Brain Cell Injury Research Articles

Revolutionizing Stroke Care: Nanotechnology-Based Brain Delivery as a Novel Paradigm for Treatment and Diagnosis.

Stroke, a severe medical condition arising from abnormalities in the coagulation-fibrinolysis cycle and metabolic processes, results in brain cell impairment and injury due to blood flow obstruction within the brain. Prompt and efficient therapeutic approaches are imperative to control and preserve brain functions. Conventional stroke medications, including fibrinolytic agents, play a crucial role in facilitating reperfusion to the ischemic brain. However, their clinical efficacy is hampered by short plasma half-lives, limited brain tissue distribution attributed to the blood-brain barrier (BBB), and lack of targeted drug delivery to the ischemic region. To address these challenges, diverse nanomedicine strategies, such as vesicular systems, polymeric nanoparticles, dendrimers, exosomes, inorganic nanoparticles, and biomimetic nanoparticles, have emerged. These platforms enhance drug pharmacokinetics by facilitating targeted drug accumulation at the ischemic site. By leveraging nanocarriers, engineered drug delivery systems hold the potential to overcome challenges associated with conventional stroke medications. This comprehensive review explores the pathophysiological mechanism underlying stroke and BBB disruption in stroke. Additionally, this review investigates the utilization of nanocarriers for current therapeutic and diagnostic interventions in stroke management. By addressing these aspects, the review aims to provide insight into potential strategies for improving stroke treatment and diagnosis through a nanomedicine approach.

Short report: Plasma based biomarkers detect radiation induced brain injury in cancer patients treated for brain metastasis: A pilot study.

Radiotherapy has an important role in the treatment of brain metastases but carries risk of short and/or long-term toxicity, termed radiation-induced brain injury (RBI). As the diagnosis of RBI is crucial for correct patient management, there is an unmet need for reliable biomarkers for RBI. The aim of this proof-of concept study is to determine the utility of brain-derived circulating free DNA (BncfDNA), identified by specific methylation patterns for neurons, astrocytes, and oligodendrocytes, as biomarkers brain injury induced by radiotherapy. Twenty-four patients with brain metastases were monitored clinically and radiologically before, during and after brain radiotherapy, and blood for BncfDNA analysis (98 samples) was concurrently collected. Sixteen patients were treated with whole brain radiotherapy and eight patients with stereotactic radiosurgery. During follow-up nine RBI events were detected, and all correlated with significant increase in BncfDNA levels compared to baseline. Additionally, resolution of RBI correlated with a decrease in BncfDNA. Changes in BncfDNA were independent of tumor response. Elevated BncfDNA levels reflects brain cell injury incurred by radiotherapy. further research is needed to establish BncfDNA as a novel plasma-based biomarker for brain injury induced by radiotherapy.

CD8+ T cells in brain injury and neurodegeneration

The interaction between the peripheral immune system and the brain is increasingly being recognized as an important layer of neuroimmune regulation and plays vital roles in brain homeostasis as well as neurological disorders. As an important population of T-cell lymphocytes, the roles of CD8+ T cells in infectious diseases and tumor immunity have been well established. Recently, increasing number of complex functions of CD8+ T cells in brain disorders have been revealed. However, an advanced summary and discussion of the functions and mechanisms of CD8+ T cells in brain injury and neurodegeneration are still lacking. Here, we described the differentiation and function of CD8+ T cells, reviewed the involvement of CD8+ T cells in the regulation of brain injury including stroke and traumatic brain injury and neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), and discussed therapeutic prospects and future study goals. Understanding these processes will promote the investigation of T-cell immunity in brain disorders and provide new intervention strategies for the treatment of brain injury and neurodegeneration.

Folic acid protects against age-associated apoptosis and telomere attrition of neural stem cells in senescence-accelerated mouse prone 8.

Folic acid (FA) could improve cognitive performances and attenuate brain cell injury in the aging brain, FA supplementation is also associated with inhibiting neural stem cells (NSCs) apoptosis. However, its role in age-associated telomere attrition remains unclear. We hypothesized that FA supplementation attenuates age-associated apoptosis of NSCs via alleviating telomere attrition in senescence-accelerated mouse prone 8 (SAMP8). In this study, 4-month-old male SAMP8 mice were assigned equal numbers to four different diet groups (n=15). Fifteen age-matched senescence-accelerated mouse resistant 1 (SAMR1) (Con-R) were used as the standard aging control group, feeding the FA-normal diet. After folic acid treatment 6-month, all mice were sacrificed. NSCs apoptosis, proliferation, oxidative damage and telomere length have been evaluated by immunofluorescence and Q-fluorescent in situ hybridization. The results showed that FA supplementation inhibited age-associated NSCs apoptosis and prevented telomere attrition in the cerebral cortex of SAMP8 mice. Importantly, this effect might be interpreted by the decreased levels of oxidative damage. In conclusion, we demonstrate it may be one of the mechanisms that FA inhibiting age-associated NSCs apoptosis by alleviating telomere length shortening.

A survey of methods for brain tumor segmentation-based MRI images

Abstract Brain imaging techniques play an important role in determining the causes of brain cell injury. Therefore, earlier diagnosis of these diseases can be led to give rise to bring huge benefits in improving treatment possibilities and avoiding any potential complications that may occur to the patient. Recently, brain tumor segmentation has become a common task in medical image analysis due to its efficacy in diagnosing the type, size, and location of the tumor in automatic methods. Several researchers have developed new methods in order to obtain the best results in brain tumor segmentation, including using deep learning techniques such as the convolutional neural network (CNN). The goal of this survey is to present a brief overview of magnetic resonance imaging (MRI) modalities and discuss common methods of brain tumor segmentation from MRI images, including brain tumor segmentation using deep learning techniques, as well as the most important contributions in this field, which have shown significant improvements in recent years. Finally, we focused in summary on the building blocks of the CNN algorithms used for image segmentation. In entire survey methodology, it has been observed that hybrid techniques and CNN-based segmentation are more effective for brain tumor segmentation from MRI images.

The Weakened Interaction Between HECTD4 and GluN2B in Ischemic Stroke Promotes Calcium Overload and Brain Injury Through a Mechanism Involving the Decrease of GluN2B and MALT1 Ubiquitination.

Glutamate receptor ionotropic NMDA 2B (GluN2B) plays an essential role in calcium overload during excitotoxicity. Reverse-phase nano-liquid chromatography-tandem mass spectrometry has revealed an interaction between GluN2B and HECT domain E3 ubiquitin protein ligase 4 (HECTD4), an E3 ubiquitin ligase highly expressed in the brain. As a potential substrate for HECTD4, mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) acts as a scaffold with hydrolysis activity. This study explores the relationship between HECTD4, GluN2B, and MALT1, focusing on their role in brain injury in ischemic stroke. Rats were subjected to 2h-ischemia followed by 24-h reperfusion to establish an ischemic stroke model. We observed the downregulation of HECTD4 and the upregulation of MALT1. Additionally, an increased GluN2B phosphorylation was concomitant with weakened interactions between HECTD4 and GluN2B, followed by decreased striatal-enriched protein phosphatase (STEP61). Knockdown of HECTD4 exacerbated hypoxia- or NMDA-induced injury in nerve cells coincident with a decrease in GluN2B and MALT1 ubiquitination, and an increase in GluN2B phosphorylation as well as an increase in intracellular calcium level, which were counteracted by MALT1 siRNA. Blockage of MALT1 with its inhibitor or siRNA reduced STEP61 degradation, accompanied by a decrease in GluN2B phosphorylation, intracellular calcium concentration, and brain cell injury, which were reversed by overexpression of MALT1. Based on these observations, we conclude that the downregulation of HECTD4 in ischemic stroke rat brain accounts for calcium overload and brain injury due to activating GluN2B directly and indirectly through a mechanism involving the reduced ubiquitination of GluN2B and MALT1, respectively.

Dipsacoside B Exerts a Beneficial Effect on Brain Injury in the Ischemic Stroke Rat through Inhibition of Mitochondrial E3 Ubiquitin Ligase 1.

Upregulation of mitochondrial E3 ubiquitin ligase 1 (Mul1) contributes to brain injury in ischemic stroke due to disturbance of mitochondrial dynamics, and bioinformatics analysis predicts that Mul1 is a potential target of Dipsacoside B. The aim of the study was to explore whether Dipsacoside B can exert a beneficial effect on brain injury in the ischemic stroke rat via targeting Mul1. The SD rat brains or PC12 cells were subjected to 2 h-ischemia or 8 h-hypoxia plus 24 h-reperfusion or 24 h-reoxygenation to establish the ischemic stroke rat model in vivo or in vitro, which were treated with Dipsacoside B at different dosages. The brain or PC12 cell injury, relevant protein levels and mitochondrial functions were measured by methods of biochemistry, flow cytometry or Western blot. The neurological dysfunction and brain injury (such as infarction and apoptosis) observed in the ischemic stroke rats were accompanied by increases in Mul1 and Dynamin-related protein 1 (Drp1) levels along with decreases in mitofusin 2 (Mfn2) level and ATP production. These effects were attenuated by Dipsacoside B. Consistently, cell injury (necroptosis and apoptosis) occurred in the PC12 cells exposed to hypoxia concomitant with the upregulation of Mul1 and Drp1 along with downregulation of Mfn2 and mitochondrial functions (such as increases in reactive oxygen species production and mitochondrial fission and decreases in mitochondrial membrane potential and ATP production).These phenomena were reversed in the presence of Dipsacoside B. Dipsacoside B can protect the rat brain against ischemic injury via inhibition of Mul1 due to the improvement of mitochondrial function.

The roles, mechanism, and mobilization strategy of endogenous neural stem cells in brain injury

Brain injury poses a heavy disease burden in the world, resulting in chronic deficits. Therapies for brain injuries have been focused on pharmacologic, small molecule, endocrine and cell-based therapies. Endogenous neural stem cells (eNSCs) are a group of stem cells which can be activated in vivo by damage, neurotrophic factors, physical factor stimulation, and physical exercise. The activated eNSCs can proliferate, migrate and differentiate into neuron, oligodendrocyte and astrocyte, and play an important role in brain injury repair and neural plasticity. The roles of eNSCs in the repair of brain injury include but are not limited to ameliorating cognitive function, improving learning and memory function, and promoting functional gait behaviors. The activation and mobilization of eNSCs is important to the repair of injured brain. In this review we describe the current knowledge of the common character of brain injury, the roles and mechanism of eNSCs in brain injury. And then we discuss the current mobilization strategy of eNSCs following brain injury. We hope that a comprehensive awareness of the roles and mobilization strategy of eNSCs in the repair of cerebral ischemia may help to find some new therapeutic targets and strategy for treatment of stroke.

Decreased Expression of CIRP Induced by Therapeutic Hypothermia Correlates with Reduced Early Brain Injury after Subarachnoid Hemorrhage.

Early brain injury is considered to be a primary reason for the poor prognosis of patients suffering from subarachnoid hemorrhage (SAH). Due to its pro-inflammatory activity, cold-inducible RNA-binding protein (CIRP) has been implicated in the ischemic brain insult, but its possible interplay with hypothermia in SAH treatment remains to be evaluated. One-hundred and thirty-eight Sprague-Dawley rats (300–350 g males) were randomly allocated into the following groups: sham-operated (Sham); SAH; and SAH + hypothermia (SAH + H), each comprised of 46 animals. After treatments, the brain tissues of the three groups were randomly collected after 12 h, 1 d, 3 d, and 7 d, and the expression levels of the CIRP and mitochondrial apoptosis pathway-related proteins Bax, Bcl-2, caspase-9, caspase-3, and cytochrome c measured using Western blotting and real-time PCR. Brain damage was assessed by TUNEL and Nissl staining, the electron microscopy of brain tissue slices as well as functional rotarod tests. Expression of CIRP, Bax, caspase-9, caspase-3, and cytochrome c as well as reduced motor function incidence were higher in the SAH group, particularly during the first 3 d after SAH induction. Hypothermia blunted these SAH responses and apoptosis, thereby indicating reduced inflammatory signaling and less brain cell injury in the early period after SAH. Hypothermia treatment was found to effectively protect the brain tissue from early SAH injury in a rat model and its further evaluation as a therapeutic modality in SAH patients requires further study.

Behavioral Assessment of Sensory, Motor, Emotion, and Cognition in Rodent Models of Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is the second most common type of stroke and has one of the highest fatality rates of any disease. There are many clinical signs and symptoms after ICH due to brain cell injury and network disruption resulted from the rupture of a tiny artery and activation of inflammatory cells, such as motor dysfunction, sensory impairment, cognitive impairment, and emotional disturbance, etc. Thus, researchers have established many tests to evaluate behavioral changes in rodent ICH models, in order to achieve a better understanding and thus improvements in the prognosis for the clinical treatment of stroke. This review summarizes existing protocols that have been applied to assess neurologic function outcomes in the rodent ICH models such as pain, motor, cognition, and emotion tests. Pain tests include mechanical, hot, and cold pain tests; motor tests include the following 12 types: neurologic deficit scale test, staircase test, rotarod test, cylinder test, grid walk test, forelimb placing test, wire hanging test, modified neurologic severity score, beam walking test, horizontal ladder test, and adhesive removal test; learning and memory tests include Morris water maze, Y-maze, and novel object recognition test; emotion tests include elevated plus maze, sucrose preference test, tail suspension test, open field test, and forced swim test. This review discusses these assessments by examining their rationale, setup, duration, baseline, procedures as well as comparing their pros and cons, thus guiding researchers to select the most appropriate behavioral tests for preclinical ICH research.

Microglial/Macrophage polarization and function in brain injury and repair after stroke.

Stroke is a leading cause of disability and mortality, with limited treatment options. After stroke injury, microglia and CNS‐resident macrophages are rapidly activated and regulate neuropathological processes to steer the course of functional recovery. To accelerate this recovery, microglia can engulf dying cells and clear irreparably‐damaged tissues, thereby creating a microenvironment that is more suitable for the formation of new neural circuitry. In addition, monocyte‐derived macrophages cross the compromised blood‐brain barrier to infiltrate the injured brain. The specific functions of myeloid lineage cells in brain injury and repair are diverse and dependent on phenotypic polarization statuses. However, it remains to be determined to what degree the CNS‐invading macrophages occupy different functional niches from CNS‐resident microglia. In this review, we describe the physiological characteristics and functions of microglia in the developing and adult brain. We also review (a) the activation and phenotypic polarization of microglia and macrophages after stroke, (b) molecular mechanisms that control polarization status, and (c) the contribution of microglia to brain pathology versus repair. Finally, we summarize current breakthroughs in therapeutic strategies that calibrate microglia/macrophage responses after stroke.

Serum Levels of the Biomarkers Associated with Astrocytosis, Neurodegeneration, and Demyelination: Neurological Benefits of Citicoline Treatment of Patients with Ischemic Stroke and Atrial Fibrillation.

Ischemic stroke is a main complication of atrial fibrillation (cardiac arrhythmia). The aim of our study was to estimate the effects of citicoline (CDP-choline) therapy on the levels of circulating neurospecific protein markers in serum of the patients with ischemic stroke and atrial fibrillation. Fiftyfour patients (mean age 76 years) treated with citicoline in a dose of 2.0 g daily intravenously for 12 to 14 days in addition to basic treatment formed the examined group. Thirty-two patients (mean age 68.5 years) obtained only standard therapy and formed the control group. Serum levels of neuronal and glial protein markers, including glial fibrillary acidic protein (GFAP), a neurofilament light subunit (NF-L), myelin basic protein (MBP), and ionized calcium-binding adaptor molecule 1 (Iba1), were measured in patients of both groups before and after treatment; an immunoblotting technique followed by densitometry analysis were used. Supplementary citicoline treatment provided significant reductions of the levels of GFAP (33%, P = 0.034), NF-L (27%, P = 0.019), and MBP (32%, P = 0.018), as compared to the initial values, while there were no marked changes in the studied parameters in the control group. The results obtained allow us to hypothesize that therapeutic benefit of citicoline in patients with ischemic stroke and atrial fibrillation can be mediated through increasing neuronal viability, protecting against axonal injury, decreasing the level of reactive astrogliosis, preventing deficiencies in the blood-brain integrity, and reducing the intensity of demyelination. However, citicoline administration exerted no effect on the blood content of microglial marker Iba-1, thus possibly preserving an important functional significance of microglia, which is needed to resolve local inflammation and clear cellular debris, and also provide protective factors to reduce cell injury in the ischemic brain. The obtained results indicate that serum levels of neurospecific biomarkers are significant and clinically relevant indices of the efficiency of treatment of the above-mentioned pathologies and can be used for further investigations of the stroke pathophysiology and molecular mechanisms of nootropic-mediated neuroprotection.

Cytokines and neuron-specific proteins in pediatric viral encephalitis and convulsive syndrome. I. Viral encephalitis

Convulsive syndrome in children is manifested in the three forms: febrile convulsions in acute infections, symptomatic convulsions during acute neuroinfection, as well as onset of epilepsy requiring careful differentiation to prescribe adequate therapy. A threat of convulsive syndrome spreads beyond complications related to ongoing infection, because its development is associated with the risk of emerging symptomatic epilepsy in the future. Postencephalitic epilepsy developing in children within the first years after viral encephalitis has been specifically highlighted. A necessity to identify groups at risk of developing epilepsy gave a momentum to seek out for biomarkers of epileptogenesis reflecting the features of systemic and local inflammatory process in the central nervous system during the immune response to infection. Cytokines mainly mediating inflammation are currently examined being studied as candidate biomarkers of the risk of epilepsy. On the other hand, neuron-specific proteins known as inflammation biomarkers identified in various diseases of the central nervous system are being investigated to reveal brain cell injury in neuroinfections and epilepsy. Here we review publications assessing a potential to use inflammation biomarkers (cytokines and neuron-specific proteins) to diagnose and monitor pediatric neurological diseases associated with convulsive syndrome. The first part of the review describes the results of determining the inflammation biomarkers in the blood and cerebrospinal fluid during acute viral encephalitis/encephalopathy associated with various neurotropic viruses (herpes viruses, flaviviruses, enteroviruses). A significance of diverse biomarkers in predicting an outcome and long-term disease consequences are discussed.

Therapeutic Effect of Perioperative Mild Hypothermia on Postoperative Neurological Outcomes in Patients with Acute Stanford Type A Aortic Dissection.

Postoperative patients of acute Stanford type A aortic dissection (AAAD) often experience complications consisting of nervous system injury. Mild hypothermia therapy has been proven to provide the therapeutic effect of cerebral protection. We aimed to investigate the therapeutic effects of perioperative mild hypothermia on postoperative neurological outcomes in patients with AAAD. A prospective randomized controlled study was conducted on adult patients undergoing aortic dissection surgery between February 2017 and December 2017. Patients in the treatment group underwent mild hypothermia (34° to 35°C) immediately after surgery, and in the conventional therapy group, patients were rewarmed to normal body temperature (36° to 37°C). Postoperative time to regain consciousness, postoperative serum neuron-specific enolase (NSE) and S-100β levels, cerebral tissue oxygen saturation, presence of delirium or permanent neurological dysfunction, intensive care unit (ICU) and hospital stay duration, and 28-day mortality were compared. We enrolled 55 patients who underwent AAAD surgery and were randomly allocated into to 2 groups, 27 patients in the treatment group and 28 patients in the conventional therapy group. Compared with the conventional therapy group, postoperative time to regain consciousness was much shorter for patients in the mild hypothermia group (12.65 hours, interquartile range [IQR] 8.28 to 23.82, versus 25.80 hours, IQR 14.00 to 59.80; P = .02), and the rate of regaining consciousness in 24 hours after surgery was much higher (74.07% versus 46.42%; P = .037). At the same time, the ICU stay of patients in the mild hypothermia therapy group was significantly shorter than that in the conventional therapy group (5.53 ± 3.13 versus 9.35 ± 8.76 days; P = .038). Cerebral tissue oxygen saturation, incidence of delirium or permanent neurological dysfunction, duration of hospital stay, and 28-day mortality showed no statistical difference. Postoperative serum NSE and S-100β levels increased compared with preoperative baseline values in both groups (P < .05), and the serum NSE levels of patients in the mild hypothermia therapy was significantly lower than the conventional therapy group 1 hour (P = .049) and 6 hours (P = .04) after surgery. There was no difference in the chest drainage volume or shivering between the 2 groups 24 hours after surgery. Perioperative mild hypothermia therapy is able to significantly reduce brain cell injury and shorten the postoperative time to regain consciousness, thus improving the neurological prognosis of patients with AAAD.

Oxymatrine protects neonatal rat against hypoxic-ischemic brain damage via PI3K/Akt/GSK3β pathway

AimsIn this study we aimed to explore the specific effect and mechanism of oxymatrine on neonatal rats hypoxic-ischemic brain damage. Materials and methodsHypoxia-ischemia damage model was built by ligaturing the left common carotid artery in 7-day-old rat. Rat pups in OMT group received intraperitoneal injection with oxymatrine (120 mg/kg). Oxygen glucose deprivation/reperfusion model was created in hippocampal neurons. Neurological behavioral, histopathological alteration, cell viability, intracellular Ca2+ concentration, MMP and cell apoptosis were used in damage evaluation. Key findingsThe results shown that oxymatrine regulated brain damage and cell apoptosis by controlling NR2B-PI3K/Akt/GSK3β signaling pathway. SignificanceNeonatal hypoxic-ischemic brain damage is a destructive injury that leading to death and detrimental neurological deficits. Oxymatrine is a natural alkaloid compound that can alleviate the ischemic cerebral infarction. In the study, 120 mg/kg oxymatrine decreased neuroethology damage and neuronal damage in the cerebral cortex and the hippocampus CA3. Moreover, 0.2, 1, 5 μg/ml oxymatrine improved cell survival, decreased cell apoptosis. The utilization of LY293004 (PI3K signaling pathway inhibitor) also supported that oxymatrine ameliorated neonatal hypoxic-ischemic brain damage and cell injury by controlling NR2B-PI3K/Akt/GSK3β signaling pathway.

Aralia taibaiensis Protects against I/R-Induced Brain Cell Injury through the Akt/SIRT1/FOXO3a Pathway.

Background Saponin from Aralia taibaiensis (sAT) showed excellent antioxidative effects in several models; however, its effects on brain cells were unknown to us. The present study was designed to evaluate the protective effects of sAT on ischemia/reperfusion- (I/R-) induced injury and clarify its mechanisms. Methods In vitro, HT22 cells were pretreated with sAT and then subjected to I/R. Apoptosis rate, mitochondrial function, and antioxidant proteins were measured. To clarify the mechanisms, siRNA were used. In vivo, sAT was pretreated through intragastric administration for 7 days and the I/R model was induced. The neurobehavioral scores, infarction volumes, and some cytokines in the brain were measured. Protein levels were investigated by Western blotting. Results The results showed that sAT treatment significantly protected cells from I/R-induced cell apoptosis and mitochondrial dysfunction. The antioxidant protein levels were increased in a dose-dependent manner. Further study revealed that sAT induced the deacetylation and phosphorylation of PGC-1α and FOXO3a. sAT treatment also induced the phosphorylation levels of Akt and the expression levels of SIRT1. Using the specific targeted siRNA transfection, the interplay relationship between Akt, SIRT1, PGC-1α, and FOXO3a was verified. Furthermore, the same protective effects were also observed in rats subjected to I/R. Conclusion sAT protected brain cells from I/R-induced mitochondrial oxidative stress and dysfunction through regulating the Akt/SIRT1/FOXO3a/PGC-1α pathway.

Drs. Lambert and Maksymowych reply.

We read with interest the letter in this issue by Hall-Craggs and colleagues1 discussing the developing field of diffusion-weighted imaging (DWI) and its application for quantification of inflammation in rheumatology. As proponents of quantification in medical imaging, we agree that DWI does indeed have some advantages. Its ability to objectively quantify diffusivity of water molecules in the brain was well established many years ago2 and is now absolutely essential for magnetic resonance imaging (MRI) of stroke, providing unique information about brain cell injury due to hypoxia. DWI is now often used for detection and characterization of tumors3. However, its application for assessment of inflammation outside the brain is at an earlier stage of development. One potentially exciting application may be the assessment of synovitis, where conventional sequences have difficulty distinguishing inflamed synovium from effusion without intravenous (IV) injection of a contrast agent. If DWI turns out to be a suitable substitute for the IV injection4, it would be … Address correspondence to Prof. R.G. Lambert, Department of Radiology and Diagnostic Imaging, University of Alberta, 2A2.WMC, 8440-112 St., Edmonton, Alberta T6G 2B7, Canada. E-mail: rlambert{at}ualberta.ca

Ammonium accumulation and chemokine decrease in culture media of Gcdh−/− 3D reaggregated brain cell cultures

Glutaric Aciduria type I (GA-I) is caused by mutations in the GCDH gene. Its deficiency results in accumulation of the key metabolites glutaric acid (GA) and 3-hydroxyglutaric acid (3-OHGA) in body tissues and fluids. Present knowledge on the neuropathogenesis of GA-I suggests that GA and 3-OHGA have toxic properties on the developing brain.We analyzed morphological and biochemical features of 3D brain cell aggregates issued from Gcdh−/− mice at two different developmental stages, day-in-vitro (DIV) 8 and 14, corresponding to the neonatal period and early childhood. We also induced a metabolic stress by exposing the aggregates to 10 mM l-lysine (Lys).Significant amounts of GA and 3-OHGA were detected in Gcdh−/− aggregates and their culture media. Ammonium was significantly increased in culture media of Gcdh−/− aggregates at the early developmental stage. Concentrations of GA, 3-OHGA and ammonium increased significantly after exposure to Lys. Gcdh−/− aggregates manifested morphological alterations of all brain cell types at DIV 8 while at DIV 14 they were only visible after exposure to Lys. Several chemokine levels were significantly decreased in culture media of Gcdh−/− aggregates at DIV 14 and after exposure to Lys at DIV 8.This new in vitro model for brain damage in GA-I mimics well in vivo conditions. As seen previously in WT aggregates exposed to 3-OHGA, we confirmed a significant ammonium production by immature Gcdh−/− brain cells. We described for the first time a decrease of chemokines in Gcdh−/− culture media which might contribute to brain cell injury in GA-I.

Complement-dependent bystander injury to neurons in AQP4-IgG seropositive neuromyelitis optica

BackgroundAquaporin-4-immunoglobulin G (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (herein called NMO) is an autoimmune disease of the central nervous system in which AQP4-IgG binding to AQP4 on astrocytes results in complement-dependent astrocyte injury and secondary inflammation, demyelination, and neuron loss. We previously reported evidence for a complement bystander mechanism for early oligodendrocyte injury in NMO. Herein, we tested the hypothesis that complement bystander injury, which involves diffusion to nearby cells of activated soluble complement components from complement-injured astrocytes, is a general phenomenon that may contribute to neuronal injury in NMO.MethodsPrimary cocultures of rat astrocytes and cortical neurons were established to study complement-dependent cell death after exposure to AQP4-IgG and complement. In animal experiments, AQP4-IgG was delivered to adult rats by intracerebral injection. Cell cultures and rat brain were studied by immunofluorescence.ResultsIn primary astrocyte-neuron cocultures, addition of AQP4-IgG and complement resulted in death of neurons nearby astrocytes. Deposition of complement membrane attack complex C5b-9 was seen on neurons nearby astrocytes, whereas C1q, the initiating protein in the complement pathway, was seen only on astrocytes. Neuron death was not seen with a complement inhibitor, with C1q- or C6-depleted complement, in pure neuron cultures exposed to AQP4-IgG and complement or in cocultures exposed to an astrocyte toxin. Intracerebral injection in rats of AQP4-IgG and a fixable dead cell fluorescent marker produced death of neurons near astrocytes, with C5b-9 deposition. Neuron death was not seen in rats receiving a complement inhibitor or in AQP4-IgG-injected AQP4 knockout rats.ConclusionThese results support a novel mechanism for early neuron injury in NMO and provide evidence that complement bystander injury may be a general phenomenon for brain cell injury following AQP4-IgG-targeted astrocyte death.

Proceedings from the NIMH symposium on "NeuroAIDS in Africa: neurological and neuropsychiatric complications of HIV".

Despite major advances in HIV-1 treatment, the prevalence of HIV-associated neurocognitive disorders (HAND) remains a problem, particularly as individuals on suppressive treatment continue to live longer. To facilitate discussion on emerging and future directions in HAND research, a meeting was held in Durban, South Africa in March 2015 as part of the Society of Neuroscientists of Africa (SONA) conference. The objective of the meeting was to assess the impact of HIV subtype diversity on HAND and immunological dysfunction. The meeting brought together international leaders in the area of neurological complications of HIV-1 infection with special focus on the African population. Research presentations indicated that HAND was highly prevalent and that inflammatory cytokines and immune-activation played important roles in progression of neurocognitive impairment. Furthermore, children on antiretroviral therapy were also at risk for developing neurocognitive impairment. With respect to the effect of HIV-1 subtype diversity, analyses of HIV-1 clade C infection among South Africans revealed that clade C infection induced cognitive impairment that was independent of the substitution in HIV-1 Trans-Activator of Transcription (Tat; C31S). At the cellular level, a Zambian study showed that clade C infection resulted in reduced brain cell death compared with clade B infection suggesting clade specific variations in mediating brain cell injury. Furthermore, ex vivo Tat protein from clade CRF02_AG, prevalent in West/ Central Africa, exhibited reduced disruption of brain endothelium compared with clade B Tat protein. Discussions shed light on future research directions aimed at understanding biomarkers and disease mechanisms critical for HAND.