once a week for five weeks. Two weeks later, the animals underwent extraction of their first lower molars, bilaterally. After clinical confirmation of the osteonecrosis, PRP was injected randomly into one of the extraction sockets of each rat. Three weeks later, all rats were sacrificed in order to obtain histological sections. The analysis of epithelialization was performed by McNamar’s test, and the analysis of osteogenesis and angiogenesis was performed by the Wilcoxon Sign Rank test. P value was set at 0.05. Results: We found no significant differences between the two groups regarding the amount of epithelialization, angiogenesis or sequestrum formation (P > 0.05), but a significant difference was seen between the two groups regarding the amount of existing vital bone (P < 0.05). Conclusions: Our study demonstrates positive results (preservation or regeneration of bone) using PRP in treatment of BRONJ. Although PRP may enhance osseous regeneration, long-term follow-ups are required to confirm its benefits. PMID:25032151

  3. Isobolographic analysis of interaction between cyclooxygenase inhibitors and tramadol in acetic acid-induced writhing in mice.

    PubMed

    Satyanarayana, Padi S V; Jain, Naveen K; Singh, Amarjit; Kulkarni, Shrinivas K

    2004-07-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are the most commonly used analgesics in the management of acute and chronic pain. Combined use of NSAIDs and opioids has been indicated for achieving better analgesia with reduced side effects. The present study was aimed at evaluating the combination of different NSAIDs, which inhibit cyclooxygenase (COX) enzymes and tramadol against acetic acid-induced writhing in mice. The expected beneficial effect of combination regimen was analyzed by isobolographic analysis. The oral and intrathecally administered tramadol, a mu-opioid and naproxen, a nonselective COX inhibitor produced dose-dependent antinociception, however, rofecoxib, a selective COX-2 inhibitor lacked analgesic efficacy in writhing test. Isobolographic analysis showed synergistic or supra-additive interactions for the combinations of naproxen and tramadol after oral and intrathecal administration. However, similar interaction was not observed when tramadol was combined with rofecoxib. Pretreatment with naloxone partially reversed the antinociceptive effect of tramadol per se and its combination with naproxen without modifying the per se effect of NSAID. The results demonstrated marked synergistic interaction between naproxen and tramadol and such interaction involved opioid as well as non-opioid mechanisms of tramadol and inhibition of COX-1 but not COX-2 by naproxen.

  4. A new 5-lipoxygenase selective inhibitor derived from Artocarpus communis strongly inhibits arachidonic acid-induced ear edema.

    PubMed

    Koshihara, Y; Fujimoto, Y; Inoue, H

    1988-06-01

    Natural compounds isolated from the Indonesian plant, Artocarpus communis, inhibit 5-lipoxygenase of cultured mastocytoma cells. One of five compounds, AC-5-1, strongly inhibits 5-lipoxygenase with a half-inhibition dose of 5 +/- 0.12 X 10(-8) M. However, prostaglandin synthesizing activity is not inhibited until 10(-5) M. AC-5-1 is a highly selective inhibitor for 5-lipoxygenase. The AC-5-1 at 10(-5) M inhibits 96% of leukotriene C4 synthesis of mouse peritoneal cells facilitated by calcium-ionophore. Arachidonic acid-induced ear edema of mice, an in vivo inflammatory model, involving leukotriene induction, is strongly inhibited by AC-5-1 in a dose-dependent manner. The inhibition is the strongest of any inhibitors of 5-lipoxygenase reported previously. Since the natural compound AC-5-1 can selectively inhibit 5-lipoxygenase and affect in vivo inflammation, it will be interesting to investigate the role of leukotrienes on inflammation and other physiological processes.

  5. DFT study of the molecular mechanism of Lewis acid induced [4 + 3] cycloadditions of 2-alkylacroleins with cyclopentadiene.

    PubMed

    Domingo, Luis R; Arnó, Manuel; Sáez, José A

    2009-08-21

    The mechanism of the Lewis acid (AlCl(3)) induced [4 + 3] cycloaddition of 2-methylacrolein with cyclopentadiene (Cp) [ J. Am. Chem. Soc. 2004, 126, 2692] has been examined here through DFT calculations at the MPW1K(DCM)/6-31+G** level. Formation of these seven-membered carbocycles is a domino process that comprises three consecutive reactions. The first one is a polar Diels-Alder reaction that is initialized by the nucleophilic attack of Cp to the beta-conjugated position of acrolein, yielding the formation of the endo and exo [4 + 2] cycloadducts. The corresponding LA-[4 + 2] cycloadduct complexes equilibrate through a skeleton rearrangement with a low free activation energy with two seven-membered zwitterionic intermediates, which undergo a rapid intramolecular hydride shift to yield irreversibly the formally endo and exo [4 + 3] cycloadducts. A comparative analysis of this mechanism with that for the Lewis acid induced [4 + 3] cycloadditions of 2-silyloxyacroleins allows establishment of the requirements for the formation of the seven-membered carbocycles.

  6. Effect of ethanolic extract of leaves of Paederia foetida Linn. on acetic acid induced colitis in albino rats

    PubMed Central

    Das, Swarnamoni; Kanodia, Lalit; Mukherjee, Apurba; Hakim, Abdul

    2013-01-01

    Objectives: To evaluate the effect of ethanolic extract of leaves of Paederia foetida on acetic acid induced colitis in albino rats. Materials and Methods: Ethanolic extract of Paederia foetida (EEPF) was prepared by percolation method. Acute toxicity test was done by using Organization for Economic Cooperation and Development guidelines. Albino rats were divided into four groups of five animals each. Groups A and B received 3% gum acacia. Groups C and D received EEPF 500 mg/kg body weight (BW) and 5-aminosalisylic acid 100 mg/kg BW respectively. Colitis was induced by transrectal administration of 4% acetic acid on 5th day. All animals were sacrificed after 48 h of colitis induction and distal 10 cm of the colon was dissected. Colon was weighed for disease activity index (DAI) and scored macroscopically and microscopically. Biochemical assessment of tissue myeloperoxidase (MPO), catalase (CAT) and superoxide dismutase (SOD) was done in colonic tissue homogenate and malondialdehyde (MDA) was estimated in serum. Results: P. foetida showed significant (P < 0.05) reduction in DAI, macroscopic and microscopic lesion score as well as significant (P < 0.05) improvement in MPO, MDA, CAT, and SOD level as compared to Group B. Conclusions: The ethanolic extract of leaves of P. foetida showed significant amelioration of experimentally induced colitis, which may be attributed to its anti-inflammatory and antioxidant property. PMID:24130378

  7. The prostaglandin EP1 receptor potentiates kainate receptor activation via a protein kinase C pathway and exacerbates status epilepticus

    PubMed Central

    Rojas, Asheebo; Gueorguieva, Paoula; Lelutiu, Nadia; Quan, Yi; Shaw, Renee; Dingledine, Raymond

    2014-01-01

    Prostaglandin E2 (PGE2) regulates membrane excitability, synaptic transmission, plasticity, and neuronal survival. The consequences of PGE2 release following seizures has been the subject of much study. Here we demonstrate that the prostaglandin E2 receptor 1 (EP1, or Ptger1) modulates native kainate receptors, a family of ionotropic glutamate receptors widely expressed throughout the central nervous system. Global ablation of the EP1 gene in mice (EP1-KO) had no effect on seizure threshold after kainate injection but reduced the likelihood to enter status epilepticus. EP1-KO mice that did experience typical status epilepticus had reduced hippocampal neurodegeneration and a blunted inflammatory response. Further studies with native prostanoid and kainate receptors in cultured cortical neurons, as well as with recombinant prostanoid and kainate receptors expressed in Xenopus oocytes, demonstrated that EP1 receptor activation potentiates heteromeric but not homomeric kainate receptors via a second messenger cascade involving phospholipase C, calcium and protein kinase C. Three critical GluK5 C-terminal serines underlie the potentiation of the GluK2/GluK5 receptor by EP1 activation. Taken together, these results indicate that EP1 receptor activation during seizures, through a protein kinase C pathway, increases the probability of kainic acid induced status epilepticus, and independently promotes hippocampal neurodegeneration and a broad inflammatory response. PMID:24952362

  8. Relationship between the acid-induced cough response and airway responsiveness and obstruction in children with asthma.

    PubMed Central

    Shimizu, T.; Mochizuki, H.; Tokuyama, K.; Morikawa, A.

    1996-01-01

    BACKGROUND: In children with asthma little is known about the direct effect of the bronchoconstrictor and bronchodilator response on the cough threshold, or the relationship between bronchial responsiveness and the cough threshold. A study was undertaken to determine the effect of histamine-induced bronchoconstriction and salbutamol-induced bronchodilatation on the cough threshold in response to inhaled acetic acid, and to examine the relationship between the acetic acid cough threshold and bronchial hyperresponsiveness to histamine in children with asthma. METHODS: Nineteen children with asthma (16 boys) of mean (SE) age 10.6 (0.6) years were enrolled in the study. On day 1 each underwent a histamine inhalation challenge to determine the provocative concentration causing a fall in forced expiratory volume in one second (FEV1) of more than 20% (PC20) as an index of individual bronchial hyperresponsiveness. On day 2 the acetic acid cough threshold was determined before and just after the inhalation of the PC20 concentration of histamine, and then salbutamol (1 mg/m2) was inhaled to relieve the bronchoconstriction. Ten of the 19 patients (eight boys) of mean age 12.2 (0.7) years also tried acetic acid inhalation challenge just after salbutamol inhalation. RESULTS: There was no relationship between the bronchial responsiveness to histamine and acetic acid cough threshold in these patients. The acetic acid cough threshold after histamine inhalation was similar to that before histamine, although FEV1 decreased after histamine. In the 10 patients who also tried acetic acid inhalation challenge after salbutamol the cough threshold did not change. CONCLUSIONS: These findings suggest that acid-induced cough sensitivity and bronchomotor tone are independently regulated in children with asthma. PMID:8779132

  9. Priming by Hexanoic Acid Induce Activation of Mevalonic and Linolenic Pathways and Promotes the Emission of Plant Volatiles

    PubMed Central

    Llorens, Eugenio; Camañes, Gemma; Lapeña, Leonor; García-Agustín, Pilar

    2016-01-01

    Hexanoic acid (Hx) is a short natural monocarboxylic acid present in some fruits and plants. Previous studies reported that soil drench application of this acid induces effective resistance in tomato plants against Botrytis cinerea and Pseudomonas syringae and in citrus against Alternaria alternata and Xanthomonas citri. In this work, we performed an in deep study of the metabolic changes produced in citrus by the application of Hx in response to the challenge pathogen A. alternata, focusing on the response of the plant. Moreover, we used 13C labeled hexanoic to analyze its behavior inside the plants. Finally, we studied the volatile emission of the treated plants after the challenge inoculation. Drench application of 13C labeled hexanoic demonstrated that this molecule stays in the roots and is not mobilized to the leaves, suggesting long distance induction of resistance. Moreover, the study of the metabolic profile showed an alteration of more than 200 molecules differentially induced by the application of the compound and the inoculation with the fungus. Bioinformatics analysis of data showed that most of these altered molecules could be related with the mevalonic and linolenic pathways suggesting the implication of these pathways in the induced resistance mediated by Hx. Finally, the application of this compound showed an enhancement of the emission of 17 volatile metabolites. Taken together, this study indicates that after the application of Hx this compound remains in the roots, provoking molecular changes that may trigger the defensive response in the rest of the plant mediated by changes in the mevalonic and linolenic pathways and enhancing the emission of volatile compounds, suggesting for the first time the implication of mevalonic pathway in response to hexanoic application. PMID:27148319

  10. Excitatory amino acid transporter 2 downregulation correlates with thalamic neuronal death following kainic acid-induced status epilepticus in rat.

    PubMed

    Sakurai, Masashi; Kurokawa, Haruna; Shimada, Akinori; Nakamura, Kazuhiro; Miyata, Hajime; Morita, Takehito

    2015-02-01

    Recurrent seizures without interictal resumption (status epilepticus) have been reported to induce neuronal death in the midline thalamic region that has functional roles in memory and decision-making; however, the pathogenesis underlying status epilepticus-induced thalamic neuronal death is yet to be determined. We performed histological and immunohistochemical studies as well as cerebral blood flow measurement using 4.7 tesla magnetic resonance imaging spectrometer on midline thalamic region in Sprague-Dawley rats (n = 75, male, 7 weeks after birth, body weight 250-300 g) treated with intraperitoneal injection of kainic acid (10 mg/kg) to induce status epilepticus (n = 55) or normal saline solution (n = 20). Histological study using paraffin-embedded specimens revealed neuronal death showing ischemic-like changes and Fluoro-Jade C positivity with calcium deposition in the midline thalamic region of epileptic rats. The distribution of neuronal death was associated with focal loss of immunoreactivity for excitatory amino acid transporter 2 (EAAT2), stronger immunoreaction for glutamate and increase in number of Iba-1-positive microglial cells showing swollen cytoplasm and long processes. Double immunofluorescence study demonstrated co-expression of interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) within microglial cells, and loss of EAAT2 immunoreactivity in reactive astrocytes. These microglial alterations and astrocytic EAAT2 downregulation were also observed in tissue without obvious neuronal death in kainic acid-treated rats. These results suggest the possible role of glutamate excitotoxicity in neuronal death in the midline thalamic region following kainic acid-induced status epilepticus due to astrocytic EAAT2 downregulation following microglial activation showing upregulation of IL-1β and iNOS.

  11. Anti-inflammatory effect of Moringa oleifera Lam. seeds on acetic acid-induced acute colitis in rats

    PubMed Central

    Minaiyan, Mohsen; Asghari, Gholamreza; Taheri, Diana; Saeidi, Mozhgan; Nasr-Esfahani, Salar

    2014-01-01

    Objective: Anti-inflammatory, immuno-modulatory, and antioxidant properties of Moringa oleifera Lam. suggest that it might have beneficial effects on colitis. The present study was performed to investigate the anticolitis effect of Moringa oleifera seeds hydro-alcoholic extract (MSHE) and its chloroform fraction (MCF) on acetic acid-induced colitis in rats. Materials and Methods: Both MSHE and MCF with three increasing doses (50, 100, and 200 mg/kg) were administered orally to separate groups of male Wistar rats, 2 h before ulcer induction (using acetic acid 4%) and continued for 5 days. Prednisolone (4 mg/kg) and normal saline (1 ml/kg) were used in reference and control groups, respectively. All rats were sacrificed 24 h after the last dose (at day 6) and tissue injuries were assessed macroscopically and pathologically. Results: Extracts with three doses mentioned before were effective to reduce weight of distal colon (8 cm) as a marker for inflammation and tissue edema. Three doses of MSHE and two greater doses of MCF (100 and 200 mg/kg) were effective to reduce ulcer severity, area, and index as well as mucosal inflammation severity and extent, crypt damage, invasion involvement, total colitis index, and MPO activity compared with controls. MCF (50 mg/kg) was not significantly effective in reducing evaluated parameters of colitis compared with controls. Conclusion: It is concluded that MSHE and MCF were both effective to treat experimental colitis and this might be attributed to their similar major components, biophenols and flavonoids. Since the efficacy was evident even in low doses of MSHE, presence of active constituents with high potency in seeds is persuasive. PMID:25050310

  12. The Healing Effect of Teucrium polium in Acetic Acid-Induced Ulcerative Colitis in the Dog as an Animal Model

    PubMed Central

    Mehrabani, Davood; Bahrami, Faranak; Hosseini, Seyed Vahid; Ashraf, Mohammad Javad; Tanideh, Nader; Rezaianzadeh, Abbas; Amini, Masoud; Amini, Afshin

    2012-01-01

    BACKGROUND Inflammatory bowel diseases (IBD), which include ulcerative colitis (UC) and Crohn’s disease (CD), are debilitating and chronic disorders with unpredictable courses and complicated treatment measures. Therefore, an efficient treatment protocol seems necessary as therapeutic prophylaxis for these disorders. This study aims to determine the healing effect of Teucrium polium (T. polium) in acetic acid-induced UC in an experimental dog model. METHODS From September to December 2010, eight male (20-25 kg) crossbred dogs were used for induction of UC by 6% acetic acid, transrectally. After one week, three biopsies (10, 20 and 30 cm proximal to the anal verge) were taken from the colon of each animal for histological studies. In the presence of UC, 400 mg/kg/day of T. polium extract was administered orally and transrectally (via enema) for 30 days in six of the dogs. The remaining two dogs were used as controls and did not receive T. polium. Multiple biopsies were taken 7, 14, and 30 days after discontinuation of T. polium in the same manner as before treatment. RESULTS After administration of acetic acid, we noted the presence of multiple ulcers, diffuse inflammation, PMN infiltration in the lamina propria, glandular destruction and goblet cell depletion. Treatment with T. polium restored the colonic architecture with an increased number of healthy cells and a reduction in inflammatory cells. Damage of the surface epithelial cells and mucosal layer of the lumen were reversed, which lead to faster ulcer healing. CONCLUSION T. polium may be a treatment choice for UC and can broaden the current therapy options for UC. PMID:24829634

  13. Functional and cellular characterization of human Retinoic Acid Induced 1 (RAI1) mutations associated with Smith-Magenis Syndrome

    PubMed Central

    2010-01-01

    Background Smith-Magenis Syndrome is a contiguous gene syndrome in which the dosage sensitive gene has been identified: the Retinoic Acid Induced 1 (RAI1). Little is known about the function of human RAI1. Results We generated the full-length cDNA of the wild type protein and five mutated forms: RAI1-HA 2687delC, RAI1-HA 3103delC, RAI1 R960X, RAI1-HA Q1562R, and RAI1-HA S1808N. Four of them have been previously associated with SMS clinical phenotype. Molecular weight, subcellular localization and transcription factor activity of the wild type and mutant forms were studied by western blot, immunofluorescence and luciferase assays respectively. The wild type protein and the two missense mutations presented a higher molecular weight than expected, localized to the nucleus and activated transcription of a reporter gene. The frameshift mutations generated a truncated polypeptide with transcription factor activity but abnormal subcellular localization, and the same was true for the 1-960aa N-terminal half of RAI1. Two different C-terminal halves of the RAI1 protein (1038aa-end and 1229aa-end) were able to localize into the nucleus but had no transactivation activity. Conclusion Our results indicate that transcription factor activity and subcellular localization signals reside in two separate domains of the protein and both are essential for the correct functionality of RAI1. The pathogenic outcome of some of the mutated forms can be explained by the dissociation of these two domains. PMID:20738874

  14. Retinoic Acid Induced 1, RAI1: A Dosage Sensitive Gene Related to Neurobehavioral Alterations Including Autistic Behavior

    PubMed Central

    Carmona-Mora, Paulina; Walz, Katherina

    2010-01-01

    Genomic structural changes, such as gene Copy Number Variations (CNVs) are extremely abundant in the human genome. An enormous effort is currently ongoing to recognize and catalogue human CNVs and their associations with abnormal phenotypic outcomes. Recently, several reports related neuropsychiatric diseases (i.e. autism spectrum disorders, schizophrenia, mental retardation, behavioral problems, epilepsy) with specific CNV. Moreover, for some conditions, both the deletion and duplication of the same genomic segment are related to the phenotype. Syndromes associated with CNVs (microdeletion and microduplication) have long been known to display specific neurobehavioral traits. It is important to note that not every gene is susceptible to gene dosage changes and there are only a few dosage sensitive genes. Smith-Magenis (SMS) and Potocki-Lupski (PTLS) syndromes are associated with a reciprocal microdeletion and microduplication within chromosome 17p11.2. in humans. The dosage sensitive gene responsible for most phenotypes in SMS has been identified: the Retinoic Acid Induced 1 (RAI1). Studies on mouse models and humans suggest that RAI1 is likely the dosage sensitive gene responsible for clinical features in PTLS. In addition, the human RAI1 gene has been implicated in several neurobehavioral traits as spinocerebellar ataxia (SCA2), schizophrenia and non syndromic autism. In this review we discuss the evidence of RAI1 as a dosage sensitive gene, its relationship with different neurobehavioral traits, gene structure and mutations, and what is known about its molecular and cellular function, as a first step in the elucidation of the mechanisms that relate dosage sensitive genes with abnormal neurobehavioral outcomes. PMID:21629438

  15. Stability of the acetic acid-induced bladder irritation model in alpha chloralose-anesthetized female cats.

    PubMed

    Kullmann, F Aura; Wells, Grace I; Langdale, Christopher L; Zheng, Jihong; Thor, Karl B

    2013-01-01

    Time- and vehicle-related variability of bladder and urethral rhabdosphincter (URS) activity as well as cardiorespiratory and blood chemistry values were examined in the acetic acid-induced bladder irritation model in α-chloralose-anesthetized female cats. Additionally, bladder and urethra were evaluated histologically using Mason trichrome and toluidine blue staining. Urodynamic, cardiovascular and respiratory parameters were collected during intravesical saline infusion followed by acetic acid (0.5%) to irritate the bladder. One hour after starting acetic acid infusion, a protocol consisting of a cystometrogram, continuous infusion-induced rhythmic voiding contractions, and a 5 min "quiet period" (bladder emptied without infusion) was precisely repeated every 30 minutes. Administration of vehicle (saline i.v.) occurred 15 minutes after starting each of the first 7 cystometrograms and duloxetine (1mg/kg i.v.) after the 8(th). Acetic acid infusion into the bladder increased URS-EMG activity, bladder contraction frequency, and decreased contraction amplitude and capacity, compared to saline. Bladder activity and URS activity stabilized within 1 and 2 hours, respectively. Duloxetine administration significantly decreased bladder contraction frequency and increased URS-EMG activity to levels similar to previous reports. Cardiorespiratory parameters and blood gas levels remained consistent throughout the experiment. The epithelium of the bladder and urethra were greatly damaged and edema and infiltration of neutrophils in the lamina propria of urethra were observed. These data provide an ample evaluation of the health of the animals, stability of voiding function and appropriateness of the model for testing drugs designed to evaluate lower urinary tract as well as cardiovascular and respiratory systems function. PMID:24040064

  16. Protective Effect of the Methanolic Extract of Malva parviflora L. leaves on Acetic Acid-induced Ulcerative Colitis in Rats

    PubMed Central

    Dugani, Aisha; Dakhil, Bushra; Treesh, Soad

    2016-01-01

    Background/Aims: Inflammatory bowel disease (IBD) is a general term describing chronic, idiopathic relapsing, inflammatory conditions of the gastrointestinal tract of unknown etiology. Previous studies have indicated that Malva parviflora leaf extract possesses anti-inflammatory, antioxidant, and antiulcerogenic activity. activity. This work aimed to investigatee the anti-inflammatory effect of the methanolic (MEMP) and aqueous (AEMP) extracts of M. parviflora leaves on acetic acid-induced colitis in rats. Materials and Methods: 42 male Wistar albino rats were divided into seven groups (n = 6). Group I: Normal saline control group with no colitis; Group II: Acetic acid colitis group; Group III: 100 mg/kg/5 d MEMP; Group IV: 200 mg/kg/5 d.MEMP; Group V: 100 mg/kg/5 d AEMP; Group VI: 200 mg/kg/5 d AEMP; Group VII: Prednisolone group (2 mg/kg/5 d). Treatments were followed by induction of colitis using intrarectal instillation of 2 mL of 4% acetic acid. Colon damage was evaluated macroscopically (spleen weight/body weight, colon weight/length ratio) and the histological changes were also recorded. Results: The results of this study showed that acetic acid caused severe inflammation of the colon and a significant increase in spleen weight/body weight, and an increase in colon weight/length ratio compared with normal control group. Pretreatment with MEMP and AEMP for 5 days followed by induction of colitis resulted in a significant attenuation of spleen weight and colon weight/length ratio compared with acetic acid control group. Methanolic extract provided better anticolitic effect than aqueous extract; the effect was prominent at the dose of 200 mg/kg. Histopathological findings confirmed the protective effect of the MEMP. Conclusion: In conclusion, MEMP could ameliorate mucosal damage in experimentally induced colitis when given orally. PMID:27184642

  17. Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett’s Esophageal Adenocarcinoma Cells

    PubMed Central

    Li, Dan; Cao, Weibiao

    2016-01-01

    The mechanisms whereby bile acid reflux may accelerate the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett’s patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA. PMID:27511066

  18. Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett's Esophageal Adenocarcinoma Cells.

    PubMed

    Li, Dan; Cao, Weibiao

    2016-01-01

    The mechanisms whereby bile acid reflux may accelerate the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett's patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA. PMID:27511066

  19. Pioglitazone ameliorates behavioral, biochemical and cellular alterations in quinolinic acid induced neurotoxicity: possible role of peroxisome proliferator activated receptor-Upsilon (PPARUpsilon) in Huntington's disease.

    PubMed

    Kalonia, Harikesh; Kumar, Puneet; Kumar, Anil

    2010-08-01

    Emerging evidence indicates that PPARUpsilon activators attenuate neurodegeneration and related complications. Therefore, the present study focused on the neuroprotective potential of pioglitazone against quinolinic acid (QUIN) induced neurotoxicity. Intrastriatal (unilaterally) administration of QUIN significantly altered body weight and motor function (locomotor activity, rotarod and beam walk performance). Further, QUIN treatment significantly caused oxidative damage (increased lipid peroxidation, nitrite concentration and depleted endogenous antioxidant defense enzymes), altered mitochondrial enzyme complex (I, II and IV) activities and TNF-alpha level as compared to sham treated animals. Pioglitazone (10, 20 and 40mg/kg, p.o.) treatment significantly improved body weight and motor functions, oxidative defense. Further, pioglitazone treatment restored mitochondrial enzyme complex activity as well as TNF-alpha level as compared to QUIN treated group. While Bisphenol A diglycidyl ether (BADGE) (15mg/kg), PPARUpsilon antagonist significantly reversed the protective effect of the pioglitazone (40mg/kg) in the QUIN treated animals. Further, pioglitazone treatment significantly attenuated the striatal lesion volume in QUIN treated animals, suggesting a role for the PPARUpsilon pathway in QUIN induced neurotoxicity. Altogether, this evidence indicates that PPARUpsilon activation by pioglitazone attenuated QUIN induced neurotoxicity in animals and which could be an important therapeutic avenue to ameliorate Huntington like symptoms. PMID:20450929

  20. Sida rhomboidea.Roxb extract alleviates pathophysiological changes in experimental in vivo and in vitro models of high fat diet/fatty acid induced non-alcoholic steatohepatitis.

    PubMed

    Thounaojam, Menaka C; Jadeja, Ravirajsinh N; Dandekar, Deven S; Devkar, Ranjitsinh V; Ramachandran, A V

    2012-03-01

    The present study was aim to evaluate protective role of Sida rhomboidea.Roxb (SR) extract against high fat diet/fatty acid induced pathophysiological alterations in experimental model of non-alcoholic steatohepatitis (NASH). Effect of SR extract on plasma levels of markers of hepatic damage, plasma and hepatic lipids, mitochondrial oxidative stress, status of enzymatic and non-enzymatic antioxidants and histopathological changes in liver tissue were evaluated in high fat diet fed C57BL/6J mice. Also, the effect of SR supplementation on lipid accumulation, lipid peroxidation, cytotoxicity and cell viability were evaluated in oleic acid treated HepG2 cells. Supplementation of NASH mice with SR extract prevented high fat diet induced elevation in plasma marker enzymes of liver damage, plasma and hepatic lipids, mitochondrial oxidative stress and compromised enzymatic and non-enzymatic antioxidant status. Further, addition of SR extract to in vitro HepG2 cells minimized oleic acid induced lipid accumulation, higher lipid peroxidation, cytotoxicity and reduced cell viability. These in vivo and in vitro studies suggest that SR extract has the potential of preventing high fat/fatty acid induced NASH mainly due to its hypolipidemic and antioxidant activities.

  1. Gamma-aminobutyric acid induces tumor cells apoptosis via GABABR1·β-arrestins·JNKs signaling module.

    PubMed

    Tian, Hui; Wu, Jin-Xia; Shan, Feng-Xiao; Zhang, Shang-Nuan; Cheng, Qian; Zheng, Jun-Nian; Pei, Dong-Sheng

    2015-03-01

    Gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in central nervous system, has yet been found to widely exist in tumor tissues to regulate tumor cells growth. However, the function of GABA on inducing tumor cells apoptosis and the potential mechanism are still unclear. In order to detect whether GABA via GABAB receptor GABABR1 would activate c-Jun N-terminal kinases (JNKs) to promote tumor cells apoptosis, co-immunoprecipitation assay was used to investigate the association of β-arrestins with GABABR1 and JNKs in the different four cancer cell lines. Our observation demonstrated that β-arrestins, in addition to their role in G protein-coupled receptors desensitization, had an additional function as adapter proteins to recruit JNKs to GABABR1, thereby conferring distinct enzymatic activities upon the receptor, which may trigger JNKs signal pathway involved in the regulation of cellular growth. Activated JNKs subsequently phosphorylated downstream c-Jun to transcribe a wide variety of pro-apoptotic genes. Additionally, GABA up-regulated the ratio of pro-apoptotic protein Bax to anti-apoptotic protein Bcl-2, and thus facilitated caspase-3 cleavage, leading to tumor cells apoptosis in a mitochondrial-dependent pathway. In contrast, GABABR antagonist CGP35348 reversed GABA-induced JNKs phosphorylation and its downstream proteins activation, which consequently restrained tumor cells apoptosis. Taken together, our study suggested that GABA via its receptor GABABR1 recruited β-arrestins to facilitate the activation of JNKs cascade, resulting in tumor cells growth inhibition.

  2. Docosahexaenoic acid and other fatty acids induce a decrease in pHi in Jurkat T-cells

    PubMed Central

    Aires, Virginie; Hichami, Aziz; Moutairou, Kabirou; Khan, Naim Akhtar

    2003-01-01

    Docosahexaenoic acid (DHA) induced rapid (t1/2=33 s) and dose-dependent decreases in pHi in BCECF-loaded human (Jurkat) T-cells. Addition of 5-(N,N-dimethyl)-amiloride, an inhibitor of Na+/H+ exchanger, prolonged DHA-induced acidification as a function of time, indicating that the exchanger is implicated in pHi recovery. Other fatty acids like oleic acid, arachidonic acid, eicosapentaenoic acid, but not palmitic acid, also induced a fall in pHi in these cells. To assess the role of calcium in the DHA-induced acidification, we conducted experiments in Ca2+-free (0% Ca2+) and Ca2+-containing (100% Ca2+) buffer. We observed that there was no difference in the degree of DHA-induced transient acidification in both the experimental conditions, though pHi recovery was faster in 0% Ca2+ medium than that in 100% Ca2+ medium. In the presence of BAPTA, a calcium chelator, a rapid recovery of DHA-induced acidosis was observed. Furthermore, addition of CaCl2 into 0% Ca2+ medium curtailed DHA-evoked rapid pHi recovery. In 0% Ca2+ medium, containing BAPTA, DHA did not evoke increases in [Ca2+]i, though this fatty acid still induced a rapid acidification in these cells. These observations suggest that calcium is implicated in the long-lasting DHA-induced acidosis. DHA-induced rapid acidification may be due to its deprotonation in the plasma membrane (flip-flop model), as suggested by the following observations: (1) DHA with a –COOH group induced intracellular acidification, but this fatty acid with a –COOCH3 group failed to do so, and (2) DHA, but not propionic acid, -induced acidification was completely reversed by addition of fatty acid-free bovine serum albumin in these cells. These results suggest that DHA induces acidosis via deprotonation and Ca2+ mobilization in human T-cells. PMID:14645139

  3. Blueberry polyphenols attenuate kainic acid-induced decrements in cognition and alter inflammatory gene expression in rat hippocampus

    PubMed Central

    Shukitt-Hale, Barbara; Lau, Francis C.; Carey, Amanda N.; Galli, Rachel L.; Spangler, Edward L.; Ingram, Donald K.; Joseph, James A.

    2016-01-01

    Cognitive impairment in age-related neurodegenerative diseases such as Alzheimer's disease may be partly due to long-term exposure and increased susceptibility to inflammatory insults. In the current study, we investigated whether polyphenols in blueberries can reduce the deleterious effects of inflammation induced by central administration of kainic acid by altering the expression of genes associated with inflammation. To this end, 4-month-old male Fischer-344 (F344) rats were fed a control, 0.015% piroxicam (an NSAID) or 2% blueberry diet for 8 weeks before either Ringer's buffer or kainic acid was bilaterally micro-infused into the hippocampus. Two weeks later, following behavioral evaluation, the rats were killed and total RNA from the hippocampus was extracted and used in real-time quantitative RT-PCR (qRT-PCR) to analyze the expression of inflammation-related genes. Kainic acid had deleterious effects on cognitive behavior as kainic acid-injected rats on the control diet exhibited increased latencies to find a hidden platform in the Morris water maze compared to Ringer's buffer-injected rats and utilized non-spatial strategies during probe trials. The blueberry diet, and to a lesser degree the piroxicam diet, was able to improve cognitive performance. Immunohistochemical analyses of OX-6 expression revealed that kainic acid produced an inflammatory response by increasing the OX-6 positive areas in the hippocampus of kainic acid-injected rats. Kainic acid up-regulated the expression of the inflammatory cytokines IL-1β and TNF-α, the neurotrophic factor IGF-1, and the transcription factor NF-κB. Blueberry and piroxicam supplementations were found to attenuate the kainic acid-induced increase in the expression of IL-1β, TNF-α, and NF-κB, while only blueberry was able to augment the increased IGF-1 expression. These results indicate that blueberry polyphenols attenuate learning impairments following neurotoxic insult and exert anti-inflammatory actions

  4. Histaminergic neurons protect the developing hippocampus from kainic acid-induced neuronal damage in an organotypic coculture system.

    PubMed

    Kukko-Lukjanov, Tiina-Kaisa; Soini, Sanna; Taira, Tomi; Michelsen, Kimmo A; Panula, Pertti; Holopainen, Irma E

    2006-01-25

    The central histaminergic neuron system inhibits epileptic seizures, which is suggested to occur mainly through histamine 1 (H1) and histamine 3 (H3) receptors. However, the importance of histaminergic neurons in seizure-induced cell damage is poorly known. In this study, we used an organotypic coculture system and confocal microscopy to examine whether histaminergic neurons, which were verified by immunohistochemistry, have any protective effect on kainic acid (KA)-induced neuronal damage in the developing hippocampus. Fluoro-Jade B, a specific marker for degenerating neurons, indicated that, after the 12 h KA (5 microM) treatment, neuronal damage was significantly attenuated in the hippocampus cultured together with the posterior hypothalamic slice containing histaminergic neurons [HI plus HY (POST)] when compared with the hippocampus cultured alone (HI) or with the anterior hypothalamus devoid of histaminergic neurons. Moreover, alpha-fluoromethylhistidine, an inhibitor of histamine synthesis, eliminated the neuroprotective effect in KA-treated HI plus HY (POST), and extracellularly applied histamine (1 nM to 100 microM) significantly attenuated neuronal damage only at 1 nM concentration in HI. After the 6 h KA treatment, spontaneous electrical activity registered in the CA1 subregion contained significantly less burst activity in HI plus HY (POST) than in HI. Finally, in KA-treated slices, the H3 receptor antagonist thioperamide enhanced the neuroprotective effect of histaminergic neurons, whereas the H1 receptor antagonists triprolidine and mepyramine dose-dependently decreased the neuroprotection in HI plus HY (POST). Our results suggest that histaminergic neurons protect the developing hippocampus from KA-induced neuronal damage, with regulation of neuronal survival being at least partly mediated through H1 and H3 receptors.

  5. Bile acids induce monocyte differentiation toward interleukin-12 hypo-producing dendritic cells via a TGR5-dependent pathway

    PubMed Central

    Ichikawa, Riko; Takayama, Tetsuro; Yoneno, Kazuaki; Kamada, Nobuhiko; Kitazume, Mina T; Higuchi, Hajime; Matsuoka, Katsuyoshi; Watanabe, Mitsuhiro; Itoh, Hiroshi; Kanai, Takanori; Hisamatsu, Tadakazu; Hibi, Toshifumi

    2012-01-01

    Dendritic cells (DCs) are known as antigen-presenting cells and play a central role in both innate and acquired immunity. Peripheral blood monocytes give rise to resident and recruited DCs in lymph nodes and non-lymphoid tissues. The ligands of nuclear hormone receptors can modulate DC differentiation and so influence various biological functions of DCs. The role of bile acids (BAs) as signalling molecules has recently become apparent, but the functional role of BAs in DC differentiation has not yet been elucidated. We show that DCs derived from human peripheral blood monocytes cultured with a BA produce lower levels of interleukin-12 (IL-12) and tumour necrosis factor-α in response to stimulation with commensal bacterial antigens. Stimulation through the nuclear receptor farnesoid X (FXR) did not affect the differentiation of DCs. However, DCs differentiated with the specific agonist for TGR5, a transmembrane BA receptor, showed an IL-12 hypo-producing phenotype. Expression of TGR5 could only be identified in monocytes and was rapidly down-regulated during monocyte differentiation to DCs. Stimulation with 8-bromoadenosine-cyclic AMP (8-Br-cAMP), which acts downstream of TGR5 signalling, also promoted differentiation into IL-12 hypo-producing DCs. These results indicate that BAs induce the differentiation of IL-12 hypo-producing DCs from monocytes via the TGR5-cAMP pathway. PMID:22236403

  6. Somatostatin receptors.

    PubMed

    Srikant, C B; Patel, Y C

    1985-01-01

    It is now well established that the biological actions of tetradecapeptide somatostatin (somatostatin-14, S-14) are receptor-mediated. These receptors were first quantified in GH4C pituitary tumor cells using [125I-Tyr1] S-14 as radioligand which was found to exhibit high non-specific binding to membrane receptor preparations from normal tissues. Our studies have shown that [125I-Tyr11] S-14 in which the radiolabel is situated away from the N-terminus exhibits significantly lower non-specific binding and therefore is more suitable for S-14 receptor studies. In the CNS, highest concentration of S-14 receptors was found in the cerebral cortex, followed by thalamus, hypothalamus, striatum, amygdala and hippocampus while medulla-pons, cerebellum and spinal cord exhibited negligible binding. Outside the CNS membrane receptors for S-14 have been characterized in pituitary, adrenal cortex and pancreatic acini. In all these tissues a single class of high affinity binding sites for S-14 were present, the receptors in pancreatic acinar cells exhibiting significantly greater affinity for binding S-14 than in other tissues.

  7. Schistosoma mansoni: possible involvement of protein kinase C in linoleic acid-induced proteolytic enzyme release from cercariae.

    PubMed

    Matsumura, K; Mitsui, Y; Sato, K; Sakamoto, M; Aoki, Y

    1991-04-01

    antagonist, trifluoperazine (TFP), a better calmodulin antagonist on schistosome, or by verapamil, a Ca2+ channel blocker. Linoleic acid-induced release of enzyme was partially inhibited by 0.5 and 5 mM of EGTA and by 1 to 100 microM of H-7. While it was not inhibited by N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) and N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA-1004), inhibitors of cyclic nucleotide-dependent protein kinase which were used as negative controls of H-7, W-7, TFP, 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), an intracellular Ca2+ antagonist, and verapamil.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2015870

  8. The Na+/H+ Exchanger Controls Deoxycholic Acid-Induced Apoptosis by a H+-Activated, Na+-Dependent Ionic Shift in Esophageal Cells

    PubMed Central

    Goldman, Aaron; Chen, HwuDauRw; Khan, Mohammad R.; Roesly, Heather; Hill, Kimberly A.; Shahidullah, Mohammad; Mandal, Amritlal; Delamere, Nicholas A.; Dvorak, Katerina

    2011-01-01

    Apoptosis resistance is a hallmark of cancer cells. Typically, bile acids induce apoptosis. However during gastrointestinal (GI) tumorigenesis the cancer cells develop resistance to bile acid-induced cell death. To understand how bile acids induce apoptosis resistance we first need to identify the molecular pathways that initiate apoptosis in response to bile acid exposure. In this study we examined the mechanism of deoxycholic acid (DCA)-induced apoptosis, specifically the role of Na+/H+ exchanger (NHE) and Na+ influx in esophageal cells. In vitro studies revealed that the exposure of esophageal cells (JH-EsoAd1, CP-A) to DCA (0.2 mM -0.5 mM) caused lysosomal membrane perturbation and transient cytoplasmic acidification. Fluorescence microscopy in conjunction with atomic absorption spectrophotometry demonstrated that this effect on lysosomes correlated with influx of Na+, subsequent loss of intracellular K+, an increase of Ca2+ and apoptosis. However, ethylisopropyl-amiloride (EIPA), a selective inhibitor of NHE, prevented Na+, K+ and Ca2+ changes and caspase 3/7 activation induced by DCA. Ouabain and amphotericin B, two drugs that increase intracellular Na+ levels, induced similar changes as DCA (ion imbalance, caspase3/7 activation). On the contrary, DCA-induced cell death was inhibited by medium with low a Na+ concentrations. In the same experiments, we exposed rat ileum ex-vivo to DCA with or without EIPA. Severe tissue damage and caspase-3 activation was observed after DCA treatment, but EIPA almost fully prevented this response. In summary, NHE-mediated Na+ influx is a critical step leading to DCA-induced apoptosis. Cells tolerate acidification but evade DCA-induced apoptosis if NHE is inhibited. Our data suggests that suppression of NHE by endogenous or exogenous inhibitors may lead to apoptosis resistance during GI tumorigenesis. PMID:21887327

  9. The role of amino acid-induced mammalian target of rapamycin complex 1(mTORC1) signaling in insulin resistance

    PubMed Central

    Yoon, Mee-Sup; Choi, Cheol Soo

    2016-01-01

    Mammalian target of rapamycin (mTOR) controls cell growth and metabolism in response to nutrients, energy, and growth factors. Recent findings have placed the lysosome at the core of mTOR complex 1 (mTORC1) regulation by amino acids. Two parallel pathways, Rag GTPase-Ragulator and Vps34-phospholipase D1 (PLD1), regulate mTOR activation on the lysosome. This review describes the recent advances in understanding amino acid-induced mTOR signaling with a particular focus on the role of mTOR in insulin resistance. PMID:27534530

  10. Somatostatin receptors.

    PubMed

    Patel, Y C; Srikant, C B

    1997-12-01

    The diverse biological effects of somatostatin (SRIF) are mediated by a family of G protein-coupled receptors (termed sst) that are encoded by five nonallelic genes located on separate chromosomes. The receptors can be further divided into two subfamilies: sst(2,3,5) react with octapeptide and hexapeptide SRIF analogues and belong to one subclass; sst(1,4) react poorly with these compounds and fall into another subclass. This review focuses on the molecular pharmacology and function of these receptors, with particular emphasis on the ligand-binding domain, subtype-selective analogues, agonist-dependent receptor regulation and desensitization responses, subtype-specific effector coupling, and signal transduction pathways responsible for inhibiting cell secretion and cell growth or induction of apoptosis.

  11. The Histone Deacetylase Inhibitor Vaproic Acid Induces Cell Growth Arrest in Hepatocellular Carcinoma Cells via Suppressing Notch Signaling

    PubMed Central

    Sun, Guangchun; Mackey, Lily V.; Coy, David H.; Yu, Cui-Yun; Sun, Lichun

    2015-01-01

    Hepatocellular carcinoma (HCC) is a type of malignant cancer. Notch signaling is aberrantly expressed in HCC tissues with more evidence showing that this signaling plays a critical role in HCCs. In the present study, we investigate the effects of the anti-convulsant drug valproic acid (VPA) in HCC cells and its involvement in modulating Notch signaling. We found that VPA, acting as a histone deacetylase (HDAC) inhibitor, induced a decrease in HDAC4 and an increase in acetylated histone 4 (AcH4) and suppressed HCC cell growth. VPA also induced down-regulation of Notch signaling via suppressing the expression of Notch1 and its target gene HES1, with an increase of tumor suppressor p21 and p63. Furthermore, Notch1 activation via overexpressing Notch1 active form ICN1 induced HCC cell proliferation and anti-apoptosis, indicating Notch signaling played an oncogenic role in HCC cells. Meanwhile, VPA could reverse Notch1-induced increase of cell proliferation. Interestingly, VPA was also observed to stimulate the expression of G protein-coupled somatostatin receptor type 2 (SSTR2) that has been used in receptor-targeting therapies. This discovery supports a combination therapy of VPA with the SSTR2-targeting agents. Our in vitro assay did show that the combination of VPA and the peptide-drug conjugate camptothecin-somatostatin (CPT-SST) displayed more potent anti-proliferative effects on HCC cells than did each alone. VPA may be a potential drug candidate in the development of anti-HCC drugs via targeting Notch signaling, especially in combination with receptor-targeting cytotoxic agents. PMID:26366213

  12. Lipoxin receptors.

    PubMed

    Romano, Mario; Recchia, Irene; Recchiuti, Antonio

    2007-01-01

    Lipoxins (LXs) represent a class of arachidonic acid (AA) metabolites that carry potent immunoregulatory and anti-inflammatory properties, LXA4 and LXB4 being the main components of this series. LXs are generated by cooperation between 5-lipoxygenase (LO) and 12- or 15-LO during cell-cell interactions or by single cell types. LX epimers at carbon 15, the 15-epi-LXs, are formed by aspirin-acetylated cyclooxygenase-2 (COX-2) in cooperation with 5-LO. 15-epi-LXA4 is also termed aspirin-triggered LX (ATL). In vivo studies with stable LX and ATL analogs have established that these eicosanoids possess potent anti-inflammatory activities. A LXA4 receptor has been cloned. It belongs to the family of chemotactic receptors and clusters with formyl peptide receptors on chromosome 19. Therefore, it was initially denominated formyl peptide receptor like 1 (FPRL1). This receptor binds with high affinity and stereoselectivity LXA4 and ATL. It also recognizes a variety of peptides, synthetic, endogenously generated, or disease associated, but with lower affinity compared to LXA4. For this reason, this receptor has been renamed ALX. This review summarizes the current knowledge on ALX expression, signaling, and potential pathophysiological role. The involvement of additional recognition sites in LX bioactions is also discussed. PMID:17767357

  13. Benefits of agomelatine in behavioral, neurochemical and blood brain barrier alterations in prenatal valproic acid induced autism spectrum disorder.

    PubMed

    Kumar, Hariom; Sharma, B M; Sharma, Bhupesh

    2015-12-01

    Valproic acid administration during gestational period causes behavior and biochemical deficits similar to those observed in humans with autism spectrum disorder. Although worldwide prevalence of autism spectrum disorder has been increased continuously, therapeutic agents to ameliorate the social impairment are very limited. The present study has been structured to investigate the therapeutic potential of melatonin receptor agonist, agomelatine in prenatal valproic acid (Pre-VPA) induced autism spectrum disorder in animals. Pre-VPA has produced reduction in social interaction (three chamber social behavior apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complex I, II, IV). Furthermore, Pre-VPA has increased locomotor activity (actophotometer), anxiety, brain oxidative stress (thiobarbituric acid reactive species, glutathione, and catalase), nitrosative stress (nitrite/nitrate), inflammation (brain and ileum myeloperoxidase activity), calcium levels and blood brain barrier leakage in animals. Treatment with agomelatine has significantly attenuated Pre-VPA induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, agomelatine also attenuated Pre-VPA induced increase in locomotion, anxiety, brain oxidative stress, nitrosative stress, inflammation, calcium levels and blood brain barrier leakage. It is concluded that, Pre-VPA has induced autism spectrum disorder, which was attenuated by agomelatine. Agomelatine has shown ameliorative effect on behavioral, neurochemical and blood brain barrier alteration in Pre-VPA exposed animals. Thus melatonin receptor agonists may provide beneficial therapeutic strategy for managing autism spectrum disorder.

  14. Retinoic acid receptor alpha (RAralpha) Mutations in Human Leukemia.

    PubMed

    Parrado, A; Chomienne, C; Padua, R A

    2000-10-01

    The retinoic acid receptor alpha (RARalpha) plays a central role in the biology of the myeloid cellular compartment. Chromosomal translocations involving the RARalpha locus probably represent the malignant initiating events in acute promyelocytic leukemia (APL). Recent studies that identify novel interactions between RARalpha and the nuclear receptor co-activators and co-repressors, new functions of the oncogenic RARalpha fusion proteins and their catabolism in retinoic acid-induced differentiation, and the availability of new transgenic mice models have provided important insights into our understanding of the mechanisms by which mutant forms of RARalpha can be implicated in the development of leukemia. Novel alterations of the RARalpha gene identified in hematopoietic malignant disorders other than APL, such as myelodysplastic syndromes, non-APL acute myeloid leukemias and B-chronic lymphocytic leukemias, suggest that disruption of the RARalpha gene might predispose to myeloid and lymphoid disorders.

  15. Resistance to butyrate impairs bile acid-induced apoptosis in human colon adenocarcinoma cells via up-regulation of Bcl-2 and inactivation of Bax.

    PubMed

    Barrasa, Juan I; Santiago-Gómez, Angélica; Olmo, Nieves; Lizarbe, María Antonia; Turnay, Javier

    2012-12-01

    A critical risk factor in colorectal carcinogenesis and tumor therapy is the resistance to the apoptotic effects of different compounds from the intestinal lumen, among them butyrate (main regulator of colonic epithelium homeostasis). Insensitivity to butyrate-induced apoptosis yields resistance to other agents, as bile acids or chemotherapy drugs, allowing the selective growth of malignant cell subpopulations. Here we analyze bile acid-induced apoptosis in a butyrate-resistant human colon adenocarcinoma cell line (BCS-TC2.BR2) to determine the mechanisms that underlay the resistance to these agents in comparison with their parental butyrate-sensitive BCS-TC2 cells. This study demonstrates that DCA and CDCA still induce apoptosis in butyrate-resistant cells through increased ROS production by activation of membrane-associated enzymes and subsequent triggering of the intrinsic mitochondrial apoptotic pathway. Although this mechanism is similar to that described in butyrate-sensitive cells, cell viability is significantly higher in resistant cells. Moreover, butyrate-resistant cells show higher Bcl-2 levels that confer resistance to bile acid-induced apoptosis sequestering Bax and avoiding Bax-dependent pore formation in the mitochondria. We have confirmed that this resistance is reverted using the Bcl-2 inhibitor ABT-263, thus demonstrating that the lower sensitivity of butyrate-resistant cells to the apoptotic effects of bile acids is mainly due to increased Bcl-2 levels.

  16. Synergic Interaction of Rifaximin and Mutaflor (Escherichia coli Nissle 1917) in the Treatment of Acetic Acid-Induced Colitis in Rats.

    PubMed

    Dembiński, Artur; Warzecha, Zygmunt; Ceranowicz, Piotr; Dembiński, Marcin; Cieszkowski, Jakub; Gosiewski, Tomasz; Bulanda, Małgorzata; Kuśnierz-Cabala, Beata; Gałązka, Krystyna; Konturek, Peter Christopher

    2016-01-01

    Background. Inflammatory bowel disease results from the dysregulation of immune response to environmental and microbial agents in genetically susceptible individuals. The aim of the present study was to examine the effect of rifaximin and/or Mutaflor (Escherichia coli Nissle 1917, EcN) administration on the healing of acetic acid-induced colitis. Methods. Colitis was induced in male Wistar rats by rectal enema with 3.5% acetic acid solution. Rifaximin (50 mg/kg/dose) and/or Mutaflor (10(9) CFU/dose) were given intragastrically once a day. The severity of colitis was assessed at the 8th day after induction of inflammation. Results. Treatment with rifaximin significantly accelerated the healing of colonic damage. This effect was associated with significant reversion of the acetic acid-evoked decrease in mucosal blood flow and DNA synthesis. Moreover, administration of rifaximin significantly reduced concentration of proinflammatory TNF-α and activity of myeloperoxidase in colonic mucosa. Mutaflor given alone was without significant effect on activity of colitis. In contrast, Mutaflor given in combination with rifaximin significantly enhanced therapeutic effect of rifaximin. Moreover, Mutaflor led to settle of the colon by EcN and this effect was augmented by pretreatment with rifaximin. Conclusion. Rifaximin and Mutaflor exhibit synergic anti-inflammatory and therapeutic effect in acetic acid-induced colitis in rats. PMID:27433160

  17. Baicalein, a Constituent of Scutellaria baicalensis, Reduces Glutamate Release and Protects Neuronal Cell Against Kainic Acid-Induced Excitotoxicity in Rats.

    PubMed

    Chang, Yi; Lu, Cheng Wei; Lin, Tzu Yu; Huang, Shu Kuei; Wang, Su Jane

    2016-01-01

    Interest in the health benefits of flavonoids, particularly their effects on neurodegenerative disease, is increasing. This study evaluated the role of baicalein, a flavonoid compound isolated from the traditional Chinese medicine Scutellaria baicalensis, in glutamate release and glutamate neurotoxicity in the rat hippocampus. In the rat hippocampal nerve terminals (synaptosomes), baicalein inhibits depolarization-induced glutamate release, and this phenomenon is prevented by chelating the extracellular Ca[Formula: see text] ions and blocking presynaptic Cav2.2 (N-type) and Cav2.1 (P/Q-type) channel activity. In slice preparations, whole cell patch-clamp experiments revealed that baicalein reduced the frequency of miniature excitatory postsynaptic currents, without affecting their amplitude. In a kainic acid rat model, intraperitoneally administering baicalein to rats before the kainic acid intraperitoneal injection substantially attenuated kainic acid-induced neuronal cell death, c-Fos expression, and the activation of the mammalian target of rapamycin in the hippocampus. This study is the first to demonstrate that the natural compound baicalein inhibits glutamate release from hippocampal nerve terminals, and executes a protective action against kainic acid-induced excitotoxicity in vivo. The findings enhance the understanding of baicalein's action in the brain, and suggest that this natural compound is valuable for treating brain disorders related to glutamate excitotoxicity. PMID:27430911

  18. Alpha-Linolenic Acid-Induced Increase in Neurogenesis is a Key Factor in the Improvement in the Passive Avoidance Task After Soman Exposure.

    PubMed

    Piermartiri, Tetsade C B; Pan, Hongna; Chen, Jun; McDonough, John; Grunberg, Neil; Apland, James P; Marini, Ann M

    2015-09-01

    Exposure to organophosphorous (OP) nerve agents such as soman inhibits the critical enzyme acetylcholinesterase (AChE) leading to excessive acetylcholine accumulation in synapses, resulting in cholinergic crisis, status epilepticus and brain damage in survivors. The hippocampus is profoundly damaged after soman exposure leading to long-term memory deficits. We have previously shown that treatment with three sequential doses of alpha-linolenic acid, an essential omega-3 polyunsaturated fatty acid, increases brain plasticity in naïve animals. However, the effects of this dosing schedule administered after a brain insult and the underlying molecular mechanisms in the hippocampus are unknown. We now show that injection of three sequential doses of alpha-linolenic acid after soman exposure increases the endogenous expression of mature BDNF, activates Akt and the mammalian target of rapamycin complex 1 (mTORC1), increases neurogenesis in the subgranular zone of the dentate gyrus, increases retention latency in the passive avoidance task and increases animal survival. In sharp contrast, while soman exposure also increases mature BDNF, this increase did not activate downstream signaling pathways or neurogenesis. Administration of the inhibitor of mTORC1, rapamycin, blocked the alpha-linolenic acid-induced neurogenesis and the enhanced retention latency but did not affect animal survival. Our results suggest that alpha-linolenic acid induces a long-lasting neurorestorative effect that involves activation of mTORC1 possibly via a BDNF-TrkB-mediated mechanism. PMID:25920465

  19. Use of Activated Carbon in Packaging to Attenuate Formaldehyde-Induced and Formic Acid-Induced Degradation and Reduce Gelatin Cross-Linking in Solid Dosage Forms.

    PubMed

    Colgan, Stephen T; Zelesky, Todd C; Chen, Raymond; Likar, Michael D; MacDonald, Bruce C; Hawkins, Joel M; Carroll, Sophia C; Johnson, Gail M; Space, J Sean; Jensen, James F; DeMatteo, Vincent A

    2016-07-01

    Formaldehyde and formic acid are reactive impurities found in commonly used excipients and can be responsible for limiting drug product shelf-life. Described here is the use of activated carbon in drug product packaging to attenuate formaldehyde-induced and formic acid-induced drug degradation in tablets and cross-linking in hard gelatin capsules. Several pharmaceutical products with known or potential vulnerabilities to formaldehyde-induced or formic acid-induced degradation or gelatin cross-linking were subjected to accelerated stability challenges in the presence and absence of activated carbon. The effects of time and storage conditions were determined. For all of the products studied, activated carbon attenuated drug degradation or gelatin cross-linking. This novel use of activated carbon in pharmaceutical packaging may be useful for enhancing the chemical stability of drug products or the dissolution stability of gelatin-containing dosage forms and may allow for the 1) extension of a drug product's shelf-life when the limiting attribute is a degradation product induced by a reactive impurity, 2) marketing of a drug product in hotter and more humid climatic zones than currently supported without the use of activated carbon, and 3) enhanced dissolution stability of products that are vulnerable to gelatin cross-linking.

  20. Synergic Interaction of Rifaximin and Mutaflor (Escherichia coli Nissle 1917) in the Treatment of Acetic Acid-Induced Colitis in Rats

    PubMed Central

    Warzecha, Zygmunt; Ceranowicz, Piotr; Dembiński, Marcin; Cieszkowski, Jakub; Bulanda, Małgorzata; Kuśnierz-Cabala, Beata; Gałązka, Krystyna; Konturek, Peter Christopher

    2016-01-01

    Background. Inflammatory bowel disease results from the dysregulation of immune response to environmental and microbial agents in genetically susceptible individuals. The aim of the present study was to examine the effect of rifaximin and/or Mutaflor (Escherichia coli Nissle 1917, EcN) administration on the healing of acetic acid-induced colitis. Methods. Colitis was induced in male Wistar rats by rectal enema with 3.5% acetic acid solution. Rifaximin (50 mg/kg/dose) and/or Mutaflor (109 CFU/dose) were given intragastrically once a day. The severity of colitis was assessed at the 8th day after induction of inflammation. Results. Treatment with rifaximin significantly accelerated the healing of colonic damage. This effect was associated with significant reversion of the acetic acid-evoked decrease in mucosal blood flow and DNA synthesis. Moreover, administration of rifaximin significantly reduced concentration of proinflammatory TNF-α and activity of myeloperoxidase in colonic mucosa. Mutaflor given alone was without significant effect on activity of colitis. In contrast, Mutaflor given in combination with rifaximin significantly enhanced therapeutic effect of rifaximin. Moreover, Mutaflor led to settle of the colon by EcN and this effect was augmented by pretreatment with rifaximin. Conclusion. Rifaximin and Mutaflor exhibit synergic anti-inflammatory and therapeutic effect in acetic acid-induced colitis in rats. PMID:27433160

  1. Intravenous anesthetic propofol suppresses prostaglandin E2 and cysteinyl leukotriene production and reduces edema formation in arachidonic acid-induced ear inflammation.

    PubMed

    Inada, Takefumi; Hirota, Kiichi; Shingu, Koh

    2015-01-01

    Propofol is an intravenous drug widely used for anesthesia and sedation. Previously, propofol was shown to inhibit cyclo-oxygenase (COX) and 5-lipoxygenase (5-LOX) activities. Because these enzyme-inhibiting effects have only been demonstrated in vitro, this study sought to ascertain whether similar effects might also be observed in vivo. In the current studies, effects of propofol were tested in a murine model of arachidonic acid-induced ear inflammation. Specifically, propofol - as a pre-treatment -- was intraperitoneally and then topical application of arachidonic acid was performed. After 1 h, tissue biopsies were collected and tested for the presence of edema and for levels of inflammatory mediators. The results indicated that the administration of propofol significantly suppressed ear edema formation, tissue myeloperoxidase activity, and tissue production of both prostaglandin E2 and cysteinyl leukotrienes. From the data, it can be concluded that propofol could exert anti-COX and anti-5-LOX activities in an in vivo model and that these activities in turn could have, at least in part, suppressed arachidonic acid-induced edema formation in the ear.

  2. Vaccine adjuvants as potential cancer immunotherapeutics.

    PubMed

    Temizoz, Burcu; Kuroda, Etsushi; Ishii, Ken J

    2016-07-01

    Accumulated evidence obtained from various clinical trials and animal studies suggested that cancer vaccines need better adjuvants than those that are currently licensed, which include the most commonly used alum and incomplete Freund's adjuvant, because of either a lack of potent anti-tumor immunity or the induction of undesired immunity. Several clinical trials using immunostimulatory adjuvants, particularly agonistic as well as non-agonistic ligands for TLRs, C-type lectin receptors, retinoic acid-inducible gene I-like receptors and stimulator of interferon genes, have revealed their therapeutic potential not only as vaccine adjuvants but also as anti-tumor agents. Recently, combinations of such immunostimulatory or immunomodulatory adjuvants have shown superior efficacy over their singular use, suggesting that seeking optimal combinations of the currently available or well-characterized adjuvants may provide a better chance for the development of novel adjuvants for cancer immunotherapy. PMID:27006304

  3. Vaccine adjuvants as potential cancer immunotherapeutics

    PubMed Central

    Temizoz, Burcu; Kuroda, Etsushi

    2016-01-01

    Accumulated evidence obtained from various clinical trials and animal studies suggested that cancer vaccines need better adjuvants than those that are currently licensed, which include the most commonly used alum and incomplete Freund’s adjuvant, because of either a lack of potent anti-tumor immunity or the induction of undesired immunity. Several clinical trials using immunostimulatory adjuvants, particularly agonistic as well as non-agonistic ligands for TLRs, C-type lectin receptors, retinoic acid-inducible gene I-like receptors and stimulator of interferon genes, have revealed their therapeutic potential not only as vaccine adjuvants but also as anti-tumor agents. Recently, combinations of such immunostimulatory or immunomodulatory adjuvants have shown superior efficacy over their singular use, suggesting that seeking optimal combinations of the currently available or well-characterized adjuvants may provide a better chance for the development of novel adjuvants for cancer immunotherapy. PMID:27006304

  4. Role of endoperoxides in arachidonic acid-induced vasoconstriction in the isolated perfused kidney of the rat.

    PubMed Central

    Quilley, J.; McGiff, J. C.; Nasjletti, A.

    1989-01-01

    1. Administration of arachidonic acid caused dose-dependent vasoconstriction in the isolated rat kidney perfused in situ with Krebs-Henseleit solution. 2. Inhibition of cyclo-oxygenase with indomethacin or meclofenamate reduced the renal vasoconstrictor effect of arachidonic acid. 3. The renal vasoconstrictor effect of arachidonic acid was unaffected by CGS-13080 at concentrations that effectively reduced thromboxane A2 (TxA2) synthesis by platelets and the kidney. 4. The endoperoxide/TxA2 receptor antagonist, SQ 29,548, abolished the renal vasoconstrictor effect of arachidonic acid and of U46619, an endoperoxide analogue. In contrast, SQ 29,548 did not affect the renal vasoconstrictor response to angiotensin II, prostaglandin E2 or F2 alpha. 5. These data suggest that the vasoconstrictor effect of arachidonic acid in the isolated kidney of the rat is mediated by its metabolites, including the prostaglandin endoperoxides. PMID:2522332

  5. Transcriptome analysis of the hippocampal CA1 pyramidal cell region after kainic acid-induced status epilepticus in juvenile rats.

    PubMed

    Laurén, Hanna B; Lopez-Picon, Francisco R; Brandt, Annika M; Rios-Rojas, Clarissa J; Holopainen, Irma E

    2010-01-01

    Molecular mechanisms involved in epileptogenesis in the developing brain remain poorly understood. The gene array approach could reveal some of the factors involved by allowing the identification of a broad scale of genes altered by seizures. In this study we used microarray analysis to reveal the gene expression profile of the laser microdissected hippocampal CA1 subregion one week after kainic acid (KA)-induced status epilepticus (SE) in 21-day-old rats, which are developmentally roughly comparable to juvenile children. The gene expression analysis with the Chipster software generated a total of 1592 differently expressed genes in the CA1 subregion of KA-treated rats compared to control rats. The KEGG database revealed that the identified genes were involved in pathways such as oxidative phosporylation (26 genes changed), and long-term potentiation (LTP; 18 genes changed). Also genes involved in Ca(2+) homeostasis, gliosis, inflammation, and GABAergic transmission were altered. To validate the microarray results we further examined the protein expression for a subset of selected genes, glial fibrillary protein (GFAP), apolipoprotein E (apo E), cannabinoid type 1 receptor (CB1), Purkinje cell protein 4 (PEP-19), and interleukin 8 receptor (CXCR1), with immunohistochemistry, which confirmed the transcriptome results. Our results showed that SE resulted in no obvious CA1 neuronal loss, and alterations in the expression pattern of several genes during the early epileptogenic phase were comparable to previous gene expression studies of the adult hippocampus of both experimental epileptic animals and patients with temporal lobe epilepsy (TLE). However, some changes seem to occur after SE specifically in the juvenile rat hippocampus. Insight of the SE-induced alterations in gene expression and their related pathways could give us hints for the development of new target-specific antiepileptic drugs that interfere with the progression of the disease in the juvenile age

  6. Mice with hepatocyte-specific FXR deficiency are resistant to spontaneous but susceptible to cholic acid-induced hepatocarcinogenesis.

    PubMed

    Kong, Bo; Zhu, Yan; Li, Guodong; Williams, Jessica A; Buckley, Kyle; Tawfik, Ossama; Luyendyk, James P; Guo, Grace L

    2016-03-01

    Farnesoid X receptor (FXR) belongs to the nuclear receptor superfamily with its endogenous ligands bile acids. Mice with whole body FXR deficiency develop liver tumors spontaneously, but the underlying mechanism is unclear. Moreover, it is unknown whether FXR deficiency in liver alone serves as a tumor initiator or promoter during liver carcinogenesis. This study aims to evaluate the effects of hepatocyte-specific FXR deficiency (FXR(hep-/-)) in liver tumor formation. The results showed that FXR(hep-/-) mice did not show spontaneous liver tumorigenesis with aging (up to 24 mo of age). Therefore FXR(hep-/-) mice were fed a bile acid (cholic acid)-containing diet alone or along with a liver tumor initiator, diethylnitrosamine (DEN). Thirty weeks later, no tumors were found in wild-type or FXR(hep-/-) mice without any treatment or with DEN only. However, with cholic acid, while only some wild-type mice developed tumors, all FXR(hep-/-) mice presented with severe liver injury and tumors. Interestingly, FXR(hep-/-) mouse livers increased basal expression of tumor suppressor p53 protein, apoptosis, and decreased basal cyclin D1 expression, which may prevent tumor development in FXR(hep-/-) mice. However, cholic acid feeding reversed these effects in FXR(hep-/-) mice, which is associated with an increased cyclin D1 and decreased cell cycle inhibitors. More in-depth analysis indicates that the increased in cell growth might result from disturbance of the MAPK and JAK/Stat3 signaling pathways. In conclusion, this study shows that hepatic FXR deficiency may only serve as a tumor initiator, and increased bile acids is required for tumor formation likely by promoting cell proliferation. PMID:26744468

  7. Benefits of agomelatine in behavioral, neurochemical and blood brain barrier alterations in prenatal valproic acid induced autism spectrum disorder.

    PubMed

    Kumar, Hariom; Sharma, B M; Sharma, Bhupesh

    2015-12-01

    Valproic acid administration during gestational period causes behavior and biochemical deficits similar to those observed in humans with autism spectrum disorder. Although worldwide prevalence of autism spectrum disorder has been increased continuously, therapeutic agents to ameliorate the social impairment are very limited. The present study has been structured to investigate the therapeutic potential of melatonin receptor agonist, agomelatine in prenatal valproic acid (Pre-VPA) induced autism spectrum disorder in animals. Pre-VPA has produced reduction in social interaction (three chamber social behavior apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complex I, II, IV). Furthermore, Pre-VPA has increased locomotor activity (actophotometer), anxiety, brain oxidative stress (thiobarbituric acid reactive species, glutathione, and catalase), nitrosative stress (nitrite/nitrate), inflammation (brain and ileum myeloperoxidase activity), calcium levels and blood brain barrier leakage in animals. Treatment with agomelatine has significantly attenuated Pre-VPA induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, agomelatine also attenuated Pre-VPA induced increase in locomotion, anxiety, brain oxidative stress, nitrosative stress, inflammation, calcium levels and blood brain barrier leakage. It is concluded that, Pre-VPA has induced autism spectrum disorder, which was attenuated by agomelatine. Agomelatine has shown ameliorative effect on behavioral, neurochemical and blood brain barrier alteration in Pre-VPA exposed animals. Thus melatonin receptor agonists may provide beneficial therapeutic strategy for managing autism spectrum disorder. PMID:26498253

  8. Perfluorooctanoic acid induces gene promoter hypermethylation of glutathione-S-transferase Pi in human liver L02 cells.

    PubMed

    Tian, Meiping; Peng, Siyuan; Martin, Francis L; Zhang, Jie; Liu, Liangpo; Wang, Zhanlin; Dong, Sijun; Shen, Heqing

    2012-06-14

    Perfluorooctanoic acid (PFOA) is one of the most commonly used perfluorinated compounds. Being a persistent environmental pollutant, it can accumulate in human tissues via various exposure routes. PFOA may interfere in a toxic fashion on the immune system, liver, development, and endocrine systems. In utero human exposure had been associated with cord serum global DNA hypomethylation. In light of this, we investigated possible PFOA-induced DNA methylation alterations in L02 cells in order to shed light into its epigenetic-mediated mechanisms of toxicity in human liver. L02 cells were exposed to 5, 10, 25, 50 or 100 mg/L PFOA for 72h. Global DNA methylation levels were determined by LC/ESI-MS, glutathione-S-transferase Pi (GSTP) gene promoter DNA methylation was investigated by methylation-specific polymerase chain reaction (PCR) with bisulfite sequencing, and consequent mRNA expression levels were measured with quantitative real-time reverse transcriptase PCR. A dose-related increase of GSTP promoter methylation at the transcription factor specificity protein 1 (SP1) binding site was observed. However, PFOA did not significantly influence global DNA methylation; nor did it markedly alter the promoter gene methylation of p16 (cyclin-dependent kinase inhibitor 2A), ERα (estrogen receptor α) or PRB (progesterone receptor B). In addition, PFOA significantly elevated mRNA transcript levels of DNMT3A (which mediates de novo DNA methylation), Acox (lipid metabolism) and p16 (cell apoptosis). Considering the role of GSTP in detoxification, aberrant methylation may be pivotal in PFOA-mediated toxicity response via the inhibition of SP1 binding to GSTP promoter. PMID:22425687

  9. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum.

    PubMed

    Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

    2012-10-01

    Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal L-glutamate (L-Glu) and 5'-inosine monophosphate (IMP) synergistically increases duodenal HCO3- secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3- secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3- secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. L-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced L-Glu/IMP-induced HCO3- secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3- secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3- secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced L-Glu/IMP-induced HCO3- secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal L-Glu/IMP-induced and TGR5 agonist-induced HCO3- secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3- secretion.

  10. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum

    PubMed Central

    Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H.; Engel, Eli; Kaunitz, Jonathan D.

    2012-01-01

    Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal l-glutamate (l-Glu) and 5′-inosine monophosphate (IMP) synergistically increases duodenal HCO3− secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3− secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3− secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. l-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced l-Glu/IMP-induced HCO3− secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3− secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3− secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced l-Glu/IMP-induced HCO3− secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal l-Glu/IMP-induced and TGR5 agonist-induced HCO3− secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3− secretion

  11. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum.

    PubMed

    Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

    2012-10-01

    Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal L-glutamate (L-Glu) and 5'-inosine monophosphate (IMP) synergistically increases duodenal HCO3- secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3- secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3- secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. L-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced L-Glu/IMP-induced HCO3- secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3- secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3- secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced L-Glu/IMP-induced HCO3- secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal L-Glu/IMP-induced and TGR5 agonist-induced HCO3- secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3- secretion. PMID:22821947

  12. Inhibitory effect of fangchinoline on excitatory amino acids-induced neurotoxicity in cultured rat cerebellar granule cells.

    PubMed

    Kim, S D; Oh, S K; Kim, H S; Seong, Y H

    2001-04-01

    Glutamate receptors-mediated excitotoxicity is believed to play a role in the pathophysiology of neurodegenerative diseases. The present study was performed to evaluate the inhibitory effect of fangchinoline, a bis-benzylisoquinoline alkaloid, which has a characteristic as a Ca2+ channel blocker, on excitatory amino acids (EAAs)-induced neurotoxicity in cultured rat cerebellar granule neuron. Fangchinoline (1 and 5 microM) inhibited glutamate (1 mM), N-methyl-D-aspartate (NMDA; 1 mM) and kainate (100 microM)-induced neuronal cell death which was measured by trypan blue exclusion test. Fangchinoline (1 and 5 microM) inhibited glutamate release into medium induced by NMDA (1 mM) and kainate (100 microM), which was measured by HPLC. And fangchinoline (5 microM) inhibited glutamate (1 mM)-induced elevation of intracellular calcium concentration. These results suggest that inhibition of Ca2+ influx by fangchinoline may contribute to the beneficial effects on neurodegenerative effect of glutamate in pathophysiological conditions. PMID:11339637

  13. Lysophosphatidic acid induces reactive oxygen species generation by activating protein kinase C in PC-3 human prostate cancer cells

    SciTech Connect

    Lin, Chu-Cheng; Lin, Chuan-En; Lin, Yueh-Chien; Ju, Tsai-Kai; Huang, Yuan-Li; Lee, Ming-Shyue; Chen, Jiun-Hong; Lee, Hsinyu

    2013-11-01

    Highlights: •LPA induces ROS generation through LPA{sub 1} and LPA{sub 3}. •LPA induces ROS generation by activating PLC. •PKCζ mediates LPA-induced ROS generation. -- Abstract: Prostate cancer is one of the most frequently diagnosed cancers in males, and PC-3 is a cell model popularly used for investigating the behavior of late stage prostate cancer. Lysophosphatidic acid (LPA) is a lysophospholipid that mediates multiple behaviors in cancer cells, such as proliferation, migration and adhesion. We have previously demonstrated that LPA enhances vascular endothelial growth factor (VEGF)-C expression in PC-3 cells by activating the generation of reactive oxygen species (ROS), which is known to be an important mediator in cancer progression. Using flow cytometry, we showed that LPA triggers ROS generation within 10 min and that the generated ROS can be suppressed by pretreatment with the NADPH oxidase (Nox) inhibitor diphenylene iodonium. In addition, transfection with LPA{sub 1} and LPA{sub 3} siRNA efficiently blocked LPA-induced ROS production, suggesting that both receptors are involved in this pathway. Using specific inhibitors and siRNA, phospholipase C (PLC) and protein kinase C (PKC) were also suggested to participate in LPA-induced ROS generation. Overall, we demonstrated that LPA induces ROS generation in PC-3 prostate cancer cells and this is mediated through the PLC/PKC/Nox pathway.

  14. Retinoic acid-induced developmental defects are mediated by RARbeta/RXR heterodimers in the pharyngeal endoderm.

    PubMed

    Matt, Nicolas; Ghyselinck, Norbert B; Wendling, Olivia; Chambon, Pierre; Mark, Manuel

    2003-05-01

    Fusion and hypoplasia of the first two branchial arches, a defect typically observed in retinoic acid (RA) embryopathy, is generated in cultured mouse embryos upon treatment with BMS453, a synthetic compound that exhibits retinoic acid receptor beta (RARbeta) agonistic properties in transfected cells. By contrast, no branchial arch defects are observed following treatment with synthetic retinoids that exhibit RARalpha or RARgamma agonistic properties. The BMS453-induced branchial arch defects are mediated through RAR activation, as they are similar to those generated by a selective pan-RAR agonist, are prevented by a selective pan-RAR antagonist and cannot be mimicked by exposure to a pan-RXR agonist alone. They are enhanced in the presence of a pan-RXR agonist, and cannot be generated in Rarb-null embryos. Furthermore, they are accompanied, in the morphologically altered region, by ectopic expression of Rarb and of several other direct RA target genes. Therefore, craniofacial abnormalities characteristic of the RA embryopathy are mediated through ectopic activation of RARbeta/RXR heterodimers, in which the ligand-dependent activity of RXR is subordinated to that of RARbeta. Endodermal cells lining the first two branchial arches respond to treatment with the RARbeta agonist, in contrast to neural crest cells and ectoderm, which suggests that a faulty endodermal regionalization is directly responsible for RA-induced branchial arch dysmorphologies. Additionally, we provide the first in vivo evidence that the synthetic RARbeta agonist BMS453 exhibits an antagonistic activity on the two other RAR isotypes. PMID:12668623

  15. The parasitic plant Cuscuta australis is highly insensitive to abscisic acid-induced suppression of hypocotyl elongation and seed germination.

    PubMed

    Li, Juan; Hettenhausen, Christian; Sun, Guiling; Zhuang, Huifu; Li, Jian-Hong; Wu, Jianqiang

    2015-01-01

    Around 1% of angiosperms are parasitic plants. Their growth and development solely or partly depend on host plants from which they extract water, nutrients, and other molecules using a parasitic plant-specific organ, the haustorium. Strong depletion of nutrients can result in serious growth retardation and in some cases, death of the hosts. The genus Cuscuta (dodder) comprises about 200 holoparasitic species occurring on all continents. Their seedlings have no roots and cotyledons but are only string-like hypocotyls. When they contact suitable host plants, haustoria are formed and thereafter seedlings rapidly develop into vigorously growing branches without roots and leaves. This highly specialized lifestyle suggests that Cuscuta plants likely have unique physiology in development and stress responses. Using germination and seedling growth assays, we show that C. australis seeds and seedlings are highly insensitive to abscisic acid (ABA). Transcriptome analysis and protein sequence alignment with Arabidopsis, tomato, and rice homologs revealed that C. australis most likely consists of only four functional ABA receptors. Given that Cuscuta plants are no longer severely challenged by drought stress, we hypothesize that the ABA-mediated drought resistance pathway in Cuscuta spp. might have had degenerated over time during evolution. PMID:26258814

  16. Involvement of the neuronal phosphotyrosine signal adaptor N-Shc in kainic acid-induced epileptiform activity

    PubMed Central

    Baba, Shiro; Onga, Kazuko; Kakizawa, Sho; Ohyama, Kyoji; Yasuda, Kunihiko; Otsubo, Hiroshi; Scott, Brian W.; Burnham, W. McIntyre; Matsuo, Takayuki; Nagata, Izumi; Mori, Nozomu

    2016-01-01

    BDNF-TrkB signaling is implicated in experimental seizures and epilepsy. However, the downstream signaling involved in the epileptiform activity caused by TrkB receptor activation is still unknown. The aim of the present study was to determine whether TrkB-mediated N-Shc signal transduction was involved in kainic acid (KA)-induced epileptiform activity. We investigated KA-induced behavioral seizures, epileptiform activities and neuronal cell loss in hippocampus between N-Shc deficient and control mice. There was a significant reduction in seizure severity and the frequency of epileptiform discharges in N-Shc deficient mice, as compared with wild-type and C57BL/6 mice. KA-induced neuronal cell loss in the CA3 of hippocampus was also inhibited in N-Shc deficient mice. This study demonstrates that the activation of N-Shc signaling pathway contributes to an acute KA-induced epileptiform activity and neuronal cell loss in the hippocampus. We propose that the N-Shc-mediated signaling pathway could provide a potential target for the novel therapeutic approaches of epilepsy. PMID:27273072

  17. Omega-9 Oleic Acid Induces Fatty Acid Oxidation and Decreases Organ Dysfunction and Mortality in Experimental Sepsis.

    PubMed

    Gonçalves-de-Albuquerque, Cassiano Felippe; Medeiros-de-Moraes, Isabel Matos; Oliveira, Flora Magno de Jesus; Burth, Patrícia; Bozza, Patrícia Torres; Castro Faria, Mauro Velho; Silva, Adriana Ribeiro; Castro-Faria-Neto, Hugo Caire de

    2016-01-01

    Sepsis is characterized by inflammatory and metabolic alterations, which lead to massive cytokine production, oxidative stress and organ dysfunction. In severe systemic inflammatory response syndrome, plasma non-esterified fatty acids (NEFA) are increased. Several NEFA are deleterious to cells, activate Toll-like receptors and inhibit Na+/K+-ATPase, causing lung injury. A Mediterranean diet rich in olive oil is beneficial. The main component of olive oil is omega-9 oleic acid (OA), a monounsaturated fatty acid (MUFA). We analyzed the effect of OA supplementation on sepsis. OA ameliorated clinical symptoms, increased the survival rate, prevented liver and kidney injury and decreased NEFA plasma levels in mice subjected to cecal ligation and puncture (CLP). OA did not alter food intake and weight gain but diminished reactive oxygen species (ROS) production and NEFA plasma levels. Carnitine palmitoyltransferase IA (CPT1A) mRNA levels were increased, while uncoupling protein 2 (UCP2) liver expression was enhanced in mice treated with OA. OA also inhibited the decrease in 5' AMP-activated protein kinase (AMPK) expression and increased the enzyme expression in the liver of OA-treated mice compared to septic animals. We showed that OA pretreatment decreased NEFA concentration and increased CPT1A and UCP2 and AMPK levels, decreasing ROS production. We suggest that OA has a beneficial role in sepsis by decreasing metabolic dysfunction, supporting the benefits of diets high in monounsaturated fatty acids (MUFA). PMID:27078880

  18. EGFR Inhibition Blocks Palmitic Acid-induced inflammation in cardiomyocytes and Prevents Hyperlipidemia-induced Cardiac Injury in Mice.

    PubMed

    Li, Weixin; Fang, Qilu; Zhong, Peng; Chen, Lingfeng; Wang, Lintao; Zhang, Yali; Wang, Jun; Li, Xiaokun; Wang, Yi; Wang, Jingying; Liang, Guang

    2016-01-01

    Obesity is often associated with increased risk of cardiovascular diseases. Previous studies suggest that epidermal growth factor receptor (EGFR) antagonism may be effective for the treatment of angiotensin II-induced cardiac hypertrophy and diabetic cardiomyopathy. This study was performed to demonstrate if EGFR plays a role in the pathogenesis of hyperlipidemia/obesity-related cardiac injuries. The in vivo studies using both wild type (WT) and apolipoprotein E (ApoE) knockout mice fed with high fat diet (HFD) showed the beneficial effects of small-molecule EGFR inhibitors, AG1478 and 542, against obesity-induced myocardial injury. Administration of AG1478 and 542 significantly reduced myocardial inflammation, fibrosis, apoptosis, and dysfunction in both two obese mouse models. In vitro, EGFR signaling was blocked by either siRNA silencing or small-molecule EGFR inhibitors in palmitic acid (PA)-stimulated cardiomyocytes. EGFR inhibition attenuated PA-induced inflammatory response and apoptosis in H9C2 cells. Furthermore, we found that PA-induced EGFR activation was mediated by the upstream TLR4 and c-Src. This study has confirmed the detrimental effect of EGFR activation in the pathogenesis of obesity-induced cardiac inflammatory injuries in experimental mice, and has demonstrated the TLR4/c-Src-mediated mechanisms for PA-induced EGFR activation. Our data suggest that EGFR may be a therapeutic target for obesity-related cardiovascular diseases. PMID:27087279

  19. The parasitic plant Cuscuta australis is highly insensitive to abscisic acid-induced suppression of hypocotyl elongation and seed germination.

    PubMed

    Li, Juan; Hettenhausen, Christian; Sun, Guiling; Zhuang, Huifu; Li, Jian-Hong; Wu, Jianqiang

    2015-01-01

    Around 1% of angiosperms are parasitic plants. Their growth and development solely or partly depend on host plants from which they extract water, nutrients, and other molecules using a parasitic plant-specific organ, the haustorium. Strong depletion of nutrients can result in serious growth retardation and in some cases, death of the hosts. The genus Cuscuta (dodder) comprises about 200 holoparasitic species occurring on all continents. Their seedlings have no roots and cotyledons but are only string-like hypocotyls. When they contact suitable host plants, haustoria are formed and thereafter seedlings rapidly develop into vigorously growing branches without roots and leaves. This highly specialized lifestyle suggests that Cuscuta plants likely have unique physiology in development and stress responses. Using germination and seedling growth assays, we show that C. australis seeds and seedlings are highly insensitive to abscisic acid (ABA). Transcriptome analysis and protein sequence alignment with Arabidopsis, tomato, and rice homologs revealed that C. australis most likely consists of only four functional ABA receptors. Given that Cuscuta plants are no longer severely challenged by drought stress, we hypothesize that the ABA-mediated drought resistance pathway in Cuscuta spp. might have had degenerated over time during evolution.

  20. Uric Acid Induces Trophoblast Il-1β Production Via The Inflammasome: Implications For The Pathogenesis Of Preeclampsia

    PubMed Central

    Mulla, Melissa J.; Myrtolli, Kledia; Potter, Julie; Boeras, Crina; Kavathas, Paula B.; Sfakianaki, Anna K.; Tadesse, Serkelem; Norwitz, Errol R.; Guller, Seth; Abrahams, Vikki M.

    2010-01-01

    Problem Preeclampsia is associated with hyperuricemia, which correlates with the disease severity. Levels of circulating uric acid increase before the clinical manifestations, suggesting they may be causally related. Uric acid, or monosodium urate (MSU), activates the Nod-like receptor, Nalp3, leading to inflammasome activation and IL-1β processing. Since preeclampsia is associated with placental immune/inflammatory dysregulation, we sought to determine in the trophoblast, the presence of the Nalp3 inflammasome, and the effect of MSU on its activation. Method of Study Isolated first and third trimester trophoblast were assessed for expression of the inflammasome components, Nalp1, Nalp3 and ASC. First trimester trophoblast cells were incubated with or without MSU, after which, IL-1β secretion and processing and caspase-1 activation was determined. Results Trophoblast cells expressed Nalp1, Nalp3 and ASC under basal conditions. Following incubation with MSU, first trimester trophoblast IL-1β secretion was upregulated. This correlated with increased expression levels of active IL-1β and active caspase-1. ASC knockdown reduced MSU-induced IL-1β secretion. Conclusion These findings demonstrate that uric acid activates the inflammasome in the trophoblast, leading to IL-1β production. This may provide a novel mechanism for the induction of inflammation at the maternal-fetal interface leading to placental dysfunction and adverse pregnancy outcome, including preeclampsia. PMID:21352397

  1. The Parasitic Plant Cuscuta australis Is Highly Insensitive to Abscisic Acid-Induced Suppression of Hypocotyl Elongation and Seed Germination

    PubMed Central

    Li, Juan; Hettenhausen, Christian; Sun, Guiling; Zhuang, Huifu; Li, Jian-Hong; Wu, Jianqiang

    2015-01-01

    Around 1% of angiosperms are parasitic plants. Their growth and development solely or partly depend on host plants from which they extract water, nutrients, and other molecules using a parasitic plant-specific organ, the haustorium. Strong depletion of nutrients can result in serious growth retardation and in some cases, death of the hosts. The genus Cuscuta (dodder) comprises about 200 holoparasitic species occurring on all continents. Their seedlings have no roots and cotyledons but are only string-like hypocotyls. When they contact suitable host plants, haustoria are formed and thereafter seedlings rapidly develop into vigorously growing branches without roots and leaves. This highly specialized lifestyle suggests that Cuscuta plants likely have unique physiology in development and stress responses. Using germination and seedling growth assays, we show that C. australis seeds and seedlings are highly insensitive to abscisic acid (ABA). Transcriptome analysis and protein sequence alignment with Arabidopsis, tomato, and rice homologs revealed that C. australis most likely consists of only four functional ABA receptors. Given that Cuscuta plants are no longer severely challenged by drought stress, we hypothesize that the ABA-mediated drought resistance pathway in Cuscuta spp. might have had degenerated over time during evolution. PMID:26258814

  2. Cytosolic phospholipase A2-driven PGE2 synthesis within unsaturated fatty acids-induced lipid bodies of epithelial cells.

    PubMed

    Moreira, Luciana S; Piva, Bruno; Gentile, Luciana B; Mesquita-Santos, Fabio P; D'Avila, Heloisa; Maya-Monteiro, Clarissa M; Bozza, Patricia T; Bandeira-Melo, Christianne; Diaz, Bruno L

    2009-03-01

    Cytoplasmic lipid bodies (also known as lipid droplets) are intracellular deposits of arachidonic acid (AA), which can be metabolized for eicosanoid generation. PGE2 is a major AA metabolite produced by epithelial cells and can modulate restoration of epithelium homeostasis after injury. We studied lipid body biogenesis and their role in AA metabolic pathway in an epithelial cell line derived from normal rat intestinal epithelium, IEC-6 cells. Lipid bodies were virtually absent in confluent IEC-6 cells. Stimulation of confluent IEC-6 cells with unsaturated fatty acids, including AA or oleic acid (OA), induced rapid lipid body assembly that was independent on its metabolism to PGE(2), but dependent on G-coupled receptor-driven signaling through p38, PKC, and PI3 K. Newly formed lipid bodies compartmentalized cytosolic phospholipase (cPL)A(2)-alpha, while facilitated AA mobilization and synthesis of PGE(2) within epithelial cells. Thus, both lipid body-related events, including highly regulated biogenesis and functional assembly of cPLA (2)-alpha-driven enhanced AA mobilization and PGE(2)production, may have key roles in epithelial cell-driven inflammatory functions, and may represent relevant therapeutic targets of epithelial pathologies.

  3. Omega-9 Oleic Acid Induces Fatty Acid Oxidation and Decreases Organ Dysfunction and Mortality in Experimental Sepsis

    PubMed Central

    Oliveira, Flora Magno de Jesus; Burth, Patrícia; Bozza, Patrícia Torres; Castro Faria, Mauro Velho; Silva, Adriana Ribeiro; de Castro-Faria-Neto, Hugo Caire

    2016-01-01

    Sepsis is characterized by inflammatory and metabolic alterations, which lead to massive cytokine production, oxidative stress and organ dysfunction. In severe systemic inflammatory response syndrome, plasma non-esterified fatty acids (NEFA) are increased. Several NEFA are deleterious to cells, activate Toll-like receptors and inhibit Na+/K+-ATPase, causing lung injury. A Mediterranean diet rich in olive oil is beneficial. The main component of olive oil is omega-9 oleic acid (OA), a monounsaturated fatty acid (MUFA). We analyzed the effect of OA supplementation on sepsis. OA ameliorated clinical symptoms, increased the survival rate, prevented liver and kidney injury and decreased NEFA plasma levels in mice subjected to cecal ligation and puncture (CLP). OA did not alter food intake and weight gain but diminished reactive oxygen species (ROS) production and NEFA plasma levels. Carnitine palmitoyltransferase IA (CPT1A) mRNA levels were increased, while uncoupling protein 2 (UCP2) liver expression was enhanced in mice treated with OA. OA also inhibited the decrease in 5' AMP-activated protein kinase (AMPK) expression and increased the enzyme expression in the liver of OA-treated mice compared to septic animals. We showed that OA pretreatment decreased NEFA concentration and increased CPT1A and UCP2 and AMPK levels, decreasing ROS production. We suggest that OA has a beneficial role in sepsis by decreasing metabolic dysfunction, supporting the benefits of diets high in monounsaturated fatty acids (MUFA). PMID:27078880

  4. RIPPLY3 is a retinoic acid-inducible repressor required for setting the borders of the pre-placodal ectoderm

    PubMed Central

    Janesick, Amanda; Shiotsugu, Jason; Taketani, Mao; Blumberg, Bruce

    2012-01-01

    Retinoic acid signaling is a major component of the neural posteriorizing process in vertebrate development. Here, we identify a new role for the retinoic acid receptor (RAR) in the anterior of the embryo, where RAR regulates Fgf8 expression and formation of the pre-placodal ectoderm (PPE). RARα2 signaling induces key pre-placodal genes and establishes the posterolateral borders of the PPE. RAR signaling upregulates two important genes, Tbx1 and Ripply3, during early PPE development. In the absence of RIPPLY3, TBX1 is required for the expression of Fgf8 and hence, PPE formation. In the presence of RIPPLY3, TBX1 acts as a transcriptional repressor, and functions to restrict the positional expression of Fgf8, a key regulator of PPE gene expression. These results establish a novel role for RAR as a regulator of spatial patterning of the PPE through Tbx1 and RIPPLY3. Moreover, we demonstrate that Ripply3, acting downstream of RAR signaling, is a key player in establishing boundaries in the PPE. PMID:22354841

  5. Confocal Raman micro-spectroscopy for rapid and label-free detection of maleic acid-induced variations in human sperm

    PubMed Central

    Li, Ning; Chen, Diling; Xu, Yan; Liu, Songhao; Zhang, Heming

    2014-01-01

    Confocal Raman microspectroscopy is a valuable analytical tool in biological and medical research, allowing the detection of sample variations without external labels or extensive preparation. To determine whether this method can assess the effect of maleic acid on sperm, we prepared human sperm samples incubated in different concentrations of maleic acid, after which Raman spectra from the various regions of sperm cells were recorded. Following the maleic acid treatment, Raman spectra indicated significant changes. Combined with other means, we found that the structures and chemical compositions of sperm membranes were damaged, and even the sperm DNA was damaged by the incorporation of maleic acid. Thus, this technique can be used for detection and identification of maleic acid-induced changes in human sperm at a molecular level. Although this particular application of Raman microspectroscopy still requires further validation, it has potentially promise as a diagnostic tool for reproductive medicine. PMID:24877025

  6. Yogurt containing Lactobacillus gasseri OLL 2716 (LG21 yogurt) accelerated the healing of acetic acid-induced gastric ulcer in rats.

    PubMed

    Uchida, Masayuki; Shimizu, Kimiko; Kurakazu, Keiko

    2010-01-01

    We have reported that LG21 yogurt containing Lactobacillus gasseri OLL 2716 (LG21 yogurt) inhibits the formation of HCl-induced acute gastric lesions through the generation of prostaglandin E₂. This study aimed to determine the role of viable Lactobacillus in the healing of acetic acid-induced chronic gastric ulcer. LG21 yogurt or γ-ray radiated LG21 yogurt was administered orally twice a day for 10 d at a dose of 5 ml/kg. LG21 yogurt significantly accelerated the healing of the ulcer, but γ-ray radiated LG21 yogurt did not. However, both yogurts significantly inhibited HCl-induced gastric erosive lesions and enhanced the generation of gastric mucosal prostaglandin E₂. From the above results, it was found that viable bacteria are needed to accelerate the healing of chronic gastric ulcer, but not to inhibit gastric lesions.

  7. [The influence of high pressure on the 3-indoleacetic-acid-induced curvature of Avena coleoptiles in the Went-test].

    PubMed

    Chrometzka, P

    1967-12-01

    1. High atmospheric pressure causes an increase of the 3-indoleacetic-acid-induced curvature of Avena coleoptiles in the Went-test, regardless of whether the applied gas is nitrogen, hydrogen, oxygen, or air. 2. The highest increase was caused by high pressure of oxygen, the lowest by lack of oxygen. 3. The high pressure effect was also observed with coleoptiles which were treated 20 hours prior to the test and which were then kept under normal pressure. 4. High pressure of oxygen for a long period (20 hours) had a poisonous effect on the coleoptiles. They ceased to grow. Preliminary studies have shown that the respiration is enhanced if the coleoptiles have been kept under high pressure. PMID:24554325

  8. Chemometrics-assisted Spectrofluorimetric Determination of Two Co-administered Drugs of Major Interaction, Methotrexate and Aspirin, in Human Urine Following Acid-induced Hydrolysis.

    PubMed

    Maher, Hadir M; Ragab, Marwa A A; El-Kimary, Eman I

    2015-01-01

    Methotrexate (MTX) is widely used to treat rheumatoid arthritis (RA), mostly along with non-steroidal anti-inflammatory drugs (NSAIDs), the most common of which is aspirin or acetyl salicylic acid (ASA). Since NSAIDs impair MTX clearance and increase its toxicity, it was necessary to develop a simple and reliable method for the monitoring of MTX levels in urine samples, when coadministered with ASA. The method was based on the spectrofluorimetric measurement of the acid-induced hydrolysis product of MTX, 4-amino-4-deoxy-10-methylpteroic acid (AMP), along with the strongly fluorescent salicylic acid (SA), a product of acid-induced hydrolysis of aspirin and its metabolites in urine. The overlapping emission spectra were resolved using the derivative method (D method). In addition, the corresponding derivative emission spectra were convoluted using discrete Fourier functions, 8-points sin xi polynomials, (D/FF method) for better elimination of interferences. Validation of the developed methods was carried out according to the ICH guidelines. Moreover, the data obtained using derivative and convoluted derivative spectra were treated using the non-parametric Theil's method (NP), compared with the least-squares parametric regression method (LSP). The results treated with Theil's method were more accurate and precise compared with LSP since the former is less affected by the outliers. This work offers the potential of both derivative and convolution using discrete Fourier functions in addition to the effectiveness of using the NP regression analysis of data. The high sensitivity obtained by the proposed methods was promising for measuring low concentration levels of the two drugs in urine samples. These methods were efficiently used to measure the drugs in human urine samples following their co-administration. PMID:26234512

  9. Functional analysis of a tannic-acid-inducible and hypoviral-regulated small heat-shock protein Hsp24 from the chestnut blight fungus Cryphonectria parasitica.

    PubMed

    Baek, Jin-Ho; Park, Jin-Ah; Kim, Jung-Mi; Oh, Jung-Mi; Park, Seung-Moon; Kim, Dae-Hyuk

    2014-01-01

    A small heat-shock protein gene, CpHsp24, of Cryphonectria parasitica was selected based on its expression pattern, which showed that it was tannic acid inducible and that its induction was severely hampered by a hypovirus. The predicted protein sequence of CpHsp24 consisted of a hallmark α-crystalline domain flanked by a variable N-terminal and a short C-terminal region. Disruption of CpHsp24 resulted in a slow growth rate under standard growth conditions. The CpHsp24-null mutant showed enhanced sensitivity to heat shock, which was consistent with Northern and Western analyses displaying the heat-shock induction of the CpHsp24 gene and protein, respectively. Virulence tests on the excised bark revealed a severe decrease in the necrotic area of the CpHsp24-null mutant. When the hypovirus was transferred, virus-containing CpHsp24-null progeny displayed severely retarded growth patterns with hypovirulent characteristics of reduced pigmentation and sporulation. Because the tannic-acid-inducible and hypoviral-suppressible expression and the severely impaired virulence are also characteristics of the laccase3 gene (lac3), lac3 expression in the CpHsp24-null mutant was also examined. The resulting lac3 induction was severely affected in the CpHsp24-null mutant, suggesting that CpHsp24 is important for lac3 induction and that CpHsp24 may act as a molecular chaperone for the lac3 protein.

  10. Analgesic and Anti-Inflammatory Properties of Gelsolin in Acetic Acid Induced Writhing, Tail Immersion and Carrageenan Induced Paw Edema in Mice

    PubMed Central

    Gupta, Ashok Kumar; Parasar, Devraj; Sagar, Amin; Choudhary, Vikas; Chopra, Bhupinder Singh; Garg, Renu; Ashish; Khatri, Neeraj

    2015-01-01

    Plasma gelsolin levels significantly decline in several disease conditions, since gelsolin gets scavenged when it depolymerizes and caps filamentous actin released in the circulation following tissue injury. It is well established that our body require/implement inflammatory and analgesic responses to protect against cell damage and injury to the tissue. This study was envisaged to examine analgesic and anti-inflammatory activity of exogenous gelsolin (8 mg/mouse) in mice models of pain and acute inflammation. Administration of gelsolin in acetic acid-induced writhing and tail immersion tests not only demonstrated a significant reduction in the number of acetic acid-induced writhing effects, but also exhibited an analgesic activity in tail immersion test in mice as compared to placebo treated mice. Additionally, anti-inflammatory function of gelsolin (8 mg/mouse) compared with anti-inflammatory drug diclofenac sodium (10 mg/kg)] was confirmed in the carrageenan injection induced paw edema where latter was measured by vernier caliper and fluorescent tomography imaging. Interestingly, results showed that plasma gelsolin was capable of reducing severity of inflammation in mice comparable to diclofenac sodium. Analysis of cytokines and histo-pathological examinations of tissue revealed administration of gelsolin and diclofenac sodium significantly reduced production of pro-inflammatory cytokines, TNF-α and IL-6. Additionally, carrageenan groups pretreated with diclofenac sodium or gelsolin showed a marked decrease in edema and infiltration of inflammatory cells in paw tissue. Our study provides evidence that administration of gelsolin can effectively reduce the pain and inflammation in mice model. PMID:26426535

  11. Cyclic phosphatidic acid and lysophosphatidic acid induce hyaluronic acid synthesis via CREB transcription factor regulation in human skin fibroblasts.

    PubMed

    Maeda-Sano, Katsura; Gotoh, Mari; Morohoshi, Toshiro; Someya, Takao; Murofushi, Hiromu; Murakami-Murofushi, Kimiko

    2014-09-01

    Cyclic phosphatidic acid (cPA) is a naturally occurring phospholipid mediator and an analog of the growth factor-like phospholipid lysophosphatidic acid (LPA). cPA has a unique cyclic phosphate ring at the sn-2 and sn-3 positions of its glycerol backbone. We showed before that a metabolically stabilized cPA derivative, 2-carba-cPA, relieved osteoarthritis pathogenesis in vivo and induced hyaluronic acid synthesis in human osteoarthritis synoviocytes in vitro. This study focused on hyaluronic acid synthesis in human fibroblasts, which retain moisture and maintain health in the dermis. We investigated the effects of cPA and LPA on hyaluronic acid synthesis in human fibroblasts (NB1RGB cells). Using particle exclusion and enzyme-linked immunosorbent assays, we found that both cPA and LPA dose-dependently induced hyaluronic acid synthesis. We revealed that the expression of hyaluronan synthase 2 messenger RNA and protein is up-regulated by cPA and LPA treatment time dependently. We then characterized the signaling pathways up-regulating hyaluronic acid synthesis mediated by cPA and LPA in NB1RGB cells. Pharmacological inhibition and reporter gene assays revealed that the activation of the LPA receptor LPAR1, Gi/o protein, phosphatidylinositol-3 kinase (PI3K), extracellular-signal-regulated kinase (ERK), and cyclic adenosine monophosphate response element-binding protein (CREB) but not nuclear factor κB induced hyaluronic acid synthesis by the treatment with cPA and LPA in NB1RGB cells. These results demonstrate for the first time that cPA and LPA induce hyaluronic acid synthesis in human skin fibroblasts mainly through the activation of LPAR1-Gi/o followed by the PI3K, ERK, and CREB signaling pathway.

  12. Intestinal CYP3A4 protects against lithocholic acid-induced hepatotoxicity in intestine-specific VDR-deficient mice.

    PubMed

    Cheng, Jie; Fang, Zhong-Ze; Kim, Jung-Hwan; Krausz, Kristopher W; Tanaka, Naoki; Chiang, John Y L; Gonzalez, Frank J

    2014-03-01

    Vitamin D receptor (VDR) mediates vitamin D signaling involved in bone metabolism, cellular growth and differentiation, cardiovascular function, and bile acid regulation. Mice with an intestine-specific disruption of VDR (Vdr(ΔIEpC)) have abnormal body size, colon structure, and imbalance of bile acid metabolism. Lithocholic acid (LCA), a secondary bile acid that activates VDR, is among the most toxic of the bile acids that when overaccumulated in the liver causes hepatotoxicity. Because cytochrome P450 3A4 (CYP3A4) is a target gene of VDR-involved bile acid metabolism, the role of CYP3A4 in VDR biology and bile acid metabolism was investigated. The CYP3A4 gene was inserted into Vdr(ΔIEpC) mice to produce the Vdr(ΔIEpC)/3A4 line. LCA was administered to control, transgenic-CYP3A4, Vdr(ΔIEpC), and Vdr(ΔIEpC)/3A4 mice, and hepatic toxicity and bile acid levels in the liver, intestine, bile, and urine were measured. VDR deficiency in the intestine of the Vdr(ΔIEpC) mice exacerbates LCA-induced hepatotoxicity manifested by increased necrosis and inflammation, due in part to over-accumulation of hepatic bile acids including taurocholic acid and taurodeoxycholic acid. Intestinal expression of CYP3A4 in the Vdr(ΔIEpC)/3A4 mouse line reduces LCA-induced hepatotoxicity through elevation of LCA metabolism and detoxification, and suppression of bile acid transporter expression in the small intestine. This study reveals that intestinal CYP3A4 protects against LCA hepatotoxicity.

  13. Xenobiotic- and jasmonic acid-inducible signal transduction pathways have become interdependent at the Arabidopsis CYP81D11 promoter.

    PubMed

    Köster, Julia; Thurow, Corinna; Kruse, Kerstin; Meier, Alexander; Iven, Tim; Feussner, Ivo; Gatz, Christiane

    2012-05-01

    Plants modify harmful substances through an inducible detoxification system. In Arabidopsis (Arabidopsis thaliana), chemical induction of the cytochrome P450 gene CYP81D11 and other genes linked to the detoxification program depends on class II TGA transcription factors. CYP81D11 expression is also induced by the phytohormone jasmonic acid (JA) through the established pathway requiring the JA receptor CORONATINE INSENSITIVE1 (COI1) and the JA-regulated transcription factor MYC2. Here, we report that the xenobiotic- and the JA-dependent signal cascades have become interdependent at the CYP81D11 promoter. On the one hand, MYC2 can only activate the expression of CYP81D11 when both the MYC2- and the TGA-binding sites are present in the promoter. On the other hand, the xenobiotic-regulated class II TGA transcription factors can only mediate maximal promoter activity if TGA and MYC2 binding motifs, MYC2, and the JA-isoleucine biosynthesis enzymes DDE2/AOS and JAR1 are functional. Since JA levels and degradation of JAZ1, a repressor of the JA response, are not affected by reactive chemicals, we hypothesize that basal JA signaling amplifies the response to chemical stress. Remarkably, stress-induced expression levels were 3-fold lower in coi1 than in the JA biosynthesis mutant dde2-2, [corrected] revealing that COI1 can contribute to the activation of the promoter in the absence of JA. Moreover, we show that deletion of the MYC2 binding motifs abolishes the JA responsiveness of the promoter but not the responsiveness to COI1. These findings suggest that yet unknown cis-element(s) can mediate COI1-dependent transcriptional activation in the absence of JA.

  14. Arachidonic acid-induced mobilization of calcium in human neutrophils: evidence for a multicomponent mechanism of action.

    PubMed Central

    Naccache, P. H.; McColl, S. R.; Caon, A. C.; Borgeat, P.

    1989-01-01

    1. The mechanism(s) involved in the mobilization of calcium induced by arachidonic acid in human neutrophils was investigated. 2. The addition of arachidonic acid to a suspension of human neutrophils led to a time- and concentration-dependent mobilization of calcium which was the result of two separate and experimentally differentiable processes. The latter consisted of a rapid and transient phase followed by a slower and more sustained response. 3. The initial phase of calcium mobilization elicited by arachidonic acid was decreased in the presence of EGTA, inhibited by pertussis toxin as well as by nordihydroguaiaretic acid (NDGA), and diminished following a pre-incubation with leukotriene B4, but not platelet-activating factor. 4. The characteristics of the first phase of the mobilization of calcium were consistent with an interaction of the fatty acid with the leukotriene B4 receptors, either directly or indirectly following the synthesis of leukotriene B4, as well as with a release of internal calcium. 5. The second, slower and more sustained phase of calcium mobilization was more apparent at high concentrations (greater than or equal to 8-16 microM) of arachidonic acid, and was relatively insensitive to pertussis toxin, EGTA or NDGA. 6. The characteristics of the 'slow' phase of calcium mobilization by arachidonic acid are consistent with its being associated primarily with a release of calcium from internal storage pools. 7. The data presented indicate that the mechanism of mobilization of calcium by arachidonic acid in human neutrophils is complex and involves specific activation pathways employed, in part at least, by other neutrophil agonists.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2547474

  15. Effects of mimic of manganese superoxide dismutase on 2,4,6-trinitrobenzene sulfonic acid-induced colitis in rats.

    PubMed

    Wang, Yan-Hong; Dong, Jiao; Zhang, Jian-Xin; Zhai, Jing; Ge, Bin

    2016-09-01

    The mimic of manganese superoxide dismutase (MnSODm) has been synthesized and reported to have anti-inflammatory properties. However, whether MnSODm has anti-inflammatory effects on colitis and any underlying mechanisms are poorly understood. This study was to investigate therapeutic effects and mechanism of MnSODm on 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced colitis model in rats. Rats were intragastrically administered MnSODm (10, 20, and 40 mg/kg) per day for 7 days after colitis was induced by TNBS. After treated with MnSODm, the colonic macroscopic and microscopic damage scores and colonic weight/length ratios were significantly decreased compared with colitis model group. Myeloperoxidase (MPO) activity, malonyldialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 levels in colon tissues were also significantly decreased in MnSODm treatment groups. However, superoxide dismutase (SOD) activity significantly increased and phosphorylated inhibitory kappa B-alpha (IκBα), inhibitor kappa B kinase (IKKα/β), and nuclear factor-kappa Bp65 (NF-κBp65) as well as Toll-like receptor 4 (TLR4) and myeloid differentiation actor 88 (MyD88) in the colonic mucosa were significantly inhibited by MnSODm treatment. Thus, MnSODm was protective against colitis via antioxidant activity and by inhibiting inflammatory mediators by down-regulating TLR4/MyD88/NF-κB signaling pathways. These data suggest a potential therapeutic effect of MnSODm in colitis.

  16. Free fatty acid-induced PP2A hyperactivity selectively impairs hepatic insulin action on glucose metabolism.

    PubMed

    Galbo, Thomas; Olsen, Grith Skytte; Quistorff, Bjørn; Nishimura, Erica

    2011-01-01

    In type 2 Diabetes (T2D) free fatty acids (FFAs) in plasma are increased and hepatic insulin resistance is "selective", in the sense that the insulin-mediated decrease of glucose production is blunted while insulin's effect on stimulating lipogenesis is maintained. We investigated the molecular mechanisms underlying this pathogenic paradox. Primary rat hepatocytes were exposed to palmitate for twenty hours. To establish the physiological relevance of the in vitro findings, we also studied insulin-resistant Zucker Diabetic Fatty (ZDF) rats. While insulin-receptor phosphorylation was unaffected, activation of Akt and inactivation of the downstream targets Glycogen synthase kinase 3α (Gsk3α and Forkhead box O1 (FoxO1) was inhibited in palmitate-exposed cells. Accordingly, dose-response curves for insulin-mediated suppression of the FoxO1-induced gluconeogenic genes and for de novo glucose production were right shifted, and insulin-stimulated glucose oxidation and glycogen synthesis were impaired. In contrast, similar to findings in human T2D, the ability of insulin to induce triglyceride (TG) accumulation and transcription of the enzymes that catalyze de novo lipogenesis and TG assembly was unaffected. Insulin-induction of these genes could, however, be blocked by inhibition of the atypical PKCs (aPKCs). The activity of the Akt-inactivating Protein Phosphatase 2A (PP2A) was increased in the insulin-resistant cells. Furthermore, inhibition of PP2A by specific inhibitors increased insulin-stimulated activation of Akt and phosphorylation of FoxO1 and Gsk3α. Finally, PP2A mRNA levels were increased in liver, muscle and adipose tissue, while PP2A activity was increased in liver and muscle tissue in insulin-resistant ZDF rats. In conclusion, our findings indicate that FFAs may cause a selective impairment of insulin action upon hepatic glucose metabolism by increasing PP2A activity. PMID:22087313

  17. Role of parathyroid hormone-related protein in tubulointerstitial apoptosis and fibrosis after folic acid-induced nephrotoxicity.

    PubMed

    Ortega, Arantxa; Rámila, David; Ardura, Juan Antonio; Esteban, Vanesa; Ruiz-Ortega, Marta; Barat, Antonio; Gazapo, Rosa; Bosch, Ricardo J; Esbrit, Pedro

    2006-06-01

    Parathyroid hormone-related protein (PTHrP) is shortly upregulated in acute renal injury, but its pathophysiologic role is unclear. Investigated was whether PTHrP might act as a profibrogenic factor in mice that do or do not overexpress PTHrP in the proximal tubule after folic acid (FA) nephrotoxicity, a model of acute renal damage followed by partial regeneration and patchy tubulointerstitial fibrosis. It was found that constitutive PTHrP overexpression in these animals conveyed a significant increase in tubulointerstitial fibrosis, associated with both fibroblast activation (as alpha-smooth muscle actin staining) and macrophage influx, compared with control littermates at 2 to 3 wk after FA damage. Cell proliferation and survival was higher (P<0.01) in the renal interstitium of PTHrP-overexpressing mice than in control littermates within this period after injury. Moreover, the former mice had a constitutive Bcl-XL protein overexpression. In vitro studies in renal tubulointerstitial and fibroblastic cells strongly suggest that PTHrP (1-36) (100 nM) reduced FA-induced apoptosis through a dual mechanism involving Bcl-XL upregulation and Akt and Bad phosphorylation. PTHrP (1-36) also stimulated monocyte chemoattractant protein-1 expression in tubuloepithelial cells, as well as type-1 procollagen gene expression and fibronectin (mRNA levels and protein secretion) in these cells and renal fibroblastic cells. Our findings indicate that this peptide, by interaction with the PTH1 receptor, can increase tubulointerstitial cell survival and seems to act as a proinflammatory and profibrogenic factor in the FA-damaged kidney.

  18. Effects of mimic of manganese superoxide dismutase on 2,4,6-trinitrobenzene sulfonic acid-induced colitis in rats.

    PubMed

    Wang, Yan-Hong; Dong, Jiao; Zhang, Jian-Xin; Zhai, Jing; Ge, Bin

    2016-09-01

    The mimic of manganese superoxide dismutase (MnSODm) has been synthesized and reported to have anti-inflammatory properties. However, whether MnSODm has anti-inflammatory effects on colitis and any underlying mechanisms are poorly understood. This study was to investigate therapeutic effects and mechanism of MnSODm on 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced colitis model in rats. Rats were intragastrically administered MnSODm (10, 20, and 40 mg/kg) per day for 7 days after colitis was induced by TNBS. After treated with MnSODm, the colonic macroscopic and microscopic damage scores and colonic weight/length ratios were significantly decreased compared with colitis model group. Myeloperoxidase (MPO) activity, malonyldialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 levels in colon tissues were also significantly decreased in MnSODm treatment groups. However, superoxide dismutase (SOD) activity significantly increased and phosphorylated inhibitory kappa B-alpha (IκBα), inhibitor kappa B kinase (IKKα/β), and nuclear factor-kappa Bp65 (NF-κBp65) as well as Toll-like receptor 4 (TLR4) and myeloid differentiation actor 88 (MyD88) in the colonic mucosa were significantly inhibited by MnSODm treatment. Thus, MnSODm was protective against colitis via antioxidant activity and by inhibiting inflammatory mediators by down-regulating TLR4/MyD88/NF-κB signaling pathways. These data suggest a potential therapeutic effect of MnSODm in colitis. PMID:27506642

  19. Sprouty2 and -4 hypomorphism promotes neuronal survival and astrocytosis in a mouse model of kainic acid induced neuronal damage.

    PubMed

    Thongrong, Sitthisak; Hausott, Barbara; Marvaldi, Letizia; Agostinho, Alexandra S; Zangrandi, Luca; Burtscher, Johannes; Fogli, Barbara; Schwarzer, Christoph; Klimaschewski, Lars

    2016-05-01

    Sprouty (Spry) proteins play a key role as negative feedback inhibitors of the Ras/Raf/MAPK/ERK pathway downstream of various receptor tyrosine kinases. Among the four Sprouty isoforms, Spry2 and Spry4 are expressed in the hippocampus. In this study, possible effects of Spry2 and Spry4 hypomorphism on neurodegeneration and seizure thresholds in a mouse model of epileptogenesis was analyzed. The Spry2/4 hypomorphs exhibited stronger ERK activation which was limited to the CA3 pyramidal cell layer and to the hilar region. The seizure threshold of Spry2/4(+/-) mice was significantly reduced at naive state but no difference to wildtype mice was observed 1 month following KA treatment. Histomorphological analysis revealed that dentate granule cell dispersion (GCD) was diminished in Spry2/4(+/-) mice in the subchronic phase after KA injection. Neuronal degeneration was reduced in CA1 and CA3 principal neuron layers as well as in scattered neurons of the contralateral CA1 and hilar regions. Moreover, Spry2/4 reduction resulted in enhanced survival of somatostatin and neuropeptide Y expressing interneurons. GFAP staining intensity and number of reactive astrocytes markedly increased in lesioned areas of Spry2/4(+/-) mice as compared with wildtype mice. Taken together, although the seizure threshold is reduced in naive Spry2/4(+/-) mice, neurodegeneration and GCD is mitigated following KA induced hippocampal lesions, identifying Spry proteins as possible pharmacological targets in brain injuries resulting in neurodegeneration. The present data are consistent with the established functions of the ERK pathway in astrocyte proliferation as well as protection from neuronal cell death and suggest a novel role of Spry proteins in the migration of differentiated neurons.

  20. Neuroprotective effect of hemeoxygenase-1/glycogen synthase kinase-3β modulators in 3-nitropropionic acid-induced neurotoxicity in rats.

    PubMed

    Khan, A; Jamwal, S; Bijjem, K R V; Prakash, A; Kumar, P

    2015-02-26

    The present study has been designed to explore the possible interaction between hemeoxygenase-1 (HO-1) and glycogen synthase kinase-3β (GSK-3β) pathway in 3-nitropropionic acid (3-NP)-induced neurotoxicity in rats. 3-NP produces neurotoxicity by inhibition of the mitochondrial complex II (enzyme succinate dehydrogenase) and by sensitizing the N-methyl-D-aspartate receptor. Recent studies have reported the therapeutic potential of HO-1/GSK-3β modulators in different neurodegenerative disorders. However, their exact role is yet to be explored. The present study is an attempt to investigate the effect of pharmacological modulation of HO-1/GSK-3β pathway against 3-NP-induced behavioral, biochemical and molecular alterations in rat. Behavioral observation, oxidative stress, pro-inflammatory [tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)], HO-1 and GSK-3β activity were evaluated post 3-NP treatment. Findings of the present study demonstrate a significant alteration in the locomotor activity, motor coordination, oxidative burden (increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidants), pro-inflammatory mediators [TNF-α, IL-1β], HO-1 and GSK-3β activity in 3-NP-treated animals. Further, administration of hemin (10- and 30-mg/kg; i.p.) and lithium chloride (LiCl) (25- and 50-mg/kg; i.p.) prevented the alteration in body weight, motor impairments, oxidative stress and cellular markers. In addition, combined administration of hemin (10-mg/kg) and LiCl (25-mg/kg) showed synergistic effect on 3-NP-treated rats. Pretreatment with Tin (IV) protoporphyrin (40 μM/kg), HO-1 inhibitor reversed the beneficial effect of LiCl and hemin. Outcomes of the present study suggest that HO-1 and GSK-3β enzymes are involved in the pathophysiology of HD. The modulators of both the pathways might be used as adjuvants or prophylactic therapy for the treatment of HD-like symptoms.

  1. Hormesis in Cholestatic Liver Disease; Preconditioning with Low Bile Acid Concentrations Protects against Bile Acid-Induced Toxicity

    PubMed Central

    Verhaag, Esther M.; Buist-Homan, Manon; Koehorst, Martijn; Groen, Albert K.; Moshage, Han; Faber, Klaas Nico

    2016-01-01

    Introduction Cholestasis is characterized by accumulation of bile acids and inflammation, causing hepatocellular damage. Still, liver damage markers are highest in acute cholestasis and drop when this condition becomes chronic, indicating that hepatocytes adapt towards the hostile environment. This may be explained by a hormetic response in hepatocytes that limits cell death during cholestasis. Aim To investigate the mechanisms that underlie the hormetic response that protect hepatocytes against experimental cholestatic conditions. Methods HepG2.rNtcp cells were preconditioned (24 h) with sub-apoptotic concentrations (0.1–50 μM) of various bile acids, the superoxide donor menadione, TNF-α or the Farsenoid X Receptor agonist GW4064, followed by a challenge with the apoptosis-inducing bile acid glycochenodeoxycholic acid (GCDCA; 200 μM for 4 h), menadione (50 μM, 6 h) or cytokine mixture (CM; 6 h). Levels of apoptotic and necrotic cell death, mRNA expression of the bile salt export pump (ABCB11) and bile acid sensors, as well as intracellular GCDCA levels were analyzed. Results Preconditioning with the pro-apoptotic bile acids GCDCA, taurocholic acid, or the protective bile acids (tauro)ursodeoxycholic acid reduced GCDCA-induced caspase-3/7 activity in HepG2.rNtcp cells. Bile acid preconditioning did not induce significant levels of necrosis in GCDCA-challenged HepG2.rNtcp cells. In contrast, preconditioning with cholic acid, menadione or TNF-α potentiated GCDCA-induced apoptosis. GCDCA preconditioning specifically reduced GCDCA-induced cell death and not CM- or menadione-induced apoptosis. The hormetic effect of GCDCA preconditioning was concentration- and time-dependent. GCDCA-, CDCA- and GW4064- preconditioning enhanced ABCB11 mRNA levels, but in contrast to the bile acids, GW4064 did not significantly reduce GCDCA-induced caspase-3/7 activity. The GCDCA challenge strongly increased intracellular levels of this bile acid, which was not lowered by GCDCA

  2. NADPH Oxidase NOX5-S and Nuclear Factor κB1 Mediate Acid-Induced Microsomal Prostaglandin E Synthase-1 Expression in Barrett’s Esophageal Adenocarcinoma Cells

    PubMed Central

    Zhou, Xiaoxu; Li, Dan; Resnick, Murray B.; Wands, Jack

    2013-01-01

    The mechanisms of progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not known. Cycloxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) has been shown to be important in esophageal tumorigenesis. We have shown that COX-2 mediates acid-induced PGE2 production. The prostaglandin E synthase (PGES) responsible for acid-induced PGE2 production in BE, however, is not known. We found that microsomal PGES1 (mPGES1), mPGES2, and cytosolic PGES (cPGES) were present in FLO EA cells. Pulsed acid treatment significantly increased mPGES1 mRNA and protein levels but had little or no effect on mPGES2 or cPGES mRNA. Knockdown of mPGES1 by mPGES1 small interfering RNA (siRNA) blocked acid-induced increase in PGE2 production and thymidine incorporation. Knockdown of NADPH oxidase, NOX5-S, a variant lacking calcium-binding domains, by NOX5 siRNA significantly inhibited acid-induced increase in mPGES1 expression, thymidine incorporation, and PGE2 production. Overexpression of NOX5-S significantly increased the luciferase activity in FLO cells transfected with a nuclear factor κB (NF-κB) in vivo activation reporter plasmid pNF-κB-Luc. Knockdown of NF-κB1 p50 by p50 siRNA significantly decreased acid-induced increase in mPGES1 expression, thymidine incorporation, and PGE2 production. Two novel NF-κB binding elements, GGAGTCTCCC and CGGGACACCC, were identified in the mPGES1 gene promoter. We conclude that mPGES1 mediates acid-induced increase in PGE2 production and cell proliferation. Acid-induced mPGES1 expression depends on activation of NOX5-S and NF-κB1 p50. Microsomal PGES1 may be a potential target to prevent or treat EA. PMID:23439561

  3. Pattern-recognition receptors and gastric cancer.

    PubMed

    Castaño-Rodríguez, Natalia; Kaakoush, Nadeem O; Mitchell, Hazel M

    2014-01-01

    Chronic inflammation has been associated with an increased risk of several human malignancies, a classic example being gastric adenocarcinoma (GC). Development of GC is known to result from infection of the gastric mucosa by Helicobacter pylori, which initially induces acute inflammation and, in a subset of patients, progresses over time to chronic inflammation, gastric atrophy, intestinal metaplasia, dysplasia, and finally intestinal-type GC. Germ-line encoded receptors known as pattern-recognition receptors (PRRs) are critical for generating mature pro-inflammatory cytokines that are crucial for both Th1 and Th2 responses. Given that H. pylori is initially targeted by PRRs, it is conceivable that dysfunction within genes of this arm of the immune system could modulate the host response against H. pylori infection, and subsequently influence the emergence of GC. Current evidence suggests that Toll-like receptors (TLRs) (TLR2, TLR3, TLR4, TLR5, and TLR9), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) (NOD1, NOD2, and NLRP3), a C-type lectin receptor (DC-SIGN), and retinoic acid-inducible gene (RIG)-I-like receptors (RIG-I and MDA-5), are involved in both the recognition of H. pylori and gastric carcinogenesis. In addition, polymorphisms in genes involved in the TLR (TLR1, TLR2, TLR4, TLR5, TLR9, and CD14) and NLR (NOD1, NOD2, NLRP3, NLRP12, NLRX1, CASP1, ASC, and CARD8) signaling pathways have been shown to modulate the risk of H. pylori infection, gastric precancerous lesions, and/or GC. Further, the modulation of PRRs has been suggested to suppress H. pylori-induced inflammation and enhance GC cell apoptosis, highlighting their potential relevance in GC therapeutics. In this review, we present current advances in our understanding of the role of the TLR and NLR signaling pathways in the pathogenesis of GC, address the involvement of other recently identified PRRs in GC, and discuss the potential implications of PRRs in GC immunotherapy.

  4. Pattern-Recognition Receptors and Gastric Cancer

    PubMed Central

    Castaño-Rodríguez, Natalia; Kaakoush, Nadeem O.; Mitchell, Hazel M.

    2014-01-01

    Chronic inflammation has been associated with an increased risk of several human malignancies, a classic example being gastric adenocarcinoma (GC). Development of GC is known to result from infection of the gastric mucosa by Helicobacter pylori, which initially induces acute inflammation and, in a subset of patients, progresses over time to chronic inflammation, gastric atrophy, intestinal metaplasia, dysplasia, and finally intestinal-type GC. Germ-line encoded receptors known as pattern-recognition receptors (PRRs) are critical for generating mature pro-inflammatory cytokines that are crucial for both Th1 and Th2 responses. Given that H. pylori is initially targeted by PRRs, it is conceivable that dysfunction within genes of this arm of the immune system could modulate the host response against H. pylori infection, and subsequently influence the emergence of GC. Current evidence suggests that Toll-like receptors (TLRs) (TLR2, TLR3, TLR4, TLR5, and TLR9), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) (NOD1, NOD2, and NLRP3), a C-type lectin receptor (DC-SIGN), and retinoic acid-inducible gene (RIG)-I-like receptors (RIG-I and MDA-5), are involved in both the recognition of H. pylori and gastric carcinogenesis. In addition, polymorphisms in genes involved in the TLR (TLR1, TLR2, TLR4, TLR5, TLR9, and CD14) and NLR (NOD1, NOD2, NLRP3, NLRP12, NLRX1, CASP1, ASC, and CARD8) signaling pathways have been shown to modulate the risk of H. pylori infection, gastric precancerous lesions, and/or GC. Further, the modulation of PRRs has been suggested to suppress H. pylori-induced inflammation and enhance GC cell apoptosis, highlighting their potential relevance in GC therapeutics. In this review, we present current advances in our understanding of the role of the TLR and NLR signaling pathways in the pathogenesis of GC, address the involvement of other recently identified PRRs in GC, and discuss the potential implications of PRRs in GC immunotherapy

  5. Expression of pattern recognition receptors in cholesteatoma.

    PubMed

    Lee, Ho Yun; Park, Moon Suh; Byun, Jae Yong; Kim, Young Il; Yeo, Seung Geun

    2014-02-01

    Although many immunologic mechanisms have been investigated in studies of the pathogenesis of cholesteatoma, the role of pattern recognition receptors (PRRs) has not been fully determined. Therefore, we assessed innate immune responses in patients with cholesteatoma. We prospectively evaluated 21 patients with acquired cholesteatoma between August 2010 and July 2012. Cholesteatoma specimens were obtained during surgery, and skin from the external meatus of each patient was used as a control. RNA was extracted from these tissue samples, followed by real-time PCR to quantitatively assess the relative expression of toll-like receptors (TLRs), NOD-like receptors (NLRs), retinoic acid-inducible gene (RIG)-I, NO synthase (NOS) and cytokines. The levels of TLR-2, -3, -4, -6, -7, and -10, NOD-2, and IL-1 and -8 mRNAs were significantly higher in the cholesteatoma than in the skin specimens (p < .05). The expression levels of TLR-2 and -3, RIG-I, IL-6, and TNF-α mRNAs were significantly higher in cholesteatomas from women than from men. The levels of TLR-8, NOD-2, IL-12, and TNF-α mRNAs were significantly higher in recurrent than in initial cholesteatoma specimens (p < .05). Hearing level did not correlate with the levels of expression of mRNAs encoding TLRs, NLRs, NOS, RIG-I and related cytokines (p > .05). In conclusion, alterations in innate immunity triggered by PRRs are important in the pathophysiology of cholesteatoma. Gender differences and frequency of surgery may affect the expression of PRRs in cholesteatomas.

  6. The LDL receptor.

    PubMed

    Goldstein, Joseph L; Brown, Michael S

    2009-04-01

    In this article, the history of the LDL receptor is recounted by its codiscoverers. Their early work on the LDL receptor explained a genetic cause of heart attacks and led to new ways of thinking about cholesterol metabolism. The LDL receptor discovery also introduced three general concepts to cell biology: receptor-mediated endocytosis, receptor recycling, and feedback regulation of receptors. The latter concept provides the mechanism by which statins selectively lower plasma LDL, reducing heart attacks and prolonging life. PMID:19299327

  7. The protective effect of myo-inositol on hippocamal cell loss and structural alterations in neurons and synapses triggered by kainic acid-induced status epilepticus.

    PubMed

    Kotaria, Nato; Kiladze, Maia; Zhvania, Mzia G; Japaridze, Nadezhda J; Bikashvili, Tamar; Solomonia, Revaz O; Bolkvadze, Tamar

    2013-07-01

    It is known that myo-inositol pretreatment attenuates the seizure severity and several biochemical changes provoked by experimentally induced status epilepticus. However, it remains unidentified whether such properties of myo-inositol influence the structure of epileptic brain. In the present light and electron microscopic research we elucidate if pretreatment with myo-inositol has positive effect on hippocampal cell loss, and cell and synapses damage provoked by kainic acid-induced status epilepticus. Adult male Wistar rats were treated with (i) saline, (ii) saline + kainic acid, (iii) myo-inositol + kainic acid. Assessment of cell loss at 2, 14, and 30 days after treatment demonstrate cytoprotective effect of myo-inositol in CA1 and CA3 areas. It was strongly expressed in pyramidal layer of CA1, radial and oriental layers of CA3 and in less degree-in other layers of both fields. Ultrastructural alterations were described in CA1, 14 days after treatment. The structure of neurons, synapses, and porosomes are well preserved in the rats pretreated with myo-inositol in comparing with rats treated with only kainic acid.

  8. Equilibrium titrations of acid-induced unfolding-refolding and salt-induced molten globule of cytochrome c by FT-IR spectroscopy.

    PubMed

    Dong, Aichun; Lam, Troy

    2005-04-01

    Despite extensive investigations on the acid-unfolded and acid/salt-induced molten globule(-like) states of cytochrome c using variety of techniques, structural features of the acid-unfolded state in terms of residual secondary structures and the structural transition between the acid-unfolded and acid/salt-refolded states have not been fully characterized beyond the circular dichroism (CD) spectroscopy. It is unusual that secondary structure(s) of the unfolded state leading to the molten globule state, an important protein folding intermediate, as determined by CD was not fully corroborated by independent experimental method(s). In this study, we carried out an equilibrium titration of acid-induced unfolding and subsequent acid- and salt-induced refolding of cytochrome c using Fourier transform infrared spectroscopy. The spectral profiles of the equilibrium titration reveal new structural details about the acid-unfolded state and the structural transition associated with the acid/salt-refolded molten globule(-like) states of cytochrome c.

  9. Antiviral activity of human oligoadenylate synthetases-like (OASL) is mediated by enhancing retinoic acid-inducible gene I (RIG-I) signaling

    PubMed Central

    Zhu, Jianzhong; Zhang, Yugen; Ghosh, Arundhati; Cuevas, Rolando A.; Forero, Adriana; Dhar, Jayeeta; Ibsen, Mikkel Søes; Schmid-Burgk, Jonathan Leo; Schmidt, Tobias; Ganapathiraju, Madhavi K.; Fujita, Takashi; Hartmann, Rune; Barik, Sailen; Hornung, Veit; Coyne, Carolyn B.; Sarkar, Saumendra N.

    2014-01-01

    SUMMARY Virus infection is sensed in the cytoplasm by retinoic acid-inducible gene I (RIG-I, also known as DDX58), which requires RNA and polyubiquitin binding to induce type I interferon (IFN), and activate cellular innate immunity. We show that the human IFN-inducible oligoadenylate synthetases-like (OASL) protein had antiviral activity and mediated RIG-I activation by mimicking polyubiquitin. Loss of OASL expression reduced RIG-I signaling and enhanced virus replication in human cells. Conversely, OASL expression suppressed replication of a number of viruses in a RIG-I-dependent manner and enhanced RIG-I-mediated IFN induction. OASL interacted and colocalized with RIG-I, and through its C-terminal ubiquitin-like domain specifically enhanced RIG-I signaling. Bone marrow derived macrophages from mice deficient for Oasl2 showed that among the two mouse orthologs of human OASL; Oasl2 is functionally similar to human OASL. Our findings show a mechanism by which human OASL contributes to host antiviral responses by enhancing RIG-I activation. PMID:24931123

  10. Gallic Acid Induces a Reactive Oxygen Species-Provoked c-Jun NH2-Terminal Kinase-Dependent Apoptosis in Lung Fibroblasts

    PubMed Central

    Chen, Chiu-Yuan; Chen, Kun-Chieh; Yang, Tsung-Ying; Liu, Hsiang-Chun; Hsu, Shih-Lan

    2013-01-01

    Idiopathic pulmonary fibrosis is a chronic lung disorder characterized by fibroblasts proliferation and extracellular matrix accumulation. Induction of fibroblast apoptosis therefore plays a crucial role in the resolution of this disease. Gallic acid (3,4,5-trihydroxybenzoic acid), a common botanic phenolic compound, has been reported to induce apoptosis in tumor cell lines and renal fibroblasts. The present study was undertaken to examine the role of mitogen-activated protein kinases (MAPKs) in lung fibroblasts apoptosis induced by gallic acid. We found that treatment with gallic acid resulted in activation of c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and protein kinase B (PKB, Akt), but not p38MAPK, in mouse lung fibroblasts. Inhibition of JNK using pharmacologic inhibitor (SP600125) and genetic knockdown (JNK specific siRNA) significantly inhibited p53 accumulation, reduced PUMA and Fas expression, and abolished apoptosis induced by gallic acid. Moreover, treatment with antioxidants (vitamin C, N-acetyl cysteine, and catalase) effectively diminished gallic acid-induced hydrogen peroxide production, JNK and p53 activation, and cell death. These observations imply that gallic acid-mediated hydrogen peroxide formation acts as an initiator of JNK signaling pathways, leading to p53 activation and apoptosis in mouse lung fibroblasts. PMID:23533505

  11. Elucidation of Acid-induced Unfolding and Aggregation of Human Immunoglobulin IgG1 and IgG2 Fc

    PubMed Central

    Latypov, Ramil F.; Hogan, Sabine; Lau, Hollis; Gadgil, Himanshu; Liu, Dingjiang

    2012-01-01

    Understanding the underlying mechanisms of Fc aggregation is an important prerequisite for developing stable and efficacious antibody-based therapeutics. In our study, high resolution two-dimensional nuclear magnetic resonance (NMR) was employed to probe structural changes in the IgG1 Fc. A series of 1H-15N heteronuclear single-quantum correlation NMR spectra were collected between pH 2.5 and 4.7 to assess whether unfolding of CH2 domains precedes that of CH3 domains. The same pH range was subsequently screened in Fc aggregation experiments that utilized molecules of IgG1 and IgG2 subclasses with varying levels of CH2 glycosylation. In addition, differential scanning calorimetry data were collected over a pH range of 3–7 to assess changes in CH2 and CH3 thermostability. As a result, compelling evidence was gathered that emphasizes the importance of CH2 stability in determining the rate and extent of Fc aggregation. In particular, we found that Fc domains of the IgG1 subclass have a lower propensity to aggregate compared with those of the IgG2 subclass. Our data for glycosylated, partially deglycosylated, and fully deglycosylated molecules further revealed the criticality of CH2 glycans in modulating Fc aggregation. These findings provide important insights into the stability of Fc-based therapeutics and promote better understanding of their acid-induced aggregation process. PMID:22084250

  12. Protective effect of hesperidin and naringin against 3-nitropropionic acid induced Huntington's like symptoms in rats: possible role of nitric oxide.

    PubMed

    Kumar, Puneet; Kumar, Anil

    2010-01-01

    3-Nitropropionic acid (3-NP) is a well known experimental model to study Huntington's disease (HD) and associated neuropsychiatric problems. Present study has been designed to explore the protective effects of hesperidin, naringin, and their nitric oxide mechanism (if any) against 3-nitropropionic acid induced neurotoxicity in rats. Systemic 3-nitropropionic acid (10 mg/kg) treatment for 14 days in rats significantly induced HD like symptoms in rats as indicated by reduced locomotor activity, body weight, grip strength, oxidative defense and mitochondrial complex enzymes (complex-I, -II, and -IV) activities in striatum. Naringin and hesperidin pretreatment significantly attenuated behavioral alterations, oxidative stress and mitochondrial enzymes complex dysfunction in 3-NP treated group. L-Arginine (50 mg/kg) pretreatment with lower dose of hesperidin (50 mg/kg) and naringin (50 mg/kg) significantly attenuated the protective effect of hesperidin and naringin respectively. Whereas L-NAME (10 mg/kg), a non-selective NOS inhibitor pretreatment with hesperidin (50 mg/kg) and naringin (50 mg/kg) significantly potentiated their protective effect which was significant as compared to their effect per se. Study highlights the therapeutic potential of hesperidin and naringin against Huntington's like conditions and further indicates that these drugs might act through nitric oxide mechanism. PMID:19716383

  13. Uric acid induces oxidative stress and growth inhibition by activating adenosine monophosphate-activated protein kinase and extracellular signal-regulated kinase signal pathways in pancreatic β cells.

    PubMed

    Zhang, Yongneng; Yamamoto, Tetsuya; Hisatome, Ichiro; Li, Youfeng; Cheng, Weijie; Sun, Ning; Cai, Bozhi; Huang, Tianliang; Zhu, Yuzhang; Li, Zhi; Jing, Xubin; Zhou, Rui; Cheng, Jidong

    2013-08-15

    Hyperuricaemia is a disorder of purine metabolism, and is strongly associated with insulin resistance and abnormal glucose metabolism. As the producer of insulin, pancreatic β cells might be affected by elevated serum uric acid levels and contribute to the disregulated glucose metabolism. In this study, we investigated the effect of high uric acid on rat pancreatic β cell function. Under high uric acid condition, proliferation of pancreatic β cells was inhibited, production of reactive oxygen species increased, and glucose stimulated insulin secretion was also compromised. Further examination on signal transduction pathways revealed that uric acid-induced ROS is involved in the activation of adenosine monophosphate-activated protein kinase (AMPK), and extracellular signal-regulated kinase (ERK). Pharmacological inhibition of ERK activation rescued β cells from growth inhibition. More importantly, activation of ERK induced by uric acid is significantly diminished by AMPK inhibitor, indicating ERK as a downstream target of AMPK in response to high uric acid condition. We also investigated the transportation channel for uric acid into pancreatic β cells. While major urate transporter URAT1 is not expressed in β cells, organic anion transporter (OAT) inhibitor successfully blocked the activation of ERK by uric acid. Our data indicate that high uric acid levels induce oxidative damage and inhibit growth of rat pancreatic β cells by activating the AMPK and ERK signal pathways. Hyperuricemia may contribute to abnormal glucose metabolism by causing oxidative damage and function inhibition of pancreatic β cells.

  14. Alkali- or acid-induced changes in structure, moisture absorption ability and deacetylating reaction of β-chitin extracted from jumbo squid (Dosidicus gigas) pens.

    PubMed

    Jung, Jooyeoun; Zhao, Yanyun

    2014-01-01

    Alkali- or acid-induced structural modifications in β-chitin from squid (Dosidicus gigas, d'Orbigny, 1835) pens and their moisture absorption ability (MAA) and deacetylating reaction were investigated and compared with α-chitin from shrimp shells. β-Chitin was converted into the α-form after 3h in 40% NaOH or 1-3 h in 40% HCl solution, and α-chitin obtained from NaOH treatment had higher MAA than had native α-chitin, due to polymorphic destructions. In contrast, induced α-chitin from acid treatment of β-chitin had few polymorphic modifications, showing no significant change (P>0.05) in MAA. β-Chitin was more susceptible to alkali deacetylation than was α-chitin, and required a lower concentration of NaOH and shorter reaction time. These results demonstrate that alkali- or acid-treated β-chitin retained high susceptibility toward solvents, which in turn resulted in good biological activity of β-chitosan for use as a natural antioxidant and antimicrobial substance or application as edible coatings and films for various food applications.

  15. Antitussive activity of sigma-1 receptor agonists in the guinea-pig.

    PubMed

    Brown, Claire; Fezoui, Malika; Selig, William M; Schwartz, Carl E; Ellis, James L

    2004-01-01

    1. Current antitussive medications have limited efficacy and often contain the opiate-like agent dextromethorphan (DEX). The mechanism whereby DEX inhibits cough is ill defined. DEX displays affinity at both NMDA and sigma receptors, suggesting that the antitussive activity may involve central or peripheral activity at either of these receptors. This study examined and compared the antitussive activity of DEX and various putative sigma receptor agonists in the guinea-pig citric-acid cough model. 2. Intraperitoneal (i.p.) administration of DEX (30 mg kg(-1)) and the sigma-1 agonists SKF-10,047 (1-5 mg kg(-1)), Pre-084 (5 mg kg(-1)), and carbetapentane (1-5 mg kg(-1)) inhibited citric-acid-induced cough in guinea-pigs. Intraperitoneal administration of a sigma-1 antagonist, BD 1047 (1-5 mg kg(-1)), reversed the inhibition of cough elicited by SKF-10,047. In addition, two structurally dissimilar sigma agonists SKF-10,047 (1 mg ml(-1)) and Pre-084 (1 mg ml(-1)) inhibited cough when administered by aerosol. 3. Aerosolized BD 1047 (1 mg ml(-1), 30 min) prevented the antitussive action of SKF-10,047 (5 mg kg(-1)) or DEX (30 mg kg(-1)) given by i.p. administration and, likewise, i.p. administration of BD 1047 (5 mg kg(-1)) prevented the antitussive action of SKF-10,047 given by aerosol (1 mg ml(-1)). 4. These results therefore support the argument that antitussive effects of DEX may be mediated via sigma receptors, since both systemic and aerosol administration of sigma-1 receptor agonists inhibit citric-acid-induced cough in guinea-pigs. While significant systemic exposure is possible with aerosol administration, the very low doses administered (estimated <0.3 mg kg(-1)) suggest that there may be a peripheral component to the antitussive effect.

  16. Critical Role of IRF-3 in the Direct Regulation of dsRNA-Induced Retinoic Acid-Inducible Gene-I (RIG-I) Expression

    PubMed Central

    Hayakari, Ryo; Matsumiya, Tomoh; Xing, Fei; Yoshida, Hidemi; Hayakari, Makoto; Imaizumi, Tadaatsu

    2016-01-01

    The cytoplasmic viral sensor retinoic acid-inducible gene-I (RIG-I), which is also known as an IFN-stimulated gene (ISG), senses viral RNA to activate antiviral signaling. It is therefore thought that RIG-I is regulated in a STAT1-dependent manner. Although RIG-I-mediated antiviral signaling is indispensable for the induction of an appropriate adaptive immune response, the mechanism underlying the regulation of RIG-I expression remains elusive. Here, we examined the direct regulation of RIG-I expression by interferon regulatory factor 3 (IRF-3), which is an essential molecule for antiviral innate immunity. We initially found that RIG-I can be induced by dsRNA in both IFN-independent and IRF-3-dependent manners. A sequence analysis revealed that the RIG-I gene has putative IRF-3-binding sites in its promoter region. Using a combination of cellular, molecular biological, and mutational approaches, we first showed that IRF-3 can directly regulate the expression of RIG-I via a single IRF-element (IRF-E) site in the proximal promoter region of the RIG-I gene in response to dsRNA. IRF-3 is considered a master regulator in antiviral signaling for the generation of type I interferons (IFNs). Thus, our findings demonstrate that RIG-I expression induced by the IRF-3-mediated pathway may serve as a crucial antiviral factor for reinforcing a surveillance system against viral invasion through the regulation of the cytoplasmic viral sensor RIG-I. PMID:27662626

  17. Music application alleviates short-term memory impairments through increasing cell proliferation in the hippocampus of valproic acid-induced autistic rat pups.

    PubMed

    Lee, Sung-Min; Kim, Bo-Kyun; Kim, Tae-Woon; Ji, Eun-Sang; Choi, Hyun-Hee

    2016-06-01

    Autism is a neurodevelopmental disorder and this disorder shows impairment in reciprocal social interactions, deficits in communication, and restrictive and repetitive patterns of behaviors and interests. The effect of music on short-term memory in the view of cell proliferation in the hippocampus was evaluated using valproic acid-induced autistic rat pups. Animal model of autism was made by subcutaneous injection of 400-mg/kg valproic acid into the rat pups on the postnatal day 14. The rat pups in the music-applied groups were exposed to the 65-dB comfortable classic music for 1 hr once a day, starting postnatal day 15 and continued until postnatal day 28. In the present results, short-term memory was deteriorated by autism induction. The numbers of 5-bromo-2'-deoxyridine (BrdU)-positive, Ki-67-positive, and doublecortin (DCX)-positive cells in the hippocampal dentate gyrus were decreased by autism induction. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions in the hippocampus were also suppressed in the autistic rat pups. Music application alleviated short-term memory deficits with enhancing the numbers of BrdU-positive, Ki-67-positive, and DCX-positive cells in the autistic rat pups. Music application also enhanced BDNF and TrkB expressions in the autistic rat pups. The present study show that application of music enhanced hippocampal cell proliferation and alleviated short-term memory impairment through stimulating BDNF-TrkB signaling in the autistic rat pups. Music can be suggested as the therapeutic strategy to overcome the autism-induced memory deficits. PMID:27419108

  18. Music application alleviates short-term memory impairments through increasing cell proliferation in the hippocampus of valproic acid-induced autistic rat pups

    PubMed Central

    Lee, Sung-Min; Kim, Bo-Kyun; Kim, Tae-Woon; Ji, Eun-Sang; Choi, Hyun-Hee

    2016-01-01

    Autism is a neurodevelopmental disorder and this disorder shows impairment in reciprocal social interactions, deficits in communication, and restrictive and repetitive patterns of behaviors and interests. The effect of music on short-term memory in the view of cell proliferation in the hippocampus was evaluated using valproic acid-induced autistic rat pups. Animal model of autism was made by subcutaneous injection of 400-mg/kg valproic acid into the rat pups on the postnatal day 14. The rat pups in the music-applied groups were exposed to the 65-dB comfortable classic music for 1 hr once a day, starting postnatal day 15 and continued until postnatal day 28. In the present results, short-term memory was deteriorated by autism induction. The numbers of 5-bromo-2′-deoxyridine (BrdU)-positive, Ki-67-positive, and doublecortin (DCX)-positive cells in the hippocampal dentate gyrus were decreased by autism induction. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions in the hippocampus were also suppressed in the autistic rat pups. Music application alleviated short-term memory deficits with enhancing the numbers of BrdU-positive, Ki-67-positive, and DCX-positive cells in the autistic rat pups. Music application also enhanced BDNF and TrkB expressions in the autistic rat pups. The present study show that application of music enhanced hippocampal cell proliferation and alleviated short-term memory impairment through stimulating BDNF-TrkB signaling in the autistic rat pups. Music can be suggested as the therapeutic strategy to overcome the autism-induced memory deficits. PMID:27419108

  19. Gibberellic Acid-Induced Aleurone Layers Responding to Heat Shock or Tunicamycin Provide Insight into the N-Glycoproteome, Protein Secretion, and Endoplasmic Reticulum Stress1[W

    PubMed Central

    Barba-Espín, Gregorio; Dedvisitsakul, Plaipol; Hägglund, Per; Svensson, Birte; Finnie, Christine

    2014-01-01

    The growing relevance of plants for the production of recombinant proteins makes understanding the secretory machinery, including the identification of glycosylation sites in secreted proteins, an important goal of plant proteomics. Barley (Hordeum vulgare) aleurone layers maintained in vitro respond to gibberellic acid by secreting an array of proteins and provide a unique system for the analysis of plant protein secretion. Perturbation of protein secretion in gibberellic acid-induced aleurone layers by two independent mechanisms, heat shock and tunicamycin treatment, demonstrated overlapping effects on both the intracellular and secreted proteomes. Proteins in a total of 22 and 178 two-dimensional gel spots changing in intensity in extracellular and intracellular fractions, respectively, were identified by mass spectrometry. Among these are proteins with key roles in protein processing and secretion, such as calreticulin, protein disulfide isomerase, proteasome subunits, and isopentenyl diphosphate isomerase. Sixteen heat shock proteins in 29 spots showed diverse responses to the treatments, with only a minority increasing in response to heat shock. The majority, all of which were small heat shock proteins, decreased in heat-shocked aleurone layers. Additionally, glycopeptide enrichment and N-glycosylation analysis identified 73 glycosylation sites in 65 aleurone layer proteins, with 53 of the glycoproteins found in extracellular fractions and 36 found in intracellular fractions. This represents major progress in characterization of the barley N-glycoproteome, since only four of these sites were previously described. Overall, these findings considerably advance knowledge of the plant protein secretion system in general and emphasize the versatility of the aleurone layer as a model system for studying plant protein secretion. PMID:24344171

  20. Gambogic Acid Induces Apoptosis in Imatinib-Resistant Chronic Myeloid Leukemia Cells via Inducing Proteasome Inhibition and Caspase-Dependent Bcr-Abl Downregulation

    PubMed Central

    Shi, Xianping; Chen, Xin; Li, Xiaofen; Lan, Xiaoying; Zhao, Chong; Liu, Shouting; Huang, Hongbiao; Liu, Ningning; Liao, Siyan; Song, Wenbin; Zhou, Ping; Wang, Shunqing; Xu, Li; Wang, Xuejun; Dou, Q. Ping; Liu, Jinbao

    2014-01-01

    Purpose Chronic myelogenous leukemia (CML) is characterized by the constitutive activation of Bcr-Abl tyrosine kinase. Bcr-Abl-T315I is the predominant mutation that causes resistance to imatinib, cytotoxic drugs, and the second-generation tyrosine kinase inhibitors. The emergence of imatinib resistance in patients with CML leads to searching for novel approaches to the treatment of CML. Gambogic acid, a small molecule derived from Chinese herb gamboges, has been approved for phase II clinical trial for cancer therapy by the Chinese Food and Drug Administration (FDA). In this study, we investigated the effect of gambogic acid on cell survival or apoptosis in CML cells bearing Bcr-Abl-T315I or wild-type Bcr-Abl. Experimental Design CML cell lines (KBM5, KBM5-T315I, and K562), primary cells from patients with CML with clinical resistance to imatinib, and normal monocytes from healthy volunteers were treated with gambogic acid, imatinib, or their combination, followed by measuring the effects on cell growth, apoptosis, and signal pathways. The in vivo antitumor activity of gambogic acid and its combination with imatinib was also assessed with nude xenografts. Results Gambogic acid induced apoptosis and cell proliferation inhibition in CML cells and inhibited the growth of imatinib-resistant Bcr-Abl-T315I xenografts in nude mice. Our data suggest that GA-induced proteasome inhibition is required for caspase activation in both imatinib-resistant and -sensitive CML cells, and caspase activation is required for gambogic acid–induced Bcr-Abl downregulation and apoptotic cell death. Conclusions These findings suggest an alternative strategy to overcome imatinib resistance by enhancing Bcr-Abl downregulation with the medicinal compound gambogic acid, which may have great clinical significance in imatinib-resistant cancer therapy. PMID:24334603

  1. Effects of Abscisic Acid and Ethylene on the Gibberellic Acid-Induced Synthesis of α-Amylase by Isolated Wheat Aleurone Layers 1

    PubMed Central

    Varty, Keith; Arreguín, Barbarín L.; Gómez, Miguel T.; López, Pablo Jaime T.; Gómez, Miguel Angel L.

    1983-01-01

    Gibberellic acid-induced α-amylase synthesis in wheat aleurone layers (Triticum aestivum L. var Potam S-70) escaped from transcriptional control 30 h after addition of the hormone, as evidenced by the tissue's loss of susceptibility to cordycepin. Abscisic acid inhibited the accumulation of α-amylase activity when added to the tissue during this cordycepin-insensitive phase of enzyme induction. α-Amylase synthesis was not restored by the addition of cordycepin, indicating that the response to abscisic acid was not dependent upon the continuous synthesis of a short lived RNA. When ethylene was added simultaneously or some time after abscisic acid, the accumulation of α-amylase activity was sustained or quickly restored. The loss of susceptibility to cordycepin was completely prevented when aleurone layers were incubated with a combination of gibberellic and abscisic acids from the start of the induction period. This effect of abscisic acid was not reversed by ethylene. On the basis of these observations, it is suggested that abscisic acid inhibits both the transcription and translation of α-amylase mRNA, and that only the latter site of action is susceptible to reversal by ethylene. The rate of incorporation of [methyl-14C]choline into phospholipids was also inhibited by abscisic acid. Ethylene reversed this effect. The effects of abscisic acid and ethylene on phospholipid synthesis were not dependent upon the presence of gibberellic acid. No direct relationship was found between the control of α-amylase synthesis and membrane formation by abscisic acid and ethylene. PMID:16663284

  2. Calcium-dependent nitric oxide production is involved in the cytoprotective properties of n-acetylcysteine in glycochenodeoxycholic acid-induced cell death in hepatocytes

    SciTech Connect

    Gonzalez-Rubio, Sandra; Linares, Clara I.; Bello, Rosario I.; Gonzalez, Raul; Ferrin, Gustavo; Hidalgo, Ana B.; Munoz-Gomariz, Elisa; Rodriguez, Blanca A.; Barrera, Pilar; Ranchal, Isidora; Duran-Prado, Mario; De la Mata, Manuel; Muntane, Jordi

    2010-01-15

    The intracellular oxidative stress has been involved in bile acid-induced cell death in hepatocytes. Nitric oxide (NO) exerts cytoprotective properties in glycochenodeoxycholic acid (GCDCA)-treated hepatocytes. The study evaluated the involvement of Ca{sup 2+} on the regulation of NO synthase (NOS)-3 expression during N-acetylcysteine (NAC) cytoprotection against GCDCA-induced cell death in hepatocytes. The regulation of Ca{sup 2+} pools (EGTA or BAPTA-AM) and NO (L-NAME or NO donor) production was assessed during NAC cytoprotection in GCDCA-treated HepG2 cells. The stimulation of Ca{sup 2+} entrance was induced by A23187 in HepG2. Cell death, Ca{sup 2+} mobilization, NOS-1, -2 and -3 expression, AP-1 activation, and NO production were evaluated. GCDCA reduced intracellular Ca{sup 2+} concentration and NOS-3 expression, and enhanced cell death in HepG2. NO donor prevented, and L-NAME enhanced, GCDCA-induced cell death. The reduction of Ca{sup 2+} entry by EGTA, but not its release from intracellular stores by BAPTA-AM, enhanced cell death in GCDCA-treated cells. The stimulation of Ca{sup 2+} entrance by A23187 reduced cell death and enhanced NOS-3 expression in GCDCA-treated HepG2 cells. The cytoprotective properties of NAC were related to the recovery of intracellular Ca{sup 2+} concentration, NOS-3 expression and NO production induced by GCDCA-treated HepG2 cells. The increase of NO production by Ca{sup 2+}-dependent NOS-3 expression during NAC administration reduces cell death in GCDCA-treated hepatocytes.

  3. A comparative study of the antitussive activity of levodropropizine and dropropizine in the citric acid-induced cough model in normal subjects.

    PubMed

    Fumagalli, G; Cordaro, C I; Vanasia, M; Balzarotti, C; Camusso, L; Caiazzo, G; Maghini, L; Mazzocchi, M; Zennaro, M

    1992-01-01

    Levodropropizine is the levo-rotatory (S)-enantiomer of dropropizine, a racemic non-opiate antitussive agent which has been used clinically for many years. Compared with the racemic drug, levodropropizine exhibits in animal models similar antitussive activity but considerably lower central nervous system (CNS) depressant effects. It is also less likely to cause sedation in treated patients. Since the comparative antitussive potency of the two drugs in clinical experimental models has not been evaluated, the authors performed a randomized, double blind, cross over investigation in which the effects of single oral doses (60 and 90 mg) of levodropropizine and dropropizine were assessed by using the citric acid-induced cough model in eight normal volunteers. Stimulation tests involved inhalation of individual cumulative doses of citric acid (6.3 to 53.3 mg) which at pre-study assessment had been found to induce reproducibly at least ten coughs over a 30 sec period. Each subject was studied by repeating the citric acid stimulation test four times (0 h, 1 h, 2 h and 6 h) on each of five different days separated by intervals of at least three days. In the absence of drug administration (control session), cough response to citric inhalation was remarkably reproducible throughout the 6 h period of observation. A marked and statistically significant reduction in cough response (to about one third--one sixth of the pre-drug values) was observed 1 h after intake for both compounds. At subsequent testing 2 h and 6 h after dosing, cough response was still depressed and did not differ significantly from that observed at 1 h.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Molecular Analysis of the Retinoic Acid Induced 1 Gene (RAI1) in Patients with Suspected Smith-Magenis Syndrome without the 17p11.2 Deletion

    PubMed Central

    Vilboux, Thierry; Ciccone, Carla; Blancato, Jan K.; Cox, Gerald F.; Deshpande, Charu; Introne, Wendy J.; Gahl, William A.; Smith, Ann C. M.; Huizing, Marjan

    2011-01-01

    Smith-Magenis syndrome (SMS) is a complex neurobehavioral disorder characterized by multiple congenital anomalies. The syndrome is primarily ascribed to a ∼3.7 Mb de novo deletion on chromosome 17p11.2. Haploinsufficiency of multiple genes likely underlies the complex clinical phenotype. RAI1 (Retinoic Acid Induced 1) is recognized as a major gene involved in the SMS phenotype. Extensive genetic and clinical analyses of 36 patients with SMS-like features, but without the 17p11.2 microdeletion, yielded 10 patients with RAI1 variants, including 4 with de novo deleterious mutations, and 6 with novel missense variants, 5 of which were familial. Haplotype analysis showed two major RAI1 haplotypes in our primarily Caucasian cohort; the novel RAI1 variants did not occur in a preferred haplotype. RNA analysis revealed that RAI1 mRNA expression was significantly decreased in cells of patients with the common 17p11.2 deletion, as well as in those with de novo RAI1 variants. Expression levels varied in patients with familial RAI1 variants and in non-17p11.2 deleted patients without identified RAI1 defects. No correlation between SNP haplotype and RAI1 expression was found. Two clinical features, ocular abnormalities and polyembolokoilomania (object insertion), were significantly correlated with decreased RAI1 expression. While not significantly correlated, the presence of hearing loss, seizures, hoarse voice, childhood onset of obesity and specific behavioral aspects and the absence of immunologic abnormalities and cardiovascular or renal structural anomalies, appeared to be specific for the de novo RAI1 subgroup. Recognition of the combination of these features will assist in referral for RAI1 analysis of patients with SMS-like features without detectable microdeletion of 17p11.2. Moreover, RAI1 expression emerged as a genetic target for development of therapeutic interventions for SMS. PMID:21857958

  5. Gibberellic acid-induced aleurone layers responding to heat shock or tunicamycin provide insight into the N-glycoproteome, protein secretion, and endoplasmic reticulum stress.

    PubMed

    Barba-Espín, Gregorio; Dedvisitsakul, Plaipol; Hägglund, Per; Svensson, Birte; Finnie, Christine

    2014-02-01

    The growing relevance of plants for the production of recombinant proteins makes understanding the secretory machinery, including the identification of glycosylation sites in secreted proteins, an important goal of plant proteomics. Barley (Hordeum vulgare) aleurone layers maintained in vitro respond to gibberellic acid by secreting an array of proteins and provide a unique system for the analysis of plant protein secretion. Perturbation of protein secretion in gibberellic acid-induced aleurone layers by two independent mechanisms, heat shock and tunicamycin treatment, demonstrated overlapping effects on both the intracellular and secreted proteomes. Proteins in a total of 22 and 178 two-dimensional gel spots changing in intensity in extracellular and intracellular fractions, respectively, were identified by mass spectrometry. Among these are proteins with key roles in protein processing and secretion, such as calreticulin, protein disulfide isomerase, proteasome subunits, and isopentenyl diphosphate isomerase. Sixteen heat shock proteins in 29 spots showed diverse responses to the treatments, with only a minority increasing in response to heat shock. The majority, all of which were small heat shock proteins, decreased in heat-shocked aleurone layers. Additionally, glycopeptide enrichment and N-glycosylation analysis identified 73 glycosylation sites in 65 aleurone layer proteins, with 53 of the glycoproteins found in extracellular fractions and 36 found in intracellular fractions. This represents major progress in characterization of the barley N-glycoproteome, since only four of these sites were previously described. Overall, these findings considerably advance knowledge of the plant protein secretion system in general and emphasize the versatility of the aleurone layer as a model system for studying plant protein secretion.

  6. Molecular analysis of the Retinoic Acid Induced 1 gene (RAI1) in patients with suspected Smith-Magenis syndrome without the 17p11.2 deletion.

    PubMed

    Vilboux, Thierry; Ciccone, Carla; Blancato, Jan K; Cox, Gerald F; Deshpande, Charu; Introne, Wendy J; Gahl, William A; Smith, Ann C M; Huizing, Marjan

    2011-01-01

    Smith-Magenis syndrome (SMS) is a complex neurobehavioral disorder characterized by multiple congenital anomalies. The syndrome is primarily ascribed to a ∼3.7 Mb de novo deletion on chromosome 17p11.2. Haploinsufficiency of multiple genes likely underlies the complex clinical phenotype. RAI1 (Retinoic Acid Induced 1) is recognized as a major gene involved in the SMS phenotype. Extensive genetic and clinical analyses of 36 patients with SMS-like features, but without the 17p11.2 microdeletion, yielded 10 patients with RAI1 variants, including 4 with de novo deleterious mutations, and 6 with novel missense variants, 5 of which were familial. Haplotype analysis showed two major RAI1 haplotypes in our primarily Caucasian cohort; the novel RAI1 variants did not occur in a preferred haplotype. RNA analysis revealed that RAI1 mRNA expression was significantly decreased in cells of patients with the common 17p11.2 deletion, as well as in those with de novo RAI1 variants. Expression levels varied in patients with familial RAI1 variants and in non-17p11.2 deleted patients without identified RAI1 defects. No correlation between SNP haplotype and RAI1 expression was found. Two clinical features, ocular abnormalities and polyembolokoilomania (object insertion), were significantly correlated with decreased RAI1 expression. While not significantly correlated, the presence of hearing loss, seizures, hoarse voice, childhood onset of obesity and specific behavioral aspects and the absence of immunologic abnormalities and cardiovascular or renal structural anomalies, appeared to be specific for the de novo RAI1 subgroup. Recognition of the combination of these features will assist in referral for RAI1 analysis of patients with SMS-like features without detectable microdeletion of 17p11.2. Moreover, RAI1 expression emerged as a genetic target for development of therapeutic interventions for SMS.

  7. Music application alleviates short-term memory impairments through increasing cell proliferation in the hippocampus of valproic acid-induced autistic rat pups.

    PubMed

    Lee, Sung-Min; Kim, Bo-Kyun; Kim, Tae-Woon; Ji, Eun-Sang; Choi, Hyun-Hee

    2016-06-01

    Autism is a neurodevelopmental disorder and this disorder shows impairment in reciprocal social interactions, deficits in communication, and restrictive and repetitive patterns of behaviors and interests. The effect of music on short-term memory in the view of cell proliferation in the hippocampus was evaluated using valproic acid-induced autistic rat pups. Animal model of autism was made by subcutaneous injection of 400-mg/kg valproic acid into the rat pups on the postnatal day 14. The rat pups in the music-applied groups were exposed to the 65-dB comfortable classic music for 1 hr once a day, starting postnatal day 15 and continued until postnatal day 28. In the present results, short-term memory was deteriorated by autism induction. The numbers of 5-bromo-2'-deoxyridine (BrdU)-positive, Ki-67-positive, and doublecortin (DCX)-positive cells in the hippocampal dentate gyrus were decreased by autism induction. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions in the hippocampus were also suppressed in the autistic rat pups. Music application alleviated short-term memory deficits with enhancing the numbers of BrdU-positive, Ki-67-positive, and DCX-positive cells in the autistic rat pups. Music application also enhanced BDNF and TrkB expressions in the autistic rat pups. The present study show that application of music enhanced hippocampal cell proliferation and alleviated short-term memory impairment through stimulating BDNF-TrkB signaling in the autistic rat pups. Music can be suggested as the therapeutic strategy to overcome the autism-induced memory deficits.

  8. A comparative study of the antitussive activity of levodropropizine and dropropizine in the citric acid-induced cough model in normal subjects.

    PubMed

    Fumagalli, G; Cordaro, C I; Vanasia, M; Balzarotti, C; Camusso, L; Caiazzo, G; Maghini, L; Mazzocchi, M; Zennaro, M

    1992-01-01

    Levodropropizine is the levo-rotatory (S)-enantiomer of dropropizine, a racemic non-opiate antitussive agent which has been used clinically for many years. Compared with the racemic drug, levodropropizine exhibits in animal models similar antitussive activity but considerably lower central nervous system (CNS) depressant effects. It is also less likely to cause sedation in treated patients. Since the comparative antitussive potency of the two drugs in clinical experimental models has not been evaluated, the authors performed a randomized, double blind, cross over investigation in which the effects of single oral doses (60 and 90 mg) of levodropropizine and dropropizine were assessed by using the citric acid-induced cough model in eight normal volunteers. Stimulation tests involved inhalation of individual cumulative doses of citric acid (6.3 to 53.3 mg) which at pre-study assessment had been found to induce reproducibly at least ten coughs over a 30 sec period. Each subject was studied by repeating the citric acid stimulation test four times (0 h, 1 h, 2 h and 6 h) on each of five different days separated by intervals of at least three days. In the absence of drug administration (control session), cough response to citric inhalation was remarkably reproducible throughout the 6 h period of observation. A marked and statistically significant reduction in cough response (to about one third--one sixth of the pre-drug values) was observed 1 h after intake for both compounds. At subsequent testing 2 h and 6 h after dosing, cough response was still depressed and did not differ significantly from that observed at 1 h.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1295724

  9. A combined physiological and proteomic approach to reveal lactic-acid-induced alterations in Lactobacillus casei Zhang and its mutant with enhanced lactic acid tolerance.

    PubMed

    Wu, Chongde; Zhang, Juan; Chen, Wei; Wang, Miao; Du, Guocheng; Chen, Jian

    2012-01-01

    Lactobacillus casei has traditionally been recognized as a probiotic and frequently used as an adjunct culture in fermented dairy products, where acid stress is an environmental condition commonly encountered. In the present study, we carried out a comparative physiological and proteomic study to investigate lactic-acid-induced alterations in Lactobacillus casei Zhang (WT) and its acid-resistant mutant. Analysis of the physiological data showed that the mutant exhibited 33.8% higher glucose phosphoenolpyruvate:sugar phosphotransferase system activity and lower glycolytic pH compared with the WT under acidic conditions. In addition, significant differences were detected in both cells during acid stress between intracellular physiological state, including intracellular pH, H(+)-ATPase activity, and intracellular ATP pool. Comparison of the proteomic data based on 2D-DIGE and i-TRAQ indicated that acid stress invoked a global change in both strains. The mutant protected the cells against acid damage by regulating the expression of key proteins involved in cellular metabolism, DNA replication, RNA synthesis, translation, and some chaperones. Proteome results were validated by Lactobacillus casei displaying higher intracellular aspartate and arginine levels, and the survival at pH 3.3 was improved 1.36- and 2.10-fold by the addition of 50-mM aspartate and arginine, respectively. To our knowledge, this is the first demonstration that aspartate may be involved in acid tolerance in Lactobacillus casei. Results presented here may help us understand acid resistance mechanisms and help formulate new strategies to enhance the industrial applications of this species. PMID:22159611

  10. Regulation of antibacterial defense in the small intestine by the nuclear bile acid receptor

    NASA Astrophysics Data System (ADS)

    Inagaki, Takeshi; Moschetta, Antonio; Lee, Youn-Kyoung; Peng, Li; Zhao, Guixiang; Downes, Michael; Yu, Ruth T.; Shelton, John M.; Richardson, James A.; Repa, Joyce J.; Mangelsdorf, David J.; Kliewer, Steven A.

    2006-03-01

    Obstruction of bile flow results in bacterial proliferation and mucosal injury in the small intestine that can lead to the translocation of bacteria across the epithelial barrier and systemic infection. These adverse effects of biliary obstruction can be inhibited by administration of bile acids. Here we show that the farnesoid X receptor (FXR), a nuclear receptor for bile acids, induces genes involved in enteroprotection and inhibits bacterial overgrowth and mucosal injury in ileum caused by bile duct ligation. Mice lacking FXR have increased ileal levels of bacteria and a compromised epithelial barrier. These findings reveal a central role for FXR in protecting the distal small intestine from bacterial invasion and suggest that FXR agonists may prevent epithelial deterioration and bacterial translocation in patients with impaired bile flow. bacteria | biliary obstruction | epithelial barrier | ileum

  11. Retinoic acid-induced differentiation of human neuroblastoma SH-SY5Y cells is associated with changes in the abundance of G proteins.

    PubMed

    Ammer, H; Schulz, R

    1994-04-01

    Western blot analysis, using subtype-specific anti-G protein antibodies, revealed the presence of the following G protein subunits in human neuroblastoma SH-SY5Y cells: Gs alpha, Gi alpha 1, Gi alpha 2, Go alpha, Gz alpha, and G beta. Differentiation of the cells by all-trans-retinoic acid (RA) treatment (10 mumol/L; 6 days) caused substantial alterations in the abundance of distinct G protein subunits. Concomitant with an enhanced expression of mu-opioid binding sites, the levels of the inhibitory G proteins Gi alpha 1 and Gi alpha 2 were found to be significantly increased. This coordinate up-regulation is accompanied by functional changes in mu-opioid receptor-stimulated low-Km GTPase, mu-receptor-mediated adenylate cyclase inhibition, and receptor-independent guanosine 5'-(beta gamma-imido)triphosphate [Gpp(NH)p; 10 nmol/L]-mediated attenuation of adenylate cyclase activity. In contrast, increased levels of inhibitory G proteins had no effect on muscarinic cholinergic receptor-mediated adenylate cyclase inhibition. With respect to stimulatory receptor systems, a reciprocal regulation was observed for prostaglandin E1 (PGE1) receptors and Gs alpha, the G protein subunit activating adenylate cyclase. RA treatment of SH-SY5Y cells increases both the number of PGE1 binding sites and PGE1-stimulated adenylate cyclase activity, but significantly reduced amounts of Gs alpha were found. This down-regulation is paralleled by a decrease in the stimulatory activity of Gs alpha as assessed in S49 cyc- reconstitution assays.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8133263

  12. Thyroid hormone receptor can modulate retinoic acid-mediated axis formation in frog embryogenesis.

    PubMed Central

    Banker, D E; Eisenman, R N

    1993-01-01

    Thyroid hormone receptor acts as a hormone-dependent transcriptional transactivator and as a transcriptional repressor in the absence of thyroid hormone. Specifically, thyroid hormone receptor can repress retinoic acid-induced gene expression through interactions with retinoic acid receptor. (Retinoic acid is a potent teratogen in the frog Xenopus laevis, acting at early embryonic stages to interfere with the formation of anterior structures. Endogenous retinoic acid is thought to act in normal anterior-posterior axis formation.) We have previously shown that thyroid hormone receptor RNA (alpha isotype) is expressed and polysome-associated during Xenopus embryogenesis preceding thyroid gland maturation and endogenous thyroid hormone production (D. E. Banker, J. Bigler, and R. N. Eisenman, Mol. Cell. Biol. 11:5079-5089, 1991). To determine whether thyroid hormone receptor might influence the effects of retinoic acid in early frog development, we have examined the results of ectopic thyroid hormone receptor expression on retinoic acid teratogenesis. We demonstrate that microinjections of full-length thyroid hormone receptor RNA protect injected embryos from retinoic acid teratogenesis. DNA binding is apparently essential to this protective function, as truncated thyroid hormone receptors, lacking DNA-binding domains but including hormone-binding and dimerization domains, do not protect from retinoic acid. We have shown that microinjections of these dominant-interfering thyroid hormone receptors, as well as anti-thyroid hormone receptor antibodies, increase retinoic acid teratogenesis in injected embryos, presumably by inactivating endogenous thyroid hormone receptor. This finding suggests that endogenous thyroid hormone receptors may act to limit retinoic acid sensitivity. On the other hand, after thyroid hormone treatment, ectopic thyroid hormone receptor mediates teratogenesis that is indistinguishable from the dorsoanterior deficiencies produced in retinoic acid

  13. Effects of μ-opioid receptor agonists in assays of acute pain-stimulated and pain-depressed behavior in male rats: role of μ-agonist efficacy and noxious stimulus intensity.

    PubMed

    Altarifi, Ahmad A; Rice, Kenner C; Negus, S Stevens

    2015-02-01

    Pain is associated with stimulation of some behaviors and depression of others, and μ-opioid receptor agonists are among the most widely used analgesics. This study used parallel assays of pain-stimulated and pain-depressed behavior in male Sprague-Dawley rats to compare antinociception profiles for six μ-agonists that varied in efficacy at μ-opioid receptors (from highest to lowest: methadone, fentanyl, morphine, hydrocodone, buprenorphine, and nalbuphine). Intraperitoneal injection of diluted lactic acid served as an acute noxious stimulus to either stimulate stretching or depress operant responding maintained by electrical stimulation in an intracranial self-stimulation (ICSS). All μ-agonists blocked both stimulation of stretching and depression of ICSS produced by 1.8% lactic acid. The high-efficacy agonists methadone and fentanyl were more potent at blocking acid-induced depression of ICSS than acid-stimulated stretching, whereas lower-efficacy agonists displayed similar potency across assays. All μ-agonists except morphine also facilitated ICSS in the absence of the noxious stimulus at doses similar to those that blocked acid-induced depression of ICSS. The potency of the low-efficacy μ-agonist nalbuphine, but not the high-efficacy μ-agonist methadone, to block acid-induced depression of ICSS was significantly reduced by increasing the intensity of the noxious stimulus to 5.6% acid. These results demonstrate sensitivity of acid-induced depression of ICSS to a range of clinically effective μ-opioid analgesics and reveal distinctions between opioids based on efficacy at the μ-receptor. These results also support the use of parallel assays of pain-stimulated and -depressed behaviors to evaluate analgesic efficacy of candidate drugs. PMID:25406170

  14. Decreased striatal dopamine release underlies increased expression of long-term synaptic potentiation at corticostriatal synapses 24 hours after 3-nitropropionic acid induced chemical hypoxia

    PubMed Central

    Akopian, Garnik; Crawford, Cynthia; Beal, M. Flint; Cappelletti, Maurand; Jakowec, Michael W.; Petzinger, Giselle M.; Zheng, Ling; Gheorghe, Stacey L.; Reichel, Carmela M.; Chow, Robert; Walsh, John P

    2008-01-01

    The striatum is particularly sensitive to the irreversible inhibitor of succinate dehyrdrogenase 3-nitropropionic acid (3-NP). In the present study we examined early changes in behavior and dopamine and glutamate synaptic physiology created by a single systemic injection of 3-NP in Fischer 344 rats. Hind limb dystonia was seen 2 hours after 3-NP injections and rats performed poorly on balance beam and rota-rod motor tests 24 hours later. Systemic 3-NP increased NMDA receptor-dependent long-term potentiation (LTP) at corticostriatal synapses over the same time period. The 3-NP induced corticostriatal LTP was not due to increased NMDA receptor number or function, since 3-NP did not change MK-801 binding or NMDA/AMPA receptor current ratios. The LTP seen 24 hours after 3-NP was D1 receptor-dependent and reversed by exogenous addition of dopamine or a D2 receptor agonist to brain slices. High performance liquid chromatography and fast scan cyclic voltammetry revealed a decrease in dopamine content and release in rats injected 24 hours earlier with 3-NP, and much like the enhanced LTP, dopamine changes were reversed by 48 hours. Tyrosine hydroxylase expression was not changed and there was no evidence of striatal cell loss at 24–48 hours after 3-NP exposure. Sprague-Dawley rats showed similar physiological responses to systemic 3-NP, albeit with reduced sensitivity. Thus, 3-NP causes significant changes in motor behavior marked by parallel changes in striatal dopamine release and corticostriatal synaptic plasticity. PMID:18799690

  15. Acid-induced type VI secretion system is regulated by ExoR-ChvG/ChvI signaling cascade in Agrobacterium tumefaciens.

    PubMed

    Wu, Chih-Feng; Lin, Jer-Sheng; Shaw, Gwo-Chyuan; Lai, Erh-Min

    2012-09-01

    The type VI secretion system (T6SS) is a widespread, versatile protein secretion system in pathogenic Proteobacteria. Several T6SSs are tightly regulated by various regulatory systems at multiple levels. However, the signals and/or regulatory mechanisms of many T6SSs remain unexplored. Here, we report on an acid-induced regulatory mechanism activating T6SS in Agrobacterium tumefaciens, a plant pathogenic bacterium causing crown gall disease in a wide range of plants. We monitored the secretion of the T6SS hallmark protein hemolysin-coregulated protein (Hcp) from A. tumefaciens and found that acidity is a T6SS-inducible signal. Expression analysis of the T6SS gene cluster comprising the imp and hcp operons revealed that imp expression and Hcp secretion are barely detected in A. tumefaciens grown in neutral minimal medium but are highly induced with acidic medium. Loss- and gain-of-function analysis revealed that the A. tumefaciens T6SS is positively regulated by a chvG/chvI two-component system and negatively regulated by exoR. Further epistasis analysis revealed that exoR functions upstream of the chvG sensor kinase in regulating T6SS. ChvG protein levels are greatly increased in the exoR deletion mutant and the periplasmic form of overexpressed ExoR is rapidly degraded under acidic conditions. Importantly, ExoR represses ChvG by direct physical interaction, but disruption of the physical interaction allows ChvG to activate T6SS. The phospho-mimic but not wild-type ChvI response regulator can bind to the T6SS promoter region in vitro and activate T6SS with growth in neutral minimal medium. We present the first evidence of T6SS activation by an ExoR-ChvG/ChvI cascade and propose that acidity triggers ExoR degradation, thereby derepressing ChvG/ChvI to activate T6SS in A. tumefaciens. PMID:23028331

  16. Acid-Induced Type VI Secretion System Is Regulated by ExoR-ChvG/ChvI Signaling Cascade in Agrobacterium tumefaciens

    PubMed Central

    Shaw, Gwo-Chyuan; Lai, Erh-Min

    2012-01-01

    The type VI secretion system (T6SS) is a widespread, versatile protein secretion system in pathogenic Proteobacteria. Several T6SSs are tightly regulated by various regulatory systems at multiple levels. However, the signals and/or regulatory mechanisms of many T6SSs remain unexplored. Here, we report on an acid-induced regulatory mechanism activating T6SS in Agrobacterium tumefaciens, a plant pathogenic bacterium causing crown gall disease in a wide range of plants. We monitored the secretion of the T6SS hallmark protein hemolysin-coregulated protein (Hcp) from A. tumefaciens and found that acidity is a T6SS-inducible signal. Expression analysis of the T6SS gene cluster comprising the imp and hcp operons revealed that imp expression and Hcp secretion are barely detected in A. tumefaciens grown in neutral minimal medium but are highly induced with acidic medium. Loss- and gain-of-function analysis revealed that the A. tumefaciens T6SS is positively regulated by a chvG/chvI two-component system and negatively regulated by exoR. Further epistasis analysis revealed that exoR functions upstream of the chvG sensor kinase in regulating T6SS. ChvG protein levels are greatly increased in the exoR deletion mutant and the periplasmic form of overexpressed ExoR is rapidly degraded under acidic conditions. Importantly, ExoR represses ChvG by direct physical interaction, but disruption of the physical interaction allows ChvG to activate T6SS. The phospho-mimic but not wild-type ChvI response regulator can bind to the T6SS promoter region in vitro and activate T6SS with growth in neutral minimal medium. We present the first evidence of T6SS activation by an ExoR-ChvG/ChvI cascade and propose that acidity triggers ExoR degradation, thereby derepressing ChvG/ChvI to activate T6SS in A. tumefaciens. PMID:23028331

  17. Mechanisms for the activation of Toll-like receptor 2/4 by saturated fatty acids and inhibition by docosahexaenoic acid.

    PubMed

    Hwang, Daniel H; Kim, Jeong-A; Lee, Joo Young

    2016-08-15

    Saturated fatty acids can activate Toll-like receptor 2 (TLR2) and TLR4 but polyunsaturated fatty acids, particularly docosahexaenoic acid (DHA) inhibit the activation. Lipopolysaccharides (LPS) and lipopetides, ligands for TLR4 and TLR2, respectively, are acylated by saturated fatty acids. Removal of these fatty acids results in loss of their ligand activity suggesting that the saturated fatty acyl moieties are required for the receptor activation. X-ray crystallographic studies revealed that these saturated fatty acyl groups of the ligands directly occupy hydrophobic lipid binding domains of the receptors (or co-receptor) and induce the dimerization which is prerequisite for the receptor activation. Saturated fatty acids also induce the dimerization and translocation of TLR4 and TLR2 into lipid rafts in plasma membrane and this process is inhibited by DHA. Whether saturated fatty acids induce the dimerization of the receptors by interacting with these lipid binding domains is not known. Many experimental results suggest that saturated fatty acids promote the formation of lipid rafts and recruitment of TLRs into lipid rafts leading to ligand independent dimerization of the receptors. Such a mode of ligand independent receptor activation defies the conventional concept of ligand induced receptor activation; however, this may enable diverse non-microbial molecules with endogenous and dietary origins to modulate TLR-mediated immune responses. Emerging experimental evidence reveals that TLRs play a key role in bridging diet-induced endocrine and metabolic changes to immune responses.

  18. Toll-like receptors: the swiss army knife of immunity and vaccine development

    PubMed Central

    Dowling, Jennifer K; Mansell, Ashley

    2016-01-01

    Innate immune cells have a critical role in defense against infection and disease. Central to this is the broad specificity with which they can detect pathogen-associated patterns and danger-associated patterns via the pattern recognition receptors (PRRs) they express. Several families of PRRs have been identified including: Toll-like receptors (TLRs), C-type lectin-like receptors, retinoic acid-inducible gene-like receptors and nucleotide-binding oligomerization domain–like receptors. TLRs are one of the most largely studied families of PRRs. The binding of ligands to TLRs on antigen presenting cells (APCs), mainly dendritic cells, leads to APC maturation, induction of inflammatory cytokines and the priming of naive T cells to drive acquired immunity. Therefore, activation of TLRs promotes both innate inflammatory responses and the induction of adaptive immunity. Consequently, in the last two decades mounting evidence has inextricably linked TLR activation with the pathogenesis of immune diseases and cancer. It has become advantageous to harness these aspects of TLR signaling therapeutically to accelerate and enhance the induction of vaccine-specific responses and also target TLRs with the use of biologics and small molecule inhibitors for the treatment of disease. In these respects, TLRs may be considered a ‘Swiss Army' knife of the immune system, ready to respond in a multitude of infectious and disease states. Here we describe the latest advances in TLR-targeted therapeutics and the use of TLR ligands as vaccine adjuvants. PMID:27350884

  19. TBK1-like transcript negatively regulates the production of IFN and IFN-stimulated genes through RLRs-MAVS-TBK1 pathway.

    PubMed

    Zhang, Lin; Chen, Wen Qin; Hu, Yi Wei; Wu, Xiao Man; Nie, P; Chang, Ming Xian

    2016-07-01

    TANK-binding kinase 1 (TBK1) is an essential serine/threonine-protein kinase required for Toll-like receptor (TLR)- and retinoic acid-inducible gene I (RIG-I) -mediated induction of type I IFN and host antiviral defense. In the present study, TBK1-like transcript, namely TBK1L, was cloned from zebrafish. Compared with TBK1, TBK1L contains an incomplete S_TKc domain, and lacks UBL_TBK1_like domain. Realtime PCR showed that TBK1L was constitutively produced in embryos, early larvae and ZF4 cells, and unchanged in ZF4 cells following SVCV infection. Overexpression of TBK1 but not TBK1L resulted in significant activation of zebrafish IFN1 and IFN3 promoters. Similarly, TBK1L had little impact on the antiviral state of the cells. However, the overexpression of TBK1L negatively regulated the induction of zebrafish IFN1 and/or IFN3 promoters mediated by the retinoic acid-inducible gene I-like receptors (RLRs), MAVS and TBK1. In addition, the overexpression of TBK1L in zebrafish embryos led to the decreased production of many IFN-stimulated genes induced by TBK1. Collectively, these data support that zebrafish TBK1L negatively regulates RLRs-MAVS-TBK1 pathway. PMID:27060200

  20. Historical overview of nuclear receptors.

    PubMed

    Gustafsson, Jan-Ake

    2016-03-01

    This review summarizes the birth of the field of nuclear receptors, from Jensen's discovery of estrogen receptor alpha, Gustafsson's discovery of the three-domain structure of the glucocorticoid receptor, the discovery of the glucocorticoid response element and the first partial cloning of the glucocorticoid receptor. Furthermore the discovery of the novel receptors called orphan receptors is described.

  1. Intrahippocampal Administration of Ibotenic Acid Induced Cholinergic Dysfunction via NR2A/NR2B Expression: Implications of Resveratrol against Alzheimer Disease Pathophysiology

    PubMed Central

    Karthick, Chennakesavan; Periyasamy, Sabapathy; Jayachandran, Kesavan S.; Anusuyadevi, Muthuswamy

    2016-01-01

    Although several drugs revealed moderate amelioration of symptoms, none of them have sufficient potency to prevent or reverse the progression toward Alzheimer's disease (AD) pathology. Resveratrol (RSV), a polyphenolic compound has shown an outstanding therapeutic effect on a broad spectrum of diseases like age-associated neurodegeneration, inflammation etc. The present study was thus conducted to assess the therapeutic efficacy of RSV in ameliorating the deleterious effects of Ibotenic acid (IBO) in male Wistar rats. Stereotactic intrahippocampal administration of IBO (5 μg/μl) lesioned rats impairs cholinergic transmission, learning and memory performance that is rather related to AD and thus chosen as a suitable model to understand the drug efficacy in preventing AD pathophysiology. Since IBO is an agonist of glutamate, it is expected to exhibit an excitotoxic effect by altering glutamatergic receptors like NMDA receptor. The current study displayed significant alterations in the mRNA expression of NR2A and NR2B subunits of NMDA receptors, and further it is surprising to note that cholinergic receptors decreased in expression particularly α7-nAChR with increased m1AChR. RSV administration (20 mg/kg body weight, i.p.) significantly reduced these changes in IBO induced rats. Glutamatergic and cholinergic receptor alterations were associated with significant changes in the behavioral parameters of rats induced by IBO. While RSV improved spatial learning performance, attenuated immobility, and improvised open field activity in IBO induced rats. NR2B activation in the present study might mediate cell death through oxidative stress that form the basis of abnormal behavioral pattern in IBO induced rats. Interestingly, RSV that could efficiently encounter oxidative stress have significantly decreased stress markers viz., nitrite, PCO, and MDA levels by enhancing antioxidant status. Histopathological analysis displayed significant reduction in the hippocampal

  2. Standardizing Scavenger Receptor Nomenclature

    PubMed Central

    PrabhuDas, Mercy; Bowdish, Dawn; Drickamer, Kurt; Febbraio, Maria; Herz, Joachim; Kobzik, Lester; Krieger, Monty; Loike, John; Means, Terry K.; Moestrup, Soren K.; Post, Steven; Sawamura, Tatsuya; Silverstein, Samuel; Wang, Xiang-Yang; El Khoury, Joseph

    2014-01-01

    Scavenger receptors constitute a large family of proteins that are structurally diverse and participate in a wide range of biological functions. These receptors are expressed predominantly by myeloid cells and recognize a variety of ligands, including endogenous and modified host-derived molecules and microbial pathogens. There are currently eight classes of scavenger receptors, many of which have multiple names, leading to inconsistencies and confusion in the literature. To address this problem, a workshop was organized by the U.S. National Institute of Allergy and Infectious Diseases, National Institutes of Health to help develop a clear definition of scavenger receptors and a standardized nomenclature based on that definition. Fifteen experts in the scavenger receptor field attended the workshop and, after extensive discussion, reached a consensus regarding the definition of scavenger receptors and a proposed scavenger receptor nomenclature. Scavenger receptors were defined as cell surface receptors that typically bind multiple ligands and promote the removal of non-self or altered-self targets. They often function by mechanisms that include endocytosis, phagocytosis, adhesion, and signaling that ultimately lead to the elimination of degraded or harmful substances. Based on this definition, nomenclature and classification of these receptors into 10 classes were proposed. The discussion and nomenclature recommendations described in this report only refer to mammalian scavenger receptors. The purpose of this article is to describe the proposed mammalian nomenclature and classification developed at the workshop and to solicit additional feedback from the broader research community. PMID:24563502

  3. Changes and overlapping distribution in the expression of CB1/OX1-GPCRs in rat hippocampus by kainic acid-induced status epilepticus.

    PubMed

    Zhu, Fei; Wang, Xiang-Qing; Chen, Ya-Nan; Yang, Nan; Lang, Sen-Yang; Zuo, Ping-Ping; Zhang, Jia-Tang; Li, Rui-Sheng

    2015-02-01

    Status epilepticus (SE) is a life-threatening neurological disorder. It is important to discover new drugs to control SE without the development of pharmacoresistance. Focus on the cannabinoid receptor and cannabinoid-related compounds might be a good option. Cannabinoid receptor 1 (CB1) and orexin receptor 1 (OX1) both belong to the GPCR superfamily and display "cross-talk" interactions, however, there has been no study of the effect of OX1/CB1 in epilepsy. Therefore, we investigated the potential long-term effects of SE on CB1 and OX1 expression in rat hippocampus, aiming to elucidate whether they are involved in the causative mechanism of epilepsy and whether they might form a heterodimer. In this study, SE was induced with kainic acid, and results of immunohistochemistry and RT-PCR both showed that the expression of CB1 in the hippocampus increased after SE and was significantly higher compared to controls especially 1 week post-SE. However we did not find any significant difference in the expression of OX1 between the SE group and the controls at any time. Under immunofluorescence staining, we observed an overlapping distribution of CB1 and OX1 in the hippocampus. The increased expression of CB1 in the hippocampus indicates that CB1 may play an important role in the underlying mechanism of SE, but the effect of OX1 was not obvious. The overlapping distribution of CB1 and OX1 in the hippocampus indicates that they may form a heterodimer to exert their effect in epilepsy.

  4. Cathepsin L Plays a Role in Quinolinic Acid-Induced NF-Κb Activation and Excitotoxicity in Rat Striatal Neurons

    PubMed Central

    Han, Rong; Wu, Jun-Chao; Liang, Zhong-Qin; Qin, Zheng-Hong; Wang, Yan

    2013-01-01

    The present study seeks to investigate the role of cathepsin L in glutamate receptor-induced transcription factor nuclear factor-kappa B (NF-κB) activation and excitotoxicity in rats striatal neurons. Stereotaxic administration of the N-methyl-d-aspartate (NMDA) receptor agonist Quinolinic acid (QA) into the unilateral striatum was used to produce the in vivo excitotoxic model. Co-administration of QA and the cathepsin L inhibitor Z-FF-FMK or 1-Naphthalenesulfonyl-IW-CHO (NaphthaCHO) was used to assess the contribution of cathepsin L to QA-induced striatal neuron death. Western blot analysis and cathepsin L activity assay were used to assess the changes in the levels of cathepsin L after QA treatment. Western blot analysis was used to assess the changes in the protein levels of inhibitor of NF-κB alpha isoform (IκB-α) and phospho-IκB alpha (p-IκBα) after QA treatment. Immunohistochemical analysis was used to detect the effects of Z-FF-FMK or NaphthaCHO on QA-induced NF-κB. Western blot analysis was used to detect the effects of Z-FF-FMK or NaphthaCHO on QA-induced IκB-α phosphorylation and degradation, changes in the levels of IKKα, p-IKKα, TP53, caspase-3, beclin1, p62, and LC3II/LC3I. The results show that QA-induced loss of striatal neurons were strongly inhibited by Z-FF-FMK or NaphthaCHO. QA-induced degradation of IκB-α, NF-κB nuclear translocation, up-regulation of NF-κB responsive gene TP53, and activation of caspase-3 was strongly inhibited by Z-FF-FMK or NaphthaCHO. QA-induced increases in beclin 1, LC3II/LC3I, and down-regulation of p62 were reduced by Z-FF-FMK or NaphthaCHO. These results suggest that cathepsin L is involved in glutamate receptor-induced NF-κB activation. Cathepsin L inhibitors have neuroprotective effects by inhibiting glutamate receptor-induced IκB-α degradation and NF-κB activation. PMID:24073275

  5. Potentiation by sevoflurane of the gamma-aminobutyric acid-induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus.

    PubMed Central

    Wu, J.; Harata, N.; Akaike, N.

    1996-01-01

    1. The effects of a new kind of volatile anaesthetic, sevoflurane (Sev), on gamma-aminobutyric acid (GABA)-gated chloride current (Icl) in single neurones dissociated from the rat hippocampal CA1 area were examined using the nystatin perforated patch recording configuration under the voltage-clamp condition. All drugs were applied with a rapid perfusion system, termed the "Y-tube' method. 2. When the concentrations were higher than 3 x 10(-4) M, Sev, itself, induced an inward current (ISev) at a holding potential (VH) of -40 mV. The concentration-response curve of ISev was bell-shaped, with a suppressed peak and plateau currents at high concentrations (above 2 x 10(-3) M). The reversal potential of ISev (ESev) was close to the theoretical Cl- equilibrium potential, indicating that ISev was carried mainly by Cl-. 3. ISev was reversibly blocked by bicuculline (Bic), an antagonist of the GABAA receptor, in a concentration-dependent manner with a half-inhibitory concentration (IC50) of 7.2 x 10(-7) M. But ISev was insensitive to strychnine (Str), an antagonist of the glycine receptor. 4. At low concentrations (between 3 x 10(-4) and 10(-3) M), Sev markedly enhanced the 10(-6) M GABA induced current (IGABA) but reduced the IGABA with accelerating desensitization accompanied by a "hump' current after washout at high concentrations (higher than 2 x 10(-3) M). 5. Sev, 10(-3) M potentiated the current induced by low concentrations of GABA (between 10(-7) and 3 x 10(-6) M) but reduced the current induced by high concentrations (higher than 10(-5) M) of GABA with a clear acceleration of IGABA desensitization. 6. Sev, like pentobarbitone (PB), pregnanolone (PGN) or diazepam (DZP), potentiated the 10(-6) M GABA-induced response without shifting the reversal potential of IGABA. 7. ISev was augmented by PB, PGN, or DZP at concentrations that maximally potentiated IGABA, suggesting that Sev enhanced IGABA at a binding site distinct from that for PB, PGN, or DZP. 8. It is concluded

  6. P2X receptors.

    PubMed

    North, R Alan

    2016-08-01

    Extracellular adenosine 5'-triphosphate (ATP) activates cell surface P2X and P2Y receptors. P2X receptors are membrane ion channels preferably permeable to sodium, potassium and calcium that open within milliseconds of the binding of ATP. In molecular architecture, they form a unique structural family. The receptor is a trimer, the binding of ATP between subunits causes them to flex together within the ectodomain and separate in the membrane-spanning region so as to open a central channel. P2X receptors have a widespread tissue distribution. On some smooth muscle cells, P2X receptors mediate the fast excitatory junction potential that leads to depolarization and contraction. In the central nervous system, activation of P2X receptors allows calcium to enter neurons and this can evoke slower neuromodulatory responses such as the trafficking of receptors for the neurotransmitter glutamate. In primary afferent nerves, P2X receptors are critical for the initiation of action potentials when they respond to ATP released from sensory cells such as taste buds, chemoreceptors or urothelium. In immune cells, activation of P2X receptors triggers the release of pro-inflammatory cytokines such as interleukin 1β. The development of selective blockers of different P2X receptors has led to clinical trials of their effectiveness in the management of cough, pain, inflammation and certain neurodegenerative diseases.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'. PMID:27377721

  7. Retinoic acid-induced IgG production in TLR-activated human primary B cells involves ULK1-mediated autophagy.

    PubMed

    Eriksen, Agnete Bratsberg; Torgersen, Maria Lyngaas; Holm, Kristine Lillebø; Abrahamsen, Greger; Spurkland, Anne; Moskaug, Jan Øivind; Simonsen, Anne; Blomhoff, Heidi Kiil

    2015-01-01

    In the present study we have established a vital role of autophagy in retinoic acid (RA)-induced differentiation of toll-like receptor (TLR)-stimulated human B cells into Ig-secreting cells. Thus, RA enhanced autophagy in TLR9- and CD180-stimulated peripheral blood B cells, as revealed by increased levels of the autophagosomal marker LC3B-II, enhanced colocalization between LC3B and the lysosomal marker Lyso-ID, by a larger percentage of cells with more than 5 characteristic LC3B puncta, and by the concomitant reduction in the level of SQSTM1/p62. Furthermore, RA induced expression of the autophagy-inducing protein ULK1 at the transcriptional level, in a process that required the retinoic acid receptor RAR. By inhibiting autophagy with specific inhibitors or by knocking down ULK1 by siRNA, the RA-stimulated IgG production in TLR9- and CD180-mediated cells was markedly reduced. We propose that the identified prominent role of autophagy in RA-mediated IgG-production in normal human B cells provides a novel mechanism whereby vitamin A exerts its important functions in the immune system.

  8. Effects of peripherally restricted κ opioid receptor agonists on pain-related stimulation and depression of behavior in rats.

    PubMed

    Negus, S Stevens; O'Connell, Robert; Morrissey, Ember; Cheng, Kejun; Rice, Kenner C

    2012-03-01

    κ opioid receptor agonists that do not readily cross the blood-brain barrier are peripherally restricted and distribute poorly to the central nervous system after systemic administration. Peripherally restricted κ agonists have promise as candidate analgesics, because they may produce antinociception mediated by peripheral κ receptors more potently than they produce undesirable sedative and psychotomimetic effects mediated by central κ receptors. The present study used assays of pain-related stimulation and depression of behavior in rats to compare effects of 1) two peripherally restricted κ agonists [the tetrapeptide D-Phe-D-Phe-D-Ile-D-Arg-NH(2) (ffir) and the nonpeptidic compound ((R,S)-N-[2-(N-methyl-3,4-dichlorophenylacetamido)-2-(3-carboxyphenyl)-ethyl]pyrrolidine hydrochloride (ICI204448)], 2) a centrally penetrating κ agonist (salvinorin A), and 3) several reference drugs, including a nonsteroidal anti-inflammatory drug (NSAID; ketoprofen). Intraperitoneal injection of dilute lactic acid served as a noxious stimulus to stimulate a stretching response and depress intracranial self-stimulation (ICSS) maintained by the delivery of electrical brain stimulation to the medial forebrain bundle. Acid-stimulated stretching was blocked by ketoprofen, the peripherally restricted κ agonists, and salvinorin A. However, acid-induced depression of ICSS was blocked only by ketoprofen. The peripherally restricted κ agonists had little effect, and salvinorin A exacerbated acid-induced depression of ICSS. These results suggest that peripherally restricted κ agonists may be safer than centrally penetrating κ agonists but less efficacious than NSAIDS or μ opioid receptor agonists to block pain-related depression of behavior; however, the peripheral selectivity of ffir and ICI204448 is limited, and future studies with κ agonists capable of greater peripheral selectivity are warranted.

  9. Domain-confined catalytic soot combustion over Co3O4 anchored on a TiO2 nanotube array catalyst prepared by mercaptoacetic acid induced surface-grafting

    NASA Astrophysics Data System (ADS)

    Ren, Jiale; Yu, Yifu; Dai, Fangfang; Meng, Ming; Zhang, Jing; Zheng, Lirong; Hu, Tiandou

    2013-11-01

    Herein, we introduce a specially designed domain-confined macroporous catalyst, namely, the Co3O4 nanocrystals anchored on a TiO2 nanotube array catalyst, which was synthesized by using the mercaptoacetic acid induced surface-grafting method. This catalyst exhibits much better performance for catalytic soot combustion than the conventional TiO2 powder supported one in gravitational contact mode (GMC).Herein, we introduce a specially designed domain-confined macroporous catalyst, namely, the Co3O4 nanocrystals anchored on a TiO2 nanotube array catalyst, which was synthesized by using the mercaptoacetic acid induced surface-grafting method. This catalyst exhibits much better performance for catalytic soot combustion than the conventional TiO2 powder supported one in gravitational contact mode (GMC). Electronic supplementary information (ESI) available: The images of XRD, UV-vis, EDX and soot-TPR. The table providing information on Co/Ti-NA catalysts. See DOI: 10.1039/c3nr03757f

  10. The role of innate immune signals in immunity to Brucella abortus

    PubMed Central

    Gomes, Marco Túlio R.; Campos, Priscila C.; de Almeida, Leonardo A.; Oliveira, Fernanda S.; Costa, Miriam Maria S.; Marim, Fernanda M.; Pereira, Guilherme S. M.; Oliveira, Sergio C.

    2012-01-01

    Innate immunity serves as the first line of defense against infectious agents such as intracellular bacteria. The innate immune platform includes Toll-like receptors (TLRs), retinoid acid-inducible gene-I-like receptors and other cytosolic nucleic acid sensors, nucleotide-binding and oligomerization domain-like receptors, adaptors, kinases and other signaling molecules that are required to elicit effective responses against different pathogens. Our research group has been using the Gram-negative bacteria Brucella abortus as a model of pathogen. We have demonstrated that B. abortus triggers MAPK and NF-κB signaling pathways in macrophages in a MyD88 and IRAK-4-dependent manner. Furthermore, we claimed that so far TLR9 is the most important single TLR during Brucella infection. The identification of host receptors that recognize pathogen-derived nucleic acids has revealed an essential role for nucleic acid sensing in the triggering of immunity to intracellular pathogens. Besides TLRs, herein we describe recent advances in NOD1, NOD2, and type I IFN receptors in innate immune pathways during B. abortus infection. PMID:23112959

  11. Neuroprotective Effect of Uncaria rhynchophylla in Kainic Acid-Induced Epileptic Seizures by Modulating Hippocampal Mossy Fiber Sprouting, Neuron Survival, Astrocyte Proliferation, and S100B Expression

    PubMed Central

    Liu, Chung-Hsiang; Lin, Yi-Wen; Tang, Nou-Ying; Liu, Hsu-Jan; Hsieh, Ching-Liang

    2012-01-01

    Uncaria rhynchophylla (UR), which is a traditional Chinese medicine, has anticonvulsive effect in our previous studies, and the cellular mechanisms behind this are still little known. Because of this, we wanted to determine the importance of the role of UR on kainic acid- (KA-) induced epilepsy. Oral UR for 6 weeks can successfully attenuate the onset of epileptic seizure in animal tests. Hippocampal mossy fiber sprouting dramatically decreased, while neuronal survival increased with UR treatment in hippocampal CA1 and CA3 areas. Furthermore, oral UR for 6 weeks significantly attenuated the overexpression of astrocyte proliferation and S100B proteins but not γ-aminobutyric acid A (GABAA) receptors. These results indicate that oral UR for 6 weeks can successfully attenuate mossy fiber sprouting, astrocyte proliferation, and S100B protein overexpression and increase neuronal survival in KA-induced epileptic rat hippocampus PMID:21837247

  12. Role for pro-inflammatory cytokines in regulating expression of GABA transporter type 1 and 3 in specific brain regions of kainic acid-induced status epilepticus.

    PubMed

    Su, Jing; Yin, Jian; Qin, Wei; Sha, Suxu; Xu, Jun; Jiang, Changbin

    2015-03-01

    In general, pro-inflammatory cytokines (PICs) contribute to regulation of epilepsy-associated pathophysiological processes in the central nerve system. In this report, we examined the specific activation of PICs, namely IL-1β, IL-6 and TNF-α in rat brain after kainic acid (KA)-induced status epilepticus (SE). Also, we examined the role played by PICs in regulating expression of GABA transporter type 1 and 3 (GAT-1 and GAT-3, respectively), which are the two important subtypes of GATs responsible for the regulation of extracellular GABA levels in the brain. Our results show that IL-1β, IL-6 and TNF-α were significantly increased in the parietal cortex, hippocampus and amygdala of KA-rats as compared with sham control animals (P < 0.05, KA rats vs. control rats). KA-induced SE also significantly increased (P < 0.05 vs. controls) the protein expression of GAT-1 and GAT-3 in those brain regions. In addition, central administration of antagonists to IL-1β and TNF-α receptors significantly attenuated amplified GAT-1 and GAT-3 (P < 0.05 vs. vehicle control for each antagonist group). However, antagonist to IL-6 receptor failed to attenuate enhancement in expression of GAT-1 and GAT-3 induced by KA-induced SE. Overall, our data demonstrate that PIC pathways are activated in the specific brain regions during SE which thereby selectively leads to upregulation of GABA transporters. As a result, it is likely that de-inhibition of GABA system is increased in the brain. This support a role for PICs in engagement of the adaptive mechanisms associated with epileptic activity, and has pharmacological implications to target specific PICs for neuronal dysfunction and vulnerability related to epilepsy. PMID:25708016

  13. Signals and Receptors.

    PubMed

    Heldin, Carl-Henrik; Lu, Benson; Evans, Ron; Gutkind, J Silvio

    2016-04-01

    Communication between cells in a multicellular organism occurs by the production of ligands (proteins, peptides, fatty acids, steroids, gases, and other low-molecular-weight compounds) that are either secreted by cells or presented on their surface, and act on receptors on, or in, other target cells. Such signals control cell growth, migration, survival, and differentiation. Signaling receptors can be single-span plasma membrane receptors associated with tyrosine or serine/threonine kinase activities, proteins with seven transmembrane domains, or intracellular receptors. Ligand-activated receptors convey signals into the cell by activating signaling pathways that ultimately affect cytosolic machineries or nuclear transcriptional programs or by directly translocating to the nucleus to regulate transcription. PMID:27037414

  14. Mycophenolic acid induces ATP-binding cassette transporter A1 (ABCA1) expression through the PPAR{gamma}-LXR{alpha}-ABCA1 pathway

    SciTech Connect

    Xu, Yanni; Lai, Fangfang; Xu, Yang; Wu, Yexiang; Liu, Qi; Li, Ni; Wei, Yuzhen; Feng, Tingting; Zheng, Zhihui; Jiang, Wei; Yu, Liyan; Hong, Bin; Si, Shuyi

    2011-11-04

    Highlights: Black-Right-Pointing-Pointer Using an ABCA1p-LUC HepG2 cell line, we found that MPA upregulated ABCA1 expression. Black-Right-Pointing-Pointer MPA induced ABCA1 and LXR{alpha} protein expression in HepG2 cells. Black-Right-Pointing-Pointer PPAR{gamma} antagonist GW9662 markedly inhibited MPA-induced ABCA1 and LXR{alpha} protein expression. Black-Right-Pointing-Pointer The effect of MPA upregulating ABCA1 was due mainly to activation of the PPAR{gamma}-LXR{alpha}-ABCA1 pathway. -- Abstract: ATP-binding cassette transporter A1 (ABCA1) promotes cholesterol and phospholipid efflux from cells to lipid-poor apolipoprotein A-I and plays an important role in atherosclerosis. In a previous study, we developed a high-throughput screening method using an ABCA1p-LUC HepG2 cell line to find upregulators of ABCA1. Using this method in the present study, we found that mycophenolic acid (MPA) upregulated ABCA1 expression (EC50 = 0.09 {mu}M). MPA upregulation of ABCA1 expression was confirmed by real-time quantitative reverse transcription-PCR and Western blot analysis in HepG2 cells. Previous work has indicated that MPA is a potent agonist of peroxisome proliferator-activated receptor gamma (PPAR{gamma}; EC50 = 5.2-9.3 {mu}M). Liver X receptor {alpha} (LXR{alpha}) is a target gene of PPAR{gamma} and may directly regulate ABCA1 expression. Western blot analysis showed that MPA induced LXR{alpha} protein expression in HepG2 cells. Addition of PPAR{gamma} antagonist GW9662 markedly inhibited MPA-induced ABCA1 and LXR{alpha} protein expression. These data suggest that MPA increased ABCA1 expression mainly through activation of PPAR{gamma}. Thus, the effects of MPA on upregulation of ABCA1 expression were due mainly to activation of the PPAR{gamma}-LXR{alpha}-ABCA1 signaling pathway. This is the first report that the antiatherosclerosis activity of MPA is due to this mechanism.

  15. Inhibition of all-trans-retinoic acid-induced proteasome activation potentiates the differentiating effect of retinoid in acute myeloid leukemia cells.

    PubMed

    Fang, Yanfen; Zhou, Xinglu; Lin, Meihua; Ying, Meidan; Luo, Peihua; Zhu, Difeng; Lou, Jianshu; Yang, Bo; He, Qiaojun

    2011-01-01

    All-trans retinoic acid (ATRA) is nowadays considered to be the sole efficient agent for differentiation-based therapy in leukemia; however, the mechanisms of ATRA's biological effects remain largely unknown. Here we first reported that ATRA-induced myeloid leukemia differentiation was accompanied with the increased level of ubiquitin-protein conjugates and the upregulation of proteasome activity. To explore the functional role of the activated proteasome in retinoic acid (RA) signaling, the effects of proteasome inhibitors on RA-induced cell differentiation were determined. Our results demonstrated that inhibition of ATRA-elevated proteasome activity obviously promoted the myeloid maturation program triggered by ATRA, suggesting that the overactivated proteasome is not beneficial for ATRA's effects. Further studies demonstrated that the synergistic differentiating effects of ATRA and proteasome inhibitors might be associated with the protection of retinoic acid receptor alpha (RARα) from degradation by the ubiquitin-proteasome pathway (UPP). Moreover, the accumulated RARα was able to enhance the transcription of its target gene, which might also contribute to the enhanced differentiation of leukemia cells. Together, by linking the UPP to ATRA-dependent signaling, our data provide a novel insight into studying the mechanisms of ATRA-elicited cellular effects and imply the possibility of combination of ATRA and proteasome inhibitors in leukemia therapy.

  16. Lipopolysaccharide prevents valproic acid-induced apoptosis via activation of nuclear factor-κB and inhibition of p53 activation.

    PubMed

    Tsolmongyn, Bilegtsaikhan; Koide, Naoki; Odkhuu, Erdenezaya; Haque, Abedul; Naiki, Yoshikazu; Komatsu, Takayuki; Yoshida, Tomoaki; Yokochi, Takashi

    2013-04-01

    The effect of lipopolysaccharide (LPS) on valproic acid (VPA)-induced cell death was examined by using mouse RAW 264.7 macrophage cells. LPS inhibited the activation of caspase 3 and poly (ADP-ribose) polymerase and prevented VPA-induced apoptosis. LPS inhibited VPA-induced p53 activation and pifithrin-α as a p53 inhibitor as well as LPS prevented VPA-induced apoptosis. LPS abolished the increase of Bax/Bcl-2 ratio, which is a critical indicator of p53-mediated mitochondrial damage, in response to VPA. The nuclear factor (NF)-κB inhibitors, Bay 11-7082 and parthenolide, abolished the preventive action of LPS on VPA-induced apoptosis. A series of toll-like receptor ligands, Pam3CSK4, poly I:C, and CpG DNA as well as LPS prevented VPA-induced apoptosis. Taken together, LPS was suggested to prevent VPA-induced apoptosis via activation of anti-apoptotic NF-κB and inhibition of pro-apoptotic p53 activation. The detailed inhibitory mechanism of VPA-induced apoptosis by LPS is discussed.

  17. Lipopolysaccharide prevents valproic acid-induced apoptosis via activation of nuclear factor-κB and inhibition of p53 activation.

    PubMed

    Tsolmongyn, Bilegtsaikhan; Koide, Naoki; Odkhuu, Erdenezaya; Haque, Abedul; Naiki, Yoshikazu; Komatsu, Takayuki; Yoshida, Tomoaki; Yokochi, Takashi

    2013-04-01

    The effect of lipopolysaccharide (LPS) on valproic acid (VPA)-induced cell death was examined by using mouse RAW 264.7 macrophage cells. LPS inhibited the activation of caspase 3 and poly (ADP-ribose) polymerase and prevented VPA-induced apoptosis. LPS inhibited VPA-induced p53 activation and pifithrin-α as a p53 inhibitor as well as LPS prevented VPA-induced apoptosis. LPS abolished the increase of Bax/Bcl-2 ratio, which is a critical indicator of p53-mediated mitochondrial damage, in response to VPA. The nuclear factor (NF)-κB inhibitors, Bay 11-7082 and parthenolide, abolished the preventive action of LPS on VPA-induced apoptosis. A series of toll-like receptor ligands, Pam3CSK4, poly I:C, and CpG DNA as well as LPS prevented VPA-induced apoptosis. Taken together, LPS was suggested to prevent VPA-induced apoptosis via activation of anti-apoptotic NF-κB and inhibition of pro-apoptotic p53 activation. The detailed inhibitory mechanism of VPA-induced apoptosis by LPS is discussed. PMID:23770718

  18. Acidic leucine-rich nuclear phosphoprotein 32 family member B (ANP32B) contributes to retinoic acid-induced differentiation of leukemic cells

    SciTech Connect

    Yu, Yun; Shen, Shao-Ming; Zhang, Fei-Fei; Wu, Zhao-Xia; Han, Bin; Wang, Li-Shun

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer ANP32B was down-regulated during ATRA-induced leukemic cell differentiation. Black-Right-Pointing-Pointer Knockdown of ANP32B enhanced ATRA-induced leukemic cell differentiation. Black-Right-Pointing-Pointer Ectopic expression of ANP32B inhibited ATRA-induced leukemic cell differentiation. Black-Right-Pointing-Pointer ANP32B inhibited ATRA activated transcriptional activity of RAR{alpha}. -- Abstract: The acidic leucine-rich nuclear phosphoprotein 32B (ANP32B) is a member of a conserved superfamily of nuclear proteins whose functions are largely unknown. In our previous work, ANP32B was identified as a novel direct substrate for caspase-3 and acted as a negative regulator for leukemic cell apoptosis. In this work, we provided the first demonstration that ANP32B expression was down-regulated during differentiation induction of leukemic cells by all-trans retinoic acid (ATRA). Knockdown of ANP32B expression by specific shRNA enhanced ATRA-induced leukemic cell differentiation, while ectopic expression of ANP32B attenuated it, indicating an inhibitory role of ANP32B against leukemic cell differentiation. Furthermore, luciferase reporter assay revealed that ANP32B might exert this role through inhibiting the ATRA dependent transcriptional activity of retinoic acid receptor (RAR{alpha}). These data will shed new insights into understanding the biological functions of ANP32B protein.

  19. Granulocyte colony-stimulating factor (G-CSF): A saturated fatty acid-induced myokine with insulin-desensitizing properties in humans

    PubMed Central

    Ordelheide, Anna-Maria; Gommer, Nadja; Böhm, Anja; Hermann, Carina; Thielker, Inga; Machicao, Fausto; Fritsche, Andreas; Stefan, Norbert; Häring, Hans-Ulrich; Staiger, Harald

    2016-01-01

    Objective Circulating long-chain free fatty acids (FFAs) are important metabolic signals that acutely enhance fatty acid oxidation, thermogenesis, energy expenditure, and insulin secretion. However, if chronically elevated, they provoke inflammation, insulin resistance, and β-cell failure. Moreover, FFAs act via multiple signaling pathways as very potent regulators of gene expression. In human skeletal muscle cells differentiated in vitro (myotubes), we have shown in previous studies that the expression of CSF3, the gene encoding granulocyte colony-stimulating factor (G-CSF), is markedly induced upon FFA treatment and exercise. Methods and results We now report that CSF3 is induced in human myotubes by saturated, but not unsaturated, FFAs via Toll-like receptor 4-dependent and -independent pathways including activation of Rel-A, AP-1, C/EBPα, Src, and stress kinases. Furthermore, we show that human adipocytes and myotubes treated with G-CSF become insulin-resistant. In line with this, a functional polymorphism in the CSF3 gene affects adipose tissue- and whole-body insulin sensitivity and glucose tolerance in human subjects with elevated plasma FFA concentrations. Conclusion G-CSF emerges as a new player in FFA-induced insulin resistance and thus may be of interest as a target for prevention and treatment of type 2 diabetes. PMID:27069870

  20. 18α-Glycyrrhetinic Acid Induces Apoptosis of HL-60 Human Leukemia Cells through Caspases- and Mitochondria-Dependent Signaling Pathways.

    PubMed

    Huang, Yi-Chang; Kuo, Chao-Lin; Lu, Kung-Wen; Lin, Jen-Jyh; Yang, Jiun-Long; Wu, Rick Sai-Chuen; Wu, Ping-Ping; Chung, Jing-Gung

    2016-01-01

    In this study we investigate the molecular mechanisms of caspases and mitochondria in the extrinsic and intrinsic signal apoptosis pathways in human leukemia HL-60 cells after in vitro exposure to 18α-glycyrrhetinic acid (18α-GA). Cells were exposed to 18α-GA at various concentrations for various time periods and were harvested for flow cytometry total viable cell and apoptotic cell death measurements. Cells treated with 18α-GA significantly inhibited cell proliferation and induced cell apoptosis in a dose-dependent manner, with an IC50 value of 100 μM at 48 h. The cell growth inhibition resulted in induction of apoptosis and decreased the mitochondria membrane potential (ΔΨm) and increased caspase-8, -9 and -3 activities. Furthermore, cytochrome c and AIF were released from mitochondria, as shown by western blotting and confirmed by confocal laser microscopy. Western blotting showed that 18α-GA increased the levels of pro-apoptotic proteins such as Bax and Bid and decreased the anti-apoptotic proteins such as Bcl-2 and Bcl-xl, furthermore, results also showed that 18α-GA increased Fas and Fas-L which are associated with surface death receptor in HL-60 cells. Based on those observations, the present study supports the hypothesis that 18α-GA-induced apoptosis in HL-60 cells involves the activation of the both extrinsic and intrinsic apoptotic pathways. PMID:27376261

  1. Boric acid induces cytoplasmic stress granule formation, eIF2α phosphorylation, and ATF4 in prostate DU-145 cells.

    PubMed

    Henderson, Kimberly A; Kobylewski, Sarah E; Yamada, Kristin E; Eckhert, Curtis D

    2015-02-01

    Dietary boron intake is associated with reduced prostate and lung cancer risk and increased bone mass. Boron is absorbed and circulated as boric acid (BA) and at physiological concentrations is a reversible competitive inhibitor of cyclic ADP ribose, the endogenous agonist of the ryanodine receptor calcium (Ca(+2)) channel, and lowers endoplasmic reticulum (ER) [Ca(2+)]. Low ER [Ca(2+)] has been reported to induce ER stress and activate the eIF2α/ATF4 pathway. Here we report that treatment of DU-145 prostate cells with physiological levels of BA induces ER stress with the formation of stress granules and mild activation of eIF2α, GRP78/BiP, and ATF4. Mild activation of eIF2α and its downstream transcription factor, ATF4, enables cells to reconfigure gene expression to manage stress conditions and mild activation of ATF4 is also required for the differentiation of osteoblast cells. Our results using physiological levels of boric acid identify the eIF2α/ATF pathway as a plausible mode of action that underpins the reported health effects of dietary boron.

  2. Fatty acid-induced mitochondrial uncoupling in adipocytes is not a promising target for treatment of insulin resistance unless adipocyte oxidative capacity is increased.

    PubMed

    Frayn, K N; Langin, D; Karpe, F

    2008-03-01

    The release of fatty acids from white adipose tissue is regulated at several levels. We have examined the suggestion that fatty acid release might be diminished by upregulation of mitochondrial fatty acid oxidation in the adipocyte, through increasing mitochondrial uncoupling. The intrinsic oxidative capacity of white adipose tissue is low, and older studies suggest that there is little fatty acid oxidation in white adipocytes, human or rodent. We have examined data on fatty acid metabolism and O(2) consumption in human white adipose tissue in vivo, and conclude that increasing fatty acid oxidation within the oxidative capacity of the tissue would produce only small changes (a few percent) in fatty acid release. The major locus of control of fatty acid release beyond the stimulation of lipolysis is the pathway of fatty acid esterification, already probably targeted by the thiazolidinedione insulin-sensitising agents. An alternative approach would be to upregulate the mitochondrial capacity of the adipocyte. We review proof-of-concept studies in which the phenotype of the white adipocyte has been changed to resemble that of the brown adipocyte by expression of peroxisome proliferator-activated receptor coactivator-1alpha. This increases oxidative capacity and also leads to fatty acid retention through upregulation of glycerol-3-phosphate production, and hence increased fatty acid re-esterification. We conclude that prevention or treatment of insulin resistance through alteration of adipocyte fatty acid handling will require more than a simple alteration of the activity of mitochondrial beta-oxidation within normal limits.

  3. Signaling by Sensory Receptors

    PubMed Central

    Julius, David; Nathans, Jeremy

    2012-01-01

    Sensory systems detect small molecules, mechanical perturbations, or radiation via the activation of receptor proteins and downstream signaling cascades in specialized sensory cells. In vertebrates, the two principal categories of sensory receptors are ion channels, which mediate mechanosensation, thermosensation, and acid and salt taste; and G-protein-coupled receptors (GPCRs), which mediate vision, olfaction, and sweet, bitter, and umami tastes. GPCR-based signaling in rods and cones illustrates the fundamental principles of rapid activation and inactivation, signal amplification, and gain control. Channel-based sensory systems illustrate the integration of diverse modulatory signals at the receptor, as seen in the thermosensory/pain system, and the rapid response kinetics that are possible with direct mechanical gating of a channel. Comparisons of sensory receptor gene sequences reveal numerous examples in which gene duplication and sequence divergence have created novel sensory specificities. This is the evolutionary basis for the observed diversity in temperature- and ligand-dependent gating among thermosensory channels, spectral tuning among visual pigments, and odorant binding among olfactory receptors. The coding of complex external stimuli by a limited number of sensory receptor types has led to the evolution of modality-specific and species-specific patterns of retention or loss of sensory information, a filtering operation that selectively emphasizes features in the stimulus that enhance survival in a particular ecological niche. The many specialized anatomic structures, such as the eye and ear, that house primary sensory neurons further enhance the detection of relevant stimuli. PMID:22110046

  4. Co-administration of α-lipoic acid and cyclosporine aggravates colon ulceration of acetic acid-induced ulcerative colitis via facilitation of NO/COX-2/miR-210 cascade.

    PubMed

    El-Gowelli, Hanan M; Saad, Evan I; Abdel-Galil, Abdel-Galil A; Ibrahim, Einas R

    2015-11-01

    In this work, α-lipoic acid and cyclosporine demonstrated significant protection against acetic acid-induced ulcerative colitis in rats. We proposed that α-lipoic acid and cyclosporine co-administration might modulate their individual effects. Induction of ulcerative colitis in rats was performed by intra-rectal acetic acid (5% v/v) administration for 3 consecutive days. Effects of individual or combined used of α-lipoic acid (35 mg/kg ip) or cyclosporine (5mg/kg sc) for 6 days starting 2 days prior to acetic acid were assessed. Acetic acid caused colon ulceration, bloody diarrhea and weight loss. Histologically, there was mucosal atrophy and inflammatory cells infiltration in submucosa, associated with depletion of colon reduced glutathione, superoxide dismutase and catalase activities and elevated colon malondialdehyde, serum C-reactive protein (C-RP) and tumor necrosis factor-α (TNF-α). Colon gene expression of cyclooxygenase-2 and miR-210 was also elevated. These devastating effects of acetic acid were abolished upon concurrent administration of α-lipoic acid. Alternatively, cyclosporine caused partial protection against acetic acid-induced ulcerative colitis. Cyclosporine did not restore colon reduced glutathione, catalase activity, serum C-RP or TNF-α. Unexpectedly, co-administration of α-lipoic acid and cyclosporine aggravated colon ulceration. Concomitant use of α-lipoic acid and cyclosporine significantly increased nitric oxide production, cyclooxygenase-2 and miR-210 gene expression compared to all other studied groups. The current findings suggest that facilitation of nitric oxide/cyclooxygenase-2/miR-210 cascade constitutes, at least partially, the cellular mechanism by which concurrent use of α-lipoic acid and cyclosporine aggravates colon damage. Collectively, the present work highlights the probable risk of using α-lipoic acid/cyclosporine combination in ulcerative colitis patients.

  5. Role of Rho Kinase Inhibition in the Protective Effect of Fasudil and Simvastatin Against 3-Nitropropionic Acid-Induced Striatal Neurodegeneration and Mitochondrial Dysfunction in Rats.

    PubMed

    Ahmed, Lamiaa A; Darwish, Hebatallah A; Abdelsalam, Rania M; Amin, HebatAllah A

    2016-08-01

    3-Nitropropionic acid (3-NP)-induced neurotoxicity is an experimental model which mimics the pathology and motor abnormalities seen in Huntington's disease (HD) in human. The present investigation was directed to estimate the role of rho kinase (ROCK) inhibition in the possible protective effect of fasudil and simvastatin in 3-NP-induced striatal neurodegeneration in rats. Animals were injected s.c. with 3-NP (20 mg/kg/day) for 1 week with or without administration of fasudil (10 mg/kg/day, p.o.) or simvastatin (20 mg/kg/day, p.o.). At the end of experiment, motor and behavioral abnormalities were evaluated. Animals were then sacrificed for measurement of mitochondrial membrane potential as well as succinate dehydrogenase (SDH) and caspase-3 activities in striatum. Moreover, tumor necrosis factor-alpha (TNF-α) level and protein expressions of proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), ROCK, phosphorylated-Akt (p-Akt), endothelial and inducible nitric oxide synthase (eNOS and iNOS), Bax, and Bcl-2 were estimated. Finally, histological changes as demonstrated by striatum injury score, glial activation, and percentage of altered mitochondria were assessed. Both fasudil and simvastatin effectively inhibited 3-NP-induced behavioral, biochemical, and histological changes through inhibition of ROCK activity. However, fasudil provided more amelioration in histological changes, mitochondrial membrane potential and SDH activity in addition to p-Akt and PGC-1α protein expressions. The present study highlights a significant role of ROCK/p-Akt/eNOS pathway in the protective effects of fasudil and simvastatin on neurotoxicity and mitochondrial dysfunction induced by 3-NP in rats. Thus, specific inhibition of ROCK may be considered a promising new approach in the management of HD. PMID:26169112

  6. Xenobiotic- and Jasmonic Acid-Inducible Signal Transduction Pathways Have Become Interdependent at the Arabidopsis CYP81D11 Promoter1[C][W

    PubMed Central

    Köster, Julia; Thurow, Corinna; Kruse, Kerstin; Meier, Alexander; Iven, Tim; Feussner, Ivo; Gatz, Christiane

    2012-01-01

    Plants modify harmful substances through an inducible detoxification system. In Arabidopsis (Arabidopsis thaliana), chemical induction of the cytochrome P450 gene CYP81D11 and other genes linked to the detoxification program depends on class II TGA transcription factors. CYP81D11 expression is also induced by the phytohormone jasmonic acid (JA) through the established pathway requiring the JA receptor CORONATINE INSENSITIVE1 (COI1) and the JA-regulated transcription factor MYC2. Here, we report that the xenobiotic- and the JA-dependent signal cascades have become interdependent at the CYP81D11 promoter. On the one hand, MYC2 can only activate the expression of CYP81D11 when both the MYC2- and the TGA-binding sites are present in the promoter. On the other hand, the xenobiotic-regulated class II TGA transcription factors can only mediate maximal promoter activity if TGA and MYC2 binding motifs, MYC2, and the JA-isoleucine biosynthesis enzymes DDE2/AOS and JAR1 are functional. Since JA levels and degradation of JAZ1, a repressor of the JA response, are not affected by reactive chemicals, we hypothesize that basal JA signaling amplifies the response to chemical stress. Remarkably, stress-induced expression levels were 3-fold lower in coi1 than in the JA biosynthesis mutant dede2-2, revealing that COI1 can contribute to the activation of the promoter in the absence of JA. Moreover, we show that deletion of the MYC2 binding motifs abolishes the JA responsiveness of the promoter but not the responsiveness to COI1. These findings suggest that yet unknown cis-element(s) can mediate COI1-dependent transcriptional activation in the absence of JA. PMID:22452854

  7. Role of Rho Kinase Inhibition in the Protective Effect of Fasudil and Simvastatin Against 3-Nitropropionic Acid-Induced Striatal Neurodegeneration and Mitochondrial Dysfunction in Rats.

    PubMed

    Ahmed, Lamiaa A; Darwish, Hebatallah A; Abdelsalam, Rania M; Amin, HebatAllah A

    2016-08-01

    3-Nitropropionic acid (3-NP)-induced neurotoxicity is an experimental model which mimics the pathology and motor abnormalities seen in Huntington's disease (HD) in human. The present investigation was directed to estimate the role of rho kinase (ROCK) inhibition in the possible protective effect of fasudil and simvastatin in 3-NP-induced striatal neurodegeneration in rats. Animals were injected s.c. with 3-NP (20 mg/kg/day) for 1 week with or without administration of fasudil (10 mg/kg/day, p.o.) or simvastatin (20 mg/kg/day, p.o.). At the end of experiment, motor and behavioral abnormalities were evaluated. Animals were then sacrificed for measurement of mitochondrial membrane potential as well as succinate dehydrogenase (SDH) and caspase-3 activities in striatum. Moreover, tumor necrosis factor-alpha (TNF-α) level and protein expressions of proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), ROCK, phosphorylated-Akt (p-Akt), endothelial and inducible nitric oxide synthase (eNOS and iNOS), Bax, and Bcl-2 were estimated. Finally, histological changes as demonstrated by striatum injury score, glial activation, and percentage of altered mitochondria were assessed. Both fasudil and simvastatin effectively inhibited 3-NP-induced behavioral, biochemical, and histological changes through inhibition of ROCK activity. However, fasudil provided more amelioration in histological changes, mitochondrial membrane potential and SDH activity in addition to p-Akt and PGC-1α protein expressions. The present study highlights a significant role of ROCK/p-Akt/eNOS pathway in the protective effects of fasudil and simvastatin on neurotoxicity and mitochondrial dysfunction induced by 3-NP in rats. Thus, specific inhibition of ROCK may be considered a promising new approach in the management of HD.

  8. Blocking TGF-β Signaling Pathway Preserves Mitochondrial Proteostasis and Reduces Early Activation of PDGFRβ+ Pericytes in Aristolochic Acid Induced Acute Kidney Injury in Wistar Male Rats

    PubMed Central

    Pozdzik, Agnieszka A.; Giordano, Laetitia; Li, Gang; Antoine, Marie-Hélène; Quellard, Nathalie; Godet, Julie; De Prez, Eric; Husson, Cécile; Declèves, Anne-Emilie; Arlt, Volker M.; Goujon, Jean-Michel; Brochériou-Spelle, Isabelle; Ledbetter, Steven R.; Caron, Nathalie; Nortier, Joëlle L.

    2016-01-01

    Background The platelet-derived growth factor receptor β (PDGFRβ)+ perivascular cell activation becomes increasingly recognized as a main source of scar-associated kidney myofibroblasts and recently emerged as a new cellular therapeutic target. Aims In this regard, we first confirmed the presence of PDGFRβ+ perivascular cells in a human case of end-stage aristolochic acid nephropathy (AAN) and thereafter we focused on the early fibrosis events of transforming growth factor β (TGFβ) inhibition in a rat model of AAN. Materials and Methods Neutralizing anti-TGFβ antibody (1D11) and its control isotype (13C4) were administered (5 mg/kg, i.p.) at Days -1, 0, 2 and 4; AA (15 mg/kg, sc) was injected daily. Results At Day 5, 1D11 significantly suppressed p-Smad2/3 signaling pathway improving renal function impairment, reduced the score of acute tubular necrosis, peritubular capillaritis, interstitial inflammation and neoangiogenesis. 1D11 markedly decreased interstitial edema, disruption of tubular basement membrane loss of brush border, cytoplasmic edema and organelle ultrastructure alterations (mitochondrial disruption and endoplasmic reticulum edema) in proximal tubular epithelial cells. Moreover, 1D11 significantly inhibited p-PERK activation and attenuated dysregulation of unfolded protein response (UPR) pathways, endoplasmic reticulum and mitochondrial proteostasis in vivo and in vitro. Conclusions The early inhibition of p-Smad2/3 signaling pathway improved acute renal function impairment, partially prevented epithelial-endothelial axis activation by maintaining PTEC proteostasis and reduced early PDGFRβ+ pericytes-derived myofibroblasts accumulation. PMID:27379382

  9. Effects of trefoil peptide 3 on expression of TNF-alpha, TLR4, and NF-kappaB in trinitrobenzene sulphonic acid induced colitis mice.

    PubMed

    Teng, Xu; Xu, Ling-Fen; Zhou, Ping; Sun, Hong-Wei; Sun, Mei

    2009-04-01

    The trefoil factor (TFF) peptides are major secretory products of mucus cells of the gastrointestinal tract. There were evidences that administration of recombinant human TFF3 is effective in treatment of models of colitis, but the mechanism of the effects of rTFF3 is not fully understood. The main aims of this study is to evaluate effects of intraperitoneal injection recombinant human TFF3 on the expression of tumour necrosis factor alpha (TNF-alpha), toll-like receptor 4(TLR4), and nuclear factor kappaB (NF-kappaB) in trinitrobenzene sulphonic acid (TNBS) induced colitis mice. Distal colitis was induced in BALB/C mice by intracolonic administration of TNBS in ethanol. Treated with administration rhTFF3 for treatment group(5 mg/ml; approximately 0.5 mg/mouse), and normal saline for control for 5 consecutive days. Colonic damage score, tissue myeloperoxidase (MPO) activity, TLR4, NF-kappaB mRNA expression, and tissue TNF-alpha, TLR4, NF-kappaB production were determined, respectively. Once daily application of hTFF3 for 5 days after TNBS/ethanol had been injected, both microscopic and macroscopic injury and inflammatory index had been reduced compared with controls. In addition, decreased tissue TNF-alpha, TLR4, NF-kappaB production, and TLR4, NF-kappaB mRNA expression had been found. This study has shown that hTFF3 may have therapeutic potential in the treatment of inflammatory bowel disease, and one of the mechanisms may related to inhibit the TLR4/NF-kappaB signaling pathways.

  10. Lipid phosphate phosphatase-1 regulates lysophosphatidic acid-induced calcium release, NF-κB activation and interleukin-8 secretion in human bronchial epithelial cells

    PubMed Central

    2004-01-01

    LPA (lysophosphatidic acid), a potent bioactive phospholipid, elicits diverse cellular responses through activation of the G-protein-coupled receptors LPA1–LPA4. LPA-mediated signalling is partially regulated by LPPs (lipid phosphate phosphatases; LPP-1, -2 and -3) that belong to the phosphatase superfamily. This study addresses the role of LPPs in regulating LPA-mediated cell signalling and IL-8 (interleukin-8) secretion in HBEpCs (human bronchial epithelial cells). Reverse transcription–PCR and Western blotting revealed the presence and expression of LPP-1–3 in HBEpCs. Exogenous [3H]oleoyl LPA was hydrolysed to [3H]-mono-oleoylglycerol. Infection of HBEpCs with an adenoviral construct of human LPP-1 for 48 h enhanced the dephosphorylation of exogenous LPA by 2–3-fold compared with vector controls. Furthermore, overexpression of LPP-1 partially attenuated LPA-induced increases in the intracellular Ca2+ concentration, phosphorylation of IκB (inhibitory κB) and translocation of NF-κB (nuclear factor-κB) to the nucleus, and almost completely prevented IL-8 secretion. Infection of cells with an adenoviral construct of the mouse LPP-1 (R217K) mutant partially attenuated LPA-induced IL-8 secretion without altering LPA-induced changes in intracellular Ca2+ concentration, phosphorylation of IκB, NF-κB activation or IL-8 gene expression. Our results identify LPP-1 as a key regulator of LPA signalling and IL-8 secretion in HBEpCs. Thus LPPs could represent potential targets in regulating leucocyte infiltration and airway inflammation. PMID:15461590

  11. Sprouty2 and ‐4 hypomorphism promotes neuronal survival and astrocytosis in a mouse model of kainic acid induced neuronal damage

    PubMed Central

    Thongrong, Sitthisak; Hausott, Barbara; Marvaldi, Letizia; Agostinho, Alexandra S.; Zangrandi, Luca; Burtscher, Johannes; Fogli, Barbara

    2015-01-01

    ABSTRACT Sprouty (Spry) proteins play a key role as negative feedback inhibitors of the Ras/Raf/MAPK/ERK pathway downstream of various receptor tyrosine kinases. Among the four Sprouty isoforms, Spry2 and Spry4 are expressed in the hippocampus. In this study, possible effects of Spry2 and Spry4 hypomorphism on neurodegeneration and seizure thresholds in a mouse model of epileptogenesis was analyzed. The Spry2/4 hypomorphs exhibited stronger ERK activation which was limited to the CA3 pyramidal cell layer and to the hilar region. The seizure threshold of Spry2/4+/− mice was significantly reduced at naive state but no difference to wildtype mice was observed 1 month following KA treatment. Histomorphological analysis revealed that dentate granule cell dispersion (GCD) was diminished in Spry2/4+/− mice in the subchronic phase after KA injection. Neuronal degeneration was reduced in CA1 and CA3 principal neuron layers as well as in scattered neurons of the contralateral CA1 and hilar regions. Moreover, Spry2/4 reduction resulted in enhanced survival of somatostatin and neuropeptide Y expressing interneurons. GFAP staining intensity and number of reactive astrocytes markedly increased in lesioned areas of Spry2/4+/− mice as compared with wildtype mice. Taken together, although the seizure threshold is reduced in naive Spry2/4+/− mice, neurodegeneration and GCD is mitigated following KA induced hippocampal lesions, identifying Spry proteins as possible pharmacological targets in brain injuries resulting in neurodegeneration. The present data are consistent with the established functions of the ERK pathway in astrocyte proliferation as well as protection from neuronal cell death and suggest a novel role of Spry proteins in the migration of differentiated neurons. © 2015 The Authors Hippocampus Published by Wiley Periodicals, Inc. PMID:26540287

  12. A tetrapod-like repertoire of innate immune receptors and effectors for coelacanths

    USGS Publications Warehouse

    Boudinot, Pierre; Zou, Jun; Ota, Tatsuya; Buonocore, Francesco; Scapigliati, Giuseppe; Canapa, Adriana; Cannon, John; Litman, Gary; Hansen, John D.

    2014-01-01

    The recent availability of both robust transcriptome and genome resources for coelacanth (Latimeria chalumnae) has led to unique discoveries for coelacanth immunity such as the lack of IgM, a central component of adaptive immunity. This study was designed to more precisely address the origins and evolution of gene families involved in the initial recognition and response to microbial pathogens, which effect innate immunity. Several multigene families involved in innate immunity are addressed, including: Toll-like receptors (TLRs), retinoic acid inducible gene 1 (RIG1)-like receptors (RLRs), the nucleotide-binding domain and leucine-rich repeat containing proteins (NLRs), diverse immunoglobulin domain-containing proteins (DICP) and modular domain immune-type receptors (MDIRs). Our analyses also include the tripartite motif-containing proteins (TRIM), which are involved in pathogen recognition as well as the positive regulation of antiviral immunity. Finally, this study addressed some of the downstream effectors of the antimicrobial response including IL-1 family members, type I and II interferons (IFN) and IFN-stimulated effectors (ISGs). Collectively, the genes and gene families in coelacanth that effect innate immune functions share characteristics both in content, structure and arrangement with those found in tetrapods but not in teleosts. The findings support the sister group relationship of coelacanth fish with tetrapods.

  13. Involvement of 5-HT2 receptors in the antinociceptive effect of Uncaria tomentosa.

    PubMed

    Jürgensen, Sofia; Dalbó, Sílvia; Angers, Paul; Santos, Adair Roberto Soares; Ribeiro-do-Valle, Rosa Maria

    2005-07-01

    Uncaria tomentosa (Willd.) DC (Rubiaceae) is a vine that grows in the Amazon rainforest. Its bark decoctions are used by Peruvian Indians to treat several diseases. Chemically, it consists mainly of oxindole alkaloids. An industrial fraction of U. tomentosa (UT fraction), containing 95% oxindole alkaloids, was used in this study in order to characterize its antinociceptive activity in chemical (acetic acid-induced abdominal writhing, formalin and capsaicin tests) and thermal (tail-flick and hot-plate tests) models of nociception in mice. UT fraction given by the i.p. route dose-dependently suppressed the behavioural response to the chemical stimuli in the models indicated and increased latencies in the thermal stimuli models. The antinociception caused by UT fraction in the formalin test was significantly attenuated by i.p. treatment of mice with ketanserin (5-HT2 receptor antagonist), but was not affected by naltrexone (opioid receptor antagonist), atropine (a nonselective muscarinic antagonist), l-arginine (precursor of nitric oxide), prazosin (alpha1-adrenoceptor antagonist), yohimbine (alpha2-adrenoceptor antagonist), and reserpine (a monoamine depleter). Together, these results indicate that UT fraction produces dose-related antinociception in several models of chemical and thermal pain through mechanisms that involve an interaction with 5-HT2 receptors.

  14. A tetrapod-like repertoire of innate immune receptors and effectors for coelacanths.

    PubMed

    Boudinot, Pierre; Zou, Jun; Ota, Tatsuya; Buonocore, Francesco; Scapigliati, Giuseppe; Canapa, Adriana; Cannon, John; Litman, Gary; Hansen, John D

    2014-09-01

    The recent availability of both robust transcriptome and genome resources for coelacanth (Latimeria chalumnae) has led to unique discoveries for coelacanth immunity such as the lack of IgM, a central component of adaptive immunity. This study was designed to more precisely address the origins and evolution of gene families involved in the initial recognition and response to microbial pathogens, which effect innate immunity. Several multigene families involved in innate immunity are addressed, including: Toll-like receptors (TLRs), retinoic acid inducible gene 1 (RIG1)-like receptors (RLRs), the nucleotide-binding domain and leucine-rich repeat containing proteins (NLRs), diverse immunoglobulin domain-containing proteins (DICP) and modular domain immune-type receptors (MDIRs). Our analyses also include the tripartite motif-containing proteins (TRIM), which are involved in pathogen recognition as well as the positive regulation of antiviral immunity. Finally, this study addressed some of the downstream effectors of the antimicrobial response including IL-1 family members, type I and II interferons (IFN) and IFN-stimulated effectors (ISGs). Collectively, the genes and gene families in coelacanth that effect innate immune functions share characteristics both in content, structure and arrangement with those found in tetrapods but not in teleosts. The findings support the sister group relationship of coelacanth fish with tetrapods.

  15. Poly I:C-induced tumor cell apoptosis mediated by pattern-recognition receptors.

    PubMed

    Zhao, Xiangzhong; Ai, Miao; Guo, Yuqi; Zhou, Xianbin; Wang, Li; Li, Xia; Yao, Chengfang

    2012-11-01

    Poly I:C is a synthetic dsRNA that can imitate a viral infection and elicit host immune responses by triggering specific pattern-recognition receptors (PRRs) such as toll-like receptor 3 and retinoic acid inducible gene I(RIG-I)-like receptors, including RIG-I and melanoma differentiation-associated gene 5. Activation of these PRRs by poly I:C triggers a signal transduction cascade that results in the activation of NF-κB and production of type I interferon. Poly I:C has been used as a vaccine adjuvant for cancer immunotherapy for several decades. Evidence from recent studies indicates that poly I:C can directly induce apoptosis in several types of tumor cells, thus providing a new therapeutic approach for cancer treatment. However, the molecular mechanism underlying the induction of apoptosis by poly I:C is still unclear. In this review, we summarize the current knowledge of poly I:C-induced tumor cell apoptosis, focusing on the key molecules and pathways involved in this process.

  16. Leukotriene receptor antagonist therapy

    PubMed Central

    Dempsey, O

    2000-01-01

    Leukotriene receptor antagonists (LTRA) are a new class of drugs for asthma treatment, available in tablet form. Their unique mechanism of action results in a combination of both bronchodilator and anti-inflammatory effects. While their optimal place in asthma management is still under review, LTRA represent an important advance in asthma pharmacotherapy.


Keywords: leukotriene receptor antagonist; asthma; montelukast; zafirlukast PMID:11085767

  17. Pretreatment by low-dose fibrates protects against acute free fatty acid-induced renal tubule toxicity by counteracting PPAR{alpha} deterioration

    SciTech Connect

    Takahashi, Kyoko; Kamijo, Yuji; Hora, Kazuhiko; Hashimoto, Koji; Higuchi, Makoto; Nakajima, Takero; Ehara, Takashi; Shigematsu, Hidekazu; Gonzalez, Frank J.; Aoyama, Toshifumi

    2011-05-01

    Development of a preventive strategy against tubular damage associated with proteinuria is of great importance. Recently, free fatty acid (FFA) toxicities accompanying proteinuria were found to be a main cause of tubular damage, which was aggravated by insufficiency of peroxisome proliferator-activated receptor alpha (PPAR{alpha}), suggesting the benefit of PPAR{alpha} activation. However, an earlier study using a murine acute tubular injury model, FFA-overload nephropathy, demonstrated that high-dose treatment of PPAR{alpha} agonist (0.5% clofibrate diet) aggravated the tubular damage as a consequence of excess serum accumulation of clofibrate metabolites due to decreased kidney elimination. To induce the renoprotective effects of PPAR{alpha} agonists without drug accumulation, we tried a pretreatment study using low-dose clofibrate (0.1% clofibrate diet) using the same murine model. Low-dose clofibrate pretreatment prevented acute tubular injuries without accumulation of its metabolites. The tubular protective effects appeared to be associated with the counteraction of PPAR{alpha} deterioration, resulting in the decrease of FFAs influx to the kidney, maintenance of fatty acid oxidation, diminution of intracellular accumulation of undigested FFAs, and attenuation of disease developmental factors including oxidative stress, apoptosis, and NF{kappa}B activation. These effects are common to other fibrates and dependent on PPAR{alpha} function. Interestingly, however, clofibrate pretreatment also exerted PPAR{alpha}-independent tubular toxicities in PPAR{alpha}-null mice with FFA-overload nephropathy. The favorable properties of fibrates are evident when PPAR{alpha}-dependent tubular protective effects outweigh their PPAR{alpha}-independent tubular toxicities. This delicate balance seems to be easily affected by the drug dose. It will be important to establish the appropriate dosage of fibrates for treatment against kidney disease and to develop a novel PPAR

  18. Peroxidase-like activity of Fe3O4@carbon nanoparticles enhances ascorbic acid-induced oxidative stress and selective damage to PC-3 prostate cancer cells.

    PubMed

    An, Qiao; Sun, Chuanyu; Li, Dian; Xu, Ke; Guo, Jia; Wang, Changchun

    2013-12-26

    Ascorbic acid (AA) is capable of inhibiting cancer cell growth by perturbing the normal redox state of cells and causing toxic effects through the generation of abundant reactive-oxygen species (ROS). However, the clinical utility of AA at a tolerable dosage is plagued by a relatively low in vivo efficacy. This study describes the development of a peroxidase-like composite nanoparticle for use in an AA-mediated therapeutic strategy. On the basis of a high-throughput, one-pot solvothermal approach, Fe3O4@C nanoparticles (NPs) were synthesized and then modified with folic acid (FA) on the surface. Particular focus is concentrated on the assessment of peroxidase-like catalytic activity by a chromogenic reaction in the presence of H2O2. The carbon shell of Fe3O4@C NPs contains partially graphitized carbon and thus facilitates electron transfer in the catalytic decomposition of H2O2, leading to the production of highly reactive hydroxyl radicals. Along with magnetic responsiveness and receptor-binding specificity, the intrinsic peroxidase-like catalytic activity of Fe3O4@C-FA NPs pronouncedly promotes AA-induced oxidative stress in cancer cells and optimizes the ROS-mediated antineoplastic efficacy of exogenous AA. In vitro experiments using human prostate cancer PC-3 cells demonstrate that Fe3O4@C-FA NPs serve as a peroxidase mimic to create hydroxyl radicals from endogenous H2O2 that is yielded in response to exogenous AA via an oxidative stress process. The usage of a dual agent leads to the enhanced cytotoxicity of PC-3 cells, and, because of the synergistic effect of NPs, the administrated dosage of AA is reduced markedly. However, because normal cells (HEK 293T cells) appear to have a higher capacity to cope with additionally generated ROS than cancer cells, the NP-AA combination shows little damage in this case, proving that selective killing of cancer cells could be achieved owing to preferential accumulation of ROS in cancer cells. A possible ROS

  19. Peroxidase-like activity of Fe3O4@carbon nanoparticles enhances ascorbic acid-induced oxidative stress and selective damage to PC-3 prostate cancer cells.

    PubMed

    An, Qiao; Sun, Chuanyu; Li, Dian; Xu, Ke; Guo, Jia; Wang, Changchun

    2013-12-26

    Ascorbic acid (AA) is capable of inhibiting cancer cell growth by perturbing the normal redox state of cells and causing toxic effects through the generation of abundant reactive-oxygen species (ROS). However, the clinical utility of AA at a tolerable dosage is plagued by a relatively low in vivo efficacy. This study describes the development of a peroxidase-like composite nanoparticle for use in an AA-mediated therapeutic strategy. On the basis of a high-throughput, one-pot solvothermal approach, Fe3O4@C nanoparticles (NPs) were synthesized and then modified with folic acid (FA) on the surface. Particular focus is concentrated on the assessment of peroxidase-like catalytic activity by a chromogenic reaction in the presence of H2O2. The carbon shell of Fe3O4@C NPs contains partially graphitized carbon and thus facilitates electron transfer in the catalytic decomposition of H2O2, leading to the production of highly reactive hydroxyl radicals. Along with magnetic responsiveness and receptor-binding specificity, the intrinsic peroxidase-like catalytic activity of Fe3O4@C-FA NPs pronouncedly promotes AA-induced oxidative stress in cancer cells and optimizes the ROS-mediated antineoplastic efficacy of exogenous AA. In vitro experiments using human prostate cancer PC-3 cells demonstrate that Fe3O4@C-FA NPs serve as a peroxidase mimic to create hydroxyl radicals from endogenous H2O2 that is yielded in response to exogenous AA via an oxidative stress process. The usage of a dual agent leads to the enhanced cytotoxicity of PC-3 cells, and, because of the synergistic effect of NPs, the administrated dosage of AA is reduced markedly. However, because normal cells (HEK 293T cells) appear to have a higher capacity to cope with additionally generated ROS than cancer cells, the NP-AA combination shows little damage in this case, proving that selective killing of cancer cells could be achieved owing to preferential accumulation of ROS in cancer cells. A possible ROS

  20. Antinociceptive effects of dehydrocorydaline in mouse models of inflammatory pain involve the opioid receptor and inflammatory cytokines

    PubMed Central

    Yin, Zhi-Yu; Li, Lu; Chu, Shuai-Shuai; Sun, Qing; Ma, Zheng-Liang; Gu, Xiao-Ping

    2016-01-01

    Dehydrocorydaline (DHC) is an alkaloidal component isolated from Rhizoma corydalis. Previous studies have shown that DHC has anti-inflammatory and anti-tumor effects and that it can protect the cardiovascular system. However, there are few studies of the antinociceptive effects of DHC in vivo. This study explored the antinociceptive effects and possible mechanisms of DHC in mice using two inflammatory pain models: the acetic acid-induced writhing test and the formalin paw test. The intraperitoneal administration of DHC (3.6, 6 or 10 mg/kg) showed a dose-dependent antinociceptive effect in the acetic acid-induced writhing test and significantly attenuated the formalin-induced pain responses in mice. The antinociceptive effects of DHC were not associated with changes in the locomotor activity or motor responses of animals, and no obvious acute or chronic toxic effects were observed in the mice. Furthermore, the use of naloxone confirmed the involvement of the opioid receptor in the central antinociceptive effects of DHC. DHC reduced formalin-induced paw edema, which indicated that DHC may produce an anti-inflammatory effect in the periphery. In the formalin test, DHC decreased the expression of caspase 6 (CASP6), TNF-α, IL-1β and IL-6 proteins in the spinal cord. These findings confirm that DHC has antinociceptive effects in mice. PMID:27272194

  1. Genetics of Taste Receptors

    PubMed Central

    Bachmanov, Alexander A.; Bosak, Natalia P.; Lin, Cailu; Matsumoto, Ichiro; Ohmoto, Makoto; Reed, Danielle R.; Nelson, Theodore M.

    2016-01-01

    Taste receptors function as one of the interfaces between internal and external milieus. Taste receptors for sweet and umami (T1R [taste receptor, type 1]), bitter (T2R [taste receptor, type 2]), and salty (ENaC [epithelial sodium channel]) have been discovered in the recent years, but transduction mechanisms of sour taste and ENaC-independent salt taste are still poorly understood. In addition to these five main taste qualities, the taste system detects such noncanonical “tastes” as water, fat, and complex carbohydrates, but their reception mechanisms require further research. Variations in taste receptor genes between and within vertebrate species contribute to individual and species differences in taste-related behaviors. These variations are shaped by evolutionary forces and reflect species adaptations to their chemical environments and feeding ecology. Principles of drug discovery can be applied to taste receptors as targets in order to develop novel taste compounds to satisfy demand in better artificial sweeteners, enhancers of sugar and sodium taste, and blockers of bitterness of food ingredients and oral medications. PMID:23886383

  2. Genetics of taste receptors.

    PubMed

    Bachmanov, Alexander A; Bosak, Natalia P; Lin, Cailu; Matsumoto, Ichiro; Ohmoto, Makoto; Reed, Danielle R; Nelson, Theodore M

    2014-01-01

    Taste receptors function as one of the interfaces between internal and external milieus. Taste receptors for sweet and umami (T1R [taste receptor, type 1]), bitter (T2R [taste receptor, type 2]), and salty (ENaC [epithelial sodium channel]) have been discovered in the recent years, but transduction mechanisms of sour taste and ENaC-independent salt taste are still poorly understood. In addition to these five main taste qualities, the taste system detects such noncanonical "tastes" as water, fat, and complex carbohydrates, but their reception mechanisms require further research. Variations in taste receptor genes between and within vertebrate species contribute to individual and species differences in taste-related behaviors. These variations are shaped by evolutionary forces and reflect species adaptations to their chemical environments and feeding ecology. Principles of drug discovery can be applied to taste receptors as targets in order to develop novel taste compounds to satisfy demand in better artificial sweeteners, enhancers of sugar and sodium taste, and blockers of bitterness of food ingredients and oral medications. PMID:23886383

  3. Dopamine Receptors and Neurodegeneration

    PubMed Central

    Rangel-Barajas, Claudia; Coronel, Israel; Florán, Benjamín

    2015-01-01

    Dopamine (DA) is one of the major neurotransmitters and participates in a number of functions such as motor coordination, emotions, memory, reward mechanism, neuroendocrine regulation etc. DA exerts its effects through five DA receptors that are subdivided in 2 families: D1-like DA receptors (D1 and D5) and the D2-like (D2, D3 and D4). All DA receptors are widely expressed in the central nervous system (CNS) and play an important role in not only in physiological conditions but also pathological scenarios. Abnormalities in the DAergic system and its receptors in the basal ganglia structures are the basis Parkinson’s disease (PD), however DA also participates in other neurodegenerative disorders such as Huntington disease (HD) and multiple sclerosis (MS). Under pathological conditions reorganization of DAergic system has been observed and most of the times, those changes occur as a mechanism of compensation, but in some cases contributes to worsening the alterations. Here we review the changes that occur on DA transmission and DA receptors (DARs) at both levels expression and signals transduction pathways as a result of neurotoxicity, inflammation and in neurodegenerative processes. The better understanding of the role of DA receptors in neuropathological conditions is crucial for development of novel therapeutic approaches to treat alterations related to neurodegenerative diseases. PMID:26425390

  4. Effects of nicotinic acetylcholine receptor agonists in assays of acute pain-stimulated and pain-depressed behaviors in rats.

    PubMed

    Freitas, Kelen C; Carroll, F Ivy; Negus, S Stevens

    2015-11-01

    Agonists at nicotinic acetylcholine receptors (nAChRs) constitute one drug class being evaluated as candidate analgesics. Previous preclinical studies have implicated α4β2 and α7 nAChRs as potential mediators of the antinociceptive effects of (–)-nicotine hydrogen tartrate (nicotine) and other nAChR agonists; however, these studies have relied exclusively on measures of pain-stimulated behavior, which can be defined as behaviors that increase in frequency, rate, or intensity after presentation of a noxious stimulus. Pain is also associated with depression of many behaviors, and drug effects can differ in assays of pain-stimulated versus pain-depressed behavior. Accordingly, this study compared the effects of nicotine, the selective α4/6β2 agonist 5-(123I)iodo-3-[2(S)-2-azetidinylmethoxy]pyridine (5-I-A-85380), and the selective α7 agonist N-(3R)-1-azabicyclo(2.2.2)oct-3-yl-4-chlorobenzamide in assays of pain-stimulated and pain-depressed behavior in male Sprague-Dawley rats. Intraperitoneal injection of dilute lactic acid served as an acute noxious stimulus to either stimulate a stretching response or depress the operant responding, which is maintained by electrical brain stimulation in an intracranial self-stimulation (ICSS) procedure. Nicotine produced a dose-dependent, time-dependent, and mecamylamine-reversible blockade of both acid-stimulated stretching and acid-induced depression of ICSS. 5-I-A-85380 also blocked both acid-stimulated stretching and acid-induced depression of ICSS, whereas N-(3R)-1-azabicyclo(2.2.2)oct-3-yl-4-chlorobenzamide produced no effect in either procedure. Both nicotine and 5-I-A-85380 were ≥10-fold more potent in blocking the acid-induced depression of ICSS than in blocking the acid-induced stimulation of stretching. These results suggest that stimulation of α4β2 and/or α6β2 nAChRs may be especially effective to alleviate the signs of pain-related behavioral depression in rats; however, nonselective behavioral effects

  5. Ionotropic Crustacean Olfactory Receptors

    PubMed Central

    Corey, Elizabeth A.; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W.

    2013-01-01

    The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling. PMID:23573266

  6. Taste Receptors in Innate Immunity

    PubMed Central

    Lee, Robert J.

    2014-01-01

    Taste receptors were first identified on the tongue, where they initiate a signaling pathway that communicates information to the brain about the nutrient content or potential toxicity of ingested foods. However, recent research has shown that taste receptors are also expressed in a myriad of other tissues, from the airway and gastrointestinal epithelia to the pancreas and brain. The functions of many of these extraoral taste receptors remain unknown, but emerging evidence suggests that bitter and sweet taste receptors in the airway are important sentinels of innate immunity. This review discusses taste receptor signaling, focusing on the G-protein coupled–receptors that detect bitter, sweet, and savory tastes, followed by an overview of extraoral taste receptors and in-depth discussion of studies demonstrating the roles of taste receptors in airway innate immunity. Future research on extraoral taste receptors has significant potential for identification of novel immune mechanisms and insights into host-pathogen interactions. PMID:25323130

  7. New insights into receptor regulation.

    PubMed

    Poste, G

    1984-11-01

    This review provides a brief summary of certain recent advances in our understanding of receptor regulation, signal transduction, and the diverse pathways by which receptor-ligand complexes are internalized and delivered to specific organelles, together with recycling of receptors back to the cell surface. Emphasis is also given to the importance of methodological advances in receptor isolation, immunologic analysis of receptor structure and function, the development of new instrumentation for microchemical characterization of very small amounts of receptor material, and the increasing use of genetic engineering techniques to isolate the genes for receptors and their regulatory subunits, to transfer such genes between cells, and to study receptor function by creating structurally modified receptors via subtle changes in gene structure. PMID:6151557

  8. Intracrine prostaglandin E(2) signalling regulates hypoxia-inducible factor-1α expression through retinoic acid receptor-β.

    PubMed

    Fernández-Martínez, Ana B; Jiménez, María I Arenas; Manzano, Victoria Moreno; Lucio-Cazaña, Francisco J

    2012-12-01

    We have previously found in human renal proximal tubular HK-2 cells that hypoxia- and all-trans retinoic acid-induced hypoxia-inducible factor-1α up-regulation is accompanied by retinoic acid receptor-β up-regulation. Here we first investigated whether hypoxia-inducible factor-1α expression is dependent on retinoic acid receptor-β and our results confirmed it since (i) hypoxia-inducible factor-1α-inducing agents hypoxia, hypoxia-mimetic agent desferrioxamine, all-trans retinoic acid and interleukin-1β increased retinoic acid receptor-β expression, (ii) hypoxia-inducible factor-1α up-regulation was prevented by retinoic acid receptor-β antagonist LE-135 or siRNA retinoic acid receptor-β and (iii) there was direct binding of retinoic acid receptor-β to the retinoic acid response element in hypoxia-inducible factor-1α promoter upon treatment with all-trans retinoic acid and 16,16-dimethyl-prostaglandin E(2). Since intracellular prostaglandin E(2) mediates hypoxia-inducible factor-1α up-regulation in normoxia in HK-2 cells, we next investigated and confirmed, its role in the up-regulation of retinoic acid receptor-β in normoxia by hypoxia-inducible factor-1α-inducing agents all-trans retinoic acid, interleukin-1β and 16,16-dimethyl-prostaglandin E(2) by inhibiting cyclooxygenases, prostaglandin influx transporter or EP receptors. Interestingly, the hypoxia-induced increase in retinoic acid receptor-β expression and accumulation of hypoxia-inducible factor-1α was also blocked by the inhibitors tested. This is the first time, to our knowledge, that retinoic acid receptor-β signalling is involved in the control of the expression of transcription factor hypoxia-inducible factor-1α in both normoxia and hypoxia and that retinoic acid receptor-β expression is found to be strictly regulated by intracellular prostaglandin E(2). Given the relevance of hypoxia-inducible factor-1α in the kidney in terms of tumorigenesis, progressive renal failure, production

  9. Olfactory receptor signaling.

    PubMed

    Antunes, Gabriela; Simoes de Souza, Fabio Marques

    2016-01-01

    The guanine nucleotide protein (G protein)-coupled receptors (GPCRs) superfamily represents the largest class of membrane protein in the human genome. More than a half of all GPCRs are dedicated to interact with odorants and are termed odorant-receptors (ORs). Linda Buck and Richard Axel, the Nobel Prize laureates in physiology or medicine in 2004, first cloned and characterized the gene family that encode ORs, establishing the foundations to the understanding of the molecular basis for odor recognition. In the last decades, a lot of progress has been done to unravel the functioning of the sense of smell. This chapter gives a general overview of the topic of olfactory receptor signaling and reviews recent advances in this field. PMID:26928542

  10. Progesterone Receptor Signaling Mechanisms.

    PubMed

    Grimm, Sandra L; Hartig, Sean M; Edwards, Dean P

    2016-09-25

    Progesterone receptor (PR) is a master regulator in female reproductive tissues that controls developmental processes and proliferation and differentiation during the reproductive cycle and pregnancy. PR also plays a role in progression of endocrine-dependent breast cancer. As a member of the nuclear receptor family of ligand-dependent transcription factors, the main action of PR is to regulate networks of target gene expression in response to binding its cognate steroid hormone, progesterone. This paper summarizes recent advances in understanding the structure-function properties of the receptor protein and the tissue/cell-type-specific PR signaling pathways that contribute to the biological actions of progesterone in the normal breast and in breast cancer. PMID:27380738

  11. CONTAMINANT INTERACTIONS WITH STEROID RECEPTORS: EVIDENCE FOR RECEPTOR BINDING.

    EPA Science Inventory

    Steroid receptors are important determinants of endocrine disrupter consequences. As the most frequently proposed mechanism of endocrine-disrupting contaminant (EDC) action, steroid receptors are not only targets of natural steroids but are also commonly sites of nonsteroidal com...

  12. Vasopressin receptor antagonists.

    PubMed

    Palmer, Biff F

    2015-01-01

    Arginine vasopressin (AVP) is the principal hormone involved in regulating the tonicity of body fluids. Less appreciated is the role that AVP plays in a variety of other physiologic functions including glucose metabolism, cardiovascular homeostasis, bone metabolism, and cognitive behavior. AVP receptor antagonists are now available and currently approved to treat hyponatremia. There is a great deal of interest in exploring the potential benefits that these drugs may play in blocking AVP-mediated effects in other organ systems. The purpose of this report is to provide an update on the expanding role of AVP receptor antagonists and what disease states these drugs may eventually be used for.

  13. Vasopressin receptor antagonists.

    PubMed

    Palmer, Biff F

    2015-01-01

    Arginine vasopressin (AVP) is the principal hormone involved in regulating the tonicity of body fluids. Less appreciated is the role that AVP plays in a variety of other physiologic functions including glucose metabolism, cardiovascular homeostasis, bone metabolism, and cognitive behavior. AVP receptor antagonists are now available and currently approved to treat hyponatremia. There is a great deal of interest in exploring the potential benefits that these drugs may play in blocking AVP-mediated effects in other organ systems. The purpose of this report is to provide an update on the expanding role of AVP receptor antagonists and what disease states these drugs may eventually be used for. PMID:25604388

  14. Biomimetic Receptors and Sensors

    PubMed Central

    Dickert, Franz L.

    2014-01-01

    In biomimetics, living systems are imitated to develop receptors for ions, molecules and bioparticles. The most pertinent idea is self-organization in analogy to evolution in nature, which created the key-lock principle. Today, modern science has been developing host-guest chemistry, a strategy of supramolecular chemistry for designing interactions of analytes with synthetic receptors. This can be realized, e.g., by self-assembled monolayers (SAMs) or molecular imprinting. The strategies are used for solid phase extraction (SPE), but preferably in developing recognition layers of chemical sensors. PMID:25436653

  15. Bile acid regulates c-Jun expression through the orphan nuclear receptor SHP induction in gastric cells

    SciTech Connect

    Park, Won Il; Park, Min Jung; An, Jin Kwang; Choi, Yung Hyun; Kim, Hye Young; Cheong, JaeHun Yang, Ung Suk

    2008-05-02

    Bile reflux is considered to be one of the most important causative factors in gastric carcinogenesis, due to the attendant inflammatory changes in the gastric mucosa. In this study, we have assessed the molecular mechanisms inherent to the contribution of bile acid to the transcriptional regulation of inflammatory-related genes. In this study, we demonstrated that bile acid induced the expression of the SHP orphan nuclear receptor at the transcriptional level via c-Jun activation. Bile acid also enhanced the protein interaction of NF-{kappa}B and SHP, thereby resulting in an increase in c-Jun expression and the production of the inflammatory cytokine, TNF{alpha}. These results indicate that bile acid performs a critical function in the regulation of the induction of inflammatory-related genes in gastric cells, and that bile acid-mediated gene expression provides a pre-clue for the development of gastric cellular malformation.

  16. Role of Transient Receptor Potential Vanilloid 4 in Neutrophil Activation and Acute Lung Injury.

    PubMed

    Yin, Jun; Michalick, Laura; Tang, Christine; Tabuchi, Arata; Goldenberg, Neil; Dan, Qinghong; Awwad, Khader; Wang, Liming; Erfinanda, Lasti; Nouailles, Geraldine; Witzenrath, Martin; Vogelzang, Alexis; Lv, Lu; Lee, Warren L; Zhang, Haibo; Rotstein, Ori; Kapus, Andras; Szaszi, Katalin; Fleming, Ingrid; Liedtke, Wolfgang B; Kuppe, Hermann; Kuebler, Wolfgang M

    2016-03-01

    The cation channel transient receptor potential vanilloid (TRPV) 4 is expressed in endothelial and immune cells; however, its role in acute lung injury (ALI) is unclear. The functional relevance of TRPV4 was assessed in vivo, in isolated murine lungs, and in isolated neutrophils. Genetic deficiency of TRPV4 attenuated the functional, histological, and inflammatory hallmarks of acid-induced ALI. Similar protection was obtained with prophylactic administration of the TRPV4 inhibitor, GSK2193874; however, therapeutic administration of the TRPV4 inhibitor, HC-067047, after ALI induction had no beneficial effect. In isolated lungs, platelet-activating factor (PAF) increased vascular permeability in lungs perfused with trpv4(+/+) more than with trpv4(-/-) blood, independent of lung genotype, suggesting a contribution of TRPV4 on blood cells to lung vascular barrier failure. In neutrophils, TRPV4 inhibition or deficiency attenuated the PAF-induced increase in intracellular calcium. PAF induced formation of epoxyeicosatrienoic acids by neutrophils, which, in turn, stimulated TRPV4-dependent Ca(2+) signaling, whereas inhibition of epoxyeicosatrienoic acid formation inhibited the Ca(2+) response to PAF. TRPV4 deficiency prevented neutrophil responses to proinflammatory stimuli, including the formation of reactive oxygen species, neutrophil adhesion, and chemotaxis, putatively due to reduced activation of Rac. In chimeric mice, however, the majority of protective effects in acid-induced ALI were attributable to genetic deficiency of TRPV4 in parenchymal tissue, whereas TRPV4 deficiency in circulating blood cells primarily reduced lung myeloperoxidase activity. Our findings identify TRPV4 as novel regulator of neutrophil activation and suggest contributions of both parenchymal and neutrophilic TRPV4 in the pathophysiology of ALI.

  17. Role of Transient Receptor Potential Vanilloid 4 in Neutrophil Activation and Acute Lung Injury.

    PubMed

    Yin, Jun; Michalick, Laura; Tang, Christine; Tabuchi, Arata; Goldenberg, Neil; Dan, Qinghong; Awwad, Khader; Wang, Liming; Erfinanda, Lasti; Nouailles, Geraldine; Witzenrath, Martin; Vogelzang, Alexis; Lv, Lu; Lee, Warren L; Zhang, Haibo; Rotstein, Ori; Kapus, Andras; Szaszi, Katalin; Fleming, Ingrid; Liedtke, Wolfgang B; Kuppe, Hermann; Kuebler, Wolfgang M

    2016-03-01

    The cation channel transient receptor potential vanilloid (TRPV) 4 is expressed in endothelial and immune cells; however, its role in acute lung injury (ALI) is unclear. The functional relevance of TRPV4 was assessed in vivo, in isolated murine lungs, and in isolated neutrophils. Genetic deficiency of TRPV4 attenuated the functional, histological, and inflammatory hallmarks of acid-induced ALI. Similar protection was obtained with prophylactic administration of the TRPV4 inhibitor, GSK2193874; however, therapeutic administration of the TRPV4 inhibitor, HC-067047, after ALI induction had no beneficial effect. In isolated lungs, platelet-activating factor (PAF) increased vascular permeability in lungs perfused with trpv4(+/+) more than with trpv4(-/-) blood, independent of lung genotype, suggesting a contribution of TRPV4 on blood cells to lung vascular barrier failure. In neutrophils, TRPV4 inhibition or deficiency attenuated the PAF-induced increase in intracellular calcium. PAF induced formation of epoxyeicosatrienoic acids by neutrophils, which, in turn, stimulated TRPV4-dependent Ca(2+) signaling, whereas inhibition of epoxyeicosatrienoic acid formation inhibited the Ca(2+) response to PAF. TRPV4 deficiency prevented neutrophil responses to proinflammatory stimuli, including the formation of reactive oxygen species, neutrophil adhesion, and chemotaxis, putatively due to reduced activation of Rac. In chimeric mice, however, the majority of protective effects in acid-induced ALI were attributable to genetic deficiency of TRPV4 in parenchymal tissue, whereas TRPV4 deficiency in circulating blood cells primarily reduced lung myeloperoxidase activity. Our findings identify TRPV4 as novel regulator of neutrophil activation and suggest contributions of both parenchymal and neutrophilic TRPV4 in the pathophysiology of ALI. PMID:26222277

  18. Computational Biology of Olfactory Receptors

    PubMed Central

    Crasto, Chiquito J.

    2011-01-01

    Olfactory receptors, in addition to being involved in first step of the physiological processes that leads to olfaction, occupy an important place in mammalian genomes. ORs constitute super families in these genomes. Elucidating ol-factory receptor function at a molecular level can be aided by a computationally derived structure and an understanding of its interactions with odor molecules. Experimental functional analyses of olfactory receptors in conjunction with computational studies serve to validate findings and generate hypotheses. We present here a review of the research efforts in: creating computational models of olfactory receptors, identifying binding strategies for these receptors with odorant molecules, performing medium to long range simulation studies of odor ligands in the receptor binding region, and identifying amino acid positions within the receptor that are responsible for ligand-binding and olfactory receptor activation. Written as a primer and a teaching tool, this review will help researchers extend the methodologies described herein to other GPCRs. PMID:21984880

  19. Synaptic Neurotransmitter-Gated Receptors

    PubMed Central

    Smart, Trevor G.; Paoletti, Pierre

    2012-01-01

    Since the discovery of the major excitatory and inhibitory neurotransmitters and their receptors in the brain, many have deliberated over their likely structures and how these may relate to function. This was initially satisfied by the determination of the first amino acid sequences of the Cys-loop receptors that recognized acetylcholine, serotonin, GABA, and glycine, followed later by similar determinations for the glutamate receptors, comprising non-NMDA and NMDA subtypes. The last decade has seen a rapid advance resulting in the first structures of Cys-loop receptors, related bacterial and molluscan homologs, and glutamate receptors, determined down to atomic resolution. This now provides a basis for determining not just the complete structures of these important receptor classes, but also for understanding how various domains and residues interact during agonist binding, receptor activation, and channel opening, including allosteric modulation. This article reviews our current understanding of these mechanisms for the Cys-loop and glutamate receptor families. PMID:22233560

  20. De Novo Transcriptome Analysis Shows That SAV-3 Infection Upregulates Pattern Recognition Receptors of the Endosomal Toll-Like and RIG-I-Like Receptor Signaling Pathways in Macrophage/Dendritic Like TO-Cells

    PubMed Central

    Xu, Cheng; Evensen, Øystein; Mweemba, Hetron Munang’andu

    2016-01-01

    A fundamental step in cellular defense mechanisms is the recognition of “danger signals” made of conserved pathogen associated molecular patterns (PAMPs) expressed by invading pathogens, by host cell germ line coded pattern recognition receptors (PRRs). In this study, we used RNA-seq and the Kyoto encyclopedia of genes and genomes (KEGG) to identify PRRs together with the network pathway of differentially expressed genes (DEGs) that recognize salmonid alphavirus subtype 3 (SAV-3) infection in macrophage/dendritic like TO-cells derived from Atlantic salmon (Salmo salar L) headkidney leukocytes. Our findings show that recognition of SAV-3 in TO-cells was restricted to endosomal Toll-like receptors (TLRs) 3 and 8 together with RIG-I-like receptors (RLRs) and not the nucleotide-binding oligomerization domain-like receptors NOD-like receptor (NLRs) genes. Among the RLRs, upregulated genes included the retinoic acid inducible gene I (RIG-I), melanoma differentiation association 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2). The study points to possible involvement of the tripartite motif containing 25 (TRIM25) and mitochondrial antiviral signaling protein (MAVS) in modulating RIG-I signaling being the first report that links these genes to the RLR pathway in SAV-3 infection in TO-cells. Downstream signaling suggests that both the TLR and RLR pathways use interferon (IFN) regulatory factors (IRFs) 3 and 7 to produce IFN-a2. The validity of RNA-seq data generated in this study was confirmed by quantitative real time qRT-PCR showing that genes up- or downregulated by RNA-seq were also up- or downregulated by RT-PCR. Overall, this study shows that de novo transcriptome assembly identify key receptors of the TLR and RLR sensors engaged in host pathogen interaction at cellular level. We envisage that data presented here can open a road map for future intervention strategies in SAV infection of salmon. PMID:27110808

  1. Evaluation of peripheral versus central effects of GABAB receptor activation using a novel, positive allosteric modulator of the GABAB receptor ADX71943, a pharmacological tool compound with a fully peripheral activity profile

    PubMed Central

    Kalinichev, M; Donovan-Rodriguez, T; Girard, F; Riguet, E; Rouillier, M; Bournique, B; Haddouk, H; Mutel, V; Poli, S

    2014-01-01

    Background and Purpose The GABAB receptor agonist, baclofen, has shown promising effects in patients suffering from pain, post-traumatic stress disorder, alcoholism, overactive bladder and gastroesophageal reflux disease. However, baclofen's short duration of action and side effects limit its wider use. Here we characterized a novel, GABAB receptor positive allosteric modulator (PAM) ADX71943. Experimental Approach In vitro, ADX71943 was assessed for pharmacological activity and selectivity using recombinant and native GABAB receptors. In vivo ADX71943 was assessed in the acetic acid-induced writhing (AAW) test in mice and formalin tests (FTs) in mice and rats. Marble burying (MB) and elevated plus maze (EPM) tests, rotarod, spontaneous locomotor activity (sLMA) and body temperature (BT) tests in mice and rats were used to investigate centrally-mediated effects. Key Results In vitro, in the presence of GABA, ADX71943 increased the potency and efficacy of agonists and showed selectivity at the GABAB receptor. ADX71943 reduced pain-associated behaviours in AAW; an effect blocked by GABAB receptor antagonist CGP63360. ADX71943 reduced pain in the FT in mice and rats, but was inactive in the MB and EPM despite reaching high concentrations in plasma. ADX71943 had no effect on BT, rotarod and sLMA. Conclusions and Implications ADX71943 showed consistent and target-related efficacy in tests of disorders that have a significant peripheral component (acute and chronic pain), while having no effect in those associated with centrally-mediated anxiety-like reactivity and side effects. Thus, ADX71943 is a useful pharmacological tool for delineation of peripherally- versus centrally-mediated effects of GABAB receptor activation. PMID:24923436

  2. Human placental calcitonin receptors.

    PubMed Central

    Nicholson, G C; D'Santos, C S; Evans, T; Moseley, J M; Kemp, B E; Michelangeli, V P; Martin, T J

    1988-01-01

    Receptors for the hypocalcaemic hormone, calcitonin (CT), have been identified in a membrane fraction prepared from term human placentae. Binding of 125I-labelled salmon CT (125I-sCT) to the membranes was time- and temperature-dependent, saturable (Bmax. 58 +/- 11 fmol/mg of protein), of high affinity (Kd 80 +/- 21 pM) and poorly reversible. Species-specific CTs and CT analogues competed for 125I-sCT binding with potencies proportional to their known biological potencies. Various unrelated peptide hormones did not compete, indicating that receptor binding was specific for CT. Photoaffinity labelling using a derivatized biologically active sCT analogue, [Arg11,18,3-nitrophenylazide-Lys14]sCT, identified a receptor component of Mr approximately 85,000, comparable with findings in osteoclasts and other target cells. The presence of CT receptors in the human placenta supports other evidence that CT may have a role in the regulation of placental function. PMID:2839149

  3. Nicotinic Receptors in Neurodegeneration

    PubMed Central

    Posadas, Inmaculada; López-Hernández, Beatriz; Ceña, Valentín

    2013-01-01

    Many studies have focused on expanding our knowledge of the structure and diversity of peripheral and central nicotinic receptors. Nicotinic acetylcholine receptors (nAChRs) are members of the Cys-loop superfamily of pentameric ligand-gated ion channels, which include GABA (A and C), serotonin, and glycine receptors. Currently, 9 alpha (α2-α10) and 3 beta (β2-β4) subunits have been identified in the central nervous system (CNS), and these subunits assemble to form a variety of functional nAChRs. The pentameric combination of several alpha and beta subunits leads to a great number of nicotinic receptors that vary in their properties, including their sensitivity to nicotine, permeability to calcium and propensity to desensitize. In the CNS, nAChRs play crucial roles in modulating presynaptic, postsynaptic, and extrasynaptic signaling, and have been found to be involved in a complex range of CNS disorders including Alzheimer’s disease (AD), Parkinson’s disease (PD), schizophrenia, Tourette´s syndrome, anxiety, depression and epilepsy. Therefore, there is growing interest in the development of drugs that modulate nAChR functions with optimal benefits and minimal adverse effects. The present review describes the main characteristics of nAChRs in the CNS and focuses on the various compounds that have been tested and are currently in phase I and phase II trials for the treatment of neurodegenerative diseases including PD, AD and age-associated memory and mild cognitive impairment. PMID:24179465

  4. c-Jun N-terminal Kinase-Dependent Endoplasmic Reticulum Stress Pathway is Critically Involved in Arjunic Acid Induced Apoptosis in Non-Small Cell Lung Cancer Cells.

    PubMed

    Joo, HyeEun; Lee, Hyun Joo; Shin, Eun Ah; Kim, Hangil; Seo, Kyeong-Hwa; Baek, Nam-In; Kim, Bonglee; Kim, Sung-Hoon

    2016-04-01

    Though arjunic acid, a triterpene isolated from Terminalia arjuna, was known to have antioxidant, antiinflammatory, and cytotoxic effects, its underlying antitumor mechanism still remains unclear so far. Thus, in the present study, the molecular antitumor mechanism of arjunic acid was examined in A549 and H460 non-small cell lung cancer (NSCLC) cells. Arjunic acid exerted cytotoxicity by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) assay and significantly increased sub-G1 population in A549 and H460 cells by cell cycle analysis. Consistently, arjunic acid cleaved poly (ADP-ribose) polymerase (PARP), activated Bax, and phosphorylation of c-Jun N-terminal kinases (JNK), and also attenuated the expression of pro-caspase-3 and Bcl-2 in A549 and H460 cells. Furthermore, arjunic acid upregulated the expression of endoplasmic reticulum (ER) stress proteins such as IRE1 α, ATF4, p-eIF2α, and C/EBP homologous protein (CHOP) in A549 and H460 cells. Conversely, CHOP depletion attenuated the increase of sub-G1 population by arjunic acid, and also JNK inhibitor SP600125 blocked the cytotoxicity and upregulation of IRE1 α and CHOP induced by arjunic acid in A549 and H460 cells. Overall, our findings suggest that arjunic acid induces apoptosis in NSCLC cells via JNK mediated ER stress pathway as a potent chemotherapeutic agent for NSCLC. PMID:26787261

  5. Somatostatin Receptor 1 and 5 Double Knockout Mice Mimic Neurochemical Changes of Huntington's Disease Transgenic Mice

    PubMed Central

    Rajput, Padmesh S.; Kharmate, Geetanjali; Norman, Michael; Liu, Shi-He; Sastry, Bhagavatula R.; Brunicardi, Charles F.; Kumar, Ujendra

    2011-01-01

    Background Selective degeneration of medium spiny neurons and preservation of medium sized aspiny interneurons in striatum has been implicated in excitotoxicity and pathophysiology of Huntington's disease (HD). However, the molecular mechanism for the selective sparing of medium sized aspiny neurons and vulnerability of projection neurons is still elusive. The pathological characteristic of HD is an extensive reduction of the striatal mass, affecting caudate putamen. Somatostatin (SST) positive neurons are selectively spared in HD and Quinolinic acid/N-methyl-D-aspartic acid induced excitotoxicity, mimic the model of HD. SST plays neuroprotective role in excitotoxicity and the biological effects of SST are mediated by five somatostatin receptor subtypes (SSTR1-5). Methods and Findings To delineate subtype selective biological responses we have here investigated changes in SSTR1 and 5 double knockout mice brain and compared with HD transgenic mouse model (R6/2). Our study revealed significant loss of dopamine and cAMP regulated phosphoprotein of 32 kDa (DARPP-32) and comparable changes in SST, N-methyl-D-aspartic acid receptors subtypes, calbindin and brain nitric oxide synthase expression as well as in key signaling proteins including calpain, phospho-extracellular-signal-regulated kinases1/2, synapsin-IIa, protein kinase C-α and calcineurin in SSTR1/5−/− and R6/2 mice. Conversely, the expression of somatostatin receptor subtypes, enkephalin and phosphatidylinositol 3-kinases were strain specific. SSTR1/5 appears to be important in regulating NMDARs, DARPP-32 and signaling molecules in similar fashion as seen in HD transgenic mice. Conclusions This is the first comprehensive description of disease related changes upon ablation of G- protein coupled receptor gene. Our results indicate that SST and SSTRs might play an important role in regulation of neurodegeneration and targeting this pathway can provide a novel insight in understanding the pathophysiology of

  6. GABA/benzodiazepine receptor complex in long-sleep and short-sleep mice

    SciTech Connect

    Marley, R.J.

    1987-01-01

    LS mice are more sensitive to benzodiazepine-induced anesthesia; however, the two lines do not differ in their hypothermic response to flurazepam. SS mice are more resistant to 3-mercaptopropionic acid-induced seizures and more sensitive to the anticonvulsant effects of benzodiazepines. The various correlates of GABA and benzodiazepine actions probably are the results of different mechanisms of action and/or differential regional control. Bicuculline competition for /sup 3/H-GABA binding sites is greater in SS cerebellar tissue and /sup 3/H-flunitrazepam binding is greater in the mid-brain region of LS mice. GABA enhancement of /sup 3/H-flunitrazepma binding is greater in SS mice. Ethanol also enhances /sup 3/H-flunitrazepam binding and increases the levels of /sup 3/H-flunitrazepam binding above those observed for GABA. Using correlational techniques on data from LS and SS mice and several inbred mouse strains, it was demonstrated that a positive relationship exists between the degree of receptor coupling within the GABA receptor complex and the degree of resistance to seizures.

  7. Peroxisome proliferator-activated receptor-delta agonist ameliorated inflammasome activation in nonalcoholic fatty liver disease

    PubMed Central

    Lee, Hyun Jung; Yeon, Jong Eun; Ko, Eun Jung; Yoon, Eileen L; Suh, Sang Jun; Kang, Keunhee; Kim, Hae Rim; Kang, Seoung Hee; Yoo, Yang Jae; Je, Jihye; Lee, Beom Jae; Kim, Ji Hoon; Seo, Yeon Seok; Yim, Hyung Joon; Byun, Kwan Soo

    2015-01-01

    AIM: To evaluate the inflammasome activation and the effect of peroxisome proliferator-activated receptors (PPAR)-δ agonist treatment in nonalcoholic fatty liver disease (NAFLD) models. METHODS: Male C57BL/6J mice were classified according to control or high fat diet (HFD) with or without PPAR-δ agonist (GW) over period of 12 wk [control, HFD, HFD + lipopolysaccharide (LPS), HFD + LPS + GW group]. HepG2 cells were exposed to palmitic acid (PA) and/or LPS in the absence or presence of GW. RESULTS: HFD caused glucose intolerance and hepatic steatosis. In mice fed an HFD with LPS, caspase-1 and interleukin (IL)-1β in the liver were significantly increased. Treatment with GW ameliorated the steatosis and inhibited overexpression of pro-inflammatory cytokines. In HepG2 cells, PA and LPS treatment markedly increased mRNA of several nucleotide-binding and oligomerization domain-like receptor family members (NLRP3, NLRP6, and NLRP10), caspase-1 and IL-1β. PA and LPS also exaggerated reactive oxygen species production. All of the above effects of PA and LPS were reduced by GW. GW also enhanced the phosphorylation of AMPK-α. CONCLUSION: PPAR-δ agonist reduces fatty acid-induced inflammation and steatosis by suppressing inflammasome activation. Targeting the inflammasome by the PPAR-δ agonist may have therapeutic implication for NAFLD. PMID:26668503

  8. RIG-I–like receptor LGP2 protects tumor cells from ionizing radiation

    PubMed Central

    Widau, Ryan C.; Parekh, Akash D.; Ranck, Mark C.; Golden, Daniel W.; Kumar, Kiran A.; Sood, Ravi F.; Pitroda, Sean P.; Liao, Zhengkai; Huang, Xiaona; Darga, Thomas E.; Xu, David; Huang, Lei; Andrade, Jorge; Roizman, Bernard; Weichselbaum, Ralph R.; Khodarev, Nikolai N.

    2014-01-01

    An siRNA screen targeting 89 IFN stimulated genes in 14 different cancer cell lines pointed to the RIG-I (retinoic acid inducible gene I)–like receptor Laboratory of Genetics and Physiology 2 (LGP2) as playing a key role in conferring tumor cell survival following cytotoxic stress induced by ionizing radiation (IR). Studies on the role of LGP2 revealed the following: (i) Depletion of LGP2 in three cancer cell lines resulted in a significant increase in cell death following IR, (ii) ectopic expression of LGP2 in cells increased resistance to IR, and (iii) IR enhanced LGP2 expression in three cell lines tested. Studies designed to define the mechanism by which LGP2 acts point to its role in regulation of IFNβ. Specifically (i) suppression of LGP2 leads to enhanced IFNβ, (ii) cytotoxic effects following IR correlated with expression of IFNβ inasmuch as inhibition of IFNβ by neutralizing antibody conferred resistance to cell death, and (iii) mouse embryonic fibroblasts from IFN receptor 1 knockout mice are radioresistant compared with wild-type mouse embryonic fibroblasts. The role of LGP2 in cancer may be inferred from cumulative data showing elevated levels of LGP2 in cancer cells are associated with more adverse clinical outcomes. Our results indicate that cytotoxic stress exemplified by IR induces IFNβ and enhances the expression of LGP2. Enhanced expression of LGP2 suppresses the IFN stimulated genes associated with cytotoxic stress by turning off the expression of IFNβ. PMID:24434553

  9. Diversification of TAM receptor function

    PubMed Central

    Zagórska, Anna; Través, Paqui G.; Lew, Erin D.; Dransfield, Ian; Lemke, Greg

    2014-01-01

    Apoptotic cell clearance is critical for both tissue homeostasis and the resolution of inflammation. We found that the TAM receptor tyrosine kinases Axl and Mer played distinct roles as phagocytic receptors in these two settings, where they exhibited divergent expression, regulation, and activity. Mer acted as a tolerogenic receptor in resting macrophages and in settings of immune suppression. Conversely, Axl was an inflammatory response receptor whose expression was induced by pro-inflammatory stimuli. Axl and Mer displayed distinct ligand specificities, ligand-receptor complex formation in tissues, and receptor shedding upon activation. These differences notwithstanding, phagocytosis by either protein was strictly dependent on receptor activation that was triggered by bridging TAM receptor–ligand complexes to the ‘eat-me’ signal phosphatidylserine on apoptotic cell surfaces. PMID:25194421

  10. Evolutionary conservation of molecular structure and antiviral function of a viral receptor, LGP2, in amphioxus Branchiostoma japonicum.

    PubMed

    Liu, Shousheng; Liu, Yuanyuan; Yang, Shuangshuang; Huang, Youhua; Qin, Qiwei; Zhang, Shicui

    2015-12-01

    RIG-I-like (where RIG-I is retinoic acid inducible gene I) receptor LGP2 (where LGP2 is laboratory of genetics and physiology) is an important intracellular receptor that recognizes viral RNAs in innate immunity, but its origin and evolution remains unknown. Here we clearly demonstrate the presence of a RIG-I-like receptor, BjLGP2, in the basal chordate amphioxus. It is predominantly expressed in the hepatic caecum and hindgut, and is upregulated following challenge with poly(I:C). BjLGP2 is distributed in the cytoplasm of both grouper spleen and flounder gill (FG) cells, and the recombinant BjLGP2 interacts with poly(I:C). BjLGP2 can enhance the expression of IFN and IFN-inducible genes in FG cells upon poly(I:C) challenge. It also significantly induces the expression of the antiviral genes ifn-i and Mx as well as the signal transduction relevant genes MAVS, NF-κB, and IRF-3 in FG cells upon lymphocystis disease virus challenge. Moreover, BjLGP2 inhibits the replication of lymphocystis disease virus in FG cells and the gene transcription of Singapore grouper iridovirus in grouper spleen cells. This is the first report showing that a LGP2 protein in invertebrate species (amphioxus) is structurally conserved and plays an antiviral role similar to that of vertebrate LGP2 proteins.

  11. Evolutionary conservation of molecular structure and antiviral function of a viral receptor, LGP2, in amphioxus Branchiostoma japonicum.

    PubMed

    Liu, Shousheng; Liu, Yuanyuan; Yang, Shuangshuang; Huang, Youhua; Qin, Qiwei; Zhang, Shicui

    2015-12-01

    RIG-I-like (where RIG-I is retinoic acid inducible gene I) receptor LGP2 (where LGP2 is laboratory of genetics and physiology) is an important intracellular receptor that recognizes viral RNAs in innate immunity, but its origin and evolution remains unknown. Here we clearly demonstrate the presence of a RIG-I-like receptor, BjLGP2, in the basal chordate amphioxus. It is predominantly expressed in the hepatic caecum and hindgut, and is upregulated following challenge with poly(I:C). BjLGP2 is distributed in the cytoplasm of both grouper spleen and flounder gill (FG) cells, and the recombinant BjLGP2 interacts with poly(I:C). BjLGP2 can enhance the expression of IFN and IFN-inducible genes in FG cells upon poly(I:C) challenge. It also significantly induces the expression of the antiviral genes ifn-i and Mx as well as the signal transduction relevant genes MAVS, NF-κB, and IRF-3 in FG cells upon lymphocystis disease virus challenge. Moreover, BjLGP2 inhibits the replication of lymphocystis disease virus in FG cells and the gene transcription of Singapore grouper iridovirus in grouper spleen cells. This is the first report showing that a LGP2 protein in invertebrate species (amphioxus) is structurally conserved and plays an antiviral role similar to that of vertebrate LGP2 proteins. PMID:26442622

  12. Taste Receptor Genes

    PubMed Central

    Bachmanov, Alexander A.; Beauchamp, Gary K.

    2009-01-01

    In the past several years, tremendous progress has been achieved with the discovery and characterization of vertebrate taste receptors from the T1R and T2R families, which are involved in recognition of bitter, sweet, and umami taste stimuli. Individual differences in taste, at least in some cases, can be attributed to allelic variants of the T1R and T2R genes. Progress with understanding how T1R and T2R receptors interact with taste stimuli and with identifying their patterns of expression in taste cells sheds light on coding of taste information by the nervous system. Candidate mechanisms for detection of salts, acids, fat, complex carbohydrates, and water have also been proposed, but further studies are needed to prove their identity. PMID:17444812

  13. TSH RECEPTOR AUTOANTIBODIES

    PubMed Central

    Michalek, Krzysztof; Morshed, Syed A.; Latif, Rauf; Davies, Terry F.

    2009-01-01

    Thyrotropin receptor autoantibodies (TSHR-Abs) of the stimulating variety are the hallmark of Graves’ disease. The presence of immune defects leading to synthesis of TSHR-Abs causes hyperthyroidism and is associated with other extrathyroidal manifestations. Further characterization of these antibodies has now been made possible by the generation of monoclonal antibodies with this unique stimulating capacity as well as similar TSHR-Abs not associated with hyperthyroidism. Their present classification divides TSHR-Abs into stimulating, blocking (competing with TSH binding) and neutral (no signaling). Recent studies using monoclonal TSHR-Abs has revealed that stimulating and blocking antibodies bind to the receptor using mostly conformational epitopes, whilst neutral antibodies utilize exclusively linear peptides. Subtle differences in epitopes for stimulating and blocking antibodies account for the diversity of their biological actions. Recently non-classical signaling elicited by neutral antibodies has also been described, raising the need for a new classification of TSHR-Abs. PMID:19332151

  14. The interleukin-4 receptor: signal transduction by a hematopoietin receptor.

    PubMed

    Keegan, A D; Pierce, J H

    1994-02-01

    Over the last several years, the receptors for numerous cytokines have been molecularly characterized. Analysis of their amino acid sequences shows that some of these receptors bear certain motifs in their extracellular domains that define a family of receptors called the Hematopoietin receptor superfamily. Significant advances in characterizing the structure, function, and mechanisms of signal transduction have been made for several members of this family. The purpose of this review is to discuss the recent advances made for one of the family members, the interleukin (IL) 4 receptor. Other receptor systems have recently been reviewed elsewhere. The IL-4 receptor consists of, at the minimum, the cloned 140 kDa IL-4-binding chain with the potential for associating with other chains. The IL-4 receptor transduces its signal by activating a tyrosine kinase that phosphorylates cellular substrates, including the receptor itself, and the 170 kDa substrate called 4PS. Phosphorylated 4PS interacts with the SH2 domain of the enzyme PI-3'-kinase and increases its enzymatic activity. These early events in the IL-4 receptor initiated signaling pathway may trigger a series of signals that will ultimately lead to an IL-4 specific biologic outcome.

  15. Quantitative receptor autoradiography

    SciTech Connect

    Boast, C.A.; Snowhill, E.W.; Altar, C.A.

    1986-01-01

    Quantitative receptor autoradiography addresses the topic of technical and scientific advances in the sphere of quantitative autoradiography. The volume opens with a overview of the field from a historical and critical perspective. Following is a detailed discussion of in vitro data obtained from a variety of neurotransmitter systems. The next section explores applications of autoradiography, and the final two chapters consider experimental models. Methodological considerations are emphasized, including the use of computers for image analysis.

  16. Receptors for enterovirus 71

    PubMed Central

    Yamayoshi, Seiya; Fujii, Ken; Koike, Satoshi

    2014-01-01

    Enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease (HFMD). Occasionally, EV71 infection is associated with severe neurological diseases, such as acute encephalitis, acute flaccid paralysis and cardiopulmonary failure. Several molecules act as cell surface receptors that stimulate EV71 infection, including scavenger receptor B2 (SCARB2), P-selectin glycoprotein ligand-1 (PSGL-1), sialylated glycan, heparan sulfate and annexin II (Anx2). SCARB2 plays critical roles in attachment, viral entry and uncoating, and it can facilitate efficient EV71 infection. The three-dimensional structures of the mature EV71 virion, procapsid and empty capsid, as well as the exofacial domain of SCARB2, have been elucidated. This structural information has greatly increased our understanding of the early steps of EV71 infection. Furthermore, SCARB2 plays essential roles in the development of EV71 neurological disease in vivo. Adult mice are not susceptible to infection by EV71, but transgenic mice that express human SCARB2 become susceptible to EV71 infection and develop similar neurological diseases to those found in humans. This mouse model facilitates the in vivo investigation of many issues related to EV71. PSGL-1, sialylated glycan, heparan sulfate and Anx2 are attachment receptors, which enhance viral infection by retaining the virus on the cell surface. These molecules also contribute to viral infection in vitro either by interacting with SCARB2 or independently of SCARB2. However, the cooperative effects of these receptors, and their contribution to EV71 pathogenicity in vivo, remain to be elucidated. PMID:26038749

  17. [Lipoprotein receptors. Old acquaintances and newcomers].

    PubMed

    Ducobu, J

    1997-02-01

    Lipoprotein receptors are plasma membrane proteins of high affinity which interact with circulating lipoprotein particles. The well characterized LDL receptor continues to be analysed and some new findings on its intracellular mechanisms of action have emerged. New lipoprotein receptors have recently been described: the chylomicron remnant receptor or LDL-related protein (LRP), the lipolysis stimulated receptor (LSR), the very low density lipoprotein receptor (VLDLR), the HDL receptor (HDLR) and the scavenger receptor (SR). The molecular details of the receptors will facilitate the development of new therapeutic means to improve receptor-mediated clearance of lipoproteins.

  18. Lysophosphatidic acid induces osteocyte dendrite outgrowth

    SciTech Connect

    Karagiosis, Sue A.; Karin, Norm J.

    2007-05-25

    A method was developed to measure dendrite formation in bone cells. Lysophosphatidic acid (LPA) was found to stimulate dendrite outgrowth. It is postulated that LPA plays a role in regulating the osteocyte network in vivo.

  19. Ursodeoxycholic acid induced generalized fixed drug eruption.

    PubMed

    Ozkol, Hatice Uce; Calka, Omer; Dulger, Ahmet Cumhur; Bulut, Gulay

    2014-09-01

    Fixed drug eruption (FDE) is a rare form of drug allergies that recur at the same cutaneous or mucosal site in every usage of drug. Single or multiple round, sharply demarcated and dusky red plaques appear soon after drug exposure. Ursodeoxycholic acid (UDCA: 3α,7β-dihydroxy-5β-cholanic acid) is used for the treatment of cholestatic liver diseases. Some side effects may be observed, such as diarrhea, dyspepsia, pruritus and headaches. We encountered only three cases of lichenoid reaction regarding the use of UDCA among previous studies. In this article, we reported a generalized FDE case related to UDCA intake in a 59-year-old male patient with cholestasis for the first time in the literature. PMID:24147950

  20. LIVER TYPE FATTY ACID BINDING PROTEIN (L-FABP) GENE ABLATION REDUCES NUCLEAR LIGAND DISTRIBUTION AND PEROXISOME PROLIFERATOR ACTIVATED RECEPTOR-α ACTIVITY IN CULTURED PRIMARY HEPATOCYTES1

    PubMed Central

    McIntosh, Avery L.; Atshaves, Barbara P.; Hostetler, Heather A.; Huang, Huan; Davis, Jason; Lyuksyutova, Olga I.; Landrock, Danilo; Kier, Ann B.; Schroeder, Friedhelm

    2009-01-01

    The effect of liver type fatty acid binding protein (L-FABP) gene ablation on the uptake and distribution of long chain fatty acids (LCFA) to the nucleus by real-time laser scanning confocal imaging and peroxisome proliferator activated receptor-α (PPARα) activity was examined in cultured primary hepatocytes from livers wild-type L-FABP+/+ and gene ablated L-FABP−/− mice. Cultured primary hepatocytes from livers of L-FABP−/− mice exhibited: (i) reduced oxidation of palmitic acid, a common dietary long chain fatty acid (LCFA); (ii) reduced expression of fatty acid oxidative enzymes—proteins transcriptionally regulated by PPARα; (iii) reduced palmitic acid-induced PPARα coimmunoprecipitation with coactivator SRC1 concomitant with increased PPARα coimmunoprecipitation with coinhibitor N-CoR; (iv) reduced palmitic acid-induced PPARα. Diminished PPARα activation in L-FABP null hepatocytes was associated with lower uptake of common dietary LCFA (palmitic acid as well as its fluorescent derivative BODIPY FL C16), reduced level of total unesterified LCFA, and real-time redistribution of BODIPY FL C16 from the central nucleoplasm to the nuclear envelope. Taken together, these studies support the hypothesis that L-FABP may facilitate ligand (LCFA)-activated PPARα transcriptional activity at least in part by increasing total LCFA ligand available to PPARα for inducing PPARα-mediated transcription of proteins involved in LCFA metabolism. PMID:19285478

  1. Uric acid attenuates nitric oxide production by decreasing the interaction between endothelial nitric oxide synthase and calmodulin in human umbilical vein endothelial cells: a mechanism for uric acid-induced cardiovascular disease development.

    PubMed

    Park, Jung-Hyun; Jin, Yoon Mi; Hwang, Soojin; Cho, Du-Hyong; Kang, Duk-Hee; Jo, Inho

    2013-08-01

    The elevated level of uric acid in the body is associated with increased risk of cardiovascular diseases, which is mediated by endothelial dysfunction. However, its underlying mechanism is not fully understood, although dysregulation of endothelial nitric oxide (NO) production is likely to be involved. Using human umbilical vascular endothelial cells (HUVEC), we explored the molecular mechanism of uric acid on endothelial NO synthase (eNOS) activity and NO production. Although high dose of uric acid (12mg/dl for 24h treatment) significantly decreased eNOS activity and NO production, it did not alter eNOS expression and phosphorylations at eNOS-Ser(1177), eNOS-Thr(495) and eNOS-Ser(114). Under this condition, we also found no alterations in the dimerization and acetylation of eNOS, compared with the control. Furthermore, uric acid did not change the activity of arginase II, an enzyme degrading l-arginine, a substrate of eNOS, and intracellular level of calcium, a cofactor for eNOS activation. We also found that uric acid did not alter xanthine oxidase activity, suggesting no involvement of xanthine oxidase-derived O2(-) production in the observed inhibitory effects. In vitro and in cell coimmunoprecipitation studies, however, revealed that uric acid significantly decreased the interaction between eNOS and calmodulin (CaM), an eNOS activator, although it did not change the intracellular CaM level. Like in HUVEC, uric acid also decreased eNOS-CaM interaction in bovine aortic EC. Finally, uric acid attenuated ionomycin-induced increase in the interaction between eNOS and CaM. This study suggests firstly that uric acid decreased eNOS activity and NO production through reducing the binding between eNOS and CaM in EC. Our result may provide molecular mechanism by which uric acid induces endothelial dysfunction.

  2. Expression Analysis of SOX14 during Retinoic Acid Induced Neural Differentiation of Embryonal Carcinoma Cells and Assessment of the Effect of Its Ectopic Expression on SOXB Members in HeLa Cells

    PubMed Central

    Popovic, Jelena; Stanisavljevic, Danijela; Schwirtlich, Marija; Klajn, Andrijana; Marjanovic, Jelena; Stevanovic, Milena

    2014-01-01

    SOX14 is a member of the SOXB2 subgroup of transcription factors implicated in neural development. Although the first SOX14 gene in vertebrates was cloned and characterized more than a decade ago and its expression profile during development was revealed in various animal model systems, the role of this gene during neural development is largely unknown. In the present study we analyzed the expression of SOX14 in human NT2/D1 and mouse P19 pluripotent embryonal carcinoma cells. We demonstrated that it is expressed in both cell lines and upregulated during retinoic acid induced neural differentiation. We showed that SOX14 was expressed in both neuronal and non-neuronal differentiated derivatives, as revealed by immunocytochemistry. Since it was previously proposed that increased SOXB2 proteins level interfere with the activity of SOXB1 counteracting partners, we compared expression patterns of SOXB members during retinoic acid induction of embryonal carcinoma cells. We revealed that upregulation of SOX14 expression is accompanied by alterations in the expression patterns of SOXB1 members. In order to analyze the potential cross-talk between them, we generated SOX14 expression construct. The ectopic expression of SOX14 was demonstrated at the mRNA level in NT2/D1, P19 and HeLa cells, while an increased level of SOX14 protein was detected in HeLa cells only. By transient transfection experiments in HeLa cells we showed for the first time that ectopic expression of SOX14 repressed SOX1 expression, whereas no significant effect on SOX2, SOX3 and SOX21 was observed. Data presented here provide an insight into SOX14 expression during in vitro neural differentiation of embryonal carcinoma cells and demonstrate the effect of its ectopic expression on protein levels of SOXB members in HeLa cells. Obtained results contribute to better understanding the role of one of the most conserved SOX proteins. PMID:24637840

  3. Anti-Inflammatory and Analgesic Effects of Pyeongwisan on LPS-Stimulated Murine Macrophages and Mouse Models of Acetic Acid-Induced Writhing Response and Xylene-Induced Ear Edema

    PubMed Central

    Oh, You-Chang; Jeong, Yun Hee; Cho, Won-Kyung; Ha, Jeong-Ho; Gu, Min Jung; Ma, Jin Yeul

    2015-01-01

    Pyeongwisan (PW) is an herbal medication used in traditional East Asian medicine to treat anorexia, abdominal distension, borborygmus and diarrhea caused by gastric catarrh, atony and dilatation. However, its effects on inflammation-related diseases are unknown. In this study, we investigated the biological effects of PW on lipopolysaccharide (LPS)-mediated inflammation in macrophages and on local inflammation in vivo. We investigated the biological effects of PW on the production of inflammatory mediators, pro-inflammatory cytokines and related products as well as the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) in LPS-stimulated macrophages. Additionally, we evaluated the analgesic effect on the acetic acid-induced writhing response and the inhibitory activity on xylene-induced ear edema in mice. PW showed anti-inflammatory effects by inhibiting the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and interleukin-1β (IL-1β). In addition, PW strongly suppressed inducible nitric oxide synthase (iNOS), a NO synthesis enzyme, induced heme oxygenase-1 (HO-1) expression and inhibited NF-κB activation and MAPK phosphorylation. Also, PW suppressed TNF-α, IL-6 and IL-1β cytokine production in LPS-stimulated peritoneal macrophage cells. Furthermore, PW showed an analgesic effect on the writhing response and an inhibitory effect on mice ear edema. We demonstrated the anti-inflammatory effects and inhibitory mechanism in macrophages as well as inhibitory activity of PW in vivo for the first time. Our results suggest the potential value of PW as an inflammatory therapeutic agent developed from a natural substance. PMID:25569097

  4. Melatonin Receptor Genes in Vertebrates

    PubMed Central

    Li, Di Yan; Smith, David Glenn; Hardeland, Rüdiger; Yang, Ming Yao; Xu, Huai Liang; Zhang, Long; Yin, Hua Dong; Zhu, Qing

    2013-01-01

    Melatonin receptors are members of the G protein-coupled receptor (GPCR) family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A) and MT2 (or Mel1b or MTNR1B) receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C), has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor. PMID:23712359

  5. Receptor binding properties of amperozide.

    PubMed

    Svartengren, J; Simonsson, P

    1990-01-01

    The receptor pharmacology of amperozide was investigated with in vitro radioligand binding technique. Amperozide possessed a high affinity to the 5-HT2 receptors (Ki = 16.5 +/- 2.1 nM) and a moderate affinity to alpha 1-adrenergic receptors of rat cerebral cortical membranes (Ki = 172 +/- 14 nM). The affinity of amperozide for striatal and limbic dopamine D2 receptors was low and not significantly different (Ki +/- S.E.M. = 540 +/- 59 nM vs 403 +/- 42 nM; p less than 0.11, n = 4). The affinity for striatal and limbic 5-HT2 receptors was measured as well and found to be very close to the affinity to the cerebral cortical 5-HT2 receptor. The drug affinity for D2 and 5-HT2 receptors seems thus not to be influenced by the location of the receptor moiety. The affinity for several other rat brain receptors such as 5-HT1A, alpha 2-adrenergic, dopamine D1, muscarinic M1 and M2, opiate sigma and beta 2-adrenergic was low. The pseudo-Hill coefficient of the amperozide competition binding curve was consistently higher than one indicating antagonistic and complex interactions with the 5-HT2 receptor or with alpha 1-adrenergic and dopamine D2 receptors. The antagonistic properties of amperozide were investigated by its ability to antagonize the serotonin-induced formation of inositol-1-phosphate in human blood platelets. Amperozide inhibited this 5-HT2 receptor-mediated intracellular response with similar potency as ketanserin. These results suggest that amperozide is a selective 5-HT2 receptor antagonist.

  6. Angiotensin II receptors in testes

    SciTech Connect

    Millan, M.A.; Aguilera, G.

    1988-05-01

    Receptors for angiotensin II (AII) were identified and characterized in testes of rats and several primate species. Autoradiographic analysis of the binding of 125I-labeled (Sar1,Ile8)AII to rat, rhesus monkey, cebus monkey, and human testicular slide-mounted frozen sections indicated specific binding to Leydig cells in the interstitium. In rat collagenase-dispersed interstitial cells fractionated by Percoll gradient, AII receptor content was parallel to that of hCG receptors, confirming that the AII receptors are in the Leydig cells. In rat dispersed Leydig cells, binding was specific for AII and its analogs and of high affinity (Kd, 4.8 nM), with a receptor concentration of 15 fmol/10(6) cells. Studies of AII receptors in rat testes during development reveals the presence of high receptor density in newborn rats which decreases toward the adult age (4934 +/- 309, 1460 +/- 228, 772 +/- 169, and 82 +/- 12 fmol/mg protein at 5, 15, 20, and 30 days of age, respectively) with no change in affinity. At all ages receptors were located in the interstitium, and the decrease in binding was parallel to the decrease in the interstitial to tubular ratio observed with age. AII receptor properties in membrane-rich fractions from prepuberal testes were similar in the rat and rhesus monkey. Binding was time and temperature dependent, reaching a plateau at 60 min at 37 C, and was increased by divalent cations, EGTA, and dithiothreitol up to 0.5 mM. In membranes from prepuberal monkey testes, AII receptors were specific for AII analogs and of high affinity (Kd, 4.2 nM) with a receptor concentration of 7599 +/- 1342 fmol/mg protein. The presence of AII receptors in Leydig cells in rat and primate testes in conjunction with reports of the presence of other components of the renin-angiotensin system in the testes suggests that the peptide has a physiological role in testicular function.

  7. Angiotensin II receptor signalling.

    PubMed

    Daniels, Derek; Yee, Daniel K; Fluharty, Steven J

    2007-05-01

    Angiotensin II plays a key role in the regulation of body fluid homeostasis. To correct body fluid deficits that occur during hypovolaemia, an animal needs to ingest both water and electrolytes. Thus, it is not surprising that angiotensin II, which is synthesized in response to hypovolaemia, acts centrally to increase both water and NaCl intake. Here, we review findings relating to the properties of angiotensin II receptors that give rise to changes in behaviour. Data are described to suggest that divergent signal transduction pathways are responsible for separable behavioural responses to angiotensin II, and a hypothesis is proposed to explain how this divergence may map onto neural circuits in the brain.

  8. The human olfactory receptor repertoire

    PubMed Central

    Zozulya, Sergey; Echeverri, Fernando; Nguyen, Trieu

    2001-01-01

    Background The mammalian olfactory apparatus is able to recognize and distinguish thousands of structurally diverse volatile chemicals. This chemosensory function is mediated by a very large family of seven-transmembrane olfactory (odorant) receptors encoded by approximately 1,000 genes, the majority of which are believed to be pseudogenes in humans. Results The strategy of our sequence database mining for full-length, functional candidate odorant receptor genes was based on the high overall sequence similarity and presence of a number of conserved sequence motifs in all known mammalian odorant receptors as well as the absence of introns in their coding sequences. We report here the identification and physical cloning of 347 putative human full-length odorant receptor genes. Comparative sequence analysis of the predicted gene products allowed us to identify and define a number of consensus sequence motifs and structural features of this vast family of receptors. A new nomenclature for human odorant receptors based on their chromosomal localization and phylogenetic analysis is proposed. We believe that these sequences represent the essentially complete repertoire of functional human odorant receptors. Conclusions The identification and cloning of all functional human odorant receptor genes is an important initial step in understanding receptor-ligand specificity and combinatorial encoding of odorant stimuli in human olfaction. PMID:11423007

  9. Luminal l-glutamate enhances duodenal mucosal defense mechanisms via multiple glutamate receptors in rats

    PubMed Central

    Watanabe, Chikako; Mizumori, Misa; Kaunitz, Jonathan D.

    2009-01-01

    Presence of taste receptor families in the gastrointestinal mucosa suggests a physiological basis for local and early detection of a meal. We hypothesized that luminal l-glutamate, which is the primary nutrient conferring fundamental umami or proteinaceous taste, influences mucosal defense mechanisms in rat duodenum. We perfused the duodenal mucosa of anesthetized rats with l-glutamate (0.1–10 mM). Intracellular pH (pHi) of the epithelial cells, blood flow, and mucus gel thickness (MGT) were simultaneously and continuously measured in vivo. Some rats were pretreated with indomethacin or capsaicin. Duodenal bicarbonate secretion (DBS) was measured with flow-through pH and CO2 electrodes. We tested the effects of agonists or antagonists for metabotropic glutamate receptor (mGluR) 1 or 4 or calcium-sensing receptor (CaSR) on defense factors. Luminal l-glutamate dose dependently increased pHi and MGT but had no effect on blood flow in the duodenum. l-glutamate (10 mM)-induced cellular alkalinization and mucus secretion were inhibited by pretreatment with indomethacin or capsaicin. l-glutamate effects on pHi and MGT were mimicked by mGluR4 agonists and inhibited by an mGluR4 antagonist. CaSR agonists acidified cells with increased MGT and DBS, unlike l-glutamate. Perfusion of l-glutamate with inosinate (inosine 5′-monophosphate, 0.1 mM) enhanced DBS only in combination, suggesting synergistic activation of the l-glutamate receptor, typical of taste receptor type 1. l-leucine or l-aspartate had similar effects on DBS without any effect on pHi and MGT. Preperfusion of l-glutamate prevented acid-induced cellular injury, suggesting that l-glutamate protects the mucosa by enhancing mucosal defenses. Luminal l-glutamate may activate multiple receptors and afferent nerves and locally enhance mucosal defenses to prevent subsequent injury attributable to acid exposure in the duodenum. PMID:19643955

  10. Chemokine receptors in airway disease: which receptors to target?

    PubMed

    Owen, C

    2001-01-01

    Many disease states within the airway result in the co-ordinated infiltration of key inflammatory cells. The cellular influx is choreographed through the temporal and spatially-regulated expression of chemokines, which potentiate the migration of cells along gradients of chemotactic ligands. Chemokines act as ligands for the chemokine receptors; a distinct class of G-protein-coupled receptor. Over 40 chemokine ligands and 18 chemokine receptors have been identified on human cells. Chemokine receptors are divided into several classes; the two most prominent of which are the CC- and CXC-chemokine receptors, classified through the spatial arrangement of two conserved cysteine residues. The role of chemokine receptors such as CCR2, CCR3, CCR4, CCR8 and the CXC chemokine receptors; CXCR1 and CXCR2 on cell types of relevance to respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD) and chronic bronchitis will be explored in this review. Chemokines have proven to be amenable drug targets for the development of low molecular weight antagonists by the pharmaceutical industry. So far, no chemokine receptor antagonist has entered the clinic in trials for respiratory disease, but over the next few years it is expected that many will do so, at which time the potential of these exciting new targets will be fully realised.

  11. GABAB receptors modulate NMDA receptor calcium signals in dendritic spines.

    PubMed

    Chalifoux, Jason R; Carter, Adam G

    2010-04-15

    Metabotropic GABA(B) receptors play a fundamental role in modulating the excitability of neurons and circuits throughout the brain. These receptors influence synaptic transmission by inhibiting presynaptic release or activating postsynaptic potassium channels. However, their ability to directly influence different types of postsynaptic glutamate receptors remains unresolved. Here we examine GABA(B) receptor modulation in layer 2/3 pyramidal neurons from the mouse prefrontal cortex. We use two-photon laser-scanning microscopy to study synaptic modulation at individual dendritic spines. Using two-photon optical quantal analysis, we first demonstrate robust presynaptic modulation of multivesicular release at single synapses. Using two-photon glutamate uncaging, we then reveal that GABA(B) receptors strongly inhibit NMDA receptor calcium signals. This postsynaptic modulation occurs via the PKA pathway and does not affect synaptic currents mediated by AMPA or NMDA receptors. This form of GABA(B) receptor modulation has widespread implications for the control of calcium-dependent neuronal function.

  12. Axonal GABAA receptors.

    PubMed

    Trigo, Federico F; Marty, Alain; Stell, Brandon M

    2008-09-01

    Type A GABA receptors (GABA(A)Rs) are well established as the main inhibitory receptors in the mature mammalian forebrain. In recent years, evidence has accumulated showing that GABA(A)Rs are prevalent not only in the somatodendritic compartment of CNS neurons, but also in their axonal compartment. Evidence for axonal GABA(A)Rs includes new immunohistochemical and immunogold data: direct recording from single axonal terminals; and effects of local applications of GABA(A)R modulators on action potential generation, on axonal calcium signalling, and on neurotransmitter release. Strikingly, whereas presynaptic GABA(A)Rs have long been considered inhibitory, the new studies in the mammalian brain mostly indicate an excitatory action. Depending on the neuron that is under study, axonal GABA(A)Rs can be activated by ambient GABA, by GABA spillover, or by an autocrine action, to increase either action potential firing and/or transmitter release. In certain neurons, the excitatory effects of axonal GABA(A)Rs persist into adulthood. Altogether, axonal GABA(A)Rs appear as potent neuronal modulators of the mammalian CNS.

  13. The Multifaceted Mineralocorticoid Receptor

    PubMed Central

    Gomez-Sanchez, Elise; Gomez-Sanchez, Celso E.

    2015-01-01

    The primary adrenal cortical steroid hormones, aldosterone, and the glucocorticoids cortisol and corticosterone, act through the structurally similar mineralocorticoid (MR) and glucocorticoid receptors (GRs). Aldosterone is crucial for fluid, electrolyte, and hemodynamic homeostasis and tissue repair; the significantly more abundant glucocorticoids are indispensable for energy homeostasis, appropriate responses to stress, and limiting inflammation. Steroid receptors initiate gene transcription for proteins that effect their actions as well as rapid non-genomic effects through classical cell signaling pathways. GR and MR are expressed in many tissues types, often in the same cells, where they interact at molecular and functional levels, at times in synergy, others in opposition. Thus the appropriate balance of MR and GR activation is crucial for homeostasis. MR has the same binding affinity for aldosterone, cortisol, and corticosterone. Glucocorticoids activate MR in most tissues at basal levels and GR at stress levels. Inactivation of cortisol and corticosterone by 11β-HSD2 allows aldosterone to activate MR within aldosterone target cells and limits activation of the GR. Under most conditions, 11β-HSD1 acts as a reductase and activates cortisol/corticosterone, amplifying circulating levels. 11β-HSD1 and MR antagonists mitigate inappropriate activation of MR under conditions of oxidative stress that contributes to the pathophysiology of the cardiometabolic syndrome; however, MR antagonists decrease normal MR/GR functional interactions, a particular concern for neurons mediating cognition, memory, and affect. PMID:24944027

  14. Kinins and peptide receptors.

    PubMed

    Regoli, Domenico; Gobeil, Fernand

    2016-04-01

    This paper is divided into two sections: the first contains the essential elements of the opening lecture presented by Pr. Regoli to the 2015 International Kinin Symposium in S. Paulo, Brazil on June 28th and the second is the celebration of Dr. Regoli's 60 years of research on vasoactive peptides. The cardiovascular homeostasis derives from a balance of two systems, the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS). The biologically active effector entity of RAS is angiotensin receptor-1 (AT-1R), and that of KKS is bradykinin B2 receptor (B2R). The first mediates vasoconstriction, the second is the most potent and efficient vasodilator. Thanks to its complex and multi-functional mechanism of action, involving nitric oxide (NO), prostacyclin and endothelial hyperpolarizing factor (EDHF). B2R is instrumental for the supply of blood, oxygen and nutrition to tissues. KKS is present on the vascular endothelium and functions as an autacoid playing major roles in cardiovascular diseases (CVDs) and diabetes. KKS exerts a paramount role in the prevention of thrombosis and atherosclerosis. Such knowledge emphasizes the already prominent value of the ACE-inhibitors (ACEIs) for the treatment of CVDs and diabetes. Indeed, the ACEIs, thanks to their double action (block of the RAS and potentiation of the KKS) are the ideal agents for a rational treatment of these diseases. PMID:26408609

  15. Leptin and its receptors.

    PubMed

    Wada, Nobuhiro; Hirako, Satoshi; Takenoya, Fumiko; Kageyama, Haruaki; Okabe, Mai; Shioda, Seiji

    2014-11-01

    Leptin is mainly produced in the white adipose tissue before being secreted into the blood and transported across the blood-brain barrier. Leptin binds to a specific receptor (LepR) that has numerous subtypes (LepRa, LepRb, LepRc, LepRd, LepRe, and LepRf). LepRb, in particular, is expressed in several brain nuclei, including the arcuate nucleus, the paraventricular nucleus, and the dorsomedial, lateral and ventromedial regions of the hypothalamus. LepRb is also co-expressed with several neuropeptides, including proopiomelanocortin, neuropeptide Y, galanin, galanin-like peptide, gonadotropin-releasing hormone, tyrosine hydroxylase and neuropeptide W. Functionally, LepRb induces activation of the JAK2/ERK, /STAT3, /STAT5 and IRS/PI3 kinase signaling cascades, which are important for the regulation of energy homeostasis and appetite in mammals. In this review, we discuss the structure, genetics and distribution of the leptin receptors, and their role in cell signaling mechanisms. PMID:25218975

  16. Angiotensin II receptor heterogeneity

    SciTech Connect

    Herblin, W.F.; Chiu, A.T.; McCall, D.E.; Ardecky, R.J.; Carini, D.J.; Duncia, J.V.; Pease, L.J.; Wong, P.C.; Wexler, R.R.; Johnson, A.L. )

    1991-04-01

    The possibility of receptor heterogeneity in the angiotensin II (AII) system has been suggested previously, based on differences in Kd values or sensitivity to thiol reagents. One of the authors earliest indications was the frequent observation of incomplete inhibition of the binding of AII to adrenal cortical membranes. Autoradiographic studies demonstrated that all of the labeling of the rat adrenal was blocked by unlabeled AII or saralasin, but not by DuP 753. The predominant receptor in the rat adrenal cortex (80%) is sensitive to dithiothreitol (DTT) and DuP 753, and is designated AII-1. The residual sites in the adrenal cortex and almost all of the sites in the rat adrenal medulla are insensitive to both DTT and DuP 753, but were blocked by EXP655. These sites have been confirmed by ligand binding studies and are designated AII-2. The rabbit adrenal cortex is unique in yielding a nonuniform distribution of AII-2 sites around the outer layer of glomerulosa cells. In the rabbit kidney, the sites on the glomeruli are AII-1, but the sites on the kidney capsule are AII-2. Angiotensin III appears to have a higher affinity for AII-2 sites since it inhibits the binding to the rabbit kidney capsule but not the glomeruli. Elucidation of the distribution and function of these diverse sites should permit the development of more selective and specific therapeutic strategies.

  17. Sulfonamide inhibitors of α2β1 integrin reveal the essential role of collagen receptors in in vivo models of inflammation

    PubMed Central

    Nissinen, Liisa; Ojala, Marika; Langen, Barbara; Dost, Rita; Pihlavisto, Marjo; Käpylä, Jarmo; Marjamäki, Anne; Heino, Jyrki

    2015-01-01

    Small molecule inhibitors of α2β1 integrin, a major cellular collagen receptor, have been reported to inhibit platelet function, kidney injury, and angiogenesis. Since α2β1 integrin is abundantly expressed on various inflammation-associated cells, we tested whether recently developed α2β1 blocking sulfonamides have anti-inflammatory properties. Integrin α2β1 inhibitors were shown to reduce the signs of inflammation in arachidonic acid-induced ear edema, PAF stimulated air pouch, ovalbumin-induced skin hypersensitivity, adjuvant arthritis, and collagen-induced arthritis. Thus, these sulfonamides are potential drugs for acute and allergic inflammation, hypersensitivity, and arthritis. One sulfonamide with potent anti-inflammatory activity has previously been reported to be selective for activated integrins, but not to inhibit platelet function. Thus, the experiments also revealed fundamental differences in the action of nonactivated and activated α2β1 integrins in inflammation when compared to thrombosis. PMID:26171226

  18. [Adrenergic receptors of blood platelets].

    PubMed

    Lanza, F; Cazenave, J P

    1987-01-01

    Blood platelets possess adrenergic receptors and are stimulated by adrenaline in the circulation. This review summarizes the state of knowledge of the pharmacology of adrenergic receptors and the biochemical mechanisms of platelet activation by adrenaline in various physiological and pathological conditions. PMID:2837727

  19. Sensory receptors in monotremes.

    PubMed

    Proske, U; Gregory, J E; Iggo, A

    1998-07-29

    This is a summary of the current knowledge of sensory receptors in skin of the bill of the platypus, Ornithorhynchus anatinus, and the snout of the echidna, Tachyglossus aculeatus. Brief mention is also made of the third living member of the monotremes, the long-nosed echidna, Zaglossus bruijnii. The monotremes are the only group of mammals known to have evolved electroreception. The structures in the skin responsible for the electric sense have been identified as sensory mucous glands with an expanded epidermal portion that is innervated by large-diameter nerve fibres. Afferent recordings have shown that in both platypuses and echidnas the receptors excited by cathodal (negative) pulses and inhibited by anodal (positive) pulses. Estimates give a total of 40,000 mucous sensory glands in the upper and lower bill of the platypus, whereas there are only about 100 in the tip of the echidna snout. Recording of electroreceptor-evoked activity from the brain of the platypus have shown that the largest area dedicated to somatosensory input from the bill, S1, shows alternating rows of mechanosensory and bimodal neurons. The bimodal neurons respond to both electrosensory and mechanical inputs. In skin of the platypus bill and echidna snout, apart from the electroreceptors, there are structures called push rods, which consist of a column of compacted cells that is able to move relatively independently of adjacent regions of skin. At the base of the column are Merkel cell complexes, known to be type I slowly adapting mechanoreceptors, and lamellated corpuscles, probably vibration receptors. It has been speculated that the platypus uses its electric sense to detect the electromyographic activity from moving prey in the water and for obstacle avoidance. Mechanoreceptors signal contact with the prey. For the echidna, a role for the electrosensory system has not yet been established during normal foraging behaviour, although it has been shown that it is able to detect the presence

  20. Allosteric Modulation of Chemoattractant Receptors

    PubMed Central

    Allegretti, Marcello; Cesta, Maria Candida; Locati, Massimo

    2016-01-01

    Chemoattractants control selective leukocyte homing via interactions with a dedicated family of related G protein-coupled receptor (GPCR). Emerging evidence indicates that the signaling activity of these receptors, as for other GPCR, is influenced by allosteric modulators, which interact with the receptor in a binding site distinct from the binding site of the agonist and modulate the receptor signaling activity in response to the orthosteric ligand. Allosteric modulators have a number of potential advantages over orthosteric agonists/antagonists as therapeutic agents and offer unprecedented opportunities to identify extremely selective drug leads. Here, we resume evidence of allosterism in the context of chemoattractant receptors, discussing in particular its functional impact on functional selectivity and probe/concentration dependence of orthosteric ligands activities. PMID:27199992

  1. Nicotinic receptors and schizophrenia.

    PubMed

    Ripoll, Nadège; Bronnec, Marie; Bourin, Michel

    2004-07-01

    The incidence of smoking is very high in non-schizophrenic subjects presenting various psychiatric disorders (35 to 54%). However, the incidence of smoking is extremely high in schizophrenic patients: 80% to 90%, versus 25% to 30% of the general population. Various studies have demonstrated that the use of tobacco transiently restores the schizophrenic patient's cognitive and sensory deficits. Smoking cessation also appears to exacerbate the symptoms of the disease. Post-mortem binding studies have revealed a disturbance of nicotinic receptor expression, affecting the alpha(7) and alpha(4)beta(2) subunits, in various cerebral areas. Genetic linkage studies have also shown that the alpha(7) subunit is involved in schizophrenia. This review assesses the involvement of the nicotinic system in schizophrenia and suggests ways in which this system may participate in the pathophysiology of this disease.

  2. Androgen receptor genomic regulation

    PubMed Central

    Jin, Hong-Jian; Kim, Jung

    2013-01-01

    The transcriptional activity of the androgen receptor (AR) is not only critical for the normal development and function of the prostate but also pivotal to the onset and progression of prostate cancer (PCa). The studies of AR transcriptional regulation were previously limited to a handful of AR-target genes. Owing to the development of various high-throughput genomic technologies, significant advances have been made in recent years. Here we discuss the discoveries of genome-wide androgen-regulated genes in PCa cell lines, animal models and tissues using expression microarray and sequencing, the mapping of genomic landscapes of AR using Combining Chromatin Immunoprecipitation (ChIP)-on-chip and ChIP-seq assays, the interplay of transcriptional cofactors in defining AR binding profiles, and the genomic regulation and AR reprogramming in advanced PCa. PMID:25237629

  3. The somatostatin receptor family.

    PubMed

    Patel, Y C; Greenwood, M T; Panetta, R; Demchyshyn, L; Niznik, H; Srikant, C B

    1995-01-01

    The diverse biological effects of somatostatin (SST) are mediated through a family of G protein coupled receptors of which 5 members have been recently identified by molecular cloning. This review focuses on the molecular biology, pharmacology, expression, and function of these receptors with particular emphasis on the human (h) homologs. hSSTRs are encoded by a family of 5 genes which map to separate chromosomes and which, with one exception, are intronless. SSTR2 gives rise to spliced variants, SSTR2A and 2B. hSSTR1-4 display weak selectivity for SST-14 binding whereas hSSTR5 is SST-28 selective. Based on structural similarity and reactivity for octapeptide and hexapeptide SST analogs, hSSTR2,3, and 5 belong to a similar SSTR subclass. hSSTR1 and 4 react poorly with these analogs and belong to a separate subclass. All 5 hSSTRs are functionally coupled to inhibition of adenylyl cyclase via pertussis toxin sensitive GTP binding proteins. Some of the subtypes are also coupled to tyrosine phosphatase (SSTR1,2), Ca2+ channels (SSTR2), Na+/H+ exchanger (SSTR1), PLA-2 (SSTR4), and MAP kinase (SSTR4). mRNA for SSTR1-5 is widely expressed in brain and peripheral organs and displays an overlapping but characteristic pattern that is subtype-selective, and tissue- and species-specific. Pituitary and islet tumors express several SSTR genes suggesting that multiple SSTR subtypes are coexpressed in the same cell. Structure-function studies indicate that the core residues in SST-14 ligand Phe6-Phe11 dock within a ligand binding pocket located in TMDs 3-7 which is lined by hydrophobic and charged amino acid residues.

  4. Generation of a Potent Low Density Lipoprotein Receptor-related Protein 1 (LRP1) Antagonist by Engineering a Stable Form of the Receptor-associated Protein (RAP) D3 Domain.

    PubMed

    Prasad, Joni M; Migliorini, Mary; Galisteo, Rebeca; Strickland, Dudley K

    2015-07-10

    The low density lipoprotein receptor-related protein 1 (LRP1) is a member of the low density lipoprotein receptor family and plays important roles in a number of physiological and pathological processes. Expression of LRP1 requires the receptor-associated protein (RAP), a molecular chaperone that binds LRP1 and other low density lipoprotein receptor family members in the endoplasmic reticulum and traffics with them to the Golgi where the acidic environment causes its dissociation. Exogenously added RAP is a potent LRP1 antagonist and binds to LRP1 on the cell surface, preventing ligands from binding. Following endocytosis, RAP dissociates in the acidic endosome, allowing LRP1 to recycle back to the cell surface. The acid-induced dissociation of RAP is mediated by its D3 domain, a relatively unstable three-helical bundle that denatures at pH <6.2 due to protonation of key histidine residues on helices 2 and 3. To develop an LRP1 inhibitor that does not dissociate at low pH, we introduced a disulfide bond between the second and third helices in the RAP D3 domain. By combining this disulfide bond with elimination of key histidine residues, we generated a stable RAP molecule that is resistant to both pH- and heat-induced denaturation. This molecule bound to LRP1 with high affinity at both neutral and acidic pH and proved to be a potent inhibitor of LRP1 function both in vitro and in vivo, suggesting that our stable RAP molecule may be useful in multiple pathological settings where LRP1 blockade has been shown to be effective.

  5. Fabrication of folic acid-sensitive gold nanoclusters for turn-on fluorescent imaging of overexpression of folate receptor in tumor cells.

    PubMed

    Li, Hongchang; Cheng, Yuqing; Liu, Yong; Chen, Bo

    2016-09-01

    Based on the fluorescence quenching of folic acid-sensitive bovine serum albumin-directed gold nanoclusters (BSA-AuNCs) via folic acid-induced the change of environment around BSA-AuNCs, we have constructed a turn on fluorescence imaging of folate receptor overexpressed tumor cells. In this paper, the primary fluorescence intensity of BSA-AuNCs was quenched via self-assembly of folic acid onto BSA-AuNCs to produce negligible fluorescence background, the linear range of the method was 0.1-100μg/mL with the limit of detection (LOD) of 30ng/mL (S/N=3); In the presence of overexpression of folate receptor on the surface of tumor cells, the primary fluorescence intensity of BSA-AuNCs turned on by folic acid desorbing from BSA-AuNCs, the linear range of method was 0.12-2μg/mL with the LOD of 20ng/mL (S/N=3). Additionally, due to specific and high affinity of folic acid and folate receptor, the probe had high selectivity for folate receptor, other interferences hardly changed the fluorescence intensity of the probe. Moreover, the text for cytotoxicity implied that the probe had no toxicity for tumor cells. Consequently, using the fluorescence probe, satisfactory results for the turn on imaging of folate receptor overexpressed tumor cells were obtained. A novel turn-on and red fluorescent probe for folate receptor overexpressed tumor cells was developed based on the recovery of fluorescence intensity of folic acid-sensitive BSA-AuNCs.

  6. Free fatty acids and protein kinase C activation induce GPR120 (free fatty acid receptor 4) phosphorylation.

    PubMed

    Sánchez-Reyes, Omar B; Romero-Ávila, M Teresa; Castillo-Badillo, Jean A; Takei, Yoshinori; Hirasawa, Akira; Tsujimoto, Gozoh; Villalobos-Molina, Rafael; García-Sáinz, J Adolfo

    2014-01-15

    GPR120, free fatty acid receptor 4, is a recently deorphanized G protein-coupled receptor that seems to play cardinal roles in the regulation of metabolism and in the pathophysiology of inflammatory and metabolic disorders. In the present work a GPR120-Venus fusion protein was expressed in HEK293 Flp-In T-REx cells and its function (increase in intracellular calcium) and phosphorylation were studied. It was observed that the fusion protein migrated in sodium dodecyl sulfate-polyacrylamide gels as a band with a mass of ≈70-75kDa, although other bands of higher apparent weight (>130kDa) were also detected. Cell stimulation with docosahexaenoic acid or α-linolenic acid induced concentration-dependent increases in intracellular calcium and GPR120 phosphorylation. Activation of protein kinase C with phorbol esters also induced a marked receptor phosphorylation but did not alter the ability of 1µM docosahexaenoic acid to increase the intracellular calcium concentration. Phorbol ester-induced GPR120 phosphorylation, but not that induced with docosahexaenoic acid, was blocked by protein kinase C inhibitors (bis-indolyl-maleimide I and Gö 6976) suggesting that conventional kinase isoforms mediate this action. The absence of effect of protein kinase C inhibitors on agonist-induced GPR120 phosphorylation indicates that this kinase does not play a major role in agonist-induced receptor phosphorylation. Docosahexaenoic acid action was associated with marked GPR120 internalization whereas that induced with phorbol esters was smaller at early times. PMID:24239485

  7. Estrogen-related receptor β (ERRβ) – renaissance receptor or receptor renaissance?

    PubMed Central

    Divekar, Shailaja D.; Tiek, Deanna M.; Fernandez, Aileen; Riggins, Rebecca B.

    2016-01-01

    Estrogen-related receptors (ERRs) are founding members of the orphan nuclear receptor (ONR) subgroup of the nuclear receptor superfamily. Twenty-seven years of study have yet to identify cognate ligands for the ERRs, though they have firmly placed ERRα and ERRγ at the intersection of cellular metabolism and oncogenesis. The pace of discovery for novel functions of ERRβ, however, has until recently been somewhat slower than that of its family members. ERRβ has also been largely ignored in summaries and perspectives of the ONR literature. Here, we provide an overview of established and emerging knowledge of ERRβ in mouse, man, and other species, highlighting unique aspects of ERRβ biology that set it apart from the other two estrogen-related receptors, with a focus on the impact of alternative splicing on the structure and function of this receptor. PMID:27507929

  8. Estrogen-related receptor β (ERRβ) - renaissance receptor or receptor renaissance?

    PubMed

    Divekar, Shailaja D; Tiek, Deanna M; Fernandez, Aileen; Riggins, Rebecca B

    2016-01-01

    Estrogen-related receptors (ERRs) are founding members of the orphan nuclear receptor (ONR) subgroup of the nuclear receptor superfamily. Twenty-seven years of study have yet to identify cognate ligands for the ERRs, though they have firmly placed ERRα and ERRγ at the intersection of cellular metabolism and oncogenesis. The pace of discovery for novel functions of ERRβ, however, has until recently been somewhat slower than that of its family members. ERRβ has also been largely ignored in summaries and perspectives of the ONR literature. Here, we provide an overview of established and emerging knowledge of ERRβ in mouse, man, and other species, highlighting unique aspects of ERRβ biology that set it apart from the other two estrogen-related receptors, with a focus on the impact of alternative splicing on the structure and function of this receptor.

  9. Estrogen-related receptor β (ERRβ) - renaissance receptor or receptor renaissance?

    PubMed

    Divekar, Shailaja D; Tiek, Deanna M; Fernandez, Aileen; Riggins, Rebecca B

    2016-01-01

    Estrogen-related receptors (ERRs) are founding members of the orphan nuclear receptor (ONR) subgroup of the nuclear receptor superfamily. Twenty-seven years of study have yet to identify cognate ligands for the ERRs, though they have firmly placed ERRα and ERRγ at the intersection of cellular metabolism and oncogenesis. The pace of discovery for novel functions of ERRβ, however, has until recently been somewhat slower than that of its family members. ERRβ has also been largely ignored in summaries and perspectives of the ONR literature. Here, we provide an overview of established and emerging knowledge of ERRβ in mouse, man, and other species, highlighting unique aspects of ERRβ biology that set it apart from the other two estrogen-related receptors, with a focus on the impact of alternative splicing on the structure and function of this receptor. PMID:27507929

  10. Dengue Virus Impairs Mitochondrial Fusion by Cleaving Mitofusins.

    PubMed

    Yu, Chia-Yi; Liang, Jian-Jong; Li, Jin-Kun; Lee, Yi-Ling; Chang, Bi-Lan; Su, Chan-I; Huang, Wei-Jheng; Lai, Michael M C; Lin, Yi-Ling

    2015-12-01

    Mitochondria are highly dynamic subcellular organelles participating in many signaling pathways such as antiviral innate immunity and cell death cascades. Here we found that mitochondrial fusion was impaired in dengue virus (DENV) infected cells. Two mitofusins (MFN1 and MFN2), which mediate mitochondrial fusion and participate in the proper function of mitochondria, were cleaved by DENV protease NS2B3. By knockdown and overexpression approaches, these two MFNs showed diverse functions in DENV infection. MFN1 was required for efficient antiviral retinoic acid-inducible gene I-like receptor signaling to suppress DENV replication, while MFN2 participated in maintaining mitochondrial membrane potential (MMP) to attenuate DENV-induced cell death. Cleaving MFN1 and MFN2 by DENV protease suppressed mitochondrial fusion and deteriorated DENV-induced cytopathic effects through subverting interferon production and facilitating MMP disruption. Thus, MFNs participate in host defense against DENV infection by promoting the antiviral response and cell survival, and DENV regulates mitochondrial morphology by cleaving MFNs to manipulate the outcome of infection. PMID:26717518

  11. Solid-state NMR resonance assignments of the filament-forming CARD domain of the innate immunity signaling protein MAVS.

    PubMed

    He, Lichun; Lührs, Thorsten; Ritter, Christiane

    2015-10-01

    The mitochondrial antiviral signalling protein (MAVS) is a central signal transduction hub in the innate immune response against viral infections. Viral RNA present in the cytoplasm is detected by retinoic acid inducible gene I like receptors, which then activate MAVS via heterotypic interactions between their respective caspase activation and recruitment domains (CARD). This leads to the formation of active, high molecular weight MAVS complexes formed by homotypic interactions between the single N-terminal CARDs of MAVS. Filaments formed by the N-terminal MAVS(CARD) alone are sufficient to induce the autocatalytic conversion from a monomeric to an aggregated state in a prion-like manner. Here, we present the nearly complete spectroscopic (13)C and (15)N resonance assignments of human MAVS(CARD) filaments obtained from a single sample by magic angle spinning solid-state NMR spectroscopy. The corresponding secondary chemical shifts suggest that the filamentous form of MAVS(CARD) retains an exclusively alpha-helical fold that is very similar to the X-ray structure determined previously from monomeric MAVS(CARD)-maltose binding protein fusion constructs.

  12. PPM1A silences cytosolic RNA sensing and antiviral defense through direct dephosphorylation of MAVS and TBK1.

    PubMed

    Xiang, Weiwen; Zhang, Qian; Lin, Xia; Wu, Shiying; Zhou, Yao; Meng, Fansen; Fan, Yunyun; Shen, Tao; Xiao, Mu; Xia, Zongping; Zou, Jian; Feng, Xin-Hua; Xu, Pinglong

    2016-07-01

    Cytosolic RNA sensing is a prerequisite for initiation of innate immune response against RNA viral pathogens. Signaling through RIG-I (retinoic acid-inducible gene I)-like receptors (RLRs) to TBK1 (Tank-binding kinase 1)/IKKε (IκB kinase ε) kinases is transduced by mitochondria-associated MAVS (mitochondrial antiviral signaling protein). However, the precise mechanism of how MAVS-mediated TBK1/IKKε activation is strictly controlled still remains obscure. We reported that protein phosphatase magnesium-dependent 1A (PPM1A; also known as PP2Cα), depending on its catalytic ability, dampened the RLR-IRF3 (interferon regulatory factor 3) axis to silence cytosolic RNA sensing signaling. We demonstrated that PPM1A was an inherent partner of the TBK1/IKKε complex, targeted both MAVS and TBK1/IKKε for dephosphorylation, and thus disrupted MAVS-driven formation of signaling complex. Conversely, a high level of MAVS can dissociate the TBK1/PPM1A complex to override PPM1A-mediated inhibition. Loss of PPM1A through gene ablation in human embryonic kidney 293 cells and mouse primary macrophages enabled robustly enhanced antiviral responses. Consequently, Ppm1a(-/-) mice resisted to RNA virus attack, and transgenic zebrafish expressing PPM1A displayed profoundly increased RNA virus vulnerability. These findings identify PPM1A as the first known phosphatase of MAVS and elucidate the physiological function of PPM1A in antiviral immunity on whole animals. PMID:27419230

  13. PPM1A silences cytosolic RNA sensing and antiviral defense through direct dephosphorylation of MAVS and TBK1.

    PubMed

    Xiang, Weiwen; Zhang, Qian; Lin, Xia; Wu, Shiying; Zhou, Yao; Meng, Fansen; Fan, Yunyun; Shen, Tao; Xiao, Mu; Xia, Zongping; Zou, Jian; Feng, Xin-Hua; Xu, Pinglong

    2016-07-01

    Cytosolic RNA sensing is a prerequisite for initiation of innate immune response against RNA viral pathogens. Signaling through RIG-I (retinoic acid-inducible gene I)-like receptors (RLRs) to TBK1 (Tank-binding kinase 1)/IKKε (IκB kinase ε) kinases is transduced by mitochondria-associated MAVS (mitochondrial antiviral signaling protein). However, the precise mechanism of how MAVS-mediated TBK1/IKKε activation is strictly controlled still remains obscure. We reported that protein phosphatase magnesium-dependent 1A (PPM1A; also known as PP2Cα), depending on its catalytic ability, dampened the RLR-IRF3 (interferon regulatory factor 3) axis to silence cytosolic RNA sensing signaling. We demonstrated that PPM1A was an inherent partner of the TBK1/IKKε complex, targeted both MAVS and TBK1/IKKε for dephosphorylation, and thus disrupted MAVS-driven formation of signaling complex. Conversely, a high level of MAVS can dissociate the TBK1/PPM1A complex to override PPM1A-mediated inhibition. Loss of PPM1A through gene ablation in human embryonic kidney 293 cells and mouse primary macrophages enabled robustly enhanced antiviral responses. Consequently, Ppm1a(-/-) mice resisted to RNA virus attack, and transgenic zebrafish expressing PPM1A displayed profoundly increased RNA virus vulnerability. These findings identify PPM1A as the first known phosphatase of MAVS and elucidate the physiological function of PPM1A in antiviral immunity on whole animals.

  14. Colony-stimulating factor 1 receptor (CSF1R) signaling in injured neurons facilitates protection and survival.

    PubMed

    Luo, Jian; Elwood, Fiona; Britschgi, Markus; Villeda, Saul; Zhang, Hui; Ding, Zhaoqing; Zhu, Liyin; Alabsi, Haitham; Getachew, Ruth; Narasimhan, Ramya; Wabl, Rafael; Fainberg, Nina; James, Michelle L; Wong, Gordon; Relton, Jane; Gambhir, Sanjiv S; Pollard, Jeffrey W; Wyss-Coray, Tony

    2013-01-14

    Colony-stimulating factor 1 (CSF1) and interleukin-34 (IL-34) are functional ligands of the CSF1 receptor (CSF1R) and thus are key regulators of the monocyte/macrophage lineage. We discovered that systemic administration of human recombinant CSF1 ameliorates memory deficits in a transgenic mouse model of Alzheimer's disease. CSF1 and IL-34 strongly reduced excitotoxin-induced neuronal cell loss and gliosis in wild-type mice when administered systemically before or up to 6 h after injury. These effects were accompanied by maintenance of cAMP responsive element-binding protein (CREB) signaling in neurons rather than in microglia. Using lineage-tracing experiments, we discovered that a small number of neurons in the hippocampus and cortex express CSF1R under physiological conditions and that kainic acid-induced excitotoxic injury results in a profound increase in neuronal receptor expression. Selective deletion of CSF1R in forebrain neurons in mice exacerbated excitotoxin-induced death and neurodegeneration. We conclude that CSF1 and IL-34 provide powerful neuroprotective and survival signals in brain injury and neurodegeneration involving CSF1R expression on neurons.

  15. Schedule of NMDA receptor subunit expression and functional channel formation in the course of in vitro-induced neurogenesis.

    PubMed

    Varju, P; Schlett, K; Eisel, U; Madarász, E

    2001-06-01

    NE-7C2 neuroectodermal cells derived from forebrain vesicles of p53-deficient mouse embryos (E9) produce neurons and astrocytes in vitro if induced by all-trans retinoic acid. The reproducible morphological stages of neurogenesis were correlated with the expression of various NMDA receptor subunits. RT-PCR studies revealed that GluRepsilon1 and GluRepsilon4 subunit mRNAs were transcribed by both non-induced and neuronally differentiated cells. GluRepsilon3 subunit mRNAs were not synthesized by NE-7C2 cells and increased numbers of messages from the GluRepsilon2 gene were detected only after neural network formation. The presence of the GluRzeta1 protein was detected throughout neural induction, whereas retinoic acid-induced neuron formation elevated the amount of exon 21 (C1)- and exon 22 (C2)-containing GluRzeta1 mRNAs and resulted in the appearance of exon 5 (N1)-containing transcripts. NMDA-elicited Ca(2+)-signals were detected only in cells displaying neuronal morphology, but preceding the appearance of synapsin-I immunoreactivity. Our findings demonstrated that, in spite of the presence of subunits necessary for channel formation, functional channels were formed by NE-7C2 cells no sooner than the time of neurite maturation. The data show that the cell line provides a suitable model to analyse the mechanisms involved in NMDA receptor gene expression before the appearance of synaptic communication.

  16. Control of retinoic acid receptor heterodimerization by ligand-induced structural transitions. A novel mechanism of action for retinoid antagonists.

    PubMed

    Depoix, C; Delmotte, M H; Formstecher, P; Lefebvre, P

    2001-03-23

    Heterodimerization of retinoic acid receptors (RARs) with 9-cis-retinoic receptors (RXRs) is a prerequisite for binding of RXR.RAR dimers to DNA and for retinoic acid-induced gene regulation. Whether retinoids control RXR/RAR solution interaction remains a debated question, and we have used in vitro and in vivo protein interaction assays to investigate the role of ligand in modulating RXR/RAR interaction in the absence of DNA. Two-hybrid assay in mammalian cells demonstrated that only RAR agonists were able to increase significantly RAR interaction with RXR, whereas RAR antagonists inhibited RXR binding to RAR. Quantitative glutathione S-transferase pull-down assays established that there was a strict correlation between agonist binding affinity for the RAR monomer and the affinity of RXR for liganded RAR, but RAR antagonists were inactive in inducing RXR recruitment to RAR in vitro. Alteration of coactivator- or corepressor-binding interfaces of RXR or RAR did not alter ligand-enhanced dimerization. In contrast, preventing the formation of a stable holoreceptor structure upon agonist binding strongly altered RXR.RAR dimerization. Finally, we observed that RAR interaction with RXR silenced RXR ligand-dependent activation function. We propose that ligand-controlled dimerization of RAR with RXR is an important step in the RXR.RAR activation process. This interaction is dependent upon adequate remodeling of the AF-2 structure and amenable to pharmacological inhibition by structurally modified retinoids.

  17. Lysophospholipid receptors in drug discovery

    PubMed Central

    Kihara, Yasuyuki; Mizuno, Hirotaka; Chun, Jerold

    2014-01-01

    Lysophospholipids (LPs), including lysophosphatidic acid (LPA), sphingosine 1-phospate (S1P), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS), are bioactive lipids that transduce signals through their specific cell-surface G protein-coupled receptors, LPA1–6, S1P1–5, LPI1, and LysoPS1–3, respectively. These LPs and their receptors have been implicated in both physiological and pathophysiological processes such as autoimmune diseases, neurodegenerative diseases, fibrosis, pain, cancer, inflammation, metabolic syndrome, bone formation, fertility, organismal development, and other effects on most organ systems. Advances in the LP receptor field have enabled the development of novel small molecules targeting LP receptors for several diseases. Most notably, fingolimod (FTY720, Gilenya, Novartis), an S1P receptor modulator, became the first FDA-approved medicine as an orally bioavailable drug for treating relapsing forms of multiple sclerosis. This success is currently being followed by multiple, mechanistically related compounds targeting S1P receptor subtypes, which are in various stages of clinical development. In addition, an LPA1 antagonist, BMS-986020 (Bristol-Myers Squibb), is in Phase 2 clinical development for treating idiopathic pulmonary fibrosis, as is a distinct compound, SAR100842 (Sanofi) for the treatment of systemic sclerosis and related fibrotic diseases. This review summarizes the current state of drug discovery in the LP receptor field. PMID:25499971

  18. Hot receptors in the brain

    PubMed Central

    Steenland, Hendrik W; Ko, Shanelle W; Wu, Long-Jun; Zhuo, Min

    2006-01-01

    Two major approaches have been employed for the development of novel drugs to treat chronic pain. The most traditional approach identifies molecules involved in pain as potential therapeutic targets and has focused mainly on the periphery and spinal cord. A more recent approach identifies molecules that are involved in long-term plasticity. Drugs developed through the latter approach are predicted to treat chronic, but not physiological or acute, pain. The TRPV1 (transient receptor potential vanilloid-1) receptor is involved in nociceptive processing, and is a candidate therapeutic target for pain. While most research on TRPV1 receptors has been conducted at the level of the spinal cord and peripheral structures, considerably less research has focused on supraspinal structures. This short paper summarizes progress made on TRPV1 receptors, and reviews research on the expression and function of TRPV1 receptors in supraspinal structures. We suggest that the TRPV1 receptor may be involved in pain processing in higher brain structures, such as the anterior cingulate cortex. In addition, some regions of the brain utilize the TRPV1 receptor for functions apparently unrelated to pain. PMID:17092351

  19. The growth hormone secretagogue receptor.

    PubMed

    Cruz, Conrad Russell Young; Smith, Roy G

    2008-01-01

    The neuroendocrine hormone ghrelin, a recently discovered acylated peptide with numerous activities in various organ systems, exerts most of its known effects on the body through a highly conserved G-protein-coupled receptor, the growth hormone secretagogue receptor (GHSR) type 1a. The GHSR's wide expression in different tissues reflects activity of its ligands in the hypothalamic-pituitary, cardiovascular, immune, gastrointestinal, and reproductive systems. Its extensive cellular distribution along with its important actions on the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and other neuroendocrine and metabolic systems suggest a pivotal role in governing the mechanisms of aging. A more comprehensive characterization of the receptor, and a more thorough identification of its various agonists and antagonists, will undoubtedly introduce important clinical applications in age-related states like anorexia, cardiovascular pathology, cancer, impaired energy balance, and immune dysfunction. Although present knowledge points to a single functional receptor and a single endogenous ligand, recent investigations suggest the existence of additional GHSR subtypes, as well as other endogenous agonists. It has been more than a decade since the landmark cloning of this ubiquitous, highly conserved receptor, and the considerable extent of its effects on normal physiology and disease states have filled the literature with incredible insights on how organisms regulate various functions through subtle signaling processes. But science has barely scratched the surface, and we can be assured that the mysteries surrounding the precise nature of ghrelin and its receptor(s) are only beginning to unravel. PMID:17983853

  20. Evolution of vertebrate opioid receptors

    PubMed Central

    Dreborg, Susanne; Sundström, Görel; Larsson, Tomas A.; Larhammar, Dan

    2008-01-01

    The opioid peptides and receptors have prominent roles in pain transmission and reward mechanisms in mammals. The evolution of the opioid receptors has so far been little studied, with only a few reports on species other than tetrapods. We have investigated species representing a broader range of vertebrates and found that the four opioid receptor types (delta, kappa, mu, and NOP) are present in most of the species. The gene relationships were deduced by using both phylogenetic analyses and chromosomal location relative to 20 neighboring gene families in databases of assembled genomes. The combined results show that the vertebrate opioid receptor gene family arose by quadruplication of a large chromosomal block containing at least 14 other gene families. The quadruplication seems to coincide with, and, therefore, probably resulted from, the two proposed genome duplications in early vertebrate evolution. We conclude that the quartet of opioid receptors was already present at the origin of jawed vertebrates ≈450 million years ago. A few additional opioid receptor gene duplications have occurred in bony fishes. Interestingly, the ancestral receptor gene duplications coincide with the origin of the four opioid peptide precursor genes. Thus, the complete vertebrate opioid system was already established in the first jawed vertebrates. PMID:18832151

  1. Lysophospholipid receptors in drug discovery.

    PubMed

    Kihara, Yasuyuki; Mizuno, Hirotaka; Chun, Jerold

    2015-05-01

    Lysophospholipids (LPs), including lysophosphatidic acid (LPA), sphingosine 1-phospate (S1P), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS), are bioactive lipids that transduce signals through their specific cell-surface G protein-coupled receptors, LPA1-6, S1P1-5, LPI1, and LysoPS1-3, respectively. These LPs and their receptors have been implicated in both physiological and pathophysiological processes such as autoimmune diseases, neurodegenerative diseases, fibrosis, pain, cancer, inflammation, metabolic syndrome, bone formation, fertility, organismal development, and other effects on most organ systems. Advances in the LP receptor field have enabled the development of novel small molecules targeting LP receptors for several diseases. Most notably, fingolimod (FTY720, Gilenya, Novartis), an S1P receptor modulator, became the first FDA-approved medicine as an orally bioavailable drug for treating relapsing forms of multiple sclerosis. This success is currently being followed by multiple, mechanistically related compounds targeting S1P receptor subtypes, which are in various stages of clinical development. In addition, an LPA1 antagonist, BMS-986020 (Bristol-Myers Squibb), is in Phase 2 clinical development for treating idiopathic pulmonary fibrosis, as a distinct compound, SAR100842 (Sanofi) for the treatment of systemic sclerosis and related fibrotic diseases. This review summarizes the current state of drug discovery in the LP receptor field. PMID:25499971

  2. Sigma receptors and cocaine abuse.

    PubMed

    Narayanan, Sanju; Mesangeau, Christophe; Poupaert, Jacques H; McCurdy, Christopher R

    2011-01-01

    Sigma receptors have been well documented as a protein target for cocaine and have been shown to be involved in the toxic and stimulant actions of cocaine. Strategies to reduce the access of cocaine to sigma receptors have included antisense oligonucleotides to the sigma-1 receptor protein as well as small molecule ligand with affinity for sigma receptor sites. These results have been encouraging as novel protein targets that can attenuate the actions of cocaine are desperately needed as there are currently no medications approved for treatment of cocaine toxicity or addiction. Many years of research in this area have yet to produce an effective treatment and much focus was on dopamine systems. A flurry of research has been carried out to elucidate the role of sigma receptors in the blockade of cocaine effects but this research has yet to yield a clinical agent. This review summarizes the work to date on the linkage of sigma receptors and the actions of cocaine and the progress that has been made with regard to small molecules. Although there is still a lack of an agent in clinical trials with a sigma receptor mechanism of action, work is progressing and the ligands are becoming more selective for sigma systems and the potential remains high. PMID:21050176

  3. Nuclear hormone receptors in podocytes

    PubMed Central

    2012-01-01

    Nuclear receptors are a family of ligand-activated, DNA sequence-specific transcription factors that regulate various aspects of animal development, cell proliferation, differentiation, and homeostasis. The physiological roles of nuclear receptors and their ligands have been intensively studied in cancer and metabolic syndrome. However, their role in kidney diseases is still evolving, despite their ligands being used clinically to treat renal diseases for decades. This review will discuss the progress of our understanding of the role of nuclear receptors and their ligands in kidney physiology with emphasis on their roles in treating glomerular disorders and podocyte injury repair responses. PMID:22995171

  4. Aryl hydrocarbon receptor-driven signals inhibit collagen synthesis in the gut.

    PubMed

    Monteleone, Ivan; Zorzi, Francesca; Marafini, Irene; Di Fusco, Davide; Dinallo, Vincenzo; Caruso, Roberta; Izzo, Roberta; Franzè, Eleonora; Colantoni, Alfredo; Pallone, Francesco; Monteleone, Giovanni

    2016-04-01

    Fibrostrictures (FS) are a major complication of Crohn's disease (CD). Pathogenesis of FS is not fully understood, but activation of fibroblasts and excessive collagen deposition are crucial in the development of FS. Here, we investigated the role of aryl hydrocarbon receptor (AhR) in intestinal fibrosis. AhR RNA and protein expression were evaluated in intestinal fibroblasts of CD patients and controls. CD fibroblasts were stimulated with TGF-β1 or TNF-α in the presence or absence of the AhR activator Ficz, an AhR antagonist CH223191, or a specific AhR-silencing RNA. In CD fibroblasts, TGF-β1 and TNF-α increased Col1A1, Col3A1 and α-SMA transcripts and collagen secretion and this effect was reduced by Ficz and upregulated by CH22319. TGF-β1 or TNF-α induced activation of p38 and ERK1/2 MAP kinases was decreased by Ficz and increased by CH223191. The inhibitory effect of Ficz on Map kinase activation and collagen induction was abolished by AhR silencing. To assess the role of AhR in vivo, mice with trinitrobenzene-sulfonic-acid induced colonic fibrosis were given Ficz or CH223191. Mice given either Ficz or CH223191 produced less or more collagen respectively as compared with control mice. Our results indicate that AhR is a negative regulator of profibrotic signals in the gut. PMID:26786786

  5. 3,4-methylenedioxymethamphetamine increases excitability in the dentate gyrus: role of 5HT2A receptor-induced PGE2 signaling.

    PubMed

    Collins, Stuart A; Huff, Courtney; Chiaia, Nicolas; Gudelsky, Gary A; Yamamoto, Bryan K

    2016-03-01

    3,4-methylenedioxymethamphetamine (MDMA) is a widely abused psychostimulant, which causes release of serotonin in various forebrain regions. Recently, we reported that MDMA increases extracellular glutamate concentrations in the dentate gyrus, via activation of 5HT2A receptors. We examined the role of prostaglandin signaling in mediating the effects of 5HT2A receptor activation on the increases in extracellular glutamate and the subsequent long-term loss of parvalbumin interneurons in the dentate gyrus caused by MDMA. Administration of MDMA into the dentate gyrus of rats increased PGE2 concentrations which was prevented by coadministration of MDL100907, a 5HT2A receptor antagonist. MDMA-induced increases in extracellular glutamate were inhibited by local administration of SC-51089, an inhibitor of the EP1 prostaglandin receptor. Systemic administration of SC-51089 during injections of MDMA prevented the decreases in parvalbumin interneurons observed 10 days later. The loss of parvalbumin immunoreactivity after MDMA exposure coincided with a decrease in paired-pulse inhibition and afterdischarge threshold in the dentate gyrus. These changes were prevented by inhibition of EP1 and 5HT2A receptors during MDMA. Additional experiments revealed an increased susceptibility to kainic acid-induced seizures in MDMA-treated rats, which could be prevented with SC51089 treatments during MDMA exposure. Overall, these findings suggest that 5HT2A receptors mediate MDMA-induced PGE2 signaling and subsequent increases in glutamate. This signaling mediates parvalbumin cell losses as well as physiologic changes in the dentate gyrus, suggesting that the lack of the inhibition provided by these neurons increases the excitability within the dentate gyrus of MDMA-treated rats. We hypothesized that the widely abused psychostimulant MDMA causes a loss of parvalbumin (PV) cells and increases excitability in the dentate gyrus. MDMA increases serotonin (5HT) release and activates 5HT2A

  6. Quantitative receptor radioautography in the study of receptor-receptor interactions in the nucleus tractus solitarii.

    PubMed

    Fior-Chadi, D R; Fuxe, K

    1998-02-01

    The nucleus tractus solitarii (NTS) in the dorsomedial medulla comprises a wide range of neuropeptides and biogenic amines. Several of them are related to mechanisms of central blood pressure control. Angiotensin II (Ang II), neuropeptide Y (NPY) and noradrenaline (NA) are found in the NTS cells, as well as their receptors. Based on this observation we have evaluated the modulatory effect of these peptide receptors on alpha 2-adrenoceptors in the NTS. Using quantitative receptor radioautography, we observed that NPY and Ang II receptors decreased the affinity of alpha 2-adrenoceptors for their agonists in the NTS of the rat. Cardiovascular experiments agreed with the in vitro data. Coinjection of a threshold dose of Ang II or of the NPY agonists together with an ED50 dose of adrenergic agonists such as NA, adrenaline and clonidine counteracted the depressor effect produced by the alpha 2-agonist in the NTS. The results provide evidence for the existence of an antagonistic interaction between Ang II AT1 receptors and NPY receptor subtypes with the alpha 2-adrenoceptors in the NTS. This receptor interaction may reduce the transduction over the alpha 2-adrenoceptors which can be important in central cardiovascular regulation and in the development of hypertension.

  7. Recombinant soluble adenovirus receptor

    DOEpatents

    Freimuth, Paul I.

    2002-01-01

    Disclosed are isolated polypeptides from human CAR (coxsackievirus and adenovirus receptor) protein which bind adenovirus. Specifically disclosed are amino acid sequences which corresponds to adenovirus binding domain D1 and the entire extracellular domain of human CAR protein comprising D1 and D2. In other aspects, the disclosure relates to nucleic acid sequences encoding these domains as well as expression vectors which encode the domains and bacterial cells containing such vectors. Also disclosed is an isolated fusion protein comprised of the D1 polypeptide sequence fused to a polypeptide sequence which facilitates folding of D1 into a functional, soluble domain when expressed in bacteria. The functional D1 domain finds application for example in a therapeutic method for treating a patient infected with a virus which binds to D1, and also in a method for identifying an antiviral compound which interferes with viral attachment. Also included is a method for specifically targeting a cell for infection by a virus which binds to D1.

  8. Receptor-mediated mitophagy.

    PubMed

    Yamaguchi, Osamu; Murakawa, Tomokazu; Nishida, Kazuhiko; Otsu, Kinya

    2016-06-01

    Mitochondria are essential organelles that supply ATP through oxidative phosphorylation to maintain cellular homeostasis. Extrinsic or intrinsic agents can impair mitochondria, and these impaired mitochondria can generate reactive oxygen species (ROS) as byproducts, inducing cellular damage and cell death. The quality control of mitochondria is essential for the maintenance of normal cellular functions, particularly in cardiomyocytes, because they are terminally differentiated. Accumulation of damaged mitochondria is characteristic of various diseases, including heart failure, neurodegenerative disease, and aging-related diseases. Mitochondria are generally degraded through autophagy, an intracellular degradation system that is conserved from yeast to mammals. Autophagy is thought to be a nonselective degradation process in which cytoplasmic proteins and organelles are engulfed by isolation membrane to form autophagosomes in eukaryotic cells. However, recent studies have described the process of selective autophagy, which targets specific proteins or organelles such as mitochondria. Mitochondria-specific autophagy is called mitophagy. Dysregulation of mitophagy is implicated in the development of chronic diseases including neurodegenerative diseases, metabolic diseases, and heart failure. In this review, we discuss recent progress in research on mitophagy receptors. PMID:27021519

  9. Selective Estrogen Receptor Modulators.

    PubMed

    An, Ki-Chan

    2016-08-01

    Selective estrogen receptor modulators (SERMs) are now being used as a treatment for breast cancer, osteoporosis and postmenopausal symptoms, as these drugs have features that can act as an estrogen agonist and an antagonist, depending on the target tissue. After tamoxifen, raloxifene, lasofoxifene and bazedoxifene SERMs have been developed and used for treatment. The clinically decisive difference among these drugs (i.e., the key difference) is their endometrial safety. Compared to bisphosphonate drug formulations for osteoporosis, SERMs are to be used primarily in postmenopausal women of younger age and are particularly recommended if there is a family history of invasive breast cancer, as their use greatly reduces the incidence of this type of cancer in women. Among the above mentioned SERMs, raloxifene has been widely used in prevention and treatment of postmenopausal osteoporosis and vertebral compression fractures, and clinical studies are now underway to test the comparative advantages of raloxifene with those of bazedoxifene, a more recently developed SERM. Research on a number of adverse side effects of SERM agents is being performed to determine the long-term safety of this class of compouds for treatment of osteoporosis. PMID:27559463

  10. Purinergic nerves and receptors.

    PubMed

    Burnstock, G

    1980-01-01

    The presence of a non-cholinergic, non-adrenergic component in the vertebrate autonomic nervous system is now well established. Evidence that ATP is the transmitter released from some of these nerves (called "purinergic') includes: (a) synthesis and storage of ATP in nerves: (b) release of ATP from the nerves when they are stimulated; (c) exogenously applied ATP mimicking the action of nerve-released transmitter; (d) the presence of ectoenzymes which inactivate ATP; (e) drugs which produce similar blocking or potentiating effects on the response to exogenously applied ATP and nerve stimulation. A basis for distinguishing two types of purinergic receptors has been proposed according to four criteria: relative potencies of agonists, competitive antagonists, changes in levels of cAMP and induction of prostaglandin synthesis. Thus P1 purinoceptors are most sensitive to adenosine, are competitively blocked by methylxanthines and their occupation leads to changes in cAMP accumulation; while P2 purinoceptors are most sensitive to ATP, are blocked (although not competitively) by quinidine, 2-substituted imidazolines, 2,2'-pyridylisatogen and apamin, and their occupation leads to production of prostaglandin. P2 purinoceptors mediate responses of smooth muscle to ATP released from purinergic nerves, while P1 purinoceptors mediate the presynaptic actions of adenosine on adrenergic, cholinergic and purinergic nerve terminals. PMID:6108568

  11. NMDA receptor antibodies

    PubMed Central

    Ramberger, Melanie; Bsteh, Gabriel; Schanda, Kathrin; Höftberger, Romana; Rostásy, Kevin; Baumann, Matthias; Aboulenein-Djamshidian, Fahmy; Lutterotti, Andreas; Deisenhammer, Florian; Berger, Thomas

    2015-01-01

    Objectives: To analyze the frequency of NMDA receptor (NMDAR) antibodies in patients with various inflammatory demyelinating diseases of the CNS and to determine their clinical correlates. Methods: Retrospective case-control study from 2005 to 2014 with the detection of serum IgG antibodies to NMDAR, aquaporin-4, and myelin oligodendrocyte glycoprotein by recombinant live cell-based immunofluorescence assays. Fifty-one patients with acute disseminated encephalomyelitis, 41 with neuromyelitis optica spectrum disorders, 34 with clinically isolated syndrome, and 89 with multiple sclerosis (MS) were included. Due to a known association of NMDAR antibodies with seizures and behavioral symptoms, patients with those clinical manifestations were preferentially included and are therefore overrepresented in our cohort. Nine patients with NMDAR encephalitis, 94 patients with other neurologic diseases, and 48 healthy individuals were used as controls. Results: NMDAR antibodies were found in all 9 patients with NMDAR encephalitis but in only 1 of 215 (0.5%) patients with inflammatory demyelination and in none of the controls. This patient had relapsing-remitting MS with NMDAR antibodies present at disease onset, with an increase in NMDAR antibody titer with the onset of psychiatric symptoms and cognitive deficits. Conclusion: In demyelinating disorders, NMDAR antibodies are uncommon, even in those with symptoms seen in NMDAR encephalitis. PMID:26309901

  12. Estrogen receptors and endothelium.

    PubMed

    Arnal, Jean-François; Fontaine, Coralie; Billon-Galés, Audrey; Favre, Julie; Laurell, Henrik; Lenfant, Françoise; Gourdy, Pierre

    2010-08-01

    Estrogens, and in particular 17beta-estradiol (E2), play a pivotal role in sexual development and reproduction and are also implicated in a large number of physiological processes, including the cardiovascular system. Both acetylcholine-induced and flow-dependent vasodilation are preserved or potentiated by estrogen treatment in both animal models and humans. Indeed, E2 increases the endothelial production of nitric oxide and prostacyclin and prevents early atheroma through endothelial-mediated mechanisms. Furthermore, whereas it prevents endothelial activation, E2 potentiates the ability of several subpopulations of the circulating or resident immune cells to produce proinflammatory cytokines. The balance between these 2 actions could determine the final effect in a given pathophysiological process. E2 also promotes endothelial healing, as well as angiogenesis. Estrogen actions are essentially mediated by 2 molecular targets: estrogen receptor-alpha (ERalpha) and ERbeta. The analysis of mouse models targeted for ERalpha or ERbeta demonstrated a prominent role of ERalpha in vascular biology. ERalpha directly modulates transcription of target genes through 2 activation functions (AFs), AF-1 and AF-2. Interestingly, an AF-1-deficient ERalpha isoform can be physiologically expressed in the endothelium and appears sufficient to mediate most of the vasculoprotective actions of E2. In contrast, AF-1 is necessary for the E2 actions in reproductive targets. Thus, it appears conceivable to uncouple the vasculoprotective and sexual actions with appropriate selective ER modulators. PMID:20631350

  13. Selective Estrogen Receptor Modulators

    PubMed Central

    2016-01-01

    Selective estrogen receptor modulators (SERMs) are now being used as a treatment for breast cancer, osteoporosis and postmenopausal symptoms, as these drugs have features that can act as an estrogen agonist and an antagonist, depending on the target tissue. After tamoxifen, raloxifene, lasofoxifene and bazedoxifene SERMs have been developed and used for treatment. The clinically decisive difference among these drugs (i.e., the key difference) is their endometrial safety. Compared to bisphosphonate drug formulations for osteoporosis, SERMs are to be used primarily in postmenopausal women of younger age and are particularly recommended if there is a family history of invasive breast cancer, as their use greatly reduces the incidence of this type of cancer in women. Among the above mentioned SERMs, raloxifene has been widely used in prevention and treatment of postmenopausal osteoporosis and vertebral compression fractures, and clinical studies are now underway to test the comparative advantages of raloxifene with those of bazedoxifene, a more recently developed SERM. Research on a number of adverse side effects of SERM agents is being performed to determine the long-term safety of this class of compouds for treatment of osteoporosis. PMID:27559463

  14. Nicotinic receptors and Alzheimer's disease.

    PubMed

    Bourin, Michel; Ripoll, Nadège; Dailly, Eric

    2003-01-01

    Nicotinic receptors (NRs) belong to the group of polymeric receptors of the cell membrane and are key elements of cholinergic transmission. Numerous subtypes of NRs exist with the alpha 4 beta 2 and alpha 7 types being encountered most frequently. Deficiencies in NRs seem to play a role in Alzheimer's disease, which is characterised by accumulation of senile plaques, mainly composed of beta-amyloid peptide (beta A). Although the aetiology of this disease is unknown, different pathogenesis hypotheses implicating alpha 7 NRs have been proposed, with the receptors exerting a direct or indirect action on the mechanism of beta A toxicity. Allosteric modulators of NRs, such as the cholinesterase inhibitor galantamine, that facilitate the action of acetylcholine on these receptors may provide therapeutic benefits in the areas of cognition, attention and antineurodegenerative activity.

  15. Receptor-targeted metalloradiopharmaceuticals. Final technical report

    SciTech Connect

    Green, Mark A.

    2000-03-22

    Copper (II) and platinum (II) coordination complexes were prepared and characterized. These complexes were designed to afford structural homology with steroidal and non-steroidal estrogens for possible use as receptor-targeted radiopharmaceuticals. While weak affinity for the estrogen receptor was detectable, none would appear to have sufficient receptor-affinity for estrogen-receptor-targeted imaging or therapy.

  16. L-glutamate Receptor In Paramecium

    NASA Astrophysics Data System (ADS)

    Bernal-Martínez, Juan; Ortega-Soto, Arturo

    2004-09-01

    Behavioral, electrophysiological and biochemical experiments were performed in order to establish the presence of a glutamate receptor in the ciliate Paramecium. It was found that an AMPA/KA receptor is functionally expressed in Paramecium and that this receptor is immunologically and fillogenetically related to the AMPA/KA receptor present in vertebrates.

  17. Cellular receptors and HCV entry.

    PubMed

    Flint, Mike; Tscherne, Donna M

    2009-01-01

    After attachment to specific receptors on the surfaces of target cells, hepatitis C virus (HCV) particles are thought to be internalized to endosomes, where low pH induces fusion between the viral and cellular membranes, delivering the HCV genome into the cytoplasm. Here, we describe methods to study the early events in HCV infection; the interactions with cellular receptors and the mechanism of entry.

  18. [Pathologic manifestations of hormonal receptor mutations].

    PubMed

    Milgrom, E

    2000-01-01

    Mutations of receptor genes are involved in various aspects of thyroid and gonadal pathology. Activating mutations of TSH and LH receptors are associated with hyperthyroidism and premature puberty. These mutations are dominant and lead to the synthesis of a constitutive receptor, i.e. a receptor active even in the absence of hormone. Inactivating mutations of TSH, gonadotropin and GnRH receptors are recessive. They determine either a hypothyroidism or a hypogonadism. In the case of alterations of gonadotropin receptors the hypogonadism is hypergonadotrophic. It is hypogonadotrophic in the case of mutations of the GnRH receptor. PMID:10989556

  19. Nuclear Receptors, RXR, and the Big Bang.

    PubMed

    Evans, Ronald M; Mangelsdorf, David J

    2014-03-27

    Isolation of genes encoding the receptors for steroids, retinoids, vitamin D, and thyroid hormone and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors and, in particular, of the retinoid X receptor (RXR) positioned nuclear receptors at the epicenter of the "Big Bang" of molecular endocrinology. This Review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multicellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism.

  20. Nuclear Receptors, RXR & the Big Bang

    PubMed Central

    Evans, Ronald M.; Mangelsdorf, David J.

    2014-01-01

    Summary Isolation of genes encoding the receptors for steroids, retinoids, vitamin D and thyroid hormone, and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors, and in particular of the retinoid X receptor (RXR), positioned nuclear receptors at the epicenter of the “Big Bang” of molecular endocrinology. This review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multi-cellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism. PMID:24679540

  1. Nuclear Receptors, RXR, and the Big Bang.

    PubMed

    Evans, Ronald M; Mangelsdorf, David J

    2014-03-27

    Isolation of genes encoding the receptors for steroids, retinoids, vitamin D, and thyroid hormone and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors and, in particular, of the retinoid X receptor (RXR) positioned nuclear receptors at the epicenter of the "Big Bang" of molecular endocrinology. This Review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multicellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism. PMID:24679540

  2. Farnesoid X Receptor Protects against Kidney Injury in Uninephrectomized Obese Mice.

    PubMed

    Gai, Zhibo; Gui, Ting; Hiller, Christian; Kullak-Ublick, Gerd A

    2016-01-29

    Activation of the farnesoid X receptor (FXR) has indicated a therapeutic potential for this nuclear bile acid receptor in the prevention of diabetic nephropathy and obesity-induced renal damage. Here, we investigated the protective role of FXR against kidney damage induced by obesity in mice that had undergone uninephrectomy, a model resembling the clinical situation of kidney donation by obese individuals. Mice fed a high-fat diet developed the core features of metabolic syndrome, with subsequent renal lipid accumulation and renal injury, including glomerulosclerosis, interstitial fibrosis, and albuminuria. The effects were accentuated by uninephrectomy. In human renal biopsies, staining of 4-hydroxynonenal (4-HNE), glucose-regulated protein 78 (Grp78), and C/EBP-homologous protein, markers of endoplasmic reticulum stress, was more prominent in the proximal tubules of 15 obese patients compared with 16 non-obese patients. In mice treated with the FXR agonist obeticholic acid, renal injury, renal lipid accumulation, apoptosis, and changes in lipid peroxidation were attenuated. Moreover, disturbed mitochondrial function was ameliorated and the mitochondrial respiratory chain recovered following obeticholic acid treatment. Culturing renal proximal tubular cells with free fatty acid and FXR agonists showed that FXR activation protected cells from free fatty acid-induced oxidative stress and endoplasmic reticulum stress, as denoted by a reduction in the level of reactive oxygen species staining and Grp78 immunostaining, respectively. Several genes involved in glutathione metabolism were induced by FXR activation in the remnant kidney, which was consistent with a decreased glutathione disulfide/glutathione ratio. In summary, FXR activation maintains endogenous glutathione homeostasis and protects the kidney in uninephrectomized mice from obesity-induced injury.

  3. Antinociceptive activity of NK1 receptor antagonists: non-specific effects of racemic RP67580.

    PubMed Central

    Rupniak, N. M.; Boyce, S.; Williams, A. R.; Cook, G.; Longmore, J.; Seabrook, G. R.; Caeser, M.; Iversen, S. D.; Hill, R. G.

    1993-01-01

    1. Release of substance P in the dorsal horn is considered a primary event in the perception of pain. The profile of racemic RP67580, a non-peptide antagonist at the NK1 (substance P) receptor, was examined in a range of antinociception tests on rodents. 2. At doses up to 30 mg kg-1, s.c. racemic RP67580 exhibited antinociceptive activity in writhing and formalin paw tests in mice and gerbils. Acetic acid induced writhing and the licking response to formalin were reduced to 40-50% of the level observed in vehicle-treated animals (P < 0.05). However, this agent was not active in mouse tail flick, rat paw pressure or rat and guinea-pig formalin paw tests. 3. Like racemic RP67580, the calcium channel blockers nifedipine (30 mg kg-1, i.p.) and verapamil (10 or 20 mg kg-1, s.c.) inhibited the response to formalin by approximately 60% in gerbils (P < 0.05 compared with vehicle-treated animals). 4. Evidence for calcium channel antagonist activity of RP67580 was obtained in vitro. Racemic RP67580 inhibited calcium entry into depolarized strips of guinea-pig ileum longitudinal muscle myenteric plexus (apparent KB = 587 +/- 115 nM), inhibited [3H]-diltiazem binding to rabbit skeletal membranes (IC50 = 298 nM) and depressed high threshold calcium currents in neurones cultured from rat cortex (10% inhibition at 10 microM). 5. These findings indicate that the acute antinociceptive effects of RP67580 may not be attributable to a specific interaction with NK1 receptors and may be mediated via calcium channel blockade. PMID:8306108

  4. Nicotinic receptors and attention.

    PubMed

    Hahn, Britta

    2015-01-01

    Facilitation of different attentional functions by nicotinic acetylcholine receptor (nAChR) agonists may be of therapeutic potential in disease conditions such as Alzheimer's disease or schizophrenia. For this reason, the neuronal mechanisms underlying these effects have been the focus of research in humans and in preclinical models. Attention-enhancing effects of the nonselective nAChR agonist nicotine can be observed in human nonsmokers and in laboratory animals, suggesting that benefits go beyond a reversal of withdrawal deficits in smokers. The ultimate aim is to develop compounds acting with greater selectivity than nicotine at a subset of nAChRs, with an effects profile narrowly matching the targeted cognitive deficits and minimizing unwanted effects. To date, compounds tested clinically target the nAChR subtypes most abundant in the brain. To help pinpoint more selectively expressed subtypes critical for attention, studies have aimed at identifying the secondary neurotransmitter systems whose stimulation mediates the attention-enhancing properties of nicotine. Evidence indicates that noradrenaline and glutamate, but not dopamine release, are critical mediators. Thus, attention-enhancing nAChR agents could spare the system central to nicotine dependence. Neuroimaging studies suggest that nAChR agonists act on a variety of brain systems by enhancing activation, reducing activation, and enhancing deactivation by attention tasks. This supports the notion that effects on different attentional functions may be mediated by distinct central mechanisms, consistent with the fact that nAChRs interact with a multitude of brain sites and neurotransmitter systems. The challenge will be to achieve the optimal tone at the right subset of nAChR subtypes to modulate specific attentional functions, employing not just direct agonist properties, but also positive allosteric modulation and low-dose antagonism.

  5. Gravity receptors and responses

    NASA Technical Reports Server (NTRS)

    Brown, Allan H.

    1989-01-01

    The overall process of gravity sensing and response processes in plants may be divided conveniently into at least four components or stages: Stimulus susception (a physical event, characteristically the input to the G receptor system of environmental information about the G force magnitude, its vector direction, or both); information perception (an influence of susception on some biological structure or process that can be described as the transformation of environmental information into a biologicallly meaningful change); information transport (the export, if required, of an influence (often chemical) to cells and organs other than those at the sensor location); and biological response (almost always (in plants) a growth change of some kind). Some analysts of the process identify, between information perception and information transport, an additional stage, transduction, which would emphasize the importance of a transformation from one form of information to another, for example from mechanical statolith displacement to an electric, chemical, or other alteration that was its indirect result. These four (or five) stages are temporally sequential. Even if all that occurs at each stage can not be confidently identified, it seems evident that during transduction and transport, matters dealt with are found relatively late in the information flow rather than at the perception stage. As more and more is learned about the roles played by plant hormones which condition the G responses, the mechanism(s) of perception which should be are not necessarily better understood. However, if by asking the right questions and being lucky with experiments perhaps the discovery of how some process (such as sedimentation of protoplasmic organelles) dictates what happens down stream in the information flow sequence may be made.

  6. Phenobarbital and Insulin Reciprocate Activation of the Nuclear Receptor Constitutive Androstane Receptor through the Insulin Receptor

    PubMed Central

    Yasujima, Tomoya; Saito, Kosuke; Moore, Rick

    2016-01-01

    Phenobarbital (PB) antagonized insulin to inactivate the insulin receptor and attenuated the insulin receptor downstream protein kinase B (AKT)–forkhead box protein O1 and extracellular signal-regulated kinase 1/2 signals in mouse primary hepatocytes and HepG2 cells. Hepatic AKT began dephosphorylation in an early stage of PB treatment, and blood glucose levels transiently increased in both wild-type and constitutive androstane receptor (CAR) knockout (KO) mice. On the other hand, blood glucose levels increased in wild-type mice, but not KO mice, in later stages of PB treatment. As a result, PB, acting as an insulin receptor antagonist, elicited CAR-independent increases and CAR-dependent decreases of blood glucose levels at these different stages of treatment, respectively. Reciprocally, insulin activation of the insulin receptor repressed CAR activation and induction of its target CYP2B6 gene in HepG2 cells. Thus, PB and insulin cross-talk through the insulin receptor to regulate glucose and drug metabolism reciprocally. PMID:26994072

  7. Phenobarbital and Insulin Reciprocate Activation of the Nuclear Receptor Constitutive Androstane Receptor through the Insulin Receptor.

    PubMed

    Yasujima, Tomoya; Saito, Kosuke; Moore, Rick; Negishi, Masahiko

    2016-05-01

    Phenobarbital (PB) antagonized insulin to inactivate the insulin receptor and attenuated the insulin receptor downstream protein kinase B (AKT)-forkhead box protein O1 and extracellular signal-regulated kinase 1/2 signals in mouse primary hepatocytes and HepG2 cells. Hepatic AKT began dephosphorylation in an early stage of PB treatment, and blood glucose levels transiently increased in both wild-type and constitutive androstane receptor (CAR) knockout (KO) mice. On the other hand, blood glucose levels increased in wild-type mice, but not KO mice, in later stages of PB treatment. As a result, PB, acting as an insulin receptor antagonist, elicited CAR-independent increases and CAR-dependent decreases of blood glucose levels at these different stages of treatment, respectively. Reciprocally, insulin activation of the insulin receptor repressed CAR activation and induction of its target CYP2B6 gene in HepG2 cells. Thus, PB and insulin cross-talk through the insulin receptor to regulate glucose and drug metabolism reciprocally.

  8. Proteinase-activated receptors (PARs) – focus on receptor-receptor-interactions and their physiological and pathophysiological impact

    PubMed Central

    2013-01-01

    Proteinase-activated receptors (PARs) are a subfamily of G protein-coupled receptors (GPCRs) with four members, PAR1, PAR2, PAR3 and PAR4, playing critical functions in hemostasis, thrombosis, embryonic development, wound healing, inflammation and cancer progression. PARs are characterized by a unique activation mechanism involving receptor cleavage by different proteinases at specific sites within the extracellular amino-terminus and the exposure of amino-terminal “tethered ligand“ domains that bind to and activate the cleaved receptors. After activation, the PAR family members are able to stimulate complex intracellular signalling networks via classical G protein-mediated pathways and beta-arrestin signalling. In addition, different receptor crosstalk mechanisms critically contribute to a high diversity of PAR signal transduction and receptor-trafficking processes that result in multiple physiological effects. In this review, we summarize current information about PAR-initiated physical and functional receptor interactions and their physiological and pathological roles. We focus especially on PAR homo- and heterodimerization, transactivation of receptor tyrosine kinases (RTKs) and receptor serine/threonine kinases (RSTKs), communication with other GPCRs, toll-like receptors and NOD-like receptors, ion channel receptors, and on PAR association with cargo receptors. In addition, we discuss the suitability of these receptor interaction mechanisms as targets for modulating PAR signalling in disease. PMID:24215724

  9. Radiopharmaceuticals for somatostatin receptor imaging.

    PubMed

    Mikołajczak, Renata; Maecke, Helmut R

    2016-01-01

    The aim of this review is to summarize the developments and briefly characterize the somatostatin analogs which are currently used for somatostatin receptor imaging in clinical routine or in early phase clinical trials. Somatostatin (sst) receptor targeting with radiolabeled peptides has become an integral part in nuclear oncology during the last 20 years. This integration process has been initiated in Europe with the introduction to the market of 111In-DTPA-DPhe1-octreotide [111In-pentetreotide]. Introducing 99mTc in somatostatin receptor targeting radiopeptides resulted in much better image quality, higher sensitivity of tumor detection and lower mean effective dose for the examined patient. The next generation are 68Ga labeled somatostatin analogs. Due to the spatial resolution of PET technique and increasing number of PET scanners, the PET or PET/CT technique became very important in somatostatin receptor imaging. Until up to a couple of years ago the analogs of somatostatin were constructed aiming at their agonistic behavior, expecting that their internalization with the receptor acti-vated by the radiolabeled ligand and its retention within the tumor cell are crucial for efficient imaging and therapy. Recently it has been shown that the antagonists recognize more binding sites at the tumor cell membrane and hence offer an improved diagnostic efficacy, especially when the density of sst receptors is low. This approach may in future improve diagnostic value of somatostatin receptor imaging techniques. The developments in tracer design are followed by the improvements in imaging techniques. The new SPECT scanners offer resolution close to that of PET, which might open a new era for 99mTc and other SPECT radiotracers. PMID:27479790

  10. Scavenger receptor class B type I: a multifunctional receptor.

    PubMed

    Valacchi, Giuseppe; Sticozzi, Claudia; Lim, Yunsook; Pecorelli, Alessandra

    2011-07-01

    The scavenger receptor class B type I (SR-B1) plays an important role in meditating the uptake of HDL-derived cholesterol and cholesteryl ester in the liver and steroidogenic tissues. In addition to being ubiquitous, SR-B1 is a high-density lipoprotein (HDL) receptor in many tissues, though the mechanism by which SR-B1 does this is unclear. Other than its role as an HDL receptor, SR-B1 is also involved in pathogen recognition; its expression can be modulated by lipopolysaccharide and oxidative stress; and it plays a significant role in the uptake of lipid soluble vitamins, such as vitamin E and carotenoids. In this short review, we have summarized the biological aspects to which SR-B1 has been thus far associated.

  11. Transferrin Receptor Controls AMPA Receptor Trafficking Efficiency and Synaptic Plasticity

    PubMed Central

    Liu, Ke; Lei, Run; Li, Qiong; Wang, Xin-Xin; Wu, Qian; An, Peng; Zhang, Jianchao; Zhu, Minyan; Xu, Zhiheng; Hong, Yang; Wang, Fudi; Shen, Ying; Li, Hongchang; Li, Huashun

    2016-01-01

    Transferrin receptor (TFR) is an important iron transporter regulating iron homeostasis and has long been used as a marker for clathrin mediated endocytosis. However, little is known about its additional function other than iron transport in the development of central nervous system (CNS). Here we demonstrate that TFR functions as a regulator to control AMPA receptor trafficking efficiency and synaptic plasticity. The conditional knockout (KO) of TFR in neural progenitor cells causes mice to develop progressive epileptic seizure, and dramatically reduces basal synaptic transmission and long-term potentiation (LTP). We further demonstrate that TFR KO remarkably reduces the binding efficiency of GluR2 to AP2 and subsequently decreases AMPA receptor endocytosis and recycling. Thus, our study reveals that TFR functions as a novel regulator to control AMPA trafficking efficiency and synaptic plasticity. PMID:26880306

  12. Ionotropic Glutamate Receptors & CNS Disorders

    PubMed Central

    Bowie, Derek

    2008-01-01

    Disorders of the central nervous system (CNS) are complex disease states that represent a major challenge for modern medicine. Although etiology is often unknown, it is established that multiple factors such as defects in genetics and/or epigenetics, the environment as well as imbalance in neurotransmitter receptor systems are all at play in determining an individual’s susceptibility to disease. Gene therapy is currently not available and therefore, most conditions are treated with pharmacological agents that modify neurotransmitter receptor signaling. Here, I provide a review of ionotropic glutamate receptors (iGluRs) and the roles they fulfill in numerous CNS disorders. Specifically, I argue that our understanding of iGluRs has reached a critical turning point to permit, for the first time, a comprehensive re-evaluation of their role in the cause of disease. I illustrate this by highlighting how defects in AMPA receptor trafficking are important to Fragile X mental retardation and ectopic expression of kainate (KA) receptor synapses contributes to the pathology of temporal lobe epilepsy. Finally, I discuss how parallel advances in studies of other neurotransmitter systems may allow pharmacologists to work towards a cure for many CNS disorders rather than developing drugs to treat their symptoms. PMID:18537642

  13. Biased signaling at chemokine receptors.

    PubMed

    Corbisier, Jenny; Galès, Céline; Huszagh, Alexandre; Parmentier, Marc; Springael, Jean-Yves

    2015-04-10

    The ability of G protein-coupled receptors (GPCRs) to activate selective signaling pathways according to the conformation stabilized by bound ligands (signaling bias) is a challenging concept in the GPCR field. Signaling bias has been documented for several GPCRs, including chemokine receptors. However, most of these studies examined the global signaling bias between G protein- and arrestin-dependent pathways, leaving unaddressed the potential bias between particular G protein subtypes. Here, we investigated the coupling selectivity of chemokine receptors CCR2, CCR5, and CCR7 in response to various ligands with G protein subtypes by using bioluminescence resonance energy transfer biosensors monitoring directly the activation of G proteins. We also compared data obtained with the G protein biosensors with those obtained with other functional readouts, such as β-arrestin-2 recruitment, cAMP accumulation, and calcium mobilization assays. We showed that the binding of chemokines to CCR2, CCR5, and CCR7 activated the three Gαi subtypes (Gαi1, Gαi2, and Gαi3) and the two Gαo isoforms (Gαoa and Gαob) with potencies that generally correlate to their binding affinities. In addition, we showed that the binding of chemokines to CCR5 and CCR2 also activated Gα12, but not Gα13. For each receptor, we showed that the relative potency of various agonist chemokines was not identical in all assays, supporting the notion that signaling bias exists at chemokine receptors.

  14. Purinergic Receptors in Ocular Inflammation

    PubMed Central

    Guzman-Aranguez, Ana; Gasull, Xavier; Diebold, Yolanda; Pintor, Jesús

    2014-01-01

    Inflammation is a complex process that implies the interaction between cells and molecular mediators, which, when not properly “tuned,” can lead to disease. When inflammation affects the eye, it can produce severe disorders affecting the superficial and internal parts of the visual organ. The nucleoside adenosine and nucleotides including adenine mononucleotides like ADP and ATP and dinucleotides such as P1,P4-diadenosine tetraphosphate (Ap4A), and P1,P5-diadenosine pentaphosphate (Ap5A) are present in different ocular locations and therefore they may contribute/modulate inflammatory processes. Adenosine receptors, in particular A2A adenosine receptors, present anti-inflammatory action in acute and chronic retinal inflammation. Regarding the A3 receptor, selective agonists like N6-(3-iodobenzyl)-5′-N-methylcarboxamidoadenosine (CF101) have been used for the treatment of inflammatory ophthalmic diseases such as dry eye and uveoretinitis. Sideways, diverse stimuli (sensory stimulation, large intraocular pressure increases) can produce a release of ATP from ocular sensory innervation or after injury to ocular tissues. Then, ATP will activate purinergic P2 receptors present in sensory nerve endings, the iris, the ciliary body, or other tissues surrounding the anterior chamber of the eye to produce uveitis/endophthalmitis. In summary, adenosine and nucleotides can activate receptors in ocular structures susceptible to suffer from inflammatory processes. This involvement suggests the possible use of purinergic agonists and antagonists as therapeutic targets for ocular inflammation. PMID:25132732

  15. Identification and mechanism of ABA receptor antagonism

    SciTech Connect

    Melcher, Karsten; Xu, Yong; Ng, Ley-Moy; Zhou, X. Edward; Soon, Fen-Fen; Chinnusamy, Viswanathan; Suino-Powell, Kelly M; Kovach, Amanda; Tham, Fook S.; Cutler, Sean R.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Xu, H. Eric

    2010-11-11

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands.

  16. Involvement of opioid receptors in the systemic and peripheral antinociceptive actions of montelukast in the animal models of pain.

    PubMed

    Ghorbanzadeh, Behnam; Mansouri, Mohammad Taghi; Sahraei, Hedayat; Alboghobeish, Soheila

    2016-05-15

    This study aimed to investigate the involvement of opioid receptors in the systemic and peripheral antinociceptive activities of montelukast in different animal models of pain. Rats and mice were injected with montelukast to produce analgesia. The formalin and acetic acid-induced writhing tests were used to assess the nociceptive activity. The results showed that i.p. administration of montelukast (0.3-10mg/kg) dose-dependently reduced flinching behavior in both the first and second phases of formalin test with mean ED50 of 0.55 and 5.31mg/kg, respectively. Also, intraplantar administration of montelukast (3-30μg/paw) produced antinociception against the two phases of formalin assay in a dose-dependent way with mean ED30 of 2.92 and 8.11μg/paw, respectively. Furthermore, pre-treatment with naloxone (a non-selective opioid receptor antagonist) significantly inhibited both the systemic and also peripheral antinociceptive actions of montelukast in formalin test. In writhing test, the results showed that intraperitoneal administration of montelukast (3-10mg/kg) significantly reduced the writhe number induced by acetic acid in mice. Moreover, co-administration of non-effective doses of montelukast (0.3 and 1mg/kg; i.p.) and morphine (0.25mg/kg; i.p.) significantly decreased the writhes number induced by acetic acid. Also, this effect was naloxone-reversible. These findings suggest that the systemic and peripheral antinociception produced by montelukast were mediated through the opioid receptors in central and peripheral nervous systems. Moreover, combination of montelukast and morphine could be noted as a new strategy for pain relief. PMID:26948314

  17. Chimeric, mutant orexin receptors show key interactions between orexin receptors, peptides and antagonists.

    PubMed

    Tran, Da-Thao; Bonaventure, Pascal; Hack, Michael; Mirzadegan, Taraneh; Dvorak, Curt; Letavic, Michael; Carruthers, Nicholas; Lovenberg, Timothy; Sutton, Steven W

    2011-09-30

    Orexin receptor antagonists are being investigated as therapeutic agents for insomnia and addictive disorders. In this study the interactions between the orexin receptors (orexin 1 receptor and orexin 2 receptor), orexin peptides, and small molecule orexin antagonists were explored. To study these phenomena, a variety of mutant orexin receptors was made and tested using receptor binding and functional assays. Domains of the two orexin receptors were exchanged to show the critical ligand binding domains for orexin peptides and representative selective orexin receptor antagonists. Results from domain exchanges between the orexin receptors suggest that transmembrane domain 3 is crucially important for receptor interactions with small molecule antagonists. These data also suggest that the orexin peptides occupy a larger footprint, interacting with transmembrane domain 1, the amino terminus and transmembrane domain 5 as well as transmembrane domain 3. Transmembrane domain 3 has been shown to be an important part of the small molecule binding pocket common to rhodopsin and β2-adrenergic receptors. Additional orexin receptor 2 point mutations were made based on the common arrangement of receptor transmembrane domains shown in the G-protein coupled receptor crystal structure literature and the impact of orexin 2 receptor residue threonine 135 on the ligand selectivity of the 2 orexin receptors. These data support a model of the orexin receptor binding pocket in which transmembrane domains 3 and 5 are prominent contributors to ligand binding and functional activity. The data also illustrate key contact points for ligand interactions in the consensus small molecule pocket of these receptors.

  18. 5-Hydroxytryptamine type 7 receptor neuroprotection against NMDA-induced excitotoxicity is PDGFβ receptor dependent.

    PubMed

    Vasefi, Maryam S; Kruk, Jeff S; Heikkila, John J; Beazely, Michael A

    2013-04-01

    The serotonin (5-HT) type 7 receptor is expressed throughout the CNS including the hippocampus. Long-term (2-24 h) activation of 5-HT7 receptors regulates growth factor receptor expression, including the expression of platelet-derived growth factor (PDGF) β receptors. Direct activation of PDGFβ receptors in primary hippocampal and cortical neurons inhibits NMDA receptor activity and attenuates NMDA receptor-induced neurotoxicity. Our objective was to investigate whether the 5-HT7 receptor-induced increase in PDGFβ receptor expression would be similarly neuroprotective. We demonstrate that 5-HT7 receptor agonist treatment in primary hippocampal neurons also increases the expression of phospholipase C (PLC) γ, a downstream effector of PDGFβ receptors associated with the inhibition of NMDA receptor activity. To determine if the up-regulation of PDGFβ receptors is neuroprotective, primary hippocampal neurons were incubated with the 5-HT7 receptor agonist, LP 12, for 24 h. Indeed, LP 12 treatment prevented NMDA-induced neurotoxicity and this effect was dependent on PDGFβ receptor kinase activity. Treatment of primary neurons with LP 12 also differentially altered NMDA receptor subunit expression, reducing the expression of NR1 and NR2B, but not NR2A. These findings demonstrate the potential for providing growth factor receptor-dependent neuroprotective effects using small-molecule ligands of G protein-coupled receptors.

  19. Signaling from Axon Guidance Receptors

    PubMed Central

    Bashaw, Greg J.; Klein, Rüdiger

    2010-01-01

    Determining how axon guidance receptors transmit signals to allow precise pathfinding decisions is fundamental to our understanding of nervous system development and may suggest new strategies to promote axon regeneration after injury or disease. Signaling mechanisms that act downstream of four prominent families of axon guidance cues—netrins, semaphorins, ephrins, and slits—have been extensively studied in both invertebrate and vertebrate model systems. Although details of these signaling mechanisms are still fragmentary and there appears to be considerable diversity in how different guidance receptors regulate the motility of the axonal growth cone, a number of common themes have emerged. Here, we review recent insights into how specific receptors for each of these guidance cues engage downstream regulators of the growth cone cytoskeleton to control axon guidance. PMID:20452961

  20. Monoallelic Expression of Olfactory Receptors

    PubMed Central

    Monahan, Kevin; Lomvardas, Stavros

    2016-01-01

    The sense of smell collects vital information about the environment by detecting a multitude of chemical odorants. Breadth and sensitivity are provided by a huge number of chemosensory receptor proteins, including more than 1,400 olfactory receptors (ORs). Organizing the sensory information generated by these receptors so that it can be processed and evaluated by the central nervous system is a major challenge. This challenge is overcome by monogenic and monoallelic expression of OR genes. The single OR expressed by each olfactory sensory neuron determines the neuron’s odor sensitivity and the axonal connections it will make to downstream neurons in the olfactory bulb. The expression of a single OR per neuron is accomplished by coupling a slow chromatin-mediated activation process to a fast negative-feedback signal that prevents activation of additional ORs. Singular OR activation is likely orchestrated by a network of interchromosomal enhancer interactions and large-scale changes in nuclear architecture. PMID:26359778

  1. Cannabinoids, cannabinoid receptors and tinnitus.

    PubMed

    Smith, Paul F; Zheng, Yiwen

    2016-02-01

    One hypothesis suggests that tinnitus is a form of sensory epilepsy, arising partly from neuronal hyperactivity in auditory regions of the brain such as the cochlear nucleus and inferior colliculus. Although there is currently no effective drug treatment for tinnitus, anti-epileptic drugs are used in some cases as a potential treatment option. There is increasing evidence to suggest that cannabinoid drugs, i.e. cannabinoid receptor agonists, can also have anti-epileptic effects, at least in some cases and in some parts of the brain. It has been reported that cannabinoid CB1 receptors and the endogenous cannabinoid, 2-arachidonylglycerol (2-AG), are expressed in the cochlear nucleus and that they are involved in the regulation of plasticity. This review explores the question of whether cannabinoid receptor agonists are likely to be pro- or anti-epileptic in the cochlear nucleus and therefore whether cannabinoids and Cannabis itself are likely to make tinnitus better or worse.

  2. Plant pattern-recognition receptors.

    PubMed

    Zipfel, Cyril

    2014-07-01

    Plants are constantly exposed to would-be pathogens in their immediate environment. Yet, despite relying on innate immunity only, plants are resistant to most microbes. They employ pattern-recognition receptors (PRRs) for sensitive and rapid detection of the potential danger caused by microbes and pests. Plant PRRs are either surface-localized receptor kinases (RKs) or receptor-like proteins (RLPs) containing various ligand-binding ectodomains that perceive pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). In this review, I summarize our current knowledge of plant PRRs and their ligands, illustrating the multiple molecular strategies employed by plant PRRs to activate innate immune signaling to survive.

  3. Host receptors for bacteriophage adsorption.

    PubMed

    Bertozzi Silva, Juliano; Storms, Zachary; Sauvageau, Dominic

    2016-02-01

    The adsorption of bacteriophages (phages) onto host cells is, in all but a few rare cases, a sine qua non condition for the onset of the infection process. Understanding the mechanisms involved and the factors affecting it is, thus, crucial for the investigation of host-phage interactions. This review provides a survey of the phage host receptors involved in recognition and adsorption and their interactions during attachment. Comprehension of the whole infection process, starting with the adsorption step, can enable and accelerate our understanding of phage ecology and the development of phage-based technologies. To assist in this effort, we have established an open-access resource--the Phage Receptor Database (PhReD)--to serve as a repository for information on known and newly identified phage receptors. PMID:26755501

  4. Signaling from axon guidance receptors.

    PubMed

    Bashaw, Greg J; Klein, Rüdiger

    2010-05-01

    Determining how axon guidance receptors transmit signals to allow precise pathfinding decisions is fundamental to our understanding of nervous system development and may suggest new strategies to promote axon regeneration after injury or disease. Signaling mechanisms that act downstream of four prominent families of axon guidance cues--netrins, semaphorins, ephrins, and slits--have been extensively studied in both invertebrate and vertebrate model systems. Although details of these signaling mechanisms are still fragmentary and there appears to be considerable diversity in how different guidance receptors regulate the motility of the axonal growth cone, a number of common themes have emerged. Here, we review recent insights into how specific receptors for each of these guidance cues engage downstream regulators of the growth cone cytoskeleton to control axon guidance. PMID:20452961

  5. Receptor use by pathogenic arenaviruses.

    PubMed

    Reignier, Therese; Oldenburg, Jill; Noble, Beth; Lamb, Erika; Romanowski, Victor; Buchmeier, Michael J; Cannon, Paula M

    2006-09-15

    The arenavirus family contains several important human pathogens including Lassa fever virus (LASV), lymphocytic choriomeningitis virus (LCMV) and the New World clade B viruses Junin (JUNV) and Machupo (MACV). Previously, alpha-dystroglycan (alpha-DG) was identified as a receptor recognized by LASV and certain strains of LCMV. However, other studies have suggested that alpha-DG is probably not used by the clade B viruses, and the receptor(s) for these pathogens is currently unknown. Using pseudotyped retroviral vectors displaying arenavirus glycoproteins (GPs), we are able to explore the role played by the GP in viral entry in the absence of other viral proteins. By examining the ability of the vectors to transduce DG knockout murine embryonic stem (ES) cells, we have confirmed that LASV has an absolute requirement for alpha-DG in these cells. However, the LCMV GP can still direct substantial entry into murine ES cells in the absence of alpha-DG, even when the GP from the clone 13 variant is used that has previously been reported to be highly dependent on alpha-DG for entry. We also found that neither LASV or LCMV pseudotyped vectors were able to transduce human or murine lymphocytes, presumably due to the glycosylation state of alpha-DG in these cells. In contrast, the JUNV and MACV GPs displayed broad tropism on human, murine and avian cell types, including lymphocytes, and showed no requirement for alpha-DG in murine ES cells. These findings highlight the importance of molecules other than alpha-DG for arenavirus entry. An alternate receptor is present on murine ES cells that can be used by LCMV but not by LASV, and which is not available on human or murine lymphocytes, while a distinct and widely expressed receptor(s) is used by the clade B viruses.

  6. Nuclear receptors constitutive androstane receptor and pregnane X receptor ameliorate cholestatic liver injury

    PubMed Central

    Stedman, Catherine A. M.; Liddle, Christopher; Coulter, Sally A.; Sonoda, Junichiro; Alvarez, Jacqueline G. A.; Moore, David D.; Evans, Ronald M.; Downes, Michael

    2005-01-01

    Cholestasis is associated with accumulation of bile acids and lipids, and l