1
|
Pesticide Pollution: Detrimental Outcomes and Possible Mechanisms of Fish Exposure to Common Organophosphates and Triazines. J Xenobiot 2022; 12:236-265. [PMID: 36135714 PMCID: PMC9500960 DOI: 10.3390/jox12030018] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/28/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Pesticides are well known for their high levels of persistence and ubiquity in the environment, and because of their capacity to bioaccumulate and disrupt the food chain, they pose a risk to animals and humans. With a focus on organophosphate and triazine pesticides, the present review aims to describe the current state of knowledge regarding spatial distribution, bioaccumulation, and mode of action of frequently used pesticides. We discuss the processes by which pesticides and their active residues are accumulated and bioconcentrated in fish, as well as the toxic mechanisms involved, including biological redox activity, immunotoxicity, neuroendocrine disorders, and cytotoxicity, which is manifested in oxidative stress, lysosomal and mitochondrial damage, inflammation, and apoptosis/autophagy. We also explore potential research strategies to close the gaps in our understanding of the toxicity and environmental risk assessment of organophosphate and triazine pesticides.
Collapse
|
2
|
Tsai CY, Dai KY, Fang C, Wu JCC, Chan SHH. PTEN/FLJ10540/PI3K/Akt cascade in experimental brain stem death: A newfound role for a classical tumorigenic signaling pathway. Biochem Pharmacol 2018; 155:207-212. [PMID: 30008438 DOI: 10.1016/j.bcp.2018.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/01/2018] [Indexed: 12/28/2022]
Abstract
Despite great advances in contemporary medicine, brain death still remains enigmatic and its cellular and molecular mechanisms unsettled. This review summarizes recent findings that substantiate the notion that PTEN/FLJ10540/PI3K/Akt cascade, the classical tumorigenic signaling pathway, is actively engaged in experimental brain stem death. These results were based on a clinically relevant animal model that employs the pesticide mevinphos as the experimental insult in Sprague-Dawley rats to mimic brain stem death in patients died of organophosphate poisoning. The neural substrate investigated is the rostral ventrolateral medulla (RVLM), a brain stem site classically known to maintain arterial pressure (AP) and is established to be the origin of a "life-and-death" signal detected from AP, which reflects brain stem cardiovascular dysregulation that precedes death. Activation of PI3K/Akt signaling pathway in the RVLM upregulates the nuclear factor-κB/nitric oxide synthase II/peroxynitrite cascade, resulting in impairment of brain stem cardiovascular regulation that leads to the loss of the "life-and-death" signal in experimental brain stem death. This process is reinforced by FLJ10540, a PI3K-association protein; and is counteracted by PTEN, a negative regulator of PI3K/Akt signaling. The concept that a classical signaling pathway in tumorigenesis is also an active player in cardiovascular dysregulation in brain stem death provides new ramifications for translational medicine. It promulgates the concept that rather than focusing on a particular disease condition, a new vista for future therapeutic strategy against both fatal eventualities should target at this common cellular cascade.
Collapse
Affiliation(s)
- Ching-Yi Tsai
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China.
| | - Kuang-Yu Dai
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | - Chi Fang
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | - Jacqueline C C Wu
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | - Samuel H H Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China.
| |
Collapse
|
3
|
PTEN, a negative regulator of PI3K/Akt signaling, sustains brain stem cardiovascular regulation during mevinphos intoxication. Neuropharmacology 2017; 123:175-185. [DOI: 10.1016/j.neuropharm.2017.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 01/06/2023]
|
4
|
Darwiche W, Delanaud S, Dupont S, Ghamlouch H, Ramadan W, Joumaa W, Bach V, Gay-Quéheillard J. Impact of prenatal and postnatal exposure to the pesticide chlorpyrifos on the contraction of rat ileal muscle strips: involvement of an inducible nitric oxide synthase-dependent pathway. Neurogastroenterol Motil 2017; 29. [PMID: 27545116 DOI: 10.1111/nmo.12918] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/11/2016] [Indexed: 12/13/2022]
Abstract
BACKGROUND Prenatal/postnatal exposure to insecticides has been linked to developmental disorders in adulthood. Chlorpyrifos (CPF) is a widely used organophosphorus acetylcholinesterase (AChE)-inhibiting insecticide. The present study established whether prenatal and postnatal exposure to CPF is associated with intestinal motor dysfunction in adult rats. METHODS Three groups of pregnant rats were exposed to either CPF (1 or 5 mg/kg/day; the CPF1 and CPF5 groups) or vehicle (the control group) by gavage from gestational day 1 until weaning. At weaning, the pups were separated from their dams and individually gavaged (with the same dose) until postnatal day 60. We then measured in vivo intestinal transit and the in vitro contractile responses of ileal smooth muscle strips to electrical field stimulation. Expression of inducible nitric oxide synthase (iNOS) in the ileum was determined using qRT-PCR and immunoblots. Morphometry and AChE assays were also performed. KEY RESULTS At adulthood, the mean body mass was lower in the CPF1 and CPF5 groups than in controls. CPF5 exposure was associated with weaker in vitro contraction of ileal muscle strips, which was reversed by adding the NOS inhibitor (L-NAME). There was no significant intergroup difference in the mean in vivo transit time. Exposure to CPF was associated with greater iNOS expression, lower AChE activity and reduced circular and longitudinal smooth muscle thickness. CONCLUSIONS & INFERENCES Prenatal and postnatal exposure to CPF in the rat is associated with weaker contraction of ileal longitudinal smooth muscle via a nitrergic mechanism with increased iNOS expression.
Collapse
Affiliation(s)
- W Darwiche
- PériTox, Périnatalité & Risques Toxiques, UMR-I 01 INERIS, Université de Picardie Jules Verne, Amiens, France.,PhyToxE, PhysioToxicité Environnementale, Lebanese University, Nabatieh, Lebanon
| | - S Delanaud
- PériTox, Périnatalité & Risques Toxiques, UMR-I 01 INERIS, Université de Picardie Jules Verne, Amiens, France
| | - S Dupont
- EA4666, LNPC, Université de Picardie Jules Verne, Amiens, France
| | - H Ghamlouch
- EA4666, LNPC, Université de Picardie Jules Verne, Amiens, France
| | - W Ramadan
- PhyToxE, PhysioToxicité Environnementale, Lebanese University, Nabatieh, Lebanon.,Department of Biological and Chemical Sciences, School of Arts and Sciences, Lebanese International University, Beirut, Lebanon
| | - W Joumaa
- PhyToxE, PhysioToxicité Environnementale, Lebanese University, Nabatieh, Lebanon
| | - V Bach
- PériTox, Périnatalité & Risques Toxiques, UMR-I 01 INERIS, Université de Picardie Jules Verne, Amiens, France
| | - J Gay-Quéheillard
- PériTox, Périnatalité & Risques Toxiques, UMR-I 01 INERIS, Université de Picardie Jules Verne, Amiens, France
| |
Collapse
|
5
|
Tsai CY, Su CH, Chan JYH, Chan SHH. Nitrosative Stress-Induced Disruption of Baroreflex Neural Circuits in a Rat Model of Hepatic Encephalopathy: A DTI Study. Sci Rep 2017; 7:40111. [PMID: 28079146 PMCID: PMC5228038 DOI: 10.1038/srep40111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 12/02/2016] [Indexed: 12/11/2022] Open
Abstract
The onset of hepatic encephalopathy (HE) in liver failure is associated with high mortality; the underlying mechanism is undecided. Here we report that in an acute liver failure model employing intraperitoneal administration of thioacetamide in Sprague-Dawley rats, diffusion weighted imaging revealed a progressive reduction in apparent diffusion coefficient in the brain stem. Diffusion tensor imaging further showed that the connectivity between nucleus tractus solitarii (NTS), the terminal site of baroreceptor afferents in brain stem and rostral ventrolateral medulla (RVLM), the origin of sympathetic innervation of blood vessels, was progressively disrupted until its disappearance, coincidental with the irreversible cessation of baroreflex-mediated sympathetic vasomotor tone signifying clinically the occurrence of brain death. In addition, superoxide, nitric oxide, peroxynitrite and ammonia levels in the NTS or RVLM were elevated, alongside swelling of astroctytes. A scavenger of peroxynitrite, but not an antioxidant, delivered intracisternally reversed all these events. We conclude that nitrosative stress because of augmented peroxynitrite related to accumulation of ammonia and swelling of astrocytes in the NTS or RVLM, leading to cytotoxic edema in the brain stem and severance of the NTS-RVLM connectivity, underpins the defunct baroreflex-mediated sympathetic vasomotor tone that accounts for the high mortality associated with HE.
Collapse
Affiliation(s)
- Ching-Yi Tsai
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Chia-Hao Su
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Julie Y H Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Samuel H H Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| |
Collapse
|
6
|
Tsai CY, Li FCH, Wu CHY, Chang AYW, Chan SHH. Sumoylation of IkB attenuates NF-kB-induced nitrosative stress at rostral ventrolateral medulla and cardiovascular depression in experimental brain death. J Biomed Sci 2016; 23:65. [PMID: 27658615 PMCID: PMC5034413 DOI: 10.1186/s12929-016-0283-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/02/2016] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Small ubiquitin-related modifier (SUMO) is a group of proteins that participates in post-translational modifications. One known SUMO target is the transcription factor nuclear factor-kB (NF-kB) that plays a pivotal role in many disease processes; sumoylation inactivates NF-kB by conjugation with inhibitors of NF-kB (IkB). Our laboratory demonstrated previously that transcriptional upregulation of nitric oxide synthase II (NOS II) by NF-kB, leading to nitrosative stress by the formation of peroxynitrite in the rostral ventrolateral medulla (RVLM), underpins the defunct brain stem cardiovascular regulation that precedes brain death. Based on an experimental endotoxemia model, this study evaluated the hypothesis that sumoylation plays a pro-life role in brain death by interacting with the NF-kB/NOS II/peroxynitrite signaling pathway in the RVLM. RESULTS In Sprague-Dawley rats, intravenous administration of Escherichia coli lipopolysaccharide (LPS; 10 mg kg-1) elicited an augmentation of SUMO-1 and ubiquitin-conjugase 9 (Ubc9) mRNA or protein levels, alongside SUMO-1-conjugated proteins in the RVLM. Immunoneutralization of SUMO-1 or Ubc9 in the RVLM significantly potentiated the already diminished sumoylation of IkBα and intensified NF-kB activation and NOS II/peroxynitrite expression in this brain stem substrate, together with exacerbated fatality, cardiovascular depression and reduction of an experimental index of a life-and-death signal detected from arterial pressure that disappears in comatose patients signifying failure of brain stem cardiovascular regulation before brain death. CONCLUSION We conclude that sumoylation of IkB in the RVLM ameliorates the defunct brain stem cardiovascular regulation that underpins brain death in our experimental endotoxemia modal by reducing nitrosative stress via inhibition of IkB degradation that diminishes the induction of the NF-kB/NOS II/peroxynitrite signaling cascade.
Collapse
Affiliation(s)
- Ching-Yi Tsai
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301 Taiwan Republic of China
| | - Faith C. H. Li
- Institute of Physiology, National Cheng Kung University, Tainan, Taiwan Republic of China
| | - Carol H. Y. Wu
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301 Taiwan Republic of China
| | - Alice Y. W. Chang
- Institute of Physiology, National Cheng Kung University, Tainan, Taiwan Republic of China
| | - Samuel H. H. Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301 Taiwan Republic of China
| |
Collapse
|
7
|
Su CH, Tsai CY, Chang AY, Chan JY, Chan SH. MRI/DTI of the Brain Stem Reveals Reversible and Irreversible Disruption of the Baroreflex Neural Circuits: Clinical Implications. Theranostics 2016; 6:837-48. [PMID: 27162554 PMCID: PMC4860892 DOI: 10.7150/thno.14837] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/06/2016] [Indexed: 01/29/2023] Open
Abstract
Baroreflex is the physiological mechanism for the maintenance of blood pressure and heart rate. Impairment of baroreflex is not a disease per se. However, depending on severity, the eventuality of baroreflex dysfunction varies from inconvenience in daily existence to curtailment of mobility to death. Despite universal acceptance, neuronal traffic within the contemporary neural circuits during the execution of baroreflex has never been visualized. By enhancing signal detection and fine-tuning the scanning parameters, we have successfully implemented tractographic analysis of the medulla oblongata in mice that allowed for visualization of connectivity between key brain stem nuclei in the baroreflex circuits. When viewed in conjunction with radiotelemetric analysis of the baroreflex, we found that under pathophysiological conditions when the disrupted connectivity between key nuclei in the baroreflex circuits was reversible, the associated disease condition (e.g. neurogenic hypertension) was amenable to remedial measures. Nevertheless, fatality ensues under pathological conditions (e.g. hepatic encephalopathy) when the connectivity between key substrates in the baroreflex circuits was irreversibly severed. MRI/DTI also prompted partial re-wiring of the contemporary circuit for baroreflex-mediated sympathetic vasomotor tone, and unearthed an explanation for the time lapse between brain death and the inevitable asystole signifying cardiac death that follows.
Collapse
Affiliation(s)
- Chia-Hao Su
- 1. Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Ching-Yi Tsai
- 1. Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Alice Y.W. Chang
- 2. Institute of Physiology, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Julie Y.H. Chan
- 1. Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Samuel H.H. Chan
- 1. Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| |
Collapse
|
8
|
Tsai CY, Chen CH, Chang AYW, Chan JYH, Chan SHH. Upregulation of FLJ10540, a PI3K-association protein, in rostral ventrolateral medulla impairs brain stem cardiovascular regulation during mevinphos intoxication. Biochem Pharmacol 2014; 93:34-41. [PMID: 25449601 DOI: 10.1016/j.bcp.2014.10.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 10/29/2014] [Indexed: 12/15/2022]
Abstract
FLJ10540, originally identified as a microtubule-associated protein, induces cell proliferation and migration during tumorigenesis via the formation of FLJ10540-PI3K complex and enhancement of PI3K kinase activity. Interestingly, activation of PI3K/Akt cascade, leading to upregulation of nitric oxide synthase II (NOS II)/peroxynitrite signaling in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, mediates the impairment of brain stem cardiovascular regulation induced by the pesticide mevinphos. We evaluated the hypothesis that upregulation of FLJ10540 in the RVLM is upstream to this repertoire of signaling cascade that underpins mevinphos-induced circulatory depression. Microinjection bilaterally of mevinphos (10nmol) into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension that was accompanied by an increase (Phase I), followed by a decrease (Phase II) of an experimental index for baroreflex-mediated sympathetic vasomotor tone. There was augmentation in FLJ10540 mRNA in the RVLM or FLJ10540 protein in RVLM neurons, both of which were causally and temporally related to an augmentation of binding between the catalytic subunit (p110) and regulatory subunit (p85) of PI3K, phosphorylation of Akt at Thr308 site, and NOS II, superoxide or peroxynitrite level in the RVLM. Immunoneutralization of FJL10540 in the RVLM significantly antagonized those biochemical changes, and blunted the progressive hypotension and the reduced baroreflex-mediated sympathetic vasomotor tone during mevinphos intoxication. We conclude that upregulation of FLJ10540 in the RVLM elicits impairment of brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication via activation of PI3K/Akt/NOS II/peroxynitrite signaling cascade in the RVLM.
Collapse
Affiliation(s)
- Ching-Yi Tsai
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | - Chang-Han Chen
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | - Alice Y W Chang
- Institute of Physiology, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Julie Y H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | - Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China.
| |
Collapse
|
9
|
Tsai CY, Chang AYW, Chan JYH, Chan SHH. Activation of PI3K/Akt signaling in rostral ventrolateral medulla impairs brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication. Biochem Pharmacol 2014; 88:75-85. [PMID: 24462917 DOI: 10.1016/j.bcp.2014.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 11/27/2022]
Abstract
As the most widely used pesticides in the globe, the organophosphate compounds are understandably linked with the highest incidence of suicidal poisoning. Whereas the elicited toxicity is often associated with circulatory depression, the underlying mechanisms require further delineation. Employing the pesticide mevinphos as our experimental tool, we evaluated the hypothesis that transcriptional upregulation of nitric oxide synthase II (NOS II) by NF-κB on activation of the PI3K/Akt cascade in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, underpins the circulatory depressive effects of organophosphate poisons. Microinjection of mevinphos (10 nmol) bilaterally into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension that was accompanied sequentially by an increase (Phase I) and a decrease (Phase II) of an experimental index for the baroreflex-mediated sympathetic vasomotor tone. There were also progressive augmentations in PI3K or Akt enzyme activity and phosphorylation of p85 or Akt(Thr308) subunit in the RVLM that were causally related to an increase in NF-κB transcription activity and elevation in NOS II or peroxynitrite expression. Loss-of-function manipulations of PI3K or Akt in the RVLM significantly antagonized the reduced baroreflex-mediated sympathetic vasomotor tone and hypotension during Phase II mevinphos intoxication, and blunted the increase in NF-κB/NOS II/peroxynitrite signaling. We conclude that activation of the PI3K/Akt cascade, leading to upregulation of NF-κB/NOS II/peroxynitrite signaling in the RVLM, elicits impairment of brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication.
Collapse
Affiliation(s)
- Ching-Yi Tsai
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, ROC
| | - Alice Y W Chang
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, ROC
| | - Julie Y H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, ROC
| | - Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, ROC.
| |
Collapse
|
10
|
Chang CC, Chen SD, Lin TK, Chang WN, Liou CW, Chang AYW, Chan SHH, Chuang YC. Heat shock protein 70 protects against seizure-induced neuronal cell death in the hippocampus following experimental status epilepticus via inhibition of nuclear factor-κB activation-induced nitric oxide synthase II expression. Neurobiol Dis 2013; 62:241-9. [PMID: 24141017 DOI: 10.1016/j.nbd.2013.10.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 09/17/2013] [Accepted: 10/07/2013] [Indexed: 10/26/2022] Open
Abstract
Status epilepticus induces subcellular changes that may eventually lead to neuronal cell death in the hippocampus. Based on an animal model of status epilepticus, our laboratory showed previously that sustained hippocampal seizure activity activates nuclear factor-κB (NF-κB) and upregulates nitric oxide synthase (NOS) II gene expression, leading to apoptotic neuronal cell death in the hippocampus. The present study examined the potential modulatory role of heat shock protein 70 (HSP70) on NF-κB signaling in the hippocampus following experimental status epilepticus. In Sprague-Dawley rats, kainic acid (KA) was microinjected unilaterally into the hippocampal CA3 subfield to induce prolonged bilateral seizure activity. Expression of HSP70 was elevated as early as 1h after the elicitation of sustained seizure activity, followed by a progressive elevation that peaked at 24h. Pretreatment with an antisense oligonucleotide against hsp70 decreased the HSP70 expression, and significantly augmented IκB kinase (IKK) activity and phosphorylation of IκBα, alongside enhanced nuclear translocation and DNA binding activity of NF-κB in the hippocampal CA3 neurons and glial cells. These cellular events were followed by enhanced upregulation of NOS II and peroxynitrite expression 3h after sustained seizure activity that led to an increase of caspase-3 and DNA fragmentation in the hippocampal CA3 neurons 7days after experimental status epilepticus. We concluded that HSP70 protects against apoptotic cell death induced by NF-κB activation and NOS II-peroxynitrite signaling cascade in the hippocampal CA3 and glial cells following experimental status epilepticus via suppression of IKK activity and deactivation of IκBα.
Collapse
Affiliation(s)
- Chiung-Chih Chang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Shang-Der Chen
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Tsu-Kung Lin
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Wen-Neng Chang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chia-Wei Liou
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Alice Y W Chang
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Yao-Chung Chuang
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Department of Biological Science, National Sun Yet-sen University, Kaohsiung, Taiwan.
| |
Collapse
|
11
|
Li FCH, Li BPT, Wu JCC, Chang AYW. Transition from oxidative stress to nitrosative stress in rostral ventrolateral medulla underlies fatal intoxication induced by organophosphate mevinphos. Toxicol Sci 2013; 135:202-17. [PMID: 23824088 DOI: 10.1093/toxsci/kft147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
As the most widely used pesticides in the world, fatal incidence of suicidal poisoning by organophosphate compounds is high and is often associated with cardiovascular toxicity. Using the pesticide mevinphos as our tool, we investigated the roles of oxidative stress and nitrosative stress at the rostral ventrolateral medulla (RVLM), the brain stem site that maintains arterial pressure (AP) and sympathetic vasomotor tone, in the cardiovascular depressive effects of organophosphate poisons. Microinjection of mevinphos (10 nmol) into the RVLM of anesthetized Sprague-Dawley rats induced progressive hypotension that was accompanied by an increase (phase I), followed by a decrease (phase II) of an experimental index of baroreflex-mediated sympathetic vasomotor tone, with a fatality rate of 35%. During phase I, there was a preferential upregulation of angiotensin type I receptor (AT1R) messenger RNA (mRNA) and protein that leads to activation of NADPH oxidase (Nox) and increase in superoxide at the RVLM. Pharmacological antagonism of these signals exacerbated fatality and shorted survival time by eliminating baroreflex-mediated sympathetic vasomotor tone, AP, and heart rate. During phase II, there was a progressive upregulation of angiotensin type II receptor (AT2R) mRNA and protein that leads to increase in peroxynitrite in the RVLM, blockade of both sustained brain stem cardiovascular regulation and improved survival. We further found that AT1R and AT2R cross-interacted at transcriptional and signaling levels in the RVLM. We conclude that a transition from AT1R-mediated oxidative stress to AT2R-mediated nitrosative stress in the RVLM underlies the shift from sustained to impaired brain stem cardiovascular regulation that underpins cardiovascular fatality during mevinphos intoxication.
Collapse
Affiliation(s)
- Faith C H Li
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan, Republic of China
| | | | | | | |
Collapse
|
12
|
Pro-life role for c-Jun N-terminal kinase and p38 mitogen-activated protein kinase at rostral ventrolateral medulla in experimental brain stem death. J Biomed Sci 2012; 19:96. [PMID: 23157661 PMCID: PMC3533910 DOI: 10.1186/1423-0127-19-96] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 11/05/2012] [Indexed: 01/14/2023] Open
Abstract
Background Based on an experimental brain stem death model, we demonstrated previously that activation of the mitogen-activated protein kinase kinase 1/2 (MEK1/2)/extracellular signal-regulated kinase 1/2 (ERK1/2)/
mitogen-activated protein kinase signal-interacting kinase 1/2 (MNK1/2) cascade plays a pro-life role in the rostral ventrolateral medulla (RVLM), the origin of a life-and-death signal detected from systemic arterial pressure, which sequentially increases (pro-life) and decreases (pro-death) to reflect progressive dysfunction of central cardiovascular regulation during the advancement towards brain stem death in critically ill patients. The present study assessed the hypothesis that, in addition to ERK1/2, c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK), the other two mammalian members of MAPKs that are originally identified as stress-activated protein kinases, are activated specifically by MAPK kinase 4 (MAP2K4) or MAP2K6 and play a pro-life role in RVLM during experimental brain stem death. We further delineated the participation of phosphorylating activating transcriptional factor-2 (ATF-2) and c-Jun, the classical transcription factor activated by JNK or p38MAPK, in this process. Results An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos (Mev; 10 nmol) bilaterally into RVLM of Sprague–Dawley rats was used, alongside cardiovascular, pharmacological and biochemical evaluations. Results from ELISA showed that whereas the total JNK, p38MAPK, MAP2K4 and MAP2K6 were not affected, augmented phosphorylation of JNK at Thr183 and Tyr185 and p38MAPK at Thr180 and Tyr182, accompanied by phosphorylation of their upstream activators MAP2K4 at Ser257 and Thr261 and MAP2K6 at Ser207 and Thr211 in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Moreover, the activity of transcription factors ATF-2 at Thr71 and c-Jun at Ser73, rather than Elk-1 at Ser383 in RVLM were also augmented during the pro-life phase. Furthermore, pretreatment by microinjection into the bilateral RVLM of specific JNK inhibitors, JNK inhibitor I (100 pmol) or SP600125 (5 pmol), or specific p38MAPK inhibitors, p38MAPK inhibitor III (500 pmol) or SB203580 (2 nmol), exacerbated the depressor effect and blunted the augmented life-and-death signal exhibited during the pro-life phase. On the other hand, pretreatment with the negative control for JNK or p38MAPK inhibitor, JNK inhibitor I negative control (100 pmol) or SB202474 (2 nmol), was ineffective in the vehicle-controls and Mev-treatment groups. Conclusions Our results demonstrated that activation of JNK or p38MAPK in RVLM by their upstream activators MAP2K4 or MAP2K6 plays a preferential pro-life role by sustaining the central cardiovascular regulatory machinery during experimental brain stem death via phosphorylation and activation of nuclear transcription factor ATF-2 or c-Jun.
Collapse
|
13
|
Wu CHY, Chan JYH, Chou JLJ, Chan SHH, Chang AYW. Engagement of ubiquitination and de-ubiquitination at rostral ventrolateral medulla in experimental brain death. J Biomed Sci 2012; 19:48. [PMID: 22545670 PMCID: PMC3410792 DOI: 10.1186/1423-0127-19-48] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/30/2012] [Indexed: 01/12/2023] Open
Abstract
Background Whereas brain death is a vitally important clinical phenomenon, our contemporary understanding on its underlying cellular mechanisms remains elusive. This study evaluated whether the ubiquitin-proteasome system (UPS) in the rostral ventrolateral medulla (RVLM), a neural substrate that our laboratory identified previously to be intimately related to brain death, is engaged in this fatal process. Methods We performed proteomics, Western Blot, real-time PCR, ELISA and pharmacological experiments in conjunction with a clinically relevant experimental endotoxemia model of brain death based on intravenous administration of Escherichia coli lipopolysaccharide in adult male Sprague–Dawley rats. Results Proteomics, Western blot and enzyme activity analyses demonstrated that polyubiquitination was preserved and de-ubiquitination by ubiquitin C-terminal hydrolase isozyme-L1 (UCH-L1) was sustained, alongside increased monoubiquitin availability or proteasome activity in RVLM over the course of experimental endotoxemia. However, real-time PCR revealed no significant alteration in proteasome subunit alpha type-1, ubiquitin or UCH-L1 at mRNA level. Functionally, whereas microinjection into the bilateral RVLM of proteasome inhibitors (lactacystin or proteasome inhibitor II) potentiated survival, an inhibitor of ubiquitin-recycling (ubiquitin aldehyde) or an UCH-L1 inhibitor exacerbated mortality. Conclusions We proposed previously that the progression towards brain death entails a tug-of-war between pro-death and pro-life programs in RVLM. It is conceivable that ubiquitination or de-ubiquitination in RVLM participate in brain death by regulating the degradation of the proteins involved in those programs.
Collapse
Affiliation(s)
- Carol H Y Wu
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301, Taiwan, Republic of China
| | | | | | | | | |
Collapse
|
14
|
Chan SHH, Chan JYH, Hsu KS, Li FCH, Sun EYH, Chen WL, Chang AYW. Amelioration of central cardiovascular regulatory dysfunction by tropomyocin receptor kinase B in a mevinphos intoxication model of brain stem death. Br J Pharmacol 2012; 164:2015-28. [PMID: 21615729 DOI: 10.1111/j.1476-5381.2011.01508.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND AND PURPOSE Little information exists on the mechanisms that precipitate brain stem death, the legal definition of death in many developed countries. We investigated the role of tropomyocin receptor kinase B (TrkB) and its downstream signalling pathways in the rostral ventrolateral medulla (RVLM) during experimental brain stem death. EXPERIMENTAL APPROACH An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos bilaterally into the RVLM of Sprague-Dawley rats was used, in conjunction with cardiovascular, pharmacological and biochemical evaluations. KEY RESULTS A significant increase in TrkB protein, phosphorylation of TrkB at Tyr(516) (pTrkB(Y516) ), Shc at Tyr(317) (pShc(Y317) ) or ERK at Thr(202) /Tyr(204) , or Ras activity in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Microinjection bilaterally into RVLM of a specific TrkB inhibitor, K252a, antagonized those increases. Pretreatment with anti-pShc(Y317) antiserum, Src homology 3 binding peptide (Grb2/SOS inhibitor), farnesylthioacetic acid (Ras inhibitor), manumycin A (Ras inhibitor) or GW5074 (Raf-1 inhibitor) blunted the preferential augmentation of Ras activity or ERK phosphorylation in RVLM and blocked the up-regulated NOS I/protein kinase G (PKG) signalling, the pro-life cascade that sustains central cardiovascular regulation during experimental brain stem death. CONCLUSIONS AND IMPLICATIONS Activation of TrkB, followed by recruitment of Shc/Grb2/SOS adaptor proteins, leading to activation of Ras/Raf-1/ERK signalling pathway plays a crucial role in ameliorating central cardiovascular regulatory dysfunction via up-regulation of NOS I/PKG signalling cascade in the RVLM in brain stem death. These findings provide novel information for developing therapeutic strategies against this fatal eventuality.
Collapse
Affiliation(s)
- S H H Chan
- Center for Translational Researchin Biomedical Sciences,Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan
| | | | | | | | | | | | | |
Collapse
|
15
|
Wu CHY, Chan JYH, Chan SHH, Chang AYW. A double-edged sword role for ubiquitin-proteasome system in brain stem cardiovascular regulation during experimental brain death. PLoS One 2011; 6:e27404. [PMID: 22110641 PMCID: PMC3215722 DOI: 10.1371/journal.pone.0027404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 10/16/2011] [Indexed: 12/02/2022] Open
Abstract
Background Brain stem cardiovascular regulatory dysfunction during brain death is underpinned by an upregulation of nitric oxide synthase II (NOS II) in rostral ventrolateral medulla (RVLM), the origin of a life-and-death signal detected from blood pressure of comatose patients that disappears before brain death ensues. Furthermore, the ubiquitin-proteasome system (UPS) may be involved in the synthesis and degradation of NOS II. We assessed the hypothesis that the UPS participates in brain stem cardiovascular regulation during brain death by engaging in both synthesis and degradation of NOS II in RVLM. Methodology/Principal Findings In a clinically relevant experimental model of brain death using Sprague-Dawley rats, pretreatment by microinjection into the bilateral RVLM of proteasome inhibitors (lactacystin or proteasome inhibitor II) antagonized the hypotension and reduction in the life-and-death signal elicited by intravenous administration of Escherichia coli lipopolysaccharide (LPS). On the other hand, pretreatment with an inhibitor of ubiquitin-recycling (ubiquitin aldehyde) or ubiquitin C-terminal hydrolase isozyme L1 (UCH-L1) potentiated the elicited hypotension and blunted the prevalence of the life-and-death signal. Real-time polymerase chain reaction, Western blot, electrophoresis mobility shift assay, chromatin immunoprecipitation and co-immunoprecipitation experiments further showed that the proteasome inhibitors antagonized the augmented nuclear presence of NF-κB or binding between NF-κB and nos II promoter and blunted the reduced cytosolic presence of phosphorylated IκB. The already impeded NOS II protein expression by proteasome inhibitor II was further reduced after gene-knockdown of NF-κB in RVLM. In animals pretreated with UCH-L1 inhibitor and died before significant increase in nos II mRNA occurred, NOS II protein expression in RVLM was considerably elevated. Conclusions/Significance We conclude that UPS participates in the defunct and maintained brain stem cardiovascular regulation during experimental brain death by engaging in both synthesis and degradation of NOS II at RVLM. Our results provide information on new therapeutic initiatives against this fatal eventuality.
Collapse
Affiliation(s)
- Carol H. Y. Wu
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
- Institute of Biomedical Sciences, National Sun Yat-sen University, Taiwan, Republic of China
| | - Julie Y. H. Chan
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
| | - Samuel H. H. Chan
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
- * E-mail: (AYWC); (SHHC)
| | - Alice Y. W. Chang
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Taiwan, Republic of China
- * E-mail: (AYWC); (SHHC)
| |
Collapse
|
16
|
Jiang M, Zhang C, Wang J, Chen J, Xia C, Du D, Zhao N, Cao Y, Shen L, Zhu D. Adenosine A(2A)R modulates cardiovascular function by activating ERK1/2 signal in the rostral ventrolateral medulla of acute myocardial ischemic rats. Life Sci 2011; 89:182-7. [PMID: 21703281 DOI: 10.1016/j.lfs.2011.06.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 05/25/2011] [Accepted: 05/27/2011] [Indexed: 02/06/2023]
Abstract
AIMS To investigate the cardiovascular regulatory mechanism of adenosine A(2A) receptor (A(2A)R) in the rostral ventrolateral medulla (RVLM) in acute myocardial ischemic (AMI) rats. MAIN METHODS The animal model of AMI was established by ligating the left anterior descending coronary artery (LAD). The A(2A)R expression was examined by immunohistochemistry, western blot and real-time PCR. CGS21680 and SCH58261 (an agonist and antagonist of A(2A)R) were respectively microinjected into the RVLM. In a subgroup of rats, PD98059 (an antagonist of extracellular signal-regulated kinase (ERK1/2)) was microinjected prior to CGS21680 administration. Phosphorylation of ERK1/2 was examined by western blot. KEY FINDINGS Our results demonstrated that A(2A)R immunoreactive positive neurons, the expressions of protein and mRNA of A(2A)R in the RVLM of AMI group were increased compared with the sham group. Microinjection CGS21680 into the RVLM inhibited mean arterial pressure (MAP) and heart rate (HR) in both AMI and sham groups. The inhibition was significantly greater in AMI group than in sham group. The cardiovascular effects of CGS21680 mentioned above were almost abolished by prior administration of PD98059. The increase of ERK1/2 in the RVLM with the cardiovascular responses was induced by CGS21680 in AMI rats; this effect was also blocked by SCH58261. SIGNIFICANCE This study reveals that the activated A(2A)R in the RVLM underlies the depressor and bradycardiac responses in AMI rats via phosphorylation of ERK1/2 increasing.
Collapse
Affiliation(s)
- Meiyan Jiang
- Department of Physiology and Pathophysiology, Shanghai Medical College of Fudan University, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Jiang MY, Chen J, Wang J, Xiao F, Zhang HH, Zhang CR, Du DS, Cao YX, Shen LL, Zhu DN. Nitric oxide modulates cardiovascular function in the rat by activating adenosine A2A receptors and inhibiting acetylcholine release in the rostral ventrolateral medulla. Clin Exp Pharmacol Physiol 2011; 38:380-6. [DOI: 10.1111/j.1440-1681.2011.05521.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
18
|
Chan JYH, Tsai CY, Wu CHY, Li FCH, Dai KY, Sun EYH, Chan SHH, Chang AYW. Sumoylation of hypoxia-inducible factor-1α ameliorates failure of brain stem cardiovascular regulation in experimental brain death. PLoS One 2011; 6:e17375. [PMID: 21390240 PMCID: PMC3048406 DOI: 10.1371/journal.pone.0017375] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 02/01/2011] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND One aspect of brain death is cardiovascular deregulation because asystole invariably occurs shortly after its diagnosis. A suitable neural substrate for mechanistic delineation of this aspect of brain death resides in the rostral ventrolateral medulla (RVLM). RVLM is the origin of a life-and-death signal that our laboratory detected from blood pressure of comatose patients that disappears before brain death ensues. At the same time, transcriptional upregulation of heme oxygenase-1 in RVLM by hypoxia-inducible factor-1α (HIF-1α) plays a pro-life role in experimental brain death, and HIF-1α is subject to sumoylation activated by transient cerebral ischemia. It follows that sumoylation of HIF-1α in RVLM in response to hypoxia may play a modulatory role on brain stem cardiovascular regulation during experimental brain death. METHODOLOGY/PRINCIPAL FINDINGS A clinically relevant animal model that employed mevinphos as the experimental insult in Sprague-Dawley rat was used. Biochemical changes in RVLM during distinct phenotypes in systemic arterial pressure spectrum that reflect maintained or defunct brain stem cardiovascular regulation were studied. Western blot analysis, EMSA, ELISA, confocal microscopy and immunoprecipitation demonstrated that drastic tissue hypoxia, elevated levels of proteins conjugated by small ubiquitin-related modifier-1 (SUMO-1), Ubc9 (the only known conjugating enzyme for the sumoylation pathway) or HIF-1α, augmented sumoylation of HIF-1α, nucleus-bound translocation and enhanced transcriptional activity of HIF-1α in RVLM neurons took place preferentially during the pro-life phase of experimental brain death. Furthermore, loss-of-function manipulations by immunoneutralization of SUMO-1, Ubc9 or HIF-1α in RVLM blunted the upregulated nitric oxide synthase I/protein kinase G signaling cascade, which sustains the brain stem cardiovascular regulatory machinery during the pro-life phase. CONCLUSIONS/SIGNIFICANCE We conclude that sumoylation of HIF-1α in RVLM ameliorates brain stem cardiovascular regulatory failure during experimental brain death via upregulation of nitric oxide synthase I/protein kinase G signaling. This information should offer new therapeutic initiatives against this fatal eventuality.
Collapse
Affiliation(s)
- Julie Y. H. Chan
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, Republic of China
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
| | - Ching-Yi Tsai
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
| | - Carol H. Y. Wu
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
| | - Faith C. H. Li
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
| | - Kuang-Yu Dai
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
| | - Enya Y. H. Sun
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
| | - Samuel H. H. Chan
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
- * E-mail: (SHHC); (AYWC)
| | - Alice Y. W. Chang
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan, Republic of China
- * E-mail: (SHHC); (AYWC)
| |
Collapse
|
19
|
Chou JLJ, Wu CHY, Tsai CY, Chang AYW, Chan SHH. Proteomic investigation of a neural substrate intimately related to brain death. Proteomics 2010; 11:239-48. [PMID: 21204251 DOI: 10.1002/pmic.201000438] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/15/2010] [Accepted: 10/18/2010] [Indexed: 01/18/2023]
Abstract
Our current understanding on brain death remains limited despite its clinical importance. This study evaluated whether the proteome expressed in the rat rostral ventrolateral medulla (RVLM), a neural substrate that our laboratory identified previously to be intimately related to brain death, is uniquely different from other brain areas, using the cerebral cortex, which is defunct under persistent vegetative state for comparison. We found that a group of antioxidant proteins, including members of the peroxiredoxin (Prx) family (Prx-1, Prx-2, Prx-5, Prx-6), thioredoxin and mitochondrial manganese superoxide dismutase, exhibited significantly higher protein and mRNA expression levels in RVLM when compared to cerebral cortex. Tissue oxygen, ATP contents and ATP synthase subunits α and β in RVLM were also significantly elevated. On the other hand, protein and mRNA levels of members of the ubiquitin-proteasome system, including proteasome subunit α type-1, ubiquitin, uniquitin-conjugating enzyme E2 N, ubiquitin carboxyl-terminal hydrolase isozyme L1 and L3, were comparable in both brain regions. We conclude that a significantly elevated level of antioxidant proteins and mRNA in RVLM is consistent with the exhibition of higher tissue oxygen tension and metabolic energy production in this neural substrate, which together constitute a safeguard mechanism against brain death.
Collapse
Affiliation(s)
- Jimmy Li-Jer Chou
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County, Taiwan, Republic of China
| | | | | | | | | |
Collapse
|
20
|
Chuang YC, Chen SD, Lin TK, Chang WN, Lu CH, Liou CW, Chan SHH, Chang AYW. Transcriptional upregulation of nitric oxide synthase II by nuclear factor-kappaB promotes apoptotic neuronal cell death in the hippocampus following experimental status epilepticus. J Neurosci Res 2010; 88:1898-907. [PMID: 20155797 DOI: 10.1002/jnr.22369] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Whereas status epilepticus, or the condition of continuous epileptic seizures, produces a characteristic pattern of preferential neuronal cell loss in the hippocampus, the underlying mechanism is still unsettled. Based on an experimental model of temporal lobe status epilepticus, we demonstrated previously that prolonged seizures prompted an overproduction of nitric oxide (NO) by upregulation of NO synthase II (NOS II) in the hippocampal CA3 subfield, followed by the activation of mitochondrial apoptotic signaling cascade. Using the same animal model, the present study evaluated the hypothesis that transcriptional upregulation of NOS II gene by nuclear factor-kappaB (NF-kappaB) promotes apoptotic neuronal cell death in the hippocampus following status epilepticus. In Sprague-Dawley rats, significantly augmented nucleus-bound translocation of NF-kappaB p50 and p65 subunits and DNA binding activity of NF-kappaB were observed in hippocampal CA3 neurons as early as 30 min after elicitation of sustained seizure activity by microinjection of kainic acid into the CA3 subfield, followed by a progressive elevation that peaked at 90 min. In addition, application bilaterally into the hippocampal CA3 subfield of a selective NF-kappaB inhibitor, pyrrolidine dithiocarbamate or double-stranded kappaB decoy DNA significantly antagonized the activated NOS II-peroxynitrite signaling cascade (3 hr) and the associated manifestations of apoptotic cell death (7 days) in the hippocampus. We conclude that activation of NF-kappaB in hippocampal CA3 neurons upregulates NOS II gene expression following experimental temporal lobe status epilepticus, leading to apoptotic neuronal cell death in the hippocampus.
Collapse
Affiliation(s)
- Yao-Chung Chuang
- Department of Neurology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung County, Taiwan, Republic of China
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Dai KY, Chan SH, Chang AY. Heme oxygenase-1 plays a pro-life role in experimental brain stem death via nitric oxide synthase I/protein kinase G signaling at rostral ventrolateral medulla. J Biomed Sci 2010; 17:72. [PMID: 20819234 PMCID: PMC2941487 DOI: 10.1186/1423-0127-17-72] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 09/07/2010] [Indexed: 12/13/2022] Open
Abstract
Background Despite its clinical importance, a dearth of information exists on the cellular and molecular mechanisms that underpin brain stem death. A suitable neural substrate for mechanistic delineation on brain stem death resides in the rostral ventrolateral medulla (RVLM) because it is the origin of a life-and-death signal that sequentially increases (pro-life) and decreases (pro-death) to reflect the advancing central cardiovascular regulatory dysfunction during the progression towards brain stem death in critically ill patients. The present study evaluated the hypothesis that heme oxygnase-1 (HO-1) may play a pro-life role as an interposing signal between hypoxia-inducible factor-1 (HIF-1) and nitric oxide synthase I (NOS I)/protein kinase G (PKG) cascade in RVLM, which sustains central cardiovascular regulatory functions during brain stem death. Methods We performed cardiovascular, pharmacological, biochemical and confocal microscopy experiments in conjunction with an experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos (Mev; 10 nmol) bilaterally into RVLM of adult male Sprague-Dawley rats. Results Western blot analysis coupled with laser scanning confocal microscopy revealed that augmented HO-1 expression that was confined to the cytoplasm of RVLM neurons occurred preferentially during the pro-life phase of experimental brain stem death and was antagonized by immunoneutralization of HIF-1α or HIF-1β in RVLM. On the other hand, the cytoplasmic presence of HO-2 in RVLM neurons manifested insignificant changes during both phases. Furthermore, immunoneutralization of HO-1 or knockdown of ho-1 gene in RVLM blunted the augmented life-and-death signals exhibited during the pro-life phase. Those pretreatments also blocked the upregulated pro-life NOS I/PKG signaling without affecting the pro-death NOS II/peroxynitrite cascade in RVLM. Conclusions We conclude that transcriptional upregulation of HO-1 on activation by HIF-1 in RVLM plays a preferential pro-life role by sustaining central cardiovascular regulatory functions during brain stem death via upregulation of NOS I/PKG signaling pathway. Our results further showed that the pro-dead NOS II/peroxynitrite cascade in RVLM is not included in this repertoire of cellular events.
Collapse
Affiliation(s)
- Kuang-Yu Dai
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial, Hospital-Kaohsiung Medical Center, Kaohsiung County 83301, Taiwan
| | | | | |
Collapse
|
22
|
Dean JB. Hypercapnia causes cellular oxidation and nitrosation in addition to acidosis: implications for CO2 chemoreceptor function and dysfunction. J Appl Physiol (1985) 2010; 108:1786-95. [PMID: 20150563 PMCID: PMC2886689 DOI: 10.1152/japplphysiol.01337.2009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 02/08/2010] [Indexed: 12/22/2022] Open
Abstract
Cellular mechanisms of CO2 chemoreception are discussed and debated in terms of the stimuli produced during hypercapnic acidosis and their molecular targets: protons generated by the hydration of CO2 and dissociation of carbonic acid, which target membrane-bound proteins and lipids in brain stem neurons. The CO2 hydration reaction, however, is not the only reaction that CO2 undergoes that generates molecules capable of modifying proteins and lipids. Molecular CO2 also reacts with peroxynitrite (ONOO-), a reactive nitrogen species (RNS), which is produced from nitric oxide (*NO) and superoxide (*O2-). The CO2/ONOO- reaction, in turn, produces additional nitrosative and oxidative reactive intermediates. Furthermore, protons facilitate additional redox reactions that generate other reactive oxygen species (ROS). ROS/RNS generated by these redox reactions may act as additional stimuli of CO2 chemoreceptors since neurons in chemosensitive areas produce both *NO and *O2- and, therefore, ONOO-. Perturbing *NO, *O2-, and ONOO- activities in chemosensitive areas modulates cardiorespiration. Moreover, neurons in at least one chemosensitive area, the solitary complex, are stimulated by cellular oxidation. Together, these data raise the following two questions: 1) do pH and ROS/RNS work in tandem to stimulate CO2 chemoreceptors during hypercapnic acidosis; and 2) does nitrosative stress and oxidative stress contribute to CO2 chemoreceptor dysfunction? To begin considering these two issues and their implications for central chemoreception, this minireview has the following three goals: 1) summarize the nitrosative and oxidative reactions that occur during hypercapnic acidosis and isocapnic acidosis; 2) review the evidence that redox signaling occurs in chemosensitive areas; and 3) review the evidence that neurons in the solitary complex are stimulated by cellular oxidation.
Collapse
Affiliation(s)
- Jay B Dean
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, University of South Florida, College of Medicine, MDC 8, 12901 Bruce B. Downs Blvd., Tampa, Florida 33612, USA.
| |
Collapse
|
23
|
Chan SHH, Sun EYH, Chang AYW. Extracellular signal-regulated kinase 1/2 plays a pro-life role in experimental brain stem death via MAPK signal-interacting kinase at rostral ventrolateral medulla. J Biomed Sci 2010; 17:17. [PMID: 20226096 PMCID: PMC2848001 DOI: 10.1186/1423-0127-17-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 03/15/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As the origin of a life-and-death signal detected from systemic arterial pressure, which sequentially increases (pro-life) and decreases (pro-death) to reflect progressive dysfunction of central cardiovascular regulation during the advancement towards brain stem death in critically ill patients, the rostral ventrolateral medulla (RVLM) is a suitable neural substrate for mechanistic delineation of this fatal phenomenon. The present study assessed the hypothesis that extracellular signal-regulated kinase 1/2 (ERK1/2), a member of the mitogen-activated protein kinases (MAPKs) that is important for cell survival and is activated specifically by MAPK kinase 1/2 (MEK1/2), plays a pro-life role in RVLM during brain stem death. We further delineated the participation of MAPK signal-interacting kinase (MNK), a novel substrate of ERK in this process. METHODS An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos (Mev; 10 nmol) bilaterally into RVLM of Sprague-Dawley rats was used, in conjunction with cardiovascular, pharmacological and biochemical evaluations. RESULTS Results from ELISA showed that whereas the total ERK1/2 was not affected, augmented phosphorylation of ERK1/2 at Thr202 and Tyr204 in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Furthermore, pretreatment by microinjection into the bilateral RVLM of a specific ERK2 inhibitor, ERK activation inhibitor peptide II (1 nmol); a specific MEK1/2 inhibitor, U0126 (5 pmol); or a specific MNK1/2 inhibitor, CGP57380 (5 pmol) exacerbated the hypotension and blunted the augmented life-and-death signals exhibited during the pro-life phase. Those pretreatments also blocked the upregulated nitric oxide synthase I (NOS I)/protein kinase G (PKG) signaling, the pro-life cascade that sustains central cardiovascular regulatory functions during experimental brain stem death. CONCLUSIONS Our results demonstrated that activation of MEK1/2, ERK1/2 and MNK1/2 in RVLM plays a preferential pro-life role by sustaining the central cardiovascular regulatory machinery during brain stem death via upregulation of NOS I/PKG signaling cascade in RVLM.
Collapse
Affiliation(s)
- Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County 83301, Taiwan
| | | | | |
Collapse
|
24
|
Chang AYW, Chan JYH, Chuang YC, Chan SHH. Brain stem death as the vital determinant for resumption of spontaneous circulation after cardiac arrest in rats. PLoS One 2009; 4:e7744. [PMID: 19888468 PMCID: PMC2766834 DOI: 10.1371/journal.pone.0007744] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 10/05/2009] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Spontaneous circulation returns to less than half of adult cardiac arrest victims who received in-hospital resuscitation. One clue for this disheartening outcome arises from the prognosis that asystole invariably takes place, after a time lag, on diagnosis of brain stem death. The designation of brain stem death as the point of no return further suggests that permanent impairment of the brain stem cardiovascular regulatory machinery precedes death. It follows that a crucial determinant for successful revival of an arrested heart is that spontaneous circulation must resume before brain stem death commences. Here, we evaluated the hypothesis that maintained functional integrity of the rostral ventrolateral medulla (RVLM), a neural substrate that is intimately related to brain stem death and central circulatory regulation, holds the key to the vital time-window between cardiac arrest and resumption of spontaneous circulation. METHODOLOGY/PRINCIPAL FINDINGS An animal model of brain stem death employing the pesticide mevinphos as the experimental insult in Sprague-Dawley rats was used. Intravenous administration of lethal doses of mevinphos elicited an abrupt cardiac arrest, accompanied by elevated systemic arterial pressure and anoxia, augmented neuronal excitability and enhanced microvascular perfusion in RVLM. This period represents the vital time-window between cardiac arrest and resumption of spontaneous circulation in our experimental model. Animals with restored spontaneous circulation exhibited maintained neuronal functionality in RVLM beyond this critical time-window, alongside resumption of baseline tissue oxygen and enhancement of local blood flow. Intriguingly, animals that subsequently died manifested sustained anoxia, diminished local blood flow, depressed mitochondrial electron transport activities and reduced ATP production, leading to necrotic cell death in RVLM. That amelioration of mitochondrial dysfunction and bioenergetic failure in RVLM by coenzyme Q10, the mobile electron carrier in mitochondrial respiratory chain, or oxygenation restored spontaneous circulation further established a causal relationship between functionality of RVLM and resumed spontaneous circulation after cardiac arrest. CONCLUSIONS/SIGNIFICANCE We conclude that whereas necrotic cell death because of bioenergetic failure triggered by anoxia in RVLM, which precipitates brain stem death, negates resuscitation of an arrested heart, maintained functional integrity of this neural substrate holds the key to resumption of spontaneous circulation after cardiac arrest in rats.
Collapse
Affiliation(s)
- Alice Y. W. Chang
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County, Taiwan, Republic of China
- Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan, Republic of China
- * E-mail: (AYWC); (SHHC)
| | - Julie Y. H. Chan
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, Republic of China
| | - Yao-Chung Chuang
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County, Taiwan, Republic of China
- Department of Neurology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung County, Taiwan, Republic of China
| | - Samuel H. H. Chan
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County, Taiwan, Republic of China
- Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan, Republic of China
- * E-mail: (AYWC); (SHHC)
| |
Collapse
|
25
|
Okada S, Yamaguchi-Shima N, Shimizu T, Arai J, Yorimitsu M, Yokotani K. Brain nuclear factor kappa B is involved in the corticotropin-releasing factor-induced central activation of sympatho-adrenomedullary outflow in rats. Eur J Pharmacol 2008; 584:207-12. [PMID: 18304530 DOI: 10.1016/j.ejphar.2008.01.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 01/08/2008] [Accepted: 01/24/2008] [Indexed: 01/30/2023]
Abstract
Using urethane-anesthetized rats, we examined whether an activation of nuclear factor kappa B is involved in the corticotropin-releasing factor-induced increase in plasma levels of catecholamines. An intracerebroventricularly administered corticotropin-releasing factor (1.5 nmol/animal)-induced increase of plasma catecholamines was dose-dependently reduced by pyrrolidine dithiocarbamate (a nuclear factor kappa B antagonist) (1 and 9 nmol/animal, intracerebroventricularly) and SN50 (a peptide inhibiting nuclear factor kappa B translocation) (9 and 18 nmol/animal, intracerebroventricularly), while SN50M (an inactive control peptide for SN50, 19 nmol/animal, intracerebroventricularly) had no effect on the corticotropin-releasing factor-induced elevation of both catecholamines. Furthermore, the corticotropin-releasing factor-induced responses were also attenuated by rosiglitazone (a peroxisome proliferator-activated receptor-gamma agonist)(50 nmol/animal, intracerebroventricularly). These results suggest the involvement of brain nuclear factor kappa B in the corticotropin-releasing factor-induced central activation of the sympatho-adrenomedullary outflow in rats.
Collapse
Affiliation(s)
- Shoshiro Okada
- Department of Pharmacology, Graduate School of Medicine, Kochi University, Nankoku, Kochi 783-8505, Japan.
| | | | | | | | | | | |
Collapse
|
26
|
Mayorov DN. Nitric oxide synthase inhibition in rostral ventrolateral medulla attenuates pressor response to psychological stress in rabbits. Neurosci Lett 2007; 424:89-93. [PMID: 17709184 DOI: 10.1016/j.neulet.2007.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 06/22/2007] [Accepted: 07/20/2007] [Indexed: 01/16/2023]
Abstract
Nitric oxide (NO) has been critically implicated in the central regulation of autonomic function. We recently found, however, that acute (up to 30min) blockade of NO synthase (NOS) in the rostral ventrolateral medulla (RVLM) inhibited sympathetic baroreflex transmission, without altering the cardiovascular response to psychological (air-jet) stress in rabbits. In the present study, we examined the effect of the later phase (1-3h) of NOS inhibition in the RVLM on the pressor and sympathetic responses to air-jet stress in conscious rabbits. Air-jet evoked a sustained increase in blood pressure (+14+/-2mmHg), heart rate (+37+/-9beats/min) and renal sympathetic nerve activity (+52+/-8%). Bilateral microinjection of a NOS inhibitor l-NAME (10nmol) into RVLM did not affect resting parameters or stress responses during the first 30min after injection. Conversely, in the later phase of NOS inhibition, the pressor, tachycardic and renal sympathetic responses to air-jet stress were reversibly attenuated by 48-72%. Microinjection of l-NAME outside the RVLM did not change stress responses. Microinjection of glutamate (3nmol) into the RVLM induced similar pressor effects before and after l-NAME (+30+/-6mmHg and +26+/-6mmHg, respectively). Microinjection of d-NAME altered neither stress responses nor pressor response to glutamate. These results suggest that NOS inhibition in the RVLM has a dual effect on the autonomic response to psychological stress. In the early phase, NOS inhibition has little impact on this response. However, in the later phase, NOS inhibition attenuates the stress response, perhaps via indirect mechanisms such as altering the local redox state.
Collapse
|