scholarly journals The Polarization States of Microglia in TBI: A New Paradigm for Pharmacological Intervention

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Hangzhe Xu ◽  
Zhijiang Wang ◽  
Jianru Li ◽  
Haijian Wu ◽  
Yucong Peng ◽  
...  
Keyword(s):  
Brain Injury ◽  
Current Knowledge ◽  
Microglial Cells ◽  
Pharmacological Intervention ◽  
Secondary Brain Injury ◽  
Neuroprotective Effects ◽  
M2 Polarization ◽  
M1 Phenotype ◽  
Polarization States ◽  
M2 Phenotype

Traumatic brain injury (TBI) is a serious medical and social problem worldwide. Because of the complex pathophysiological mechanisms of TBI, effective pharmacotherapy is still lacking. The microglial cells are resident tissue macrophages located in the brain and have two major polarization states, M1 phenotype and M2 phenotype, when activated. The M1 phenotype is related to the release of proinflammatory cytokines and secondary brain injury, while the M2 phenotype has been proved to be responsible for the release of anti-inflammation cytokines and for central nervous system (CNS) repair. In animal models, pharmacological strategies inhibiting the M1 phenotype and promoting the M2 phenotype of microglial cells could alleviate cerebral damage and improve neurological function recovery after TBI. In this review, we aimed to summarize the current knowledge about the pathological significance of microglial M1/M2 polarization in the pathophysiology of TBI. In addition, we reviewed several drugs that have provided neuroprotective effects against brain injury following TBI by altering the polarization states of the microglia. We emphasized that future investigation of the regulation mechanisms of microglial M1/M2 polarization in TBI is anticipated, which could contribute to the development of new targets of pharmacological intervention in TBI.

Abstract T P80: Inhibition of Ezh2 Leads to Decreased M1 and Enhanced M2 Microglia Phenotypes

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Edward Koellhoffer ◽  
Jeremy Grenier ◽  
Rodney Ritzel ◽  
Louise McCullough
Keyword(s):  
Ischemic Stroke ◽  
Pcr Analysis ◽  
M2 Polarization ◽  
M2 Microglia ◽  
M1 Polarization ◽  
Glial Cultures ◽  
M2 Response ◽  
M1 Phenotype ◽  
Cayman Chemical ◽  
M2 Phenotype

Background: Ischemic stroke results in the activation of microglia, which may polarize toward a pro-inflammatory (M1) phenotype or an anti-inflammatory, neuroprotective (M2) phenotype. Thus, simultaneously suppressing the M1 response and promoting the M2 response could be beneficial in the treatment of stroke. Recently, the epigenetic modulator Jmjd3 has been shown to be essential for M2 polarization. However, Jmjd3 is antagonized by Ezh2 which is associated with M1 polarization. Thus, we hypothesized that inhibition of Ezh2 tilts the balance between Jmjd3 and Ezh2, thereby enhancing polarization toward an M2 phenotype and improved outcome in ischemic stroke. Methods: Mixed glial cultures were isolated from P0.5-P2 C57BL/6J mice and cultured for 14 days before microglial isolation. Microglia were rested for 24 hours before treatment every other day with 6uM GSK343 (Cayman Chemical) or DMSO vehicle control. After 7 days, microglia were stimulated with LPS or IL-4 and RNA was isolated at 4hr and 24hr post-stimulation for qRT-PCR analysis. Results: LPS-induced IL6 and IL1B expression was significantly abrogated by 71% and 53%, respectively (p<0.05), at 24hr when Ezh2 was inhibited. Additionally, Ezh2 inhibition both increased baseline expression of M2-associated genes ARG1, CD206, and IRF4 by 196%, 257%, and 395%, respectively (p<0.05), and rescued their expression in the presence of LPS at 24hr (p<0.05) in which they were otherwise significantly down-regulated. Conclusion: Pharmacological inhibition of Ezh2 limits microglial M1 polarization and enhances M2 polarization.

The Role of Free Radicals in Traumatic Brain Injury

2012 ◽  
Vol 15 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Karen M. O’Connell ◽  
Marguerite T. Littleton-Kearney
Keyword(s):  
Traumatic Brain Injury ◽  
Free Radicals ◽  
Free Radical ◽  
Brain Injury ◽  
Current Knowledge ◽  
Cellular Level ◽  
Secondary Brain Injury ◽  
Secondary Injury ◽  
The Military

Traumatic brain injury (TBI) is a significant cause of death and disability in both the civilian and the military populations. The primary impact causes initial tissue damage, which initiates biochemical cascades, known as secondary injury, that expand the damage. Free radicals are implicated as major contributors to the secondary injury. Our review of recent rodent and human research reveals the prominent role of the free radicals superoxide anion, nitric oxide, and peroxynitrite in secondary brain injury. Much of our current knowledge is based on rodent studies, and the authors identified a gap in the translation of findings from rodent to human TBI. Rodent models are an effective method for elucidating specific mechanisms of free radical-induced injury at the cellular level in a well-controlled environment. However, human TBI does not occur in a vacuum, and variables controlled in the laboratory may affect the injury progression. Additionally, multiple experimental TBI models are accepted in rodent research, and no one model fully reproduces the heterogeneous injury seen in humans. Free radical levels are measured indirectly in human studies based on assumptions from the findings from rodent studies that use direct free radical measurements. Further study in humans should be directed toward large samples to validate the findings in rodent studies. Data obtained from these studies may lead to more targeted treatment to interrupt the secondary injury cascades.

Stimulation of dopamine D2 receptor via quinpirole protects against brain damage after brain injury in mice

2020 ◽  
Author(s):  
Sayed Ibrar Alam ◽  
Min Gi Jo ◽  
Min Woo Kim ◽  
Noman Bin Abid ◽  
Myeong OK Kim
Keyword(s):  
Brain Injury ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Cortical Region ◽  
Secondary Brain Injury ◽  
Potential Candidate ◽  
Neuroprotective Effects ◽  
Dopamine D2

Abstract Backgroung Brain injury is a major risk factor for the development of chronic neurodegenerative diseases. The disease still lacks a potential candidate to treat brain injury associated neurodegeneration. In the present study we aims to investigate the expression of Dopamin D2 receptor in the cortical region as well as in striatum of the injured mouse brain and further explored the neuroprotective effects of selective D2R agonist quinpirole against brain injury-associated neuropathological events after brain injury.Methods In order to test our hypothesis, a normal mice were subjected into TBI mouse model by producing penetrating injury using scalpel blade. A dose of 1mg/kg of quinpirole was daily injected to the TBI mice via intraperitonally for 7 days after producing injury. Further, the immunoblots and immunohistochemistry analysis were performed for both in vivo and in vitro.Results Our biochemical and immunohistological results demonstrated that brain injury suppresses the expression levels of D2R and deregulate the downstream signaling molecules in the cortex and striatum afte TBI at day 7. Treatment with a selective D2R agonist quinpirole regulates GSK3-β/IL-1β/Akt signaling and reduced neuroinflamation after brain injury. Concomitantly, Quinpirole treatment regulated Blood brain-barrier breakdown, reduced neuronal apoptosis and regulated synaptic dysfunction after brain injury. This is the first evidence, which showed that quinpirole treatment reduced secondary brain injury-induced neuropathological evidence in the cortex via D2R/Akt/GSK3-β signaling pathway. Moreover, our in vitro results demonstrated that quinpirole reversed MCM-mediated deleterious effects and significantly regulated D2R/GSK3-β/Akt level in HT22 cells.Conclusion Our results suggest that regulation of Dopamine D2 receptor via quinpirole would be a promising therapeutic strategy against brain injury-induced neurodegeneration.

scholarly journals Adenosine A3 receptor as a novel therapeutic target to reduce secondary events and improve neurocognitive functions following traumatic brain injury

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Susan A. Farr ◽  
Salvatore Cuzzocrea ◽  
Emanuela Esposito ◽  
Michela Campolo ◽  
Michael L. Niehoff ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Tissue Injury ◽  
Pathological Condition ◽  
Brain Infarction ◽  
Inflammasome Activation ◽  
Secondary Brain Injury ◽  
Male Mice ◽  
Neuroprotective Effects ◽  
Secondary Tissue

Abstract Background Traumatic brain injury (TBI) is a common pathological condition that presently lacks a specific pharmacological treatment. Adenosine levels rise following TBI, which is thought to be neuroprotective against secondary brain injury. Evidence from stroke and inflammatory disease models suggests that adenosine signaling through the G protein-coupled A3 adenosine receptor (A3AR) can provide antiinflammatory and neuroprotective effects. However, the role of A3AR in TBI has not been investigated. Methods Using the selective A3AR agonist, MRS5980, we evaluated the effects of A3AR activation on the pathological outcomes and cognitive function in CD1 male mouse models of TBI. Results When measured 24 h after controlled cortical impact (CCI) TBI, male mice treated with intraperitoneal injections of MRS5980 (1 mg/kg) had reduced secondary tissue injury and brain infarction than vehicle-treated mice with TBI. These effects were associated with attenuated neuroinflammation marked by reduced activation of nuclear factor of kappa light polypeptide gene enhancer in B cells (NFκB) and MAPK (p38 and extracellular signal-regulated kinase (ERK)) pathways and downstream NOD-like receptor pyrin domain-containing 3 inflammasome activation. MRS5980 also attenuated TBI-induced CD4+ and CD8+ T cell influx. Moreover, when measured 4–5 weeks after closed head weight-drop TBI, male mice treated with MRS5980 (1 mg/kg) performed significantly better in novel object-placement retention tests (NOPRT) and T maze trials than untreated mice with TBI without altered locomotor activity or increased anxiety. Conclusion Our results provide support for the beneficial effects of small molecule A3AR agonists to mitigate secondary tissue injury and cognitive impairment following TBI.

scholarly journals SS-31 Provides Neuroprotection by Reversing Mitochondrial Dysfunction after Traumatic Brain Injury

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yihao Zhu ◽  
Handong Wang ◽  
Jiang Fang ◽  
Wei Dai ◽  
Jiang Zhou ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Mitochondrial Dysfunction ◽  
Nuclear Translocation ◽  
Neurological Diseases ◽  
Neurological Deficits ◽  
Secondary Brain Injury ◽  
Neuroprotective Effects ◽  
Weight Drop ◽  
Ros Scavenger

SS-31, a novel mitochondria-targeted peptide, has been proven to provide neuroprotection in a variety of neurological diseases. Its role as a mitochondrial reactive oxygen species (ROS) scavenger and the underlying pathophysiological mechanisms in traumatic brain injury (TBI) are still not well understood. The aim of the designed study was to investigate the potential neuroprotective effects of SS-31 and fulfill our understanding of the process of the mitochondrial change in the modified Marmarou weight-drop model of TBI. Mice were randomly divided into sham, TBI, TBI + vehicle, and TBI + SS-31 groups in this study. Peptide SS-31 (5 mg/kg) or vehicle was intraperitoneally administrated 30 min after TBI with brain samples harvested 24 h later for further analysis. SS-31 treatment significantly reversed mitochondrial dysfunction and ameliorated secondary brain injury caused by TBI. SS-31 can directly decrease the ROS content, restore the activity of superoxide dismutase (SOD), and decrease the level of malondialdehyde (MDA) and the release of cytochrome c, thus attenuating neurological deficits, brain water content, DNA damage, and neural apoptosis. Moreover, SS-31 restored the expression of SIRT1 and upregulated the nuclear translocation of PGC-1α, which were proved by Western blot and immunohistochemistry. Taken together, these data demonstrate that SS-31 improves the mitochondrial function and provides neuroprotection in mice after TBI potentially through enhanced mitochondrial rebiogenesis. The present study gives us an implication for further clinical research.

scholarly journals Neuroprotective Effect of Fractalkine on Radiation-induced Brain Injury Through Promoting the M2 Polarization of Microglia

2020 ◽  
Author(s):  
Jiaojiao Wang ◽  
Huijiao Pan ◽  
Zhenyu Lin ◽  
Chunjin Xiong ◽  
Chunhua Wei ◽  
...  
Keyword(s):  
Brain Injury ◽  
Spatial Memory ◽  
Neuroprotective Effect ◽  
Inflammatory Factors ◽  
Brain Radiotherapy ◽  
Microglia Polarization ◽  
M1 Phenotype ◽  
Radiation Induced ◽  
Underlying Mechanisms ◽  
M2 Phenotype

Abstract Radiation-induced brain injury (RIBI) is a serious complication in cancer patients receiving brain radiotherapy, and accumulating evidence suggests that microglial activation plays an important role in its pathogenesis. Fractalkine (FKN) is a crucial mediator responsible for the biological activity of microglia. In this study, the effect of FKN on activated microglial after irradiation and RIBI was explored and the underlying mechanisms were investigated. Our study demonstrated treatment with exogenous FKN diminished radiation-induced production of pro-inflammatory factors, such as IL1-β and TNFα, promoted transformation of microglial M1 phenotype to M2 phenotype after irradiation, and partially recovered the spatial memory of irradiated mice. Furthermore, upregulation of FKN/CX3CR1 via FKN lentivirus promoted radiation-induced microglial M2 transformation in the hippocampus and diminished the spatial memory injury of irradiated mice. Furthermore, while inhibiting the expression of CX3CR1, which exclusively expressed on microglia in the brain, the regulatory effect of FKN on microglia and cognitive ability of mice disappeared after radiation. In conclusion, the FKN could attenuate RIBI through the microglia polarization toward M2 phenotype by binding to CX3CR1 on microglia. Our study unveiled an important role of FKN/CX3CR1 in RIBI, indicating that promotion of FKN/CX3CR1 axis could be a promising strategy for the treatment of RIBI.

scholarly journals Perinatal Brain Injury and Inflammation: Lessons from Experimental Murine Models

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2640
Author(s):  
Aisling Leavy ◽  
Eva M. Jimenez Mateos
Keyword(s):  
Brain Injury ◽  
Neuronal Damage ◽  
Current Knowledge ◽  
Treatment Strategies ◽  
Current Treatment ◽  
Neonatal Seizures ◽  
Perinatal Brain Injury ◽  
Neuroprotective Effects ◽  
Neurological Outcomes ◽  
Neurological Effects

Perinatal brain injury or neonatal encephalopathy (NE) is a state of disturbed neurological function in neonates, caused by a number of different aetiologies. The most prominent cause of NE is hypoxic ischaemic encephalopathy, which can often induce seizures. NE and neonatal seizures are both associated with poor neurological outcomes, resulting in conditions such as cerebral palsy, epilepsy, autism, schizophrenia and intellectual disability. The current treatment strategies for NE and neonatal seizures have suboptimal success in effectively treating neonates. Therapeutic hypothermia is currently used to treat NE and has been shown to reduce morbidity and has neuroprotective effects. However, its success varies between developed and developing countries, most likely as a result of lack of sufficient resources. The first-line pharmacological treatment for NE is phenobarbital, followed by phenytoin, fosphenytoin and lidocaine as second-line treatments. While these drugs are mostly effective at halting seizure activity, they are associated with long-lasting adverse neurological effects on development. Over the last years, inflammation has been recognized as a trigger of NE and seizures, and evidence has indicated that this inflammation plays a role in the long-term neuronal damage experienced by survivors. Researchers are therefore investigating the possible neuroprotective effects that could be achieved by using anti-inflammatory drugs in the treatment of NE. In this review we will highlight the current knowledge of the inflammatory response after perinatal brain injury and what we can learn from animal models.

scholarly journals C1q/CTRP1 exerts neuroprotective effects in TBI rats by regulating inflammation and autophagy

2020 ◽  
Author(s):  
Ming Pei ◽  
Chaoqun Wang ◽  
Zhengdong Li ◽  
Jianhua Zhang ◽  
Ping Huang ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Underlying Mechanism ◽  
Inflammatory Factors ◽  
Vehicle Group ◽  
Secondary Brain Injury ◽  
Neuroprotective Effects ◽  
Cerebral Ischemia Reperfusion Injury

AbstractObjectiveC1q/CTRP1 is a newly discovered adiponectin protein, which is highly expressed in adipose and heart tissues. Recent studies have revealed that C1q/CTRP1 can regulate metabolism and inhibit inflammation. CTRP1 is also expressed in brain tissues and vascular cells of human and rat, and research on cerebral hemorrhage and cerebral ischemia-reperfusion injury demonstrates that the CTRP family can attenuate secondary brain injury and exert neuroprotective effects. Thus, this study was designed to explore the role of CTRP1 in traumatic brain injury (TBI) and the underlying mechanism.Main methodsRats were assigned into rCTRP1 group, vehicle group, and sham group. Modified Feeney’s method was used to establish a closed traumatic brain injury model. Morris water maze was used for directional navigation, reverse searching and space exploration tests in rats. In addition, Golgi-Cox staining was utilized to visualize neurons, dendrites and dendritic spines. ELISA was conducted to detect the levels of inflammatory factors (IL-6 and TNF-α). Finally, Western blot was adopted to detect the relative expression of p-mTOR and autophagy-related proteins (Beclin-1 and LC3-II).ResultsCTRP1 improved the behavioral and histopathological outcomes, inhibited the inflammatory response, activated mTOR and decreased autophagy-associated protein synthesis in TBI rats.ConclusionCTRP1 exerts neuroprotective effects in TBI rats by regulating inflammation and autophagy and has potential therapeutic properties after TBI.

scholarly journals The pathogenetic role of cerebral hyperthermia in brain lesion

2017 ◽  
Vol 95 (4) ◽  
pp. 302-309 ◽  
Author(s):  
O. A. Shevelev ◽  
A. V. Butrov ◽  
D. V. Cheboksarov ◽  
N. A. Khodorovich ◽  
N. N. Lapaev ◽  
...  
Keyword(s):  
Brain Injury ◽  
Brain Lesion ◽  
Brain Lesions ◽  
Secondary Brain Injury ◽  
Neuroprotective Effects ◽  
Pathogenetic Role ◽  
Thermal Anomalies ◽  
The Brain

Cerebral hyperthermia is a factor of pathogenesis of secondary brain injury. Microwave recording of temperature allows to identify thermal anomalies in the brain while craniocerebral hypothermia arrests their development. Craniocerebral hypothermia has marked neuroprotective effects in patients with brain lesions.

Evidence for a conditioning effect of inhalational anesthetics on angiographic vasospasm after aneurysmal subarachnoid hemorrhage

2020 ◽  
Vol 133 (1) ◽  
pp. 152-158 ◽  
Author(s):  
Umeshkumar Athiraman ◽  
Diane Aum ◽  
Ananth K. Vellimana ◽  
Joshua W. Osbun ◽  
Rajat Dhar ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Subarachnoid Hemorrhage ◽  
Brain Injury ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Multivariate Logistic Regression Analysis ◽  
Secondary Brain Injury ◽  
Large Artery ◽  
Inhalational Anesthetics ◽  
Angiographic Vasospasm ◽  
Inhalational Anesthetic

OBJECTIVEDelayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) is characterized by large-artery vasospasm, distal autoregulatory dysfunction, cortical spreading depression, and microvessel thrombi. Large-artery vasospasm has been identified as an independent predictor of poor outcome in numerous studies. Recently, several animal studies have identified a strong protective role for inhalational anesthetics against secondary brain injury after SAH including DCI—a phenomenon referred to as anesthetic conditioning. The aim of the present study was to assess the potential role of inhalational anesthetics against cerebral vasospasm and DCI in patients suffering from an SAH.METHODSAfter IRB approval, data were collected retrospectively for all SAH patients admitted to the authors’ hospital between January 1, 2010, and December 31, 2013, who received general anesthesia with either inhalational anesthetics only (sevoflurane or desflurane) or combined inhalational (sevoflurane or desflurane) and intravenous (propofol) anesthetics during aneurysm treatment. The primary outcomes were development of angiographic vasospasm and development of DCI during hospitalization. Univariate and logistic regression analyses were performed to identify independent predictors of these endpoints.RESULTSThe cohort included 157 SAH patients whose mean age was 56 ± 14 (± SD). An inhalational anesthetic–only technique was employed in 119 patients (76%), while a combination of inhalational and intravenous anesthetics was employed in 34 patients (22%). As expected, patients in the inhalational anesthetic–only group were exposed to significantly more inhalational agent than patients in the combination anesthetic group (p < 0.05). Multivariate logistic regression analysis identified inhalational anesthetic–only technique (OR 0.35, 95% CI 0.14–0.89), Hunt and Hess grade (OR 1.51, 95% CI 1.03–2.22), and diabetes (OR 0.19, 95% CI 0.06–0.55) as significant predictors of angiographic vasospasm. In contradistinction, the inhalational anesthetic–only technique had no significant impact on the incidence of DCI or functional outcome at discharge, though greater exposure to desflurane (as measured by end-tidal concentration) was associated with a lower incidence of DCI.CONCLUSIONSThese data represent the first evidence in humans that inhalational anesthetics may exert a conditioning protective effect against angiographic vasospasm in SAH patients. Future studies will be needed to determine whether optimized inhalational anesthetic paradigms produce definitive protection against angiographic vasospasm; whether they protect against other events leading to secondary brain injury after SAH, including microvascular thrombi, autoregulatory dysfunction, blood-brain barrier breakdown, neuroinflammation, and neuronal cell death; and, if so, whether this protection ultimately improves patient outcome.

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