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Kubelt C, Molkewehrum H, Lucius R, Synowitz M, Held-Feindt J, Helmers AK. Influence of Simulated Deep Brain Stimulation on the Expression of Inflammatory Mediators by Human Central Nervous System Cells In Vitro. Neuromolecular Med 2021; 24:169-182. [PMID: 34216357 PMCID: PMC9117383 DOI: 10.1007/s12017-021-08674-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 06/23/2021] [Indexed: 01/04/2023]
Abstract
Deep brain stimulation (DBS) seems to modulate inflammatory processes. Whether this modulation leads to an induction or suppression of inflammatory mediators is still controversially discussed. Most studies of the influence of electrical stimulation on inflammation were conducted in rodent models with direct current stimulation and/or long impulses, both of which differ from the pattern in DBS. This makes comparisons with the clinical condition difficult. We established an in-vitro model that simulated clinical stimulation patterns to investigate the influence of electrical stimulation on proliferation and survival of human astroglial cells, microglia, and differentiated neurons. We also examined its influence on the expression of the inflammatory mediators C-X-C motif chemokine (CXCL)12, CXCL16, CC-chemokin-ligand-2 (CCL)2, CCL20, and interleukin (IL)-1β and IL-6 by these cells using quantitative polymerase chain reaction. In addition, protein expression was assessed by immunofluorescence double staining. In our model, electrical stimulation did not affect proliferation or survival of the examined cell lines. There was a significant upregulation of CXCL12 in the astrocyte cell line SVGA, and of IL-1β in differentiated SH-SY5Y neuronal cells at both messenger RNA and protein levels. Our model allowed a valid examination of chemokines and cytokines associated with inflammation in human brain cells. With it, we detected the induction of inflammatory mediators by electrical stimulation in astrocytes and neurons.
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Affiliation(s)
- Carolin Kubelt
- Department of Neurosurgery, University Medical Center Schleswig-Holstein UKSH, Campus Kiel, Arnold-Heller-Str. 3, House D, 24105, Kiel, Germany
| | - Henri Molkewehrum
- Department of Neurosurgery, University Medical Center Schleswig-Holstein UKSH, Campus Kiel, Arnold-Heller-Str. 3, House D, 24105, Kiel, Germany
| | - Ralph Lucius
- Department of Anatomy, University of Kiel, 24118, Kiel, Germany
| | - Michael Synowitz
- Department of Neurosurgery, University Medical Center Schleswig-Holstein UKSH, Campus Kiel, Arnold-Heller-Str. 3, House D, 24105, Kiel, Germany
| | - Janka Held-Feindt
- Department of Neurosurgery, University Medical Center Schleswig-Holstein UKSH, Campus Kiel, Arnold-Heller-Str. 3, House D, 24105, Kiel, Germany
| | - Ann-Kristin Helmers
- Department of Neurosurgery, University Medical Center Schleswig-Holstein UKSH, Campus Kiel, Arnold-Heller-Str. 3, House D, 24105, Kiel, Germany.
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Ashigai H, Taniguchi Y, Matsukura Y, Ikeshima E, Nakashima K, Mizutani M, Yajima H. Roasted Barley Extract Affects Blood Flow in the Rat Tail and Increases Cutaneous Blood Flow and Skin Temperature in Humans. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:1251-1257. [PMID: 29338262 DOI: 10.1021/acs.jafc.7b04930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Roasted barley extract (RBE, "Mugicha") is a traditional Japanese beverage reported to improve blood viscosity and affect food functionality. RBE is suggested to contain 2,5-diketopiperazines, which are the functional component with neuroprotective and immunostimulatory effects that are produced in food through roasting. In this study, we investigated the effects of RBE on blood circulation, both clinically and in rats. At first, we confirmed five 2,5-diketopiperazine derivatives in RBE by LC-MS analysis. Secondarily, we revealed that RBE affects blood flow in the rat tail and compared the efficacy on rat tail blood flow among five 2,5-diketopiperazines in RBE. Especially, cyclo(d-Phe-l-Pro) was the most effective in increasing blood flow in the rat tail. We also researched the mechanism of cyclo(d-Phe-l-Pro) with rat aorta study. As a result, we confirmed that cyclo(d-Phe-l-Pro) has an effect on vasodilatation through the release of nitric oxide in the vascular endothelium. Finally, we also confirmed that RBE affects cutaneous blood flow and increases skin temperature in humans.
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Affiliation(s)
- Hiroshi Ashigai
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd. , 1-17-5 Namamugi, Tsurumi-ku, Yokohama 230-8628, Japan
| | - Yoshimasa Taniguchi
- Research Laboratories for Key Technologies, Kirin Co., Ltd. , 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Yasuko Matsukura
- Research Laboratories for Key Technologies, Kirin Co., Ltd. , 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Emiko Ikeshima
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd. , 1-17-5 Namamugi, Tsurumi-ku, Yokohama 230-8628, Japan
| | - Keiko Nakashima
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd. , 1-17-5 Namamugi, Tsurumi-ku, Yokohama 230-8628, Japan
| | - Mai Mizutani
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd. , 1-17-5 Namamugi, Tsurumi-ku, Yokohama 230-8628, Japan
| | - Hiroaki Yajima
- Research & Development Planning Department, Research & Development Division, Kirin Co., Ltd. , 4-10-2 Nakano, Nakano-ku, Tokyo 164-0001, Japan
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Ashigai H, Ikeshima E, Koizumi K, Nakashima K, Mizutani M, Yajima H. 2-Ethylpyrazine Induces Vasodilatation by Releasing Nitric Oxide in the Endothelium. Biol Pharm Bull 2017; 40:2153-2157. [PMID: 28966226 DOI: 10.1248/bpb.b17-00551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxygen transportation and regulation of some physiological processes are facilitated by blood flow. Furthermore, blood flow is regulated by various factors such as nitric oxide (NO) and the autonomic nerve system. In modern life, many people suffer from chilliness (hiesho) because of mental stress and an excessive use air-conditioning systems, which induces vasoconstriction in the peripheral skin. In this study, we focused on pyrazine derivatives, particularly compounds that are used as food flavoring materials, and investigated their effects on vascular function and blood flow. We examined the vasodilatory effect of pyrazine derivatives in the rat thoracic aorta and found 2-ethylpyrazine (2-EP) to be the most active pyrazine compound. Additionally, we found that 2-EP induces vasodilatation through the activities of endothelium-derived relaxing factors. 2-EP activates NO synthesis through the effect of endothelial NO synthase in the endothelium. As a result, cyclic GMP levels rise in smooth muscle cells and vasodilatation is induced. We also confirmed that 2-EP increases peripheral blood flow in rats. From these results, we concluded that 2-EP induces vasodilatation by inducing the release of NO and increasing peripheral blood flow.
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Affiliation(s)
- Hiroshi Ashigai
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd
| | - Emiko Ikeshima
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd
| | - Kumiko Koizumi
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd
| | - Keiko Nakashima
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd
| | - Mai Mizutani
- Research Laboratories for Health Science & Food Technologies, Kirin Co., Ltd
| | - Hiroaki Yajima
- Research & Development Planning Department, Research & Development Division, Kirin Co., Ltd
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Integrity of Cerebellar Fastigial Nucleus Intrinsic Neurons Is Critical for the Global Ischemic Preconditioning. Brain Sci 2017; 7:brainsci7100121. [PMID: 28934119 PMCID: PMC5664048 DOI: 10.3390/brainsci7100121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/15/2017] [Accepted: 09/18/2017] [Indexed: 01/25/2023] Open
Abstract
Excitation of intrinsic neurons of cerebellar fastigial nucleus (FN) renders brain tolerant to local and global ischemia. This effect reaches a maximum 72 h after the stimulation and lasts over 10 days. Comparable neuroprotection is observed following sublethal global brain ischemia, a phenomenon known as preconditioning. We hypothesized that FN may participate in the mechanisms of ischemic preconditioning as a part of the intrinsic neuroprotective mechanism. To explore potential significance of FN neurons in brain ischemic tolerance we lesioned intrinsic FN neurons with excitotoxin ibotenic acid five days before exposure to 20 min four-vessel occlusion (4-VO) global ischemia while analyzing neuronal damage in Cornu Ammoni area 1 (CA1) hippocampal area one week later. In FN-lesioned animals, loss of CA1 cells was higher by 22% compared to control (phosphate buffered saline (PBS)-injected) animals. Moreover, lesion of FN neurons increased morbidity following global ischemia by 50%. Ablation of FN neurons also reversed salvaging effects of five-minute ischemic preconditioning on CA1 neurons and morbidity, while ablation of cerebellar dentate nucleus neurons did not change effect of ischemic preconditioning. We conclude that FN is an important part of intrinsic neuroprotective system, which participates in ischemic preconditioning and may participate in naturally occurring neuroprotection, such as "diving response".
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Wang J, Dong WW, Zhang WH, Zheng J, Wang X. Electrical stimulation of cerebellar fastigial nucleus: mechanism of neuroprotection and prospects for clinical application against cerebral ischemia. CNS Neurosci Ther 2014; 20:710-6. [PMID: 24930936 DOI: 10.1111/cns.12288] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 04/28/2014] [Accepted: 05/01/2014] [Indexed: 12/18/2022] Open
Abstract
For around two decades, electrical fastigial nucleus stimulation (FNS) has been demonstrated to induce neuroprotection involving multiple mechanisms. In this review, we summarize the protective effects of FNS against cerebral ischemia through the inhibition of electrical activity around the lesion, excitotoxic damage on neurons, and brain inflammatory response, as well as apoptosis. Moreover, FNS has been reported to promote nerve tissue repair, reconstruction, and neurological rehabilitation and improve stroke-related complications including poststroke cognitive dysfunction, depression, and abnormal heart rate variability. We thus further discuss the potential of FNS for clinical applications. Given the absence of any risk of inducing sublethal damage, FNS may offer a new approach to preconditioned neuroprotection against cerebral ischemia.
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Affiliation(s)
- Jian Wang
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Neurology, The Second People's Hospital of Chengdu, Chengdu, Sichuan, China
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Garcia-Bonilla L, Benakis C, Moore J, Iadecola C, Anrather J. Immune mechanisms in cerebral ischemic tolerance. Front Neurosci 2014; 8:44. [PMID: 24624056 PMCID: PMC3940969 DOI: 10.3389/fnins.2014.00044] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/17/2014] [Indexed: 12/21/2022] Open
Abstract
Stressor-induced tolerance is a central mechanism in the response of bacteria, plants, and animals to potentially harmful environmental challenges. This response is characterized by immediate changes in cellular metabolism and by the delayed transcriptional activation or inhibition of genetic programs that are not generally stressor specific (cross-tolerance). These programs are aimed at countering the deleterious effects of the stressor. While induction of this response (preconditioning) can be established at the cellular level, activation of systemic networks is essential for the protection to occur throughout the organs of the body. This is best signified by the phenomenon of remote ischemic preconditioning, whereby application of ischemic stress to one tissue or organ induces ischemic tolerance (IT) in remote organs through humoral, cellular and neural signaling. The immune system is an essential component in cerebral IT acting simultaneously both as mediator and target. This dichotomy is based on the fact that activation of inflammatory pathways is necessary to establish IT and that IT can be, in part, attributed to a subdued immune activation after index ischemia. Here we describe the components of the immune system required for induction of IT and review the mechanisms by which a reprogrammed immune response contributes to the neuroprotection observed after preconditioning. Learning how local and systemic immune factors participate in endogenous neuroprotection could lead to the development of new stroke therapies.
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Affiliation(s)
- Lidia Garcia-Bonilla
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Corinne Benakis
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Jamie Moore
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Costantino Iadecola
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Josef Anrather
- Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
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Mayo JN, Beard RS, Price TO, Chen CH, Erickson MA, Ercal N, Banks WA, Bearden SE. Nitrative stress in cerebral endothelium is mediated by mGluR5 in hyperhomocysteinemia. J Cereb Blood Flow Metab 2012; 32:825-34. [PMID: 22186670 PMCID: PMC3345916 DOI: 10.1038/jcbfm.2011.185] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hyperhomocysteinemia (HHcy) disrupts nitric oxide (NO) signaling and increases nitrative stress in cerebral microvascular endothelial cells (CMVECs). This is mediated, in part, by protein nitrotyrosinylation (3-nitrotyrosine; 3-NT) though the mechanisms by which extracellular homocysteine (Hcy) generates intracellular 3-NT are unknown. Using a murine model of mild HHcy (cbs(+/-) mouse), we show that 3-NT is significantly elevated in cerebral microvessels with concomitant reductions in serum NO bioavailability as compared with wild-type littermate controls (cbs(+/+)). Directed pharmacology identified a receptor-dependent mechanism for 3-NT formation in CMVECs. Homocysteine increased expression of inducible NO synthase (iNOS) and formation of 3-NT, both of which were blocked by inhibition of metabotropic glutamate receptor-5 (mGluR5) with the specific antagonist 2-methyl-6-(phenylethynyl) pyridine hydrochloride. Activation of mGluR5 is both sufficient and necessary to drive the nitrative stress because direct activation using the mGluR5-specific agonist (RS)-2-chloro-5-hydroxyphenylglycine also increased iNOS expression and 3-NT formation while knockdown of mGluR5 receptor expression by short hairpin RNA (shRNA) blocked their increase in response to Hcy. Nitric oxide derived from iNOS was required for Hcy-mediated formation of 3-NT because the effect was blocked by 1400W. These results provide the first evidence for a receptor-dependent process that explains how plasma Hcy levels control intracellular nitrative stress in cerebral microvascular endothelium.
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Affiliation(s)
- Jamie N Mayo
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
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Davis MF, Lay CC, Chen-Bee CH, Frostig RD. Amount but not pattern of protective sensory stimulation alters recovery after permanent middle cerebral artery occlusion. Stroke 2011; 42:792-8. [PMID: 21317269 DOI: 10.1161/strokeaha.110.607135] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND PURPOSE Using a rodent model of ischemia (permanent middle cerebral artery occlusion), our laboratory previously demonstrated that 4.27 minutes of patterned single-whisker stimulation delivered over 120 minutes can fully protect from impending damage when initiated within 2 hours of permanent middle cerebral artery occlusion ("early"). When initiated 3 hours postpermanent middle cerebral artery occlusion ("late"), stimulation resulted in irreversible damage. Here we investigate the effect of altering pattern, distribution, or amount of stimulation in this model. METHODS We assessed the cortex using functional imaging and histological analysis with altered stimulation treatment protocols. In 2 groups of animals we administered the same number of whisker deflections but in a random rather than patterned fashion distributed either over 120 minutes or condensed into 10 minutes postpermanent middle cerebral artery occlusion. We also tested increased (full-whisker array versus single-whisker) stimulation. RESULTS Early random whisker stimulation (condensed or dispersed) resulted in protection equivalent to early patterned stimulation. Early full-whisker array patterned stimulation also resulted in complete protection but promoted faster recovery. Late full-whisker array patterned stimulation, however, resulted in loss of evoked function and infarct volumes larger than those sustained by single-whisker counterparts. CONCLUSIONS When induced early on after ischemic insult, stimulus-evoked cortical activity, irrespective of the parameters of peripheral stimulation that induced it, seems to be the important variable for neuroprotection.
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Affiliation(s)
- Melissa F Davis
- University of California-Irvine, 2205 McGaugh Hall, Ring Road, Department of Neurobiology & Behavior, UCI, Irvine CA 92697, USA
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Mechanisms of microglia-mediated neurotoxicity in a new model of the stroke penumbra. J Neurosci 2008; 28:2221-30. [PMID: 18305255 DOI: 10.1523/jneurosci.5643-07.2008] [Citation(s) in RCA: 249] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
After an ischemic stroke, neurons in the core are rapidly committed to die, whereas neuron death in the slowly developing penumbra is more amenable to therapeutic intervention. Microglia activation contributes to delayed inflammation, but because neurotoxic mechanisms in the penumbra are not well understood, we developed an in vitro model of microglia activation and propagated neuron killing. To recapitulate inflammatory triggers in the core, microglia were exposed to oxygen glucose-deprived neurons and astrocytes. To model the developing penumbra, the microglia were washed and allowed to interact with healthy naive neurons and astrocytes. We found that oxygen-glucose deprivation (OGD)-stressed neurons released glutamate, which activated microglia through their group II metabotropic glutamate receptors (mGluRs). Microglia activation involved nuclear factor kappaB (NF-kappaB), a transcription factor that promotes their proinflammatory functions. The activated microglia became neurotoxic, killing naive neurons through an apoptotic mechanism that was mediated by tumor necrosis factor-alpha (TNF-alpha), and involved activation of both caspase-8 and caspase-3. In contrast to some earlier models (e.g., microglia activation by lipopolysaccharide), neurotoxicity was not decreased by an inducible nitric oxide synthase (iNOS) inhibitor (S-methylisothiourea) or a peroxynitrite scavenger [5,10,15,20-tetrakis(N-methyl-4'-pyridyl)porphinato iron (III) chloride], and did not require p38 mitogen-activated protein kinase (MAPK) activation. The same microglia neurotoxic behavior was evoked without exposure to OGD-stressed neurons, by directly activating microglial group II mGluRs with (2S,2'R,3'R)-2-(2'3'-dicarboxycyclopropyl) glycine or glutamate, which stimulated production of TNF-alpha (not nitric oxide) and mediated TNF-alpha-dependent neurotoxicity through activation of NF-kappaB (not p38 MAPK). Together, these results support potential therapeutic strategies that target microglial group II mGluRs, TNFalpha overproduction, and NF-kappaB activation to reduce neuron death in the ischemic penumbra.
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Galea E, Heneka MT, Dello Russo C, Feinstein DL. Intrinsic regulation of brain inflammatory responses. Cell Mol Neurobiol 2004; 23:625-35. [PMID: 14514020 DOI: 10.1023/a:1025084415833] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
It is now well accepted that inflammatory responses in brain contribute to the genesis and evolution of damage in neurological diseases, trauma, and infection. Inflammatory mediators including cytokines, cell adhesion molecules, and reactive oxygen species including NO are detected in human brain and its animal models, and interventions that reduce levels or expression of these agents provide therapeutic benefit in many cases. Although in some cases, the causes of central inflammatory responses are clear--for example those due to viral infection in AIDS dementia, or those due to the secretion of proinflammatory substances by activated lymphocytes in multiple sclerosis--in other conditions the factors that allow the initiation of brain inflammation are not well understood; nor is it well known why brain inflammatory activation is not as well restricted as it is in the periphery. The concept is emerging that perturbation of endogenous regulatory mechanisms could be an important factor for initiation, maintenance, and lack of resolution of brain inflammation. Conversely, activation of intrinsic regulatory neuronal pathways could provide protection in neuroinflammatory conditions. This concept is the extension of the principle of "central neurogenic neuroprotection" formulated by Donald Reis and colleagues, which contends the existence of neuronal circuits that protect the brain against the damage initiated by excitotoxic injury. In this paper we will review work initiated in the Reis laboratory establishing that activation of endogenous neural circuits can exert anti-inflammatory actions in brain, present data suggesting that these effects could be mediated by noradrenaline, and summarize recent studies suggesting that loss of noradrenergic locus ceruleus neurons contributes to inflammatory activation in Alzheimer's disease.
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Affiliation(s)
- Elena Galea
- Department of Anesthesiology, University of Illinois, Chicago, Illinois, USA
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Abstract
1. Stimulation of the rostral-ventromedial pole of the cerebellar fastigial nucleus exerts powerful effects on systemic and cerebral circulation. 2. Excitation of fibers passing through the fastigial nucleus evokes sympathoactivation and increases in arterial pressure. 3. Increase in cerebral blood flow evoked by excitation of fibers passing through the FN is mediated by intrinsic brain mechanisms independently of metabolism. 4. Excitation of the fastigial nucleus neurons in contrast decreases arterial pressure and cerebral blood flow. The latter probably is secondary to the suppression of brain metabolism. 5. Excitation of the fastigial nucleus neurons significantly decreases damaging effects of focal and global ischemia on the brain. 6. The fastigial nucleus-evoked neuroprotection can be conditioned: 1-h stimulation protects the brain for up to 3 weeks. 7. Other brain structures such as subthalamic cerebrovasodilator area and dorsal periaqueductal gray matter also produce long-lasting brain salvage when stimulated. 8. More than one mechanism may account for neurogenic neuroprotection. 9. Early neuroprotection, which develops immediately after the stimulation, involves opening of potassium channels. 10. Delayed long-lasting neuroprotection may involve changes in genes expression resulting in suppression of inflammatory reaction and apoptotic cascade. 11. It is conceivable that intrinsic neuroprotective system exists within the brain, which renders the brain more tolerant to adverse stimuli when activated. 12. Knowledge of the mechanisms of neurogenic neuroprotection will allow developing new neuroprotective approaches.
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Affiliation(s)
- Eugene V Golanov
- Department of Neurosurgery, University of Mississippi Mediacl Center, 2500 North State Street, Jackson, Mississippi 39216, USA.
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12
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Galea E, Feinstein DL. Regulation of the expression of the inflammatory nitric oxide synthase (NOS2) by cyclic AMP. FASEB J 1999; 13:2125-37. [PMID: 10593859 DOI: 10.1096/fasebj.13.15.2125] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The enzyme nitric oxide synthase 2 (NOS2), often called inducible NOS, plays a central role in the inflammatory reactions that follow infection or tissue damage. NOS2 has been detected in virtually every cell type, and the NO it produces can perform both beneficial and detrimental actions. It is thus conceivable that regulatory mechanisms exist which control the timing and intensity of NO production by NOS2 in order to outweigh protective effects against detrimental ones. Since cyclic AMP inhibits numerous immunological reactions, studies have been carried out to determine whether cAMP-dependent pathways could inhibit NOS2 expression as well. Pharmacological studies in cultured cells show that, depending on the cell type examined, increased cAMP can exert opposite effects on the endotoxin- or cytokine-induced expression of NOS2, being either stimulatory or inhibitory in macrophages, stimulatory in adipocytes, smooth muscle, skeletal muscle, and brain endothelial cells, and inhibitory in pancreatic, liver, and brain glial cells. Regulation of NOS2 gene transcription appears to be the primary mechanism of action of cAMP, and whether it is stimulatory or inhibitory hinges on the cell-specific regulation of transcription factors including CREB, NF-kappaB, and C/EBP. Cyclic AMP must therefore be considered a modulator rather than a suppressor of NOS2 expression. This review summarizes evidence derived from in vitro studies, considers regulation of NOS2 by cAMP in vivo, and discusses possible therapeutic applications of cAMP treatment.-Galea, E., Feinstein, D. L. Regulation of the expression of the inflammatory nitric oxide synthase (NOS2) by cyclic AMP.
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Affiliation(s)
- E Galea
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Heneka MT, Feinstein DL, Galea E, Gleichmann M, Wüllner U, Klockgether T. Peroxisome proliferator-activated receptor gamma agonists protect cerebellar granule cells from cytokine-induced apoptotic cell death by inhibition of inducible nitric oxide synthase. J Neuroimmunol 1999; 100:156-68. [PMID: 10695726 DOI: 10.1016/s0165-5728(99)00192-7] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cerebellar granule cells (CGCs) can express the inducible isoform of nitric oxide synthase (iNOS) in response to inflammatory stimuli. We demonstrate that induction of iNOS in CGCs by bacterial lipopolysaccharide and pro-inflammatory cytokines results in cell death that was potentiated by excess L-arginine and inhibited by the selective iNOS inhibitor, 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine. The NO-mediated cell death was accompanied by increased caspase-3-like activity, DNA fragmentation and positive terminal transferase dUTP nick end labeling (TUNEL), suggesting that apoptosis mediates CGC cell death. Incubation of CGCs with the non-steroidal anti-inflammatory drugs (NSAIDs), ibuprofen or indomethacin, or with 15-deoxy-delta12,14 prostaglandin J2 (PGJ2) downregulates iNOS expression and reduces subsequent cell death. Since in other cell types, both NSAIDs and PGJ2 can activate the peroxisome proliferator-activated receptor-gamma (PPARgamma) and downregulate cytokine levels and iNOS expression, and since CGCs express PPARgamma in vivo and in vitro, our data suggest that activation of CGC PPARgamma mediates iNOS suppression and reduced cell death. Because PPARgamma is expressed in brains of Alzheimer's Disease (AD) patients, in which neuronal iNOS expression and apoptotic cell death have been described, these results may help explain the basis for the beneficial effects of NSAIDs in AD.
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Affiliation(s)
- M T Heneka
- Department of Neurology, University of Bonn, Germany.
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Intrinsic neurons of fastigial nucleus mediate neurogenic neuroprotection against excitotoxic and ischemic neuronal injury in rat. J Neurosci 1999. [PMID: 10234042 DOI: 10.1523/jneurosci.19-10-04142.1999] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electrical stimulation of the cerebellar fastigial nucleus (FN) elevates regional cerebral blood flow (rCBF) and arterial pressure (AP) and provides long-lasting protection against focal and global ischemic infarctions. We investigated which neuronal element in FN, perikarya or axons, mediates this central neurogenic neuroprotection and whether it also protects against excitotoxicity. In anesthetized rats, the FN was stimulated for 1 hr, and ibotenic acid (IBO) was microinjected unilaterally into the striatum. In unstimulated controls, the excitotoxic lesions averaged approximately 40 mm3. Stimulation of FN, but not dentate nucleus (DN), significantly reduced lesion volumes up to 80% when IBO was injected 15 min, 72 hr, or 10 d, but not 30 d, thereafter. In other rats, intrinsic neurons of FN or DN were destroyed by pretreatment with IBO. Five days later, the FN was stimulated, and 72 hr later, IBO was microinjected into the striatum. Lesions of FN, but not DN, abolished neuroprotection but not the elevations of rCBF and AP elicited from FN stimulation. Excitotoxic lesions of FN, but not DN, also abolished the 37% reduction in focal ischemic infarctions produced by middle cerebral artery occlusion. Excitation of intrinsic FN neurons provides long-lasting, substantial, and reversible protection of central neurons from excitotoxicity, as well as focal ischemia, whereas axons in the nucleus, probably collaterals of ramified brainstem neurons, mediate the elevations in rCBF, which do not contribute to neuroprotection. Long-lived protection against a range of injuries is an unrecognized function of FN neurons transmitted over pathways distinct from those regulating rCBF.
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