Computational Exploration of Potential CFTR Binding Sites for Type I Corrector Drugs.

Cystic fibrosis (CF) is a recessive genetic disease that is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The recent development of a class of drugs called "correctors", which repair the structure and function of mutant CFTR, has greatly enhanced the life expectancy of CF patients. These correctors target the most common disease causing CFTR mutant F508del and are exemplified by the FDA-approved VX-809. While one binding site of VX-809 to CFTR was recently elucidated by cryo-electron microscopy, four additional binding sites have been proposed in the literature and it has been theorized that VX-809 and structurally similar correctors may engage multiple CFTR binding sites. To explore these five binding sites, ensemble docking was performed on wild-type CFTR and the F508del mutant using a large library of structurally similar corrector drugs, including VX-809 (lumacaftor), VX-661 (tezacaftor), ABBV-2222 (galicaftor), and a host of other structurally related molecules. For wild-type CFTR, we find that only one site, located in membrane spanning domain 1 (MSD1), binds favorably to our ligand library. While this MSD1 site also binds our ligand library for F508del-CFTR, the F508del mutation also opens a binding site in nucleotide binding domain 1 (NBD1), which enables strong binding of our ligand library to this site. This NBD1 site in F508del-CFTR exhibits the strongest overall binding affinity for our library of corrector drugs. This data may serve to better understand the structural changes induced by mutation of CFTR and how correctors bind to the protein. Additionally, it may aid in the design of new, more effective CFTR corrector drugs.

Continuous, Nondestructive Detection of Microorganism Growth at Buried Interfaces with Vascularized Polymers.

Evaluating surface bacterial growth at buried interfaces can be problematic due to the difficulties associated with obtaining samples. In this work, we present a new method to detect signals from microorganisms at buried interfaces that is nondestructive and can be conducted continuously. Inspired by vascular systems in nature that permit chemical communication between the surface and underlying tissues of an organism, we created a system in which an inert carrier fluid could be introduced into an empty vascular network embedded in a polymer matrix. When a microorganism layer was grown on top, small molecules produced by the growth process would diffuse down into the carrier fluid, which could then be collected and analyzed. We used this system to nondestructively detect signals from a surface layer of Escherichia coli using conductivity, ultraviolet-visible (UV-vis) absorbance spectroscopy, and high-performance liquid chromatography (HPLC) for organic acids, methods that ranged in sensitivity, time-to-result, and cost. Carrier fluid from sample vascularized polymers with surface bacterial growth recorded significantly higher values in both conductivity and absorbance at 350 nm compared to controls with no bacteria after 24 h. HPLC analysis showed three clear peaks that varied between the samples with bacteria and the controls without. Tests tracking the change in signals over 48 h showed clear trends that matched the bacterial growth curves, demonstrating the system's ability to monitor changes over time. A 2D finite element model of the system closely matched the experimental results, confirming the predictability of the system. Finally, tests using clinically relevant Staphylococcus aureus and Pseudomonas aeruginosa yielded differences in conductivity, absorbance, and HPLC peak areas unique to each species. This work lays the foundation for the use of vascularized polymers as an adaptive system for the continuous, nondestructive detection of surface microorganisms at buried interfaces in both industry and medicine.

Review on Nonconventional Fibrillation Methods of Producing Cellulose Nanofibrils and Their Applications.

The production of cellulose nanofibrils (CNFs) continues to receive considerable attention because of their desirable material characteristics for a variety of consumer applications. There are, however, challenges that remain in transitioning CNFs from research to widespread adoption in the industrial sectors, including production cost and material performance. This Review covers CNFs produced from nonconventional fibrillation methods as a potential alternative solution. Pretreating biomass by biological, chemical, mechanical, or physical means can render plant feedstocks more facile for processing and thus lower energy requirements to produce CNFs. CNFs from nonconventional fibrillation methods have been investigated for various applications, including films, composites, aerogels, and Pickering emulsifiers. Continued research is needed to develop protocols to standardize the characterization (e.g., degree of fibrillation) of the lignocellulosic fibrillation processes and resulting CNF products to make them more attractive to the industry for specific product applications.

Correction to: Burden of caregivers of adult patients with schizophrenia in a predominantly African ancestry population.

In the original publication, the co-author name Kelly-Marie Chen was misspelled and Shenae Miller was missed in the author group. The correct author group has been provided in this correction.

rhIGF-1 reduces the permeability of the blood-brain barrier following intracerebral hemorrhage in mice.

Disruption of the blood-brain barrier results in the formation of edema and contributes to the loss of neurological function following intracerebral hemorrhage (ICH). This study examined insulin-like growth factor-1 (IGF-1) as a treatment and its mechanism of action for protecting the blood-brain barrier after ICH in mice. 171 Male CD-1 mice were subjected to ICH via collagenase or autologous blood. A dose study for recombinant human IGF-1 (rhIGF-1) was performed. Brain water content and behavioral deficits were evaluated at 24 and 72 h after the surgery, and Evans blue extravasation and hemoglobin assay were conducted at 24 h. Western blotting was performed for the mechanism study and interventions were used targeting the IGF-1R/GSK3ß/MEKK1 pathway. rhIGF-1 reduced edema and blood-brain barrier permeability, and improved neurobehavior outcomes. Western blots showed that rhIGF-1 reduced p-GSK3ß and MEKK1 expression, thereby increasing occludin and claudin-5 expression. Inhibition and knockdown of IGF-1R reversed the therapeutic benefits of rhIGF-1. The findings within suggest that stimulation of the IGF-1R is a therapeutic target for ICH which may lead to improved neurofunctional and blood-brain barrier protection.

IRE1α inhibition decreased TXNIP/NLRP3 inflammasome activation through miR-17-5p after neonatal hypoxic-ischemic brain injury in rats.

BACKGROUND: The endoplasmic reticulum (ER) is responsible for the control of correct protein folding and protein function which is crucial for cell survival. However, under pathological conditions, such as hypoxia-ischemia (HI), there is an accumulation of unfolded proteins thereby triggering the unfolded protein response (UPR) and causing ER stress which is associated with activation of several stress sensor signaling pathways, one of them being the inositol requiring enzyme-1 alpha (IRE1α) signaling pathway. The UPR is regarded as a potential contributor to neuronal cell death and inflammation after HI. In the present study, we sought to investigate whether microRNA-17 (miR-17), a potential IRE1α ribonuclease (RNase) substrate, arbitrates downregulation of thioredoxin-interacting protein (TXNIP) and consequent NLRP3 inflammasome activation in the immature brain after HI injury and whether inhibition of IRE1α may attenuate inflammation via miR-17/TXNIP regulation. METHODS: Postnatal day 10 rat pups (n = 287) were subjected to unilateral carotid artery ligation followed by 2.5 h of hypoxia (8% O2). STF-083010, an IRE1α RNase inhibitor, was intranasally delivered at 1 h post-HI or followed by an additional one administration per day for 2 days. MiR-17-5p mimic or anti-miR-17-5p inhibitor was injected intracerebroventricularly at 48 h before HI. Infarct volume and body weight were used to evaluate the short-term effects while brain weight, gross and microscopic brain tissue morphologies, and neurobehavioral tests were conducted for the long-term evaluation. Western blots, immunofluorescence staining, reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), and co-immunoprecipitation (Co-IP) were used for mechanism studies. RESULTS: Endogenous phosphorylated IRE1α expression was significantly increased after HI. Intranasal administration of STF-083010 alleviated brain injury and improved neurological behavior. MiR-17-5p expression was reduced after HI, and this decrease was attenuated by STF-083010 treatment. MiR-17-5p mimic administration ameliorated TXNIP expression, NLRP3 inflammasome activation, caspase-1 cleavage, and IL-1ß production, as well as brain infarct volume. Conversely, anti-miR-17-5p inhibitor reversed IRE1α inhibition-induced decrease in TXNIP expression and inflammasome activation, as well as exacerbated brain injury after HI. CONCLUSIONS: IRE1a-induced UPR pathway may contribute to inflammatory activation and brain injury following neonatal HI. IRE1a activation, through decay of miR-17-5p, elevated TXNIP expression to activate NLRP3 inflammasome and aggravated brain damage.

CpG-ODN exerts a neuroprotective effect via the TLR9/pAMPK signaling pathway by activation of autophagy in a neonatal HIE rat model.

Hypoxic Ischemic Encephalopathy (HIE) is an injury caused to the brain due to prolonged lack of oxygen and blood supply which results in death or long-term disabilities. The main aim of this study was to investigate the role of Cytosine-phospho-guanine oligodeoxynucleotide (CpG-ODN) in autophagy after HIE. Ten-day old (P10) rat pups underwent right common carotid artery ligation followed by 2.5h of hypoxia as previously described by Rice-Vannucci. At 1h post HIE, rats were intranasally administered with recombinant CpG-ODN. Time-course expression levels of endogenous key proteins, TLR9, pAMPK/AMPK, LC3II/I, and LAMP1 involved in CpG-ODN's protective effects were measured using western blot. Short (48h) and long (4w) term neurobehavior studies were performed using righting reflex, negative geotaxis, water maze, foot fault and Rota rod tests. Brain samples were collected after long term for histological analysis. Furthermore, to elucidate the pathway via which CpG-ODN confers protection, TLR9 and AMPK inhibitors were used. Time course results showed that the expression of TLR9, pAMPK/AMPK, LC3II/I, LAMP1 increased after HIE. Neurobehavioral studies showed that HIE induced a significant delay in development and resulted in cognitive and motor function deficits. However, CpG-ODN ameliorated HIE-induced outcomes and improved long term neurological deficits. In addition, CpG-ODN increased expression of pAMPK/AMPK, p-ULK1/ULK1, P-AMBRA1/AMBRA1, LC3II/I and LAMP1 while inhibition of TLR9 and AMPK reversed those effects. In summary, CpG-ODN increased HIE-induced autophagy and improved short and long term neurobehavioral outcomes which may be mediated by the TLR9/pAMPK signaling pathway after HIE.

Experimental Models Used to Assess Lymphatic Contractile Function.

Recent years have seen a renewed interest in studies of the lymphatic system. This review addresses the differences between in vivo and ex vivo methods for visualization and functional studies of lymphatic networks, with an emphasis on studies of collecting lymphatic vessels. We begin with a brief summary of the historical uses of both approaches. For the purpose of detailed comparisons, we subdivide in vivo methods into those visualizing lymphatic networks through the intact skin and those using surgically opened skin. We subdivide ex vivo methods into isobaric studies (using a pressure myograph) or isometric studies (using a wire myograph). For all four categories, we compile a comprehensive list of the advantages, disadvantages, and limitations of each preparation, with the goal of informing the research community as to the appropriate kinds of experiments best suited, and ill suited, for each.

ErbB4 protects against neuronal apoptosis via activation of YAP/PIK3CB signaling pathway in a rat model of subarachnoid hemorrhage.

Neuronal apoptosis is a central pathological process in subarachnoid hemorrhage (SAH)-induced early brain injury. Previous studies indicated that ErbB4 (EGFR family member v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4) is essential for normal development and maintenance of the nervous system. In this study, we explored the neuroprotective effects of ErbB4 and its downstream YAP (yes-associated protein)/PIK3CB signaling pathway in early brain injury after SAH in a rat model using the endovascular perforation method. Rats were neurologically evaluated with the Modified Garcia Scale and beam balance test at 24h and 72h after SAH. An ErbB4 activator Neuregulin 1ß1 (Nrg 1ß1), ErbB4 siRNA and YAP siRNA were used to explore this pathway. The expression of p-ErbB4 and YAP was significantly increased after SAH. Multiple immunofluorescence labeling experiments demonstrated that ErbB4 is mainly expressed in neurons. Activation of ErbB4 and its downstream signals improved the neurological deficits after SAH and significantly reduced neuronal cell death. Inhibition of ErbB4 reduced YAP and PIK3CB expression, and aggravated cell apoptosis. YAP knockdown reduced the PIK3CB level and eliminated the anti-apoptotic effects of ErbB4 activation. These findings indicated that ErbB4 plays a neuroprotective role in early brain injury after SAH, possibly via the YAP/PIK3CB signaling pathway.

Neuroprotective Mechanisms of Melatonin in Hemorrhagic Stroke.

Hemorrhagic stroke which consists of subarachnoid hemorrhage and intracerebral hemorrhage is a dominant cause of death and disability worldwide. Although great efforts have been made, the physiological mechanisms of these diseases are not fully understood and effective pharmacological interventions are still lacking. Melatonin (N-acetyl-5-methoxytryptamine), a neurohormone produced by the pineal gland, is a broad-spectrum antioxidant and potent free radical scavenger. More importantly, there is extensive evidence demonstrating that melatonin confers neuroprotective effects in experimental models of hemorrhagic stroke. Multiple molecular mechanisms such as antioxidant, anti-apoptosis, and anti-inflammation, contribute to melatonin-mediated neuroprotection against brain injury after hemorrhagic stroke. This review article aims to summarize current knowledge regarding the beneficial effects of melatonin in experimental models of hemorrhagic stroke and explores the underlying mechanisms. We propose that melatonin is a promising neuroprotective candidate that is worthy of further evaluation for its potential therapeutic applications in hemorrhagic stroke.

Pharmacological Inhibition of PERK Attenuates Early Brain Injury After Subarachnoid Hemorrhage in Rats Through the Activation of Akt.

Neuronal apoptosis is a central pathological process in subarachnoid hemorrhage (SAH)-induced early brain injury. Endoplasmic reticulum (ER) stress was reported to have a vital role in the pathophysiology of neuronal apoptosis in the brain. The present study was designed to investigate the potential effects of ER stress and its downstream signals in early brain injury after SAH. One hundred thirty-four rats were subjected to an endovascular perforation model of SAH. The RNA-activated protein kinase-like ER kinase (PERK) inhibitor GSK2606414 and the Akt inhibitor MK2206 were injected intracerebroventricularly. SAH grade, neurologic scores, and brain water content were measured 72 h after subarachnoid hemorrhage. Expression of PERK and its downstream signals, Akt, Bcl-2, Bax, and cleaved caspase-3, were examined using Western blot analysis. Specific cell types that expressed PERK were detected with double immunofluorescence staining. Neuronal cell death was demonstrated with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL). Our results showed that the expression of p-PERK and its downstream targets, p-eIF2α and ATF4, increased after SAH and peaked at 72 h after SAH. PERK was expressed mostly in neurons. The inhibition of PERK with GSK2606414 reduced p-PERK, p-eIF2α, and ATF4 expression. Furthermore, GSK2606414 treatment increased p-Akt levels and the Bcl-2/Bax ratio as well as decreased cleaved caspase-3 expression and neuronal death, thereby improving neurological deficits at 72 h after SAH. The selective Akt inhibitor MK2206 abolished the beneficial effects of GSK2606414. PERK, the major transducer of ER stress, is involved in neuronal apoptosis after SAH. The inhibition of PERK reduces early brain injury via Akt-related anti-apoptosis pathways. PERK may serve as a promising target for future therapeutic intervention.

Recombinant Gas6 augments Axl and facilitates immune restoration in an intracerebral hemorrhage mouse model.

Axl, a tyrosine kinase receptor, was recently identified as an essential component regulating innate immune response. Suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 are potent Axl-inducible negative inflammatory regulators. This study investigated the role of Axl signaling pathway in immune restoration in an autologous blood-injection mouse model of intracerebral hemorrhage. Recombinant growth arrest-specific 6 (Gas6) and R428 were administrated as specific agonist and antagonist. In vivo knockdown of Axl or suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 by siRNA was applied. After intracerebral hemorrhage, the expression of endogenous Axl, soluble Axl, and Gas6 was increased, whereas the expression of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 was inhibited. Recombinant growth arrest-specific 6 administration alleviated brain edema and improved neurobehavioral performances. Moreover, enhanced Axl phosphorylation with cleavage of soluble Axl (sAxl), and an upregulation of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 were observed. In vivo knockdown of Axl and R428 administration both abolished the effect of recombinant growth arrest-specific 6 on brain edema and also decreased the expression suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3. In vivo knockdown of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 aggravated cytokine releasing despite of recombinant growth arrest-specific 6. In conclusion, Axl plays essential role in immune restoration after intracerebral hemorrhage. And recombinant growth arrest-specific 6 attenuated brain injury after intracerebral hemorrhage, probably by enhancing Axl phosphorylation and production of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3.

Intranasal Administration of Interferon Beta Attenuates Neuronal Apoptosis via the JAK1/STAT3/BCL-2 Pathway in a Rat Model of Neonatal Hypoxic-Ischemic Encephalopathy.

Neonatal hypoxic-ischemic encephalopathy (HIE) is an injury that often leads to detrimental neurological deficits. Currently, there are no established therapies for HIE and it is critical to develop treatments that provide protection after HIE. The objective of this study was to investigate the ability of interferon beta (IFNß) to provide neuroprotection and reduce apoptosis after HIE. Postnatal Day 10 rat pups were subjected to unilateral carotid artery ligation followed by 2.5 hr of exposure to hypoxia (8% O2). Intranasal administration of human recombinant IFNß occurred 2 hr after HIE and infarct volume, body weight, neurobehavioral tests, histology, immunohistochemistry, brain water content, blood-brain barrier permeability, enzyme-linked immunosorbent assay, and Western blot were all used to evaluate various parameters. The results showed that both IFNß and the Type 1 interferon receptor expression decreases after HIE. Intranasal administration of human recombinant IFNß was able to be detected in the central nervous system and was able to reduce brain infarction volumes and improve neurological behavior tests 24 hr after HIE. Western blot analysis also revealed that human recombinant IFNß treatment stimulated Stat3 and Bcl-2 expression leading to a decrease in cleaved caspase-3 expression after HIE. Positive Fluoro-Jade C staining also demonstrated that IFNß treatment was able to decrease neuronal apoptosis. Furthermore, the beneficial effects of IFNß treatment were reversed when a Stat3 inhibitor was applied. Also an intraperitoneal administration of human recombinant IFNß into the systemic compartment was unable to confer the same protective effects as intranasal IFNß treatment.

Neuroprotective Effects of Valproic Acid on Blood-Brain Barrier Disruption and Apoptosis-Related Early Brain Injury in Rats Subjected to Subarachnoid Hemorrhage Are Modulated by Heat Shock Protein 70/Matrix Metalloproteinases and Heat Shock Protein 70/AKT Pathways.

BACKGROUND: Blood-brain barrier (BBB) disruption and neural apoptosis are thought to promote early brain injury (EBI) after subarachnoid hemorrhage (SAH). Previous studies have demonstrated that valproic acid (VPA) decreased brain injury in a prechiasmatic injection model of SAH in mice. It should be noted that the beneficial effects of VPA and the underlying mechanisms have not been fully elucidated. OBJECTIVE: To characterize the effects of VPA on BBB disruption and neural apoptosis and to determine mechanisms involved in EBI after SAH. METHODS: An endovascular perforation model was used to induce SAH in rats. VPA (300 mg/kg) was promptly administered after SAH induction, and the same dose was given 12 hours later. Quercetin (100 mg/kg), an inhibitor of heat shock protein 70 (HSP70), was injected into the peritoneum 2 hours before SAH induction. Mortality, SAH grades, neurological function, Evans Blue extravasation, brain edema, transmission electron microscopy, Western blot, double fluorescence labeling, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling staining also were used. RESULTS: VPA treatment decreased BBB disruption and brain edema, attenuated neural apoptosis, and improved neurobehavioral functions in EBI after SAH. Double fluorescence labeling indicated that matrix metallopeptidase 9 (MMP-9) was located predominately in neurons and endothelial cells. VPA upregulated the expression of HSP70, effectively decreased the expression and activity of MMP-9, and reduced claudin-5 and occludin degradation. Meanwhile, VPA also upregulated the expression of phosphorylated Akt and bcl-2. Both the anti-BBB disruption and antiapoptotic effects of VPA were abolished by quercetin. CONCLUSION: VPA prevented BBB disruption and alleviated neural apoptosis after SAH. The action of VPA appeared to be mediated though the HSP70/MMPs and HSP70/Akt pathways. ABBREVIATIONS: BBB, blood-brain barrierEBI, early brain injuryHSP, heat shock proteinMMP, matrix metalloproteinasePBS, phosphate-buffered salineSAH, subarachnoid hemorrhageTUNEL, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelingVPA, valproic acid.

Melatonin attenuates neuronal apoptosis through up-regulation of K(+) -Cl(-) cotransporter KCC2 expression following traumatic brain injury in rats.

Traumatic brain injury (TBI) initiates a complex cascade of neurochemical and signaling changes that leads to neuronal apoptosis, which contributes to poor outcomes for patients with TBI. The neuron-specific K(+) -Cl(-) cotransporter-2 (KCC2), the principal Cl(-) extruder in adult neurons, plays an important role in Cl(-) homeostasis and neuronal function. This present study was designed to investigate the expression pattern of KCC2 following TBI and to evaluate whether or not melatonin is able to prevent neuronal apoptosis by modulating KCC2 expression in a Sprague Dawley rat controlled cortical impact model of TBI. The time course study showed decreased mRNA and protein expression of KCC2 in the ipsilateral peri-core parietal cortex after TBI. Double immunofluorescence staining demonstrated that KCC2 is located in the plasma membrane of neurons. In addition, melatonin (10 mg/kg) was injected intraperitoneally at 5 minutes and repeated at 1, 2, 3, and 4 hours after brain trauma, and brain samples were extracted 24 hours after TBI. Compared to the vehicle group, melatonin treatment altered the down-regulation of KCC2 expression in both mRNA and protein levels after TBI. Also, melatonin treatment increased the protein levels of brain-derived neurotrophic factor (BDNF) and phosphorylated extracellular signal-regulated kinase (p-ERK). Simultaneously, melatonin administration ameliorated cortical neuronal apoptosis, reduced brain edema, and attenuated neurological deficits after TBI. In conclusion, our findings suggested that melatonin restores KCC2 expression, inhibits neuronal apoptosis and attenuates secondary brain injury after TBI, partially through activation of BDNF/ERK pathway.

Changes in Brain Swelling and Infarction Volume over Four Days After Hypoxia Ischemia in Neonatal Rats.

The leading cause of morbidity and mortality in infants is hypoxia-ischemia (HI). The current therapies for HI have limited success, in part due to a lack of understanding of HI pathophysiology and underlying mechanisms. Herein, a neonatal rat model of HI was used to examine the changes in brain swelling and infarct volume over 4 days after HI. Forty-four P10 rat pups were sacrificed at 2, 3, or 4 days post-HI. After sacrifice, the brains were removed, sliced, and stained with TTC (2,3,5-triphenyl-2H-tetrazolium chloride). Images of TTC-stained brains were used for measurement of the ipsilateral hemisphere brain volumes and infarct volumes, calculated using standard equations. The hemispheric brain volumes of HI animals in all groups was lower than that of sham animals and decreased as the post-HI sacrifice time increased. The infarct volume of HI animals was larger than that of sham animals. Infarct volumes tended to decrease over the days post-HI. The change in infarct volume is likely the result of a combination of brain growth and repair mechanisms. However, changes in the hemispheric brain volume may include tissue growth and repair mechanism, so also may be a limitation of the current algorithm used for calculating ipsilateral hemisphere brain volume.

Intranasal Osteopontin for Rodent Germinal Matrix Hemorrhage.

Germinal matrix hemorrhage (GMH) is the most common and devastating neurological problem of premature infants. Current treatment is largely ineffective and GMH has been nonpreventable. Osteopontin (OPN) is an endogenous protein that has been shown to be neuroprotective, however, it has not been tested in GMH. P7 neonatal rats were subjected to stereotactic ganglionic eminence collagenase infusion. Groups were as follows: (1) sham, (2) GMH + vehicle, (3) GMH + intranasal OPN. Seventy-two hours later, the animals were evaluated using righting reflex, blood-brain barrier (BBB) permeability by Evans blue dye leakage, brain water content, and hemoglobin assay. Intranasal OPN improved outcomes after GMH by attenuation of brain swelling, BBB function, re-bleeding, and neurological outcomes. OPN may play an important role in enhancing neuroprotective brain signaling following GMH. These observed effects may offer novel possibilities for therapy in this patient population.

Osteopontin-Rac1 on Blood-Brain Barrier Stability Following Rodent Neonatal Hypoxia-Ischemia.

Osteopontin (OPN) is a neuroprotective molecule that is upregulated following rodent neonatal hypoxic-ischemic (nHI) brain injury. Because Rac1 is a regulator of blood-brain barrier (BBB) stability, we hypothesized a role for this in OPN signaling. nHI was induced by unilateral ligation of the right carotid artery followed by hypoxia (8 % oxygen for 2 h) in P10 Sprague-Dawley rat pups. Intranasal (iN) OPN was administered at 1 h post-nHI. Groups consisted of: (1) Sham, (2) Vehicle, (3) OPN, and (4) OPN + Rac1 inhibitor (NSC23766). Evans blue dye extravasation (BBB permeability) was quantified 24 h post-nHI, and brain edema at 48 h. Increased BBB permeability and brain edema following nHI was ameliorated in the OPN treatment group. However, those rat pups receiving OPN co-treatment with the Rac1 inhibitor experienced no improvement compared with vehicle. OPN protects the BBB following nHI, and this was reversed by Rac1 inhibitor (NSC23766).