Synergistic Effects of Combined Nurr1 Overexpression and Natural Inducers on the More Efficient Production of Dopaminergic Neuron-Like Cells From Stem Cells

The development of dopaminergic (DA) neurons is a very complex process, and a combination of extrinsic and intrinsic factors involves their differentiation. Transcription factor, Nurr1 plays an essential role in the differentiation and maintenance of midbrain DA neurons. Nurr1-based therapies may restore DA function in Parkinson's disease (PD) by replacing damaged cells with differentiated cells derived from stem cells. Providing tissue-specific microenvironments such as brain extract can effectively induce dopaminergic gene expression in stem cells. The present study aimed to investigate the combined effects of Nurr1 gene overexpression and a neonatal rat brain extract (NRBE) induction on dopaminergic differentiation of P19 stem cells. In order to neural differentiation induction, stably Nurr1-transfected cells were treated with 100 μg/ml of NRBE. The differentiation potential of the cells was then evaluated during a period of 1–3 weeks via various methods. The initial evaluation of the cells by direct observation under a light microscope and cresyl violet specific staining, confirmed neuron-like morphology in the differentiated cells. In addition, different molecular and cellular techniques, including real-time PCR, immunofluorescence, and flow cytometry, demonstrated that the treated cells expressed pan-neuronal and dopaminergic markers. In all experimental groups, neuronal phenotype with dopaminergic neuron-like cells characteristics mainly appeared in the second week of the differentiation protocol. Overall, the results of the present study revealed for the first time the synergistic effects of Nurr1 gene overexpression and possible soluble factors that existed in NRBE on the differentiation of P19 stem cells into dopaminergic neuron-like cells.

Activation of TRESK background potassium channels by cloxyquin exerts protective effects against excitotoxic-induced brain injury and neuroinflammation in neonatal rats

The excitotoxicity is a common pathological mechanism of perinatal brain injuries (PBI), however neuroinflammation resulting in PBI is both a cause and a consequence of excitotoxicity. TRESK background potassium channels are an important regulator of neuronal excitability. We therefore investigated effects of activation of TRESK channels by selective activator cloxyquin on excitotoxic-induced brain injury and neuroinflammation involving brain mast cells and inflammatory cytokines in neonatal rats. An excitotoxic model mimicking human perinatal brain lesions was established via intracerebral injection of the glutamatergic agonist ibotenate to into newborn rats. P5 rat pups were intraperitoneally pretreated with vehicle, three different doses of cloxyquin (0.2, 1 and 5 mg/kg), or NMDA receptor antagonist MK-801 (positive control) 30 minutes prior to intracerebral injection of 10 µg ibotenate. Rat pups were sacrificed one or five days after the injury. Coronal brain sections were stained with cresyl-violet for histopathological examinations, and with toluidine-blue for brain mast cells assessments. Concentrations of activin A, IL-1β, IL-6 and IL-10 in brain homogenates were measured using ELISA. Cloxyquin dose-dependently ameliorated ibotenate-induced impairments in the cortical and white matter, and suppressed ibotenate-induced activation and number of brain mast cells. Moreover, cloxyquin dose-dependently reduced concentrations of activin A, IL-1β and IL-6 in the brain tissue induced by ibotenate while it elevated IL-10 level. Our findings reveal for the first time that cloxyquin, a selective activator of TRESK channels, dose-dependently exerted protective effects against excitotoxic-induced neonatal brain injury and neuroinflammation. TRESK channels may be a promising new target for the treatment of PBIs.

CXCL13 Expressed on Inflamed Cerebral Blood Vessels Recruit IL-21 Producing TFH Cells to Damage Neurons Following Stroke.

Background: Ischemic stroke is a leading cause of mortality worldwide, largely due to the inflammatory response to brain ischemia during post-stroke reperfusion. Despite ongoing intensive research, there have not been any clinically approved drugs targeting the inflammatory component to stroke. Preclinical studies have identified T cells as pro-inflammatory mediators of ischemic brain damage, yet mechanisms that regulate the infiltration and phenotype of these cells are lacking. Further understanding of how T cells migrate to the ischemic brain and facilitate neuronal death during brain ischemia can reveal novel targets for post-stroke intervention.Methods: To identify the population of T cells that produce IL-21 and contribute to stroke, we performed transient middle cerebral artery occlusion (tMCAO) in mice and performed flow cytometry on brain tissue. We also utilized immunohistochemistry in both mouse and human brain sections to identify cell types and inflammatory mediators related to stroke-induced IL-21 signaling. To mechanistically demonstrate our findings, we employed pharmacological inhibitor anti-CXCL13 and performed histological analyses with Cresyl violet to evaluate its effects on brain infarct damage. Finally, to evaluate cellular mechanisms of stroke, we exposed mouse primary neurons to oxygen glucose deprivation (OGD) conditions with or without IL-21 and measured cell viability, caspase activity and JAK/STAT signaling.Results: Flow cytometry on brains from mice following tMCAO identified a novel population of cells IL-21 producing CXCR5+ CD4+ ICOS-1+ T follicular helper cells (TFH) in the ischemic brain early after injury. We observed augmented expression of CXCL13 on inflamed brain vascular cells and demonstrated that inhibition of CXCL13 protects mice from tMCAO by restricting the migration and influence of IL-21 producing TFH cells in the ischemic brain. We also illustrate that neurons express IL-21R in the peri-infarct regions of both mice and human stroke tissue in vivo. Lastly, we found that IL-21 acts on mouse primary ischemic neurons to activate the JAK/STAT pathway and induce Caspase 3/7 mediated apoptosis in vitro. Conclusion: These findings identify a novel mechanism for how pro-inflammatory T cells are recruited to the ischemic brain to propagate stroke damage and provide a potential novel therapeutic target for stroke.

A Topographic Atlas of the Human Brainstem in the Ponto-Mesencephalic Junction Plane

The human brainstem harbors neuronal aggregates that ensure the maintenance of several vital functions. It also acts as a major relay structure for the neuronal information that travels between the cerebral cortex, the cerebellum and the spinal cord. As such, this relatively small portion of the human brain houses a multitude of ascending and descending fibers that course among numerous nuclei whose exact boundaries are still uncertain. Such a large number of nuclei and fiber tracts confined to a relatively small and compact brain region imposes upon the brainstem a highly complex cytoarchitectonic organization that still needs to be deciphered. The present work provides a topographic atlas of the human brainstem composed of 45 anatomical plates, each containing a pair of adjacent sections stained with Cresyl Violet and Luxol Fast Blue to help delineating brainstem nuclei and fiber tracts, respectively. The plates, which cover the entire midbrain, pons and medulla oblongata, are composed of equally-spaced sections referenced and aligned parallel to the ponto-mesencephalic junction rather than the fastigium or the obex. This topographic landmark is particularly suitable for neurosurgical interventions aiming at specific nuclei of the mesencephalic tegmentum. In complement, we provide 8 anatomical plates containing adjacent sections stained for choline acetyltransferase and Luxol Fast Blue, taken through the midbrain and the pons. This open access atlas of the human brainstem is intended to assist neuroanatomists, neurosurgeons and neuropathologists in their work.

Visualization of the human enteric nervous system by probe confocal laser endomicroscopy: a first real-time observation of Hirschsprung’s disease and allied disorders

Background Our group previously proved that the human enteric nervous system can be visualized with confocal laser endomicroscopy after topical application of cresyl violet using surgically resected intestine specimens. The present report documents the first in vivo visualization of the human enteric nervous system with confocal laser endomicroscopy using local cresyl violet staining. The aim of this study was to evaluate the technical feasibility and clinical efficiency of confocal laser endomicroscopy in patients with Hirschsprung’s disease and allied disorders in vivo. Methods Confocal laser endomicroscopy was performed in vivo in two patients to confirm the presence of the enteric nervous system during surgery in patients with Hirschsprung’s disease and allied disorders. Cresyl violet was gently injected from the serosal side into the muscular layer of the intestine, and scanning was performed within 30 min. Then, the scanned intestines were resected, and the visualized area of the specimens was pathologically evaluated. Results The ganglion cell nuclei and the enteric nervous system network were clearly visualized intraoperatively in both cases. The morphological findings were similar to the pathological findings of the enteric nervous system in both cases although the period of visibility was brief. Conclusion This study demonstrated the first, real-time observation of the enteric nervous system in humans using confocal laser endomicroscopy and suggest the potential to identify the enteric nervous system intra-operatively during surgery for Hirschsprung’s disease and allied disorders.

Degenerasi dan nekrosis pada neuron penyusun sistem saraf enterik di usus halus dan usus besar tikus yang diinjeksi paraquat dichloride

<p class="MDPI17abstract"><strong>Objective: </strong>In Parkinson's disease (PD) patients, there is a disruption in the function of catecholaminergic neurons in Enteric nervous system (SSE) with some symtoms: constipations and diarrhea. Paraquat dichloride (PQ) is a neurotoxic herbicide which is thought to induce PD. This study aims to study the histological features of neurons in the enteric nervous system of small and large intestines injected with PQ.</p><p class="MDPI17abstract"><strong>Methods: </strong>Ten rats were divided into 2 groups of 5 each. The control group was injected with distilled water and the treatment group was injected with PQ 7 mg/kg BW. The injection was given intraperitoneally, twice a week for 3 weeks with a volume of 1 ml/injection. Small intestine and large intestine were collected and processed for histological preparations in paraffin incisions, then stained with cresyl violet and immunohistochemistry using tyrosine hydroxylase antibody as a marker of catecholaminergic neurons. Intestinal histological preparations were observed under light microscope and analyzed descriptively.<strong></strong></p><p class="MDPI17abstract"><strong>Results: </strong>Neurons in the small intestine and large intestine of normal group rats were observed normal, while in the treatment group some neurons were normal, but some of them became degeneration in the form of chromatolysis, also necrosis which was characterized by damage of cell membranes, karyolysis, loss of most of the Nissl bodies, and decreased numbers of catecholaminergic neurons.<strong></strong></p><p class="MDPI17abstract"><strong>Conclusions: </strong>Paraquat dichloride cause changes in enteric nervous system’s neuron structures in the form of degeneration, necrosis, and a decrease in the number of catecholaminergic neurons in the small intestine and large intestine.</p>

Seizures and Interictal Epileptiform Activity in the Rat Collagenase Model for Intracerebral Hemorrhage

AimsIntracerebral hemorrhage (ICH) is a known risk factor for the development of acute symptomatic as well as late unprovoked seizures. The underlying pathophysiology of post-ICH seizures is incompletely understood and there are no reliable predictive biomarkers. An animal model to study post-ICH seizures is currently lacking. The aim of this study was to investigate (1) the occurrence of seizures and interictal epileptiform activity in the ICH rat collagenase model using long-term video-EEG monitoring (VEM) and (2) whether seizure occurrence was associated with interictal epileptiform activity and histological features.MethodsMale Sprague-Dawley rats were implanted with epidural electrodes. After 1 week of baseline VEM, collagenase was injected in left striatum to induce an ICH. VEM was continued for 180 days to assess the occurrence of post-ICH seizures and interictal epileptiform activity (spikes and epileptiform discharges). At the end of the experiment, animals were euthanized for histological characterization of the hemorrhagic lesion, using cresyl violet, Prussian blue and immunofluorescence staining.ResultsAcute symptomatic seizures occurred in 4/12 animals between 46 and 80 h after ICH induction. Late unprovoked seizures were present in 2/12 animals and started at 90 and 103 days post-ICH. Animals with late unprovoked seizures did not have acute symptomatic seizures. All electrographic seizures were accompanied by clear behavioral changes. Interictal spikes and epileptiform discharges were observed in all animals but occurred more frequently in rats with late seizures (p = 0.019 and p &lt; 0.001, respectively). Animals with acute symptomatic seizures had more extended hemorrhagic lesions and hemosiderin deposits in the piriform cortex.ConclusionBoth acute symptomatic and late unprovoked seizures were observed in the rat collagenase model. Interictal epileptiform activity was more frequently seen in animals with late seizures. Rats with acute symptomatic seizures showed more extensive lesions and hemosiderin deposits in the piriform cortex. This model could be used to further explore possible biomarkers for epileptogenesis.

Adaptation to intermittent hypoxia prevents the decrease in cerebral vascular density in rats with experimental Alzheimer’s disease

Introduction. Patients with Alzheimer’s disease (AD) have reduced cerebral vascular density (VD), which impairs blood flow to neurons and may contribute to progression of AD. Earlier we showed that prior adaptation to intermittent hypobaric hypoxia (IHH) prevented memory loss and degeneration of cortical neurons in rats with experimental AD (EAD). The aim of this study was to test if IHH might prevent EAD-induced vascular rarefaction in rats. Materials and methods. EAD was induced with bilateral injection of neurotoxic beta-amyloid peptide fragment (A) (25–35) into n. basalis magnocellularis. IHH was simulated at a 4,000 m altitude, for 4 hours a day, for 14 days. Brain blood vessels were stained by transcardiac infusion of Indian ink; brain sections were stained with 0.3 % cresyl violet by Nissle method. Vascular density was assessed in the cortex and hippocampus using the Infinity Analysis Software. Results. In the EAD rats, VD was significantly decreased in the hippocampus (13.3±0.9 vs 17.8±1.0 in field of view, FOV, p<0.03) and in the cortex (17.3±1.5 vs 22.3±1.3 in FOV, p<0.03). AIH increased VD in the hippocampus to 27.0±3.5 in FOV (p=0.01) and in cortex to 26.0±1.1 in FOV (p<0.03). In EAD+AIH rats, VD did not differ significantly from the control rats neither in the hippocampus, nor in the cortex. AIH may stimulate angiogenesis through hypoxia inducible factor-1α-mediated expression of vascular endothelial growth factor and/or by increasing expression and activity of antioxidant enzymes. Conclusion. One of the mechanisms of AIH beneficial effect in AD-related neurodegeneration is preserving the capability for compensatory angiogenesis in brain.