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Zilundu PLM, Xu X, Liaquat Z, Wang Y, Zhong K, Fu R, Zhou L. Long-Term Suppression of c-Jun and nNOS Preserves Ultrastructural Features of Lower Motor Neurons and Forelimb Function after Brachial Plexus Roots Avulsion. Cells 2021; 10:1614. [PMID: 34203264 PMCID: PMC8307634 DOI: 10.3390/cells10071614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 12/13/2022] Open
Abstract
Brachial plexus root avulsions cause debilitating upper limb paralysis. Short-term neuroprotective treatments have reported preservation of motor neurons and function in model animals while reports of long-term benefits of such treatments are scarce, especially the morphological sequelae. This morphological study investigated the long-term suppression of c-Jun- and neuronal nitric oxide synthase (nNOS) (neuroprotective treatments for one month) on the motor neuron survival, ultrastructural features of lower motor neurons, and forelimb function at six months after brachial plexus roots avulsion. Neuroprotective treatments reduced oxidative stress and preserved ventral horn motor neurons at the end of the 28-day treatment period relative to vehicle treated ones. Motor neuron sparing was associated with suppression of c-Jun, nNOS, and pro-apoptotic proteins Bim and caspases at this time point. Following 6 months of survival, neutral red staining revealed a significant loss of most of the motor neurons and ventral horn atrophy in the avulsed C6, 7, and 8 cervical segments among the vehicle-treated rats (n = 4). However, rats that received neuroprotective treatments c-Jun JNK inhibitor, SP600125 (n = 4) and a selective inhibitor of nNOS, 7-nitroindazole (n = 4), retained over half of their motor neurons in the ipsilateral avulsed side compared. Myelinated axons in the avulsed ventral horns of vehicle-treated rats were smaller but numerous compared to the intact contralateral ventral horns or neuroprotective-treated groups. In the neuroprotective treatment groups, there was the preservation of myelin thickness around large-caliber axons. Ultrastructural evaluation also confirmed the preservation of organelles including mitochondria and synapses in the two groups that received neuroprotective treatments compared with vehicle controls. Also, forelimb functional evaluation demonstrated that neuroprotective treatments improved functional abilities in the rats. In conclusion, neuroprotective treatments aimed at suppressing degenerative c-Jun and nNOS attenuated apoptosis, provided long-term preservation of motor neurons, their organelles, ventral horn size, and forelimb function.
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Affiliation(s)
- Prince Last Mudenda Zilundu
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
| | - Xiaoying Xu
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
| | - Zaara Liaquat
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen 518100, China;
| | - Yaqiong Wang
- Department of Electron Microscopy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China;
| | - Ke Zhong
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
| | - Rao Fu
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen 518100, China;
| | - Lihua Zhou
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (P.L.M.Z.); (X.X.); (K.Z.)
- Department of Anatomy, School of Medicine, Sun Yat-sen University, Shenzhen 518100, China;
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McBryde FD, Liu BH, Roloff EV, Kasparov S, Paton JFR. Hypothalamic paraventricular nucleus neuronal nitric oxide synthase activity is a major determinant of renal sympathetic discharge in conscious Wistar rats. Exp Physiol 2018; 103:419-428. [PMID: 29215757 DOI: 10.1113/ep086744] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/30/2017] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does chronic reduction of neuronally generated nitric oxide in the hypothalamic paraventricular nucleus affect the set-point regulation of blood pressure and sympathetic activity destined to the kidneys? What is the main finding and its importance? Within the hypothalamic paraventricular nucleus, nitric oxide generated by neuronal nitric oxide synthase plays a major constitutive role in suppressing long term the levels of both ongoing renal sympathetic activity and arterial pressure in conscious Wistar rats. This finding unequivocally demonstrates a mechanism by which the diencephalon exerts a tonic influence on sympathetic discharge to the kidney and may provide the basis for both blood volume and osmolality homeostasis. ABSTRACT The paraventricular nucleus (PVN) of the hypothalamus plays a crucial role in cardiovascular and neuroendocrine regulation. Application of nitric oxide donors to the PVN stimulates GABAergic transmission, and may suppress sympathetic nerve activity (SNA) to lower arterial pressure. However, the role of endogenous nitric oxide within the PVN in regulating renal SNA chronically remains to be established in conscious animals. To address this, we used our previously established lentiviral vectors to knock down neuronal nitric oxide synthase (nNOS) selectively in the PVN of conscious Wistar rats. Blood pressure and renal SNA were monitored simultaneously and continuously for 21 days (n = 14) using radio-telemetry. Renal SNA was normalized to maximal evoked discharge and expressed as a percentage change from baseline. The PVN was microinjected bilaterally with a neurone-specific tetracycline-controllable lentiviral vector, expressing a short hairpin miRNA30 interference system targeting nNOS (n = 7) or expressing a mis-sense as control (n = 7). Recordings continued for a further 18 days. The vectors also expressed green fluorescent protein, and successful expression in the PVN and nNOS knockdown were confirmed histologically post hoc. Knockdown of nNOS expression in the PVN resulted in a sustained increase in blood pressure (from 95 ± 2 to 104 ± 3 mmHg, P < 0.05), with robust concurrent sustained activation of renal SNA (>70%, P < 0.05). The study reveals a major role for nNOS-derived nitric oxide within the PVN in chronic set-point regulation of cardiovascular autonomic activity in the conscious, normotensive rat.
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Affiliation(s)
- F D McBryde
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - B H Liu
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - E V Roloff
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - S Kasparov
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - J F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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Sun JB, Li Y, Cai YF, Huang Y, Liu S, Yeung PK, Deng MZ, Sun GS, Zilundu PL, Hu QS, An RX, Zhou LH, Wang LX, Cheng X. Scutellarin protects oxygen/glucose-deprived astrocytes and reduces focal cerebral ischemic injury. Neural Regen Res 2018; 13:1396-1407. [PMID: 30106052 PMCID: PMC6108207 DOI: 10.4103/1673-5374.235293] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Scutellarin, a bioactive flavone isolated from Scutellaria baicalensis, has anti-inflammatory, anti-neurotoxic, anti-apoptotic and anti-oxidative effects and has been used to treat cardiovascular and cerebrovascular diseases in China. However, the mechanisms by which scutellarin mediates neuroprotection in cerebral ischemia remain unclear. The interaction between scutellarin and nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) was assessed by molecular docking study, which showed that scutellarin selectively binds to NOX2 with high affinity. Cultures of primary astrocytes isolated from the cerebral cortex of neonatal Sprague-Dawley rats were pretreated with 2, 10 or 50 μM scutellarin for 30 minutes. The astrocytes were then subjected to oxygen/glucose deprivation by incubation for 2 hours in glucose-free Dulbecco's modified Eagle's medium in a 95% N2/5% CO2 incubator, followed by simulated reperfusion for 22 hours. Cell viability was assessed by cell counting kit-8 assay. Expression levels of NOX2, connexin 43 and caspase-3 were assessed by western blot assay. Reactive oxygen species were measured spectrophotometrically. Pretreatment with 10 or 50 μM scutellarin substantially increased viability, reduced the expression of NOX2 and caspase-3, increased the expression of connexin 43, and diminished the levels of reactive oxygen species in astrocytes subjected to ischemia-reperfusion. We also assessed the effects of scutellarin in vivo in the rat transient middle cerebral artery occlusion model of cerebral ischemia-reperfusion injury. Rats were given intraperitoneal injection of 100 mg/kg scutellarin 2 hours before surgery. The Bederson scale was used to assess neurological deficit, and 2,3,5-triphenyltetrazolium chloride staining was used to measure infarct size. Western blot assay was used to assess expression of NOX2 and connexin 43 in brain tissue. Enzyme-linked immunosorbent assay was used to detect 8-hydroxydeoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal (4-HNE) and 3-nitrotyrosin (3-NT) in brain tissue. Immunofluorescence double staining was used to determine the co-expression of caspase-3 and NeuN. Pretreatment with scutellarin improved the neurological function of rats with focal cerebral ischemia, reduced infarct size, diminished the expression of NOX2, reduced levels of 8-OHdG, 4-HNE and 3-NT, and reduced the number of cells co-expressing caspase-3 and NeuN in the injured brain tissue. Furthermore, we examined the effect of the NOX2 inhibitor apocynin. Apocynin substantially increased connexin 43 expression in vivo and in vitro. Collectively, our findings suggest that scutellarin protects against ischemic injury in vitro and in vivo by downregulating NOX2, upregulating connexin 43, decreasing oxidative damage, and reducing apoptotic cell death.
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Affiliation(s)
- Jing-Bo Sun
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
| | - Yan Li
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
| | - Ye-Feng Cai
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
| | - Yan Huang
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
| | - Shu Liu
- Department of Anatomy, An Hui Medical University, Hefei, Anhui Province, China
| | - Patrick Kk Yeung
- Department of Biomedical Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Min-Zhen Deng
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
| | - Guang-Shun Sun
- Department of Preventive Medicine, School of Public Health, Zhong Shan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Prince Lm Zilundu
- Guangzhou Department of Anatomy, Zhong Shan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Qian-Sheng Hu
- Department of Preventive Medicine, School of Public Health, Zhong Shan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Rui-Xin An
- Guangzhou Department of Anatomy, Zhong Shan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Li-Hua Zhou
- Guangzhou Department of Anatomy, Zhong Shan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Li-Xin Wang
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
| | - Xiao Cheng
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine; Department of Second Institute of Clinical Medicine, Guangzhou University of Traditional Chinese Medicine; Guangdong Provincial Academy of Chinese Medical Sciences; Guangdong Provincial Chinese Emergency Key Laboratory, Guangzhou, Guangdong Province, China
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Qiao D, Xu J, Le C, Huang E, Liu C, Qiu P, Lin Z, Xie WB, Wang H. Insulin-like growth factor binding protein 5 (IGFBP5) mediates methamphetamine-induced dopaminergic neuron apoptosis. Toxicol Lett 2014; 230:444-53. [DOI: 10.1016/j.toxlet.2014.08.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 07/18/2014] [Accepted: 08/10/2014] [Indexed: 01/28/2023]
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González-Forero D, Moreno-López B. Retrograde response in axotomized motoneurons: nitric oxide as a key player in triggering reversion toward a dedifferentiated phenotype. Neuroscience 2014; 283:138-65. [PMID: 25168733 DOI: 10.1016/j.neuroscience.2014.08.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 08/03/2014] [Accepted: 08/14/2014] [Indexed: 12/11/2022]
Abstract
The adult brain retains a considerable capacity to functionally reorganize its circuits, which mainly relies on the prevalence of three basic processes that confer plastic potential: synaptic plasticity, plastic changes in intrinsic excitability and, in certain central nervous system (CNS) regions, also neurogenesis. Experimental models of peripheral nerve injury have provided a useful paradigm for studying injury-induced mechanisms of central plasticity. In particular, axotomy of somatic motoneurons triggers a robust retrograde reaction in the CNS, characterized by the expression of plastic changes affecting motoneurons, their synaptic inputs and surrounding glia. Axotomized motoneurons undergo a reprograming of their gene expression and biosynthetic machineries which produce cell components required for axonal regrowth and lead them to resume a functionally dedifferentiated phenotype characterized by the removal of afferent synaptic contacts, atrophy of dendritic arbors and an enhanced somato-dendritic excitability. Although experimental research has provided valuable clues to unravel many basic aspects of this central response, we are still lacking detailed information on the cellular/molecular mechanisms underlying its expression. It becomes clear, however, that the state-switch must be orchestrated by motoneuron-derived signals produced under the direction of the re-activated growth program. Our group has identified the highly reactive gas nitric oxide (NO) as one of these signals, by providing robust evidence for its key role to induce synapse elimination and increases in intrinsic excitability following motor axon damage. We have elucidated operational principles of the NO-triggered downstream transduction pathways mediating each of these changes. Our findings further demonstrate that de novo NO synthesis is not only "necessary" but also "sufficient" to promote the expression of at least some of the features that reflect reversion toward a dedifferentiated state in axotomized adult motoneurons.
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Affiliation(s)
- D González-Forero
- Grupo de Neurodegeneración y Neuroreparación (GRUNEDERE), Área de Fisiología, Instituto de Biomoléculas (INBIO), Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain.
| | - B Moreno-López
- Grupo de Neurodegeneración y Neuroreparación (GRUNEDERE), Área de Fisiología, Instituto de Biomoléculas (INBIO), Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain.
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Cheng X, Luo H, Hou Z, Huang Y, Sun J, Zhou L. Neuronal nitric oxide synthase, as a downstream signaling molecule of c‑jun, regulates the survival of differentiated PC12 cells. Mol Med Rep 2014; 10:1881-6. [PMID: 25069402 DOI: 10.3892/mmr.2014.2415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 05/09/2014] [Indexed: 11/05/2022] Open
Abstract
The high expression of c-jun and neuronal nitric oxide synthase (nNOS) generally occurs in neurons following the generation of various animal models of central neuronal diseases. However, the mechanism between them in neuronal disease remains to be elucidated. Our previous studies demonstrated that the expression of c‑jun always occurs prior to expression of nNOS in motoneuron injuries and suppression of c‑jun expression by c‑jun siRNA decreased nNOS expression in differentiated PC12 cells. The present study aimed to examine whether there was an association of up and downstream regulation or crosstalk between c‑jun and nNOS in neurons. Using a culture of differentiated PC12 cells in vitro, the expression of nNOS and c-jun in cells was investigated by immunofluorescence. The nNOS inhibitor 7‑nitroindazole (7‑NI) was used in differentiated PC12 cells to downregulate the expression of nNOS. The optimal concentration of 7‑NI on the viability and survival of cultured differentiated PC12 cells was selected using a 3‑(4,5-dimethylthiazol-2-yl)‑2,5-diphenyltetrazolium assay and the effects of 7‑NI on the activity of constitutive nitric oxide synthase (cNOS) in differentiated PC12 cells were determined using a NOS Activity Detection kit. The effects of 7‑NI on the gene expression of nNOS and c‑jun were detected by western blot analysis. The results from the immunofluorescence demonstrated that the c‑jun and nNOS protein were constantly expressed in PC12 cells. The cell viability of differentiated PC12 cells were significantly inhibited by treatment with 200 and 400 µmol/l 7‑NI, and the expression levels of the nNOS protein were significantly inhibited by treatment with 200 µmol/l 7‑NI. However, 7‑NI had no significant effect on the protein expression level of c‑jun and the total activities of cNOS. Based on our previous studies, which revealed that the nNOS gene was a downstream signaling molecule of the JNK/c‑jun signaling pathway in cultured neurons, the expression of nNOS downstream was able to be regulated by c‑jun which was the upstream molecule. Therefore, these results indicated that the association between them involved up and downregulation instead of crosstalk.
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Affiliation(s)
- Xiao Cheng
- Department of Encephalopathy, Encephalopathy Center, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong 510120, P.R. China
| | - Haoxuan Luo
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Zijun Hou
- Department of Encephalopathy, Encephalopathy Center, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong 510120, P.R. China
| | - Yan Huang
- Department of Encephalopathy, Encephalopathy Center, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong 510120, P.R. China
| | - Jingbo Sun
- Department of Encephalopathy, Encephalopathy Center, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong 510120, P.R. China
| | - Lihua Zhou
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China
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