Astrocyte-Derived CCL2 is Associated with M1 Activation and Recruitment of Cultured Microglial Cells

Background/Aims: Microglia are an essential player in central nervous system inflammation. Recent studies have demonstrated that the astrocytic chemokine, CCL2, is associated with microglial activation in vivo. However, CCL2-induced microglial activation has not yet been studied in vitro. The purpose of the current study was to understand the role of astrocyte-derived CCL2 in microglial activation and to elucidate the underlying mechanism(s). Methods: Primary astrocytes were pre-treated with CCL2 siRNA and stimulated with TNF-α. The culture medium (CM) was collected and added to cultures of microglia, which were incubated with and without CCR2 inhibitor. Microglial cells were analyzed by quantitative RT-PCR to determine whether they polarized to the M1 or M2 state. Microglial migratory ability was assessed by transwell migration assay. Results: TNF-α stimulated the release of CCL2 from astrocytes, even if the culture media containing TNF-α was replaced with fresh media after 3 h. CM from TNF-α-stimulated astrocytes successfully induced microglial activation, which was ascertained by increased activation of M1 and enhanced migration ability. In contrast, CM from astrocytes pretreated with CCL2 siRNA showed no effect on microglial activation, compared to controls. Additionally, microglia pre-treated with RS102895, a CCR2 inhibitor, were resistant to activation by CM from TNF-α-stimulated astrocytes. Conclusion: This study demonstrates that the CCL2/CCR2 pathway of astrocyte-induced microglial activation is associated with M1 polarization and enhanced migration ability, indicating that this pathway could be a useful target to ameliorate inflammation in the central nervous system.

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Paeoniflorin Attenuates Inflammatory Pain by Inhibiting Microglial Activation and Akt-NF-κB Signaling in the Central Nervous System

Cellular Physiology and Biochemistry ◽

10.1159/000490076 ◽

2018 ◽

Vol 47 (2) ◽

pp. 842-850 ◽

Cited By ~ 14

Author(s):

Bo Hu ◽

Guangtao Xu ◽

Xiaomin Zhang ◽

Long Xu ◽

Hong Zhou ◽

...

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Signaling Pathway ◽

Inflammatory Pain ◽

Microglial Activation ◽

Enzyme Linked Immunosorbent Assay ◽

Pain Model ◽

The Central Nervous System

Background/Aims: Paeoniflorin (PF) is known to have anti-inflammatory and paregoric effects, but the mechanism underlying its analgesic effect remains unclear. The aim of this study was to clarify the effect of PF on Freund’s complete adjuvant (CFA)-induced inflammatory pain and explore the underlying molecular mechanism. Methods: An inflammatory pain model was established by intraplantar injection of CFA in C57BL/6J mice. After intrathecal injection of PF daily for 8 consecutive days, thermal and mechanical withdrawal thresholds, the levels of inflammatory factors TNF-α, IL-1β and IL-6, microglial activity, and the expression of Akt-NF-κB signaling pathway in the spinal cord tissue were detected by animal ethological test, cell culture, enzyme-linked immunosorbent assay, immunofluorescence histochemistry, and western blot. Results: PF inhibited the spinal microglial activation in the CFA-induced pain model. The production of proinflammatory cytokines was decreased in the central nervous system after PF treatment both in vivo and in vitro. PF further displayed a remarkable effect on inhibiting the activation of Akt-NF-κB signaling pathway in vivo and in vitro. Conclusion: These results suggest that PF is a potential therapeutic agent for inflammatory pain and merits further investigation.

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INFLUENCE OF ANESTHESIA ON EXPERIMENTAL NEUROTROPIC VIRUS INFECTIONS

Journal of Experimental Medicine ◽

10.1084/jem.84.4.277 ◽

1946 ◽

Vol 84 (4) ◽

pp. 277-292 ◽

Cited By ~ 6

Author(s):

S. Edward Sulkin ◽

Christine Zarafonetis ◽

Andres Goth

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Diethyl Ether ◽

Cervical Region ◽

Virus Infections ◽

Ether Anesthesia ◽

Neurotropic Virus ◽

Experimental Infections

Anesthesia with diethyl ether significantly alters the course and outcome of experimental infections with the equine encephalomyelitis virus (Eastern or Western type) or with the St. Louis encephalitis virus. No comparable effect is observed in experimental infections produced with rabies or poliomyelitis (Lansing) viruses. The neurotropic virus infections altered by ether anesthesia are those caused by viruses which are destroyed in vitro by this anesthetic, and those infections not affected by ether anesthesia are caused by viruses which apparently are not destroyed by ether in vitro. Another striking difference between these two groups of viruses is their pathogenesis in the animal host; those which are inhibited in vivo by ether anesthesia tend to infect cells of the cortex, basal ganglia, and only occasionally the cervical region of the cord. On the other hand, those which are not inhibited in vivo by ether anesthesia tend to involve cells of the lower central nervous system and in the case of rabies, peripheral nerves. This difference is of considerable importance in view of the fact that anesthetics affect cells of the lower central nervous system only in very high concentrations. It is obvious from the complexity of the problem that no clear-cut statement can be made at this point as to the mechanism of the observed effect of ether anesthesia in reducing the mortality rate in certain of the experimental neurotropic virus infections. Important possibilities include a direct specific effect of diethyl ether upon the virus and a less direct effect of the anesthetic upon the virus through its alteration of the metabolism of the host cell.

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Polo-Like Kinase 4 (PLK4) Is Overexpressed in Central Nervous System Neuroblastoma (CNS-NB)

Bioengineering ◽

10.3390/bioengineering5040096 ◽

2018 ◽

Vol 5 (4) ◽

pp. 96 ◽

Cited By ~ 5

Author(s):

Anders Bailey ◽

Amreena Suri ◽

Pauline Chou ◽

Tatiana Pundy ◽

Samantha Gadd ◽

...

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Brain Tumors ◽

Meta Analysis ◽

P Value ◽

Embryonal Tumors ◽

Expression Levels ◽

Embryonal Brain

Neuroblastoma (NB) is the most common extracranial solid tumor in pediatrics, with rare occurrences of primary and metastatic tumors in the central nervous system (CNS). We previously reported the overexpression of the polo-like kinase 4 (PLK4) in embryonal brain tumors. PLK4 has also been found to be overexpressed in a variety of peripheral adult tumors and recently in peripheral NB. Here, we investigated PLK4 expression in NBs of the CNS (CNS-NB) and validated our findings by performing a multi-platform transcriptomic meta-analysis using publicly available data. We evaluated the PLK4 expression by quantitative real-time PCR (qRT-PCR) on the CNS-NB samples and compared the relative expression levels among other embryonal and non-embryonal brain tumors. The relative PLK4 expression levels of the NB samples were found to be significantly higher than the non-embryonal brain tumors (p-value < 0.0001 in both our samples and in public databases). Here, we expand upon our previous work that detected PLK4 overexpression in pediatric embryonal tumors to include CNS-NB. As we previously reported, inhibiting PLK4 in embryonal tumors led to decreased tumor cell proliferation, survival, invasion and migration in vitro and tumor growth in vivo, and therefore PLK4 may be a potential new therapeutic approach to CNS-NB.

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A genome-wide view of the de-differentiation of central nervous system endothelial cells in culture

eLife ◽

10.7554/elife.51276 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 8

Author(s):

Mark F Sabbagh ◽

Jeremy Nathans

Keyword(s):

Central Nervous System ◽

Endothelial Cells ◽

Nervous System ◽

In Vitro Culture ◽

Vascular Endothelial Cells ◽

Beta Catenin ◽

A Genome ◽

Accessible Chromatin

Vascular endothelial cells (ECs) derived from the central nervous system (CNS) variably lose their unique barrier properties during in vitro culture, hindering the development of robust assays for blood-brain barrier (BBB) function, including drug permeability and extrusion assays. In previous work (Sabbagh et al., 2018) we characterized transcriptional and accessible chromatin landscapes of acutely isolated mouse CNS ECs. In this report, we compare transcriptional and accessible chromatin landscapes of acutely isolated mouse CNS ECs versus mouse CNS ECs in short-term in vitro culture. We observe that standard culture conditions are associated with a rapid and selective loss of BBB transcripts and chromatin features, as well as a greatly reduced level of beta-catenin signaling. Interestingly, forced expression of a stabilized derivative of beta-catenin, which in vivo leads to a partial conversion of non-BBB CNS ECs to a BBB-like state, has little or no effect on gene expression or chromatin accessibility in vitro.

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Visualizing the Potential Impairment of Polymyxin B to Central Nervous System Through MR Susceptibility-Weighted Imaging

Frontiers in Pharmacology ◽

10.3389/fphar.2021.784864 ◽

2021 ◽

Vol 12 ◽

Author(s):

Ni Zhang ◽

Lichong Zhu ◽

Qiuhong Ouyang ◽

Saisai Yue ◽

Yichun Huang ◽

...

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Polymyxin B ◽

Susceptibility Weighted Imaging ◽

Gram Negative Bacteria ◽

Severe Toxicity ◽

Gram Negative ◽

The Impact

Polymyxin B (PMB) exert bactericidal effects on the cell wall of Gram-negative bacteria, leading to changes in the permeability of the cytoplasmic membrane and resulting in cell death, which is sensitive to the multi-resistant Gram-negative bacteria. However, the severe toxicity and adverse side effects largely hamper the clinical application of PMB. Although the molecular pathology of PMB neurotoxicity has been adequately studied at the cellular and molecular level. However, the impact of PMB on the physiological states of central nervous system in vivo may be quite different from that in vitro, which need to be further studied. Therefore, in the current study, the biocompatible ultra-uniform Fe3O4 nanoparticles were employed for noninvasively in vivo visualizing the potential impairment of PMB to the central nervous system. Systematic studies clearly reveal that the prepared Fe3O4 nanoparticles can serve as an appropriate magnetic resonance contrast agent with high transverse relaxivity and outstanding biosafety, which thus enables the following in vivo susceptibility-weighted imaging (SWI) studies on the PMB-treated mice models. As a result, it is first found that the blood-brain barrier (BBB) of mice may be impaired by successive PMB administration, displaying by the discrete punctate SWI signals distributed asymmetrically across brain regions in brain parenchyma. This result may pave a noninvasive approach for in-depth studies of PMB medication strategy, monitoring the BBB changes during PMB treatment, and even assessing the risk after PMB successive medication in multidrug-resistant Gram-negative bacterial infected patients from the perspective of medical imaging.

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Mitochondrial Calcium Uptake Capacity Modulates Neocortical Excitability

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2013.61 ◽

2013 ◽

Vol 33 (7) ◽

pp. 1115-1126 ◽

Cited By ~ 23

Author(s):

Basavaraju G Sanganahalli ◽

Peter Herman ◽

Fahmeed Hyder ◽

Sridhar S Kannurpatti

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Cell Types ◽

Dependent Manner ◽

Evoked Responses ◽

Blood Oxygen Level ◽

Calcium Uniporter ◽

Sensory Evoked

Local calcium (Ca2 +) changes regulate central nervous system metabolism and communication integrated by subcellular processes including mitochondrial Ca2 + uptake. Mitochondria take up Ca2 + through the calcium uniporter (mCU) aided by cytoplasmic microdomains of high Ca2 +. Known only in vitro, the in vivo impact of mCU activity may reveal Ca2 + -mediated roles of mitochondria in brain signaling and metabolism. From in vitro studies of mitochondrial Ca2 + sequestration and cycling in various cell types of the central nervous system, we evaluated ranges of spontaneous and activity-induced Ca2 + distributions in multiple subcellular compartments in vivo. We hypothesized that inhibiting (or enhancing) mCU activity would attenuate (or augment) cortical neuronal activity as well as activity-induced hemodynamic responses in an overall cytoplasmic and mitochondrial Ca2 + -dependent manner. Spontaneous and sensory-evoked cortical activities were measured by extracellular electrophysiology complemented with dynamic mapping of blood oxygen level dependence and cerebral blood flow. Calcium uniporter activity was inhibited and enhanced pharmacologically, and its impact on the multimodal measures were analyzed in an integrated manner. Ru360, an mCU inhibitor, reduced all stimulus-evoked responses, whereas Kaempferol, an mCU enhancer, augmented all evoked responses. Collectively, the results confirm aforementioned hypotheses and support the Ca2 + uptake-mediated integrative role of in vivo mitochondria on neocortical activity.

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Design, fabrication, and testing of a bioprinted nerve graft

10.32469/10355/71260 ◽

2016 ◽

Author(s):

◽

Christopher M. Owens

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Nerve Graft ◽

Loss Of Function ◽

Vitro Assay ◽

Central Nervous System Damage ◽

In Vivo Animal Model ◽

The Central Nervous System

Injuries to nerves vary in their consequences, from weakened sensation and motor function to partial or complete paralysis. In the latter case, affecting about twenty thousand Americans yearly, the injury is debilitating and results in a significant decrease in quality of life. Currently there is no effective treatment for damage to the central nervous system, in particular the spinal cord. Compared to the injuries to the central nervous system, damage in the peripheral nerves, is more common, with about sixty thousand occurrences annually. The cost of associated surgical procedures and due to loss of function is in the billions. In this thesis we present work towards the construction and testing of a fully cellular, patented nerve graft, one amongst the first of its kind. For the fabrication of the graft we are the first to employ bioprinting (either implemented through a special purpose 3D bioprinter or manually), a novel tissue engineering method rapidly gaining acceptance and utility. We first review the status of bioprinting. We then detail the fabrication process. Next we report on the testing of the graft in an in vivo animal model through electrophysiology and histology. This is followed by the introduction of a novel in vitro model, aimed at providing a fast, inexpensive and reliable method to test engineered nerve grafts. We describe our work on the optimization of the in vitro assay and then the testing of the graft using the optimized assay. We conclude with a summary of our accomplishments and make suggestions for some exciting future applications of our approach.

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Neurotrophins affect the pattern of DRG neurite growth in a bioassay that presents a choice of CNS and PNS substrates

Development ◽

10.1242/dev.121.5.1301 ◽

1995 ◽

Vol 121 (5) ◽

pp. 1301-1309 ◽

Cited By ~ 1

Author(s):

R. Tuttle ◽

W.D. Matthew

Keyword(s):

Spinal Cord ◽

Central Nervous System ◽

Nervous System ◽

Sciatic Nerve ◽

Sympathetic Neurons ◽

Neurite Growth ◽

Drg Neurons ◽

Substrate Preferences

Neurons can be categorized in terms of where their axons project: within the central nervous system, within the peripheral nervous system, or through both central and peripheral environments. Examples of these categories are cerebellar neurons, sympathetic neurons, and dorsal root ganglion (DRG) neurons, respectively. When explants containing one type of neuron were placed between cryosections of neonatal or adult sciatic nerve and neonatal spinal cord, the neurites exhibited a strong preference for the substrates that they would normally encounter in vivo: cerebellar neurites generally extended only on spinal cord, sympathetic neurites on sciatic nerve, and DRG neurites on both. Neurite growth from DRG neurons has been shown to be stimulated by neurotrophins. To determine whether neurotrophins might also affect the substrate preferences of neurites, DRG were placed between cryosections of neonatal spinal cord and adult sciatic nerve and cultured for 36 to 48 hours in the presence of various neurotrophins. While DRG cultured in NGF-containing media exhibited neurite growth over both spinal cord and sciatic nerve substrates, in the absence of neurotrophins DRG neurites were found almost exclusively on the CNS cryosection. To determine whether these neurotrophin-dependent neurite patterns resulted from the selective survival of subpopulations of DRG neurons with distinct neurite growth characteristics, a type of rescue experiment was performed: DRG cultured in neurotrophin-free medium were fed with NGF-containing medium after 36 hours in vitro and neurite growth examined 24 hours later; most DRG exhibited extensive neurite growth on both peripheral and central nervous system substrates.(ABSTRACT TRUNCATED AT 250 WORDS)

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