Abstracts


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Intravenous Implanted Neural Stem Cells Migrate to Injury Site, Reduce Infarct Volume, and Improve Behavior after Cerebral Ischemia
Chiung-Chyi Shen, Chen-Huan Lin, Yi-Chin Yang, Ming-Tsang Chiao, Wen-Yu Cheng and Jiunn-Liang Ko

Stroke represents one of the leading causes of death and disability in humans, but despite intense research, only a few options exist for the treatment of stroke-related infarction of brain tissue. Thus far, in experimental strokes, cell therapy appears to partly reverse some behavioral deficits. However, the mechanisms of action remain uncertain as most studies reveal only little, if any, evidence for neuronal replacement and observed behavioral improvements. This present study was performed to test rodent fetus forebrain derived neural stem cells (NSCs) implantation into rats subjected to suture-induced middle cerebral artery occlusion (MCAO). Efficacy of cell therapy was studied regarding behavior recovery, infarct volume, and protection possibility of related molecular mechanisms. Here, we show that grafted cells can home in on damaged regions by MCAO and significantly improve behavior of ischemic rats. Infarct volumes and brain atrophy were diminished after grafted NSCs treatment. Furthermore, we detected inflammation related molecules such as COX-2 and IL-1β and found that grafted NSCs treatment after ischemic stroke could repress expression of inflammation molecular protein levels. We also detected protein levels of heat shock protein 27 (HSP27) as a protective protein against apoptosis. The results showed that grafted NSCs treatment induced the protein level of HSP27 and down-regulated activity of caspase-3 compared with the vehicle control. Our results demonstrate that transplanted NSCs provide benefits in behavioral function recovery after MCAO and increase neuroprotection whilst repressing inflammatory destruction. These data reveal another essential explanation of cellular transplantation therapy in damage recovery from ischemic stroke and offer new therapeutic possibilities.


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Early Apoptotic Vascular Signaling is Determined by Sirt1 Through Nuclear Shuttling, Forkhead Trafficking, Bad, and Mitochondrial Caspase Activation
Jinling Hou, Zhao Zhong Chong, Yan Chen Shangand Kenneth Maiese

Complications of diabetes mellitus (DM) weigh heavily upon the endothelium that ultimately affect multiple organ systems. These concerns call for innovative treatment strategies that employ molecular pathways responsible for cell survival and longevity. Here we show in a clinically relevant model of DM with elevated D-glucose that endothelial cell (EC) SIRT1 is vital for the prevention of early membrane apoptotic phosphatidylserine externalization and subsequent DNA degradation supported by studies with modulation of SIRT1 activity and gene knockdown of SIRT1. Furthermore, during elevated D-glucose exposure, we show that SIRT1 is sequestered in the cytoplasm of ECs, but specific activation of SIRT1 shuttles the protein to the nucleus to allow for cytoprotection. The ability of SIRT1 to avert apoptosis employs the activation of protein kinase B (Akt1), the post-translational phosphorylation of the forkhead member FoxO3a, the blocked trafficking of FoxO3a to the nucleus, and the inhibition of FoxO3a to initiate a "pro-apoptotic" program as shown by complimentary gene knockdown studies ofFoxO3a. Vascular apoptotic oversight by SIRT1 extends to the direct modulation of mitochondrial membrane permeability, cytochrome c release, Bad activation, and caspase 1 and 3 activation, since inhibition of SIRT1 activity and gene knockdown of SIRT1 significantly accentuate cascade progression while SIRT1 activation abrogates these apoptotic elements. Our work identifies vascular SIRT1 and its control over early apoptotic membrane signaling, Akt1 activation, post-translational modification and trafficking of FoxO3a, mitochondrial permeability, Bad activation, and rapid caspase induction as new avenues for the treatment of vascular complications during DM.


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Characterization of Endogenous Neural Progenitor Cells after Experimental Ischemic Stroke
Chiung-Chyi Shen, Yi-Chin Yang, Ming-Tsang Chiao, Wen-Yu Cheng, Yuang-Seng Tsuei and Jiunn-Liang Ko

Neural progenitors cells are capable of promoting neurogenesis after ischemic stroke in the adult mammalian brain; however the function of these cells and their fate is still not clear. Therefore the purpose of this study investigated the relationship between neural progenitors and reactive astrocytes after middle cerebral artery occlusion (MCAO). Brain infarction was induced by occlusion of a right cerebral artery in male Wistar rats. The fate of progenitor cells and the surrounding cells was investigated by immunochemical staining for nestin, vimentin and glial fibrillary acidic protein (GFAP) positive cells at several locations. Vimentin and nestin positive cells were observed in the ipsilateral subventricular zone (SVZ), striatum, and cortex at 3 and 7 days after MCAO, but those cells were not found at 28 days after ischemia. In contrast, reactive astrocyte positive cells increased following MCAO. These reactive astrocytes induced astrocytes differentiation of progenitor cells and formed dense astroglioses surrounding the ischemic lesion. Reactive astrocytes are thought to protect the penumbra during brain ischemia. We examined which brain cell expressed nestin and GFAP in the ipsilateral co-expression at 7 days after MCAO, especially at the core of injury. These results suggest that robust reactive astrocytes after MCAO were possibly differentiation from the induced nestin-positive cells after early ischemia


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Diabetes Mellitus: Channeling Care through Cellular Discovery
Kenneth Maiese, Yan Chen Shang, Zhao Zhong Chong and Jinling Hou

Diabetes mellitus (DM) impacts a significant portion of the world's population and care for this disorder places an economic burden on the gross domestic product for any particular country. Furthermore, both Type 1 and Type 2 DM are becoming increasingly prevalent and there is increased incidence of impaired glucose tolerance in the young. The complications of DM are protean and can involve multiple systems throughout the body that are susceptible to the detrimental effects of oxidative stress and apoptotic cell injury. For these reasons, innovative strategies are necessary for the implementation of new treatments for DM that are generated through the further understanding of cellular pathways that govern the pathological consequences of DM. In particular, both the precursor for the coenzyme ß-nicotinamide adenine dinucleotide (NAD+), nicotinamide, and the growth factor erythropoietin offer novel platforms for drug discovery that involve cellular metabolic homeostasis and inflammatory cell control. Interestingly, these agents and their tightly associated pathways that consist of cell cycle regulation, protein kinase B, forkhead transcription factors, and Wnt signaling also function in a broader sense as biomarkers for disease onset and progression.


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Leptin Reduces Infarct Size in Association with Enhanced Expression of CB2, TRPV1, SIRT-1 and Leptin Receptor
Yosefa Avraham, Neta Davidi, Moran Porat, David Chernoguz, Iddo Magen, Lia Vorobeiv, Elliot M. Berry and Ronen R. Leker

Brain ischemia is associated with detrimental changes in energy production and utilization. Therefore, we hypothesized that leptin, an adipokynin hormone protecting against severe energy depletion, would reduce infarct volume and improve functional outcome after stroke. Male Sabra mice underwent permanent middle cerebral artery occlusion (PMCAO) by photothrombosis. Following initial dose-response and time-window experiments animals were treated with vehicle or leptin, were examined daily by a neurological severity score (NSS) and were sacrificed 72 hours after stroke. Infarct volume was determined and the expression of key genes involved in neuroprotection and survival including the cannabinoid receptors CB₁, CB₂ and TRPV1, SIRT-1, leptin receptor and Bcl-2 was quantified in the cortex. A separate group of mice were examined with the neurological severity scale 1, 24 and 48 hours and 1, 2 and 3 weeks after stroke, and were killed 3 weeks post stroke to examine metabolic status in the peri-infarct area. Leptin given at a dose of 1mg/kg intra-peritoneally 30 minutes after PMCAO significantly improved neurological disability and reduced infarct volume. Leptin treatment led to increased expression of CB₂ receptor, TRPV1, SIRT-1 and leptin receptor and reduced expression of CB₁ receptor. There was also a non-significant increase in Bcl-2 gene expression following leptin administration. These results suggest that leptin may be used for attenuating ischemic injury after stroke via induction of an anti-apoptotic state.


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Interleukin-1 Drives Cerebrovascular Inflammation via MAP Kinase-Independent Pathways
Peter Thornton, Barry W. McColl, Laura Cooper, Nancy J. Rothwell and Stuart M. Allan

Cerebrovascular inflammation is triggered by diverse central nervous system (CNS) insults and contributes to disease pathogenesis. The pro-inflammatory cytokine interleukin (IL)-1 is central to this cerebrovascular inflammatory response and understanding the underlying signalling mechanisms of IL-1 actions in brain endothelium may provide therapeutic targets for disease intervention. For the first time, we compare the contributions of p38, JNK and ERK mitogen-activated protein (MAP) kinase and NF-κB pathways to IL-1-induced brain endothelial activation. In cultures of primary mouse brain endothelium and the rat brain endothelial GPNT cell line, interleukin-1β (IL-1β) induced a rapid (within 5 minutes) and transient activation of p38 and JNK (but not ERK) MAP kinases. IL-1β also induced nuclear recruitment of nuclear factor (NF)-κB p65. IL-1β-induced brain endothelial expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 was insensitive to MAP kinase inhibitors. IL-1β-induced brain endothelial expression of ICAM-1 and VCAM-1 was inhibited (80-88 %) by the proteasome inhibitor MG132 or the antioxidant caffeic acid phenethyl ester (CAPE), effects suggested to be NF-κB-dependent. IL-1β-induced brain endothelial CXCL1 expression was partially inhibited by JNK MAP kinase or MG132 (62 or 56 %, respectively). However, CXCL1 secretion from brain endothelium was reduced (65 %) only by MG132, and not MAP kinase inhibitors. Similarly, IL-1β-induced neutrophil transendothelial migration was reduced (77-89 %) by MG132, but not MAP kinase inhibitors. In summary, we show that several key components of IL-1β-induced brain endothelial activation (CAM, CXCL1 expression or release and neutrophil transmigration) are largely independent of MAP kinase activity but are reduced by proteasome inhibition, possibly reflecting a requirement for NF-κB activity. Similar mechanisms may contribute to cerebrovascular inflammation in response to CNS injury.


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Human Tooth Germ Stem Cells Preserve Neuro-Protective Effects after Long-Term Cryo-Preservation
Mehmet E. Yalvac, Mustafa Ramazanoglu, Murat Tekguc, Omer F. Bayrak, Aygul K. Shafigullina, Ilnur I. Salafutdinov, Natalia L. Blatt, Andrey P. Kiyasov, Fikrettin Sahin, Andras Palotas and Albert A. Rizvano

The use of mesenchymal stem cells (MSCs) has been shown to be promising in chronic disorders such as diabetes, Alzheimer's dementia, Parkinson's disease, spinal cord injury and brain ischemia. Recent studies revealed that human tooth germs (hTG) contain MSCs which can be easily isolated, expanded and cryo-preserved. In this report, we isolated human tooth germ stem cells (hTGSCs) with MSC characteristics from third molar tooth germs, cryo-preserved them at -80°C for 6 months, and evaluated for their surface antigens, expression of pluri-potency associated genes, differentiation capacity, karyotype, and proliferation rate. These characteristics were compared to their non-frozen counterparts. In addition, neuro-protective effects of cryo-preserved cells on neuro-blastoma SH-SY5Y cells were also assessed after exposure to stress conditions induced by hydrogen-peroxide (oxidative stress) and paclitaxel (microtubule stabilizing mitotic inhibitor). After long term cryo-preservation hTGSCs expressed surface antigens CD29, CD73, CD90, CD105, and CD166, but not CD34, CD45 or CD133, which was typical for non-frozen hTGSCs. Cryo-preserved hTGSCs were able to differentiate into osteo-, adipo- and neuro-genic cells. They also showed normal karyotype after high number of population doublings and unchanged proliferation rate. On the other hand, cryo-preserved cells demonstrated a tendency for lower level of pluri-potency associated gene expression (nanog, oct4, sox2, klf4, c-myc) than non-frozen hTGSCs. hTGSCs conditioned media increased survival of SH-SY5Y cells exposed to oxidative stress or paclitaxel. These findings confirm that hTGSCs preserve their major characteristics and exert neuro-protection after long-term cryopreservation, suggesting that hTGSCs, harvested from young individuals and stored for possible use later as they grow old, might be employed in cellular therapy of age-related degenerative disorders.


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Human Platelets Express Authentic CB1 and CB2 Receptors
M. V. Catani, V. Gasperi, G. Catanzaro, S. Baldassarri, A. Bertoni, F. Sinigaglia, L. Avigliano and M. Maccarrone

In the last decade, the neurovascular effects exerted by endocannabinoids (eCBs) have attracted growing interest, because they hold the promise to open new avenues of therapeutic intervention against major causes of death in Western society. Several actions of eCBs are mediated by type-1 (CB1) or type-2 (CB2) cannabinoid receptors, yet there is no clear evidence of the presence of these proteins in platelets.

To demonstrate that CB1 and CB2 are expressed in human platelets, we analyzed their protein level by Western blotting and ELISA, visualized their cellular localization by confocal microscopy, and ascertained their functionality by binding assays. We found that CB1, and to a lesser extent CB2, are expressed in highly purified human platelets. Both receptor subtypes were predominantly localized inside the cell, thus explaining why they might remain undetected in preparations of plasma membranes.

The identification of authentic CB1 and CB2 in human platelets supports the potential exploitation of selective agonists or antagonists of these receptors as novel therapeutics to combat neurovascular disorders. It seems remarkable that some of these substances have been already used in humans to treat disease states.


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Traumatic Spinal Cord Injury Alters Angiogenic Factors and TGF-Beta1 that may Affect Vascular Recovery
Marie-Françoise Ritz, Ursula Graumann, Bertha Gutierrez and Oliver Hausmann

Traumatic spinal cord injury (SCI) disrupts the blood-spinal cord barrier and reduces the blood supply caused by microvascular changes. Vessel regression and neovascularization have been observed in the course of secondary injury contributing to microvascular remodeling after trauma. Spatio-temporal distribution of blood vessels and modulation of gene expression of several angiogenic factors have been investigated in rats after spinal cord compression injury.

Rarefaction of vessels was detectable at the injury site 2 days after SCI before they disappeared in the developing cavity after 2 and 4 weeks, whereas no changes were observed in the penumbra. Investigation of the temporal expression of angiogenic genes using quantitative RT-PCR disclosed a constant down-regulation of the vascular endothelial growth factor (VEGF), and transient decreases of angiopoietin-1 (Ang-1), platelet-derived growth factor-BB (PDGF-BB), as well as placental growth factor (PlGF), with the lowest values obtained 3 days after injury, when compared to the expression levels obtained in sham-operated rats. Hepatocyte growth factor (HGF) was the only angiogenic factor with a constant increased gene expression when compared with controls, starting at day 3 post-SCI. mRNA levels of transforming growth factor-beta 1 (TGF-β1) were elevated at every time point following SCI, whereas those encoding for the cysteine-rich protein CCN1/CYR61 were upregulated after 2 h, 6 h, and 1 week only. Our data provide an overview of the temporal modulated expression of the major angiogenic factors, hampering revascularization in the lesion during the phase of secondary injury. These findings should be considered in order to improve therapeutic interventions.


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Homocysteine Enhances Transmigration of Rat Monocytes through a Brain Capillary Endothelial Cell Monolayer via ICAM-1
Lindsay A. Hohsfield and Christian Humpel

Increased homocysteine (Hcy) levels contribute to a variety of cardiovascular and cerebrovascular diseases including stroke and Alzheimer's disease. Recent data has shown that elevated levels of Hcy can lead to blood-brain barrier (BBB) dysfunction and activation. However, the mechanism for Hcy-mediated dysfunction remains unclear. The aim of this study is to characterize the effects of moderate Hcy administration in rat brain capillary endothelial cells (BCECs), which serve as a simple model to study blood-brain barrier functions. This present study shows that addition of 20 μM Hcy for 6 days does not significantly affect BCEC survival, as measured by acridine orange staining, propidium iodide staining, and nitrite content. However, addition of 20 μM Hcy for 6 days does elevate lactate dehydrogenase (LDH) activity released into the supernatant of BCECs, as well as significantly enhances the transmigration of monocytes across the BCEC in a time-dependent manner. In addition, TNFα levels in BCEC are also elevated by Hcy, whereas inflammatory markers MIP3α and RANTES are significantly reduced. Finally, this study shows that intercellular adhesion molecule-1 (ICAM-1) expression is significantly enhanced by 20 μM Hcy treatment compared to control conditions. These results suggest that moderate levels of homocysteine can affect proinflammatory patterns expressed by BCECs, ultimately leading to BBB activation and dysfunction through enhanced monocyte transmigration and ICAM-1 expression.