Lopez-Ramirez M.A.,Open University Milton Keynes |
Lopez-Ramirez M.A.,Yale University |
Wu D.,Open University Milton Keynes |
Pryce G.,Queen Mary, University of London |
And 12 more authors.
FASEB Journal | Year: 2014
Blood-brain barrier (BBB) dysfunction is a hallmark of neurological conditions such as multiple sclerosis (MS) and stroke. However, the molecular mechanisms underlying neurovascular dysfunction during BBB breakdown remain elusive. MicroRNAs (miRNAs) have recently emerged as key regulators of pathogenic responses, although their role in central nervous system (CNS) microvascular disorders is largely unknown. We have identified miR-155 as a critical miRNA in neuroinflammation at the BBB. miR-155 is expressed at the neurovascular unit of individuals with MS and of mice with experimental autoimmune encephalomyelitis (EAE). In mice, loss of miR-155 reduced CNS extravasation of systemic tracers, both in EAE and in an acute systemic inflammation model induced by lipopolysaccharide. In cultured human brain endothelium, miR-155 was strongly and rapidly upregulated by inflammatory cytokines. miR-155 up-regulation mimicked cytokine-induced alterations in junctional organization and permeability, whereas inhibition of endogenous miR-155 partially prevented a cytokine-induced increase in permeability. Furthermore, miR-155 modulated brain endothelial barrier function by targeting not only cell-cell complex molecules such as annexin-2 and claudin-1, but also focal adhesion components such as DOCK-1 and syntenin-1. We propose that brain endothelial miR-155 is a negative regulator of BBB function that may constitute a novel therapeutic target for CNS neuroinflammatory disorders. © FASEB.
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: HEALTH.2013.2.2.1-4 | Award Amount: 15.74M | Year: 2013
Epilepsy is a devastating condition affecting over 50 million people worldwide. This multidisciplinary project is focused on the process leading to epilepsy, epileptogenesis, in adults. Our main hypothesis is that there are combinations of various causes, acting in parallel and/or in succession, that lead to epileptogenesis and development of seizures. Our central premise and vision is that a combinatorial approach is necessary to identify appropriate biomarkers and develop effective antiepileptogenic therapeutics. The project will focus on identifying novel biomarkers and their combinations for epileptogenesis after potentially epileptogenic brain insults in clinically relevant animal models, such as traumatic brain injury (TBI) and status epilepticus (SE); explore multiple basic mechanisms of epileptogenesis and their mutual interactions related to cell degeneration, circuit reorganization, inflammatory processes, free radical formation, altered neurogenesis, BBB dysfunction, genetic and epigenetic alterations; and translating these findings towards the clinic by validating biomarkers identified from animal models in human post TBI brain tissue and blood samples, post-mortem brain tissue in individuals that died soon after SE, and human brain and blood samples from chronic epilepsy cases. The project will identify novel combinatorial biomarkers and novel disease-modifying combinatorial treatment strategies for epileptogenesis, create an Epilepsy Preclinical Biobank, and validate translational potential of results from animal models in human tissue. To adequately address the proposed goals, the project will develop technological breakthroughs, such as completely novel chemogenetic approaches, novel MRI techniques, novel multimodal organic recording devices for simultaneous recordings of EEG / cellular unit activity and biochemical measurements, novel bioluminescence for in vivo promoter activity analysis, and novel systems biology approaches.
Wisniewska-Kruk J.,University of Amsterdam |
Hoeben K.A.,University of Amsterdam |
Vogels I.M.C.,University of Amsterdam |
Gaillard P.J.,To BBB technologies BV |
And 4 more authors.
Experimental Eye Research | Year: 2012
Loss of blood-retinal barrier (BRB) properties is an important feature in the pathology of diabetic macular edema (DME), but cellular mechanisms underlying BRB dysfunction are poorly understood. Therefore, we developed and characterized a novel in vitro BRB model, based on primary bovine retinal endothelial cells (BRECs). These cells were shown to maintain specific in vivo BRB properties by expressing high levels of the endothelial junction proteins occludin, claudin-5, VE-cadherin and ZO-1 at cell borders, and the specific pumps glucose transporter-1 (GLUT1) and efflux transporter P-glycoprotein (MDR1). To investigate the influence of pericytes and astrocytes on BRB maintenance in vitro, we compared five different co-culture BRB models, based on BRECs, bovine retinal pericytes (BRPCs) and rat glial cells. Co-cultures of BRECs with BRPCs and glial cells showed the highest trans-endothelial resistance (TEER) as well as decreased permeability of tracers after vascular endothelial growth factor (VEGF) stimulation, suggesting a major role for these cell types in maintaining barrier properties. To mimic the in vivo situation of DME, we stimulated BRECs with VEGF, which downregulated MDR1 and GLUT1 mRNA levels, transiently reduced expression levels of endothelial junctional proteins and altered their organization, increased the number of intercellular gaps in BRECs monolayers and influence the permeability of the model to differently-sized molecular tracers. Moreover, as has been shown in vivo, expression of plasmalemma vesicle-associated protein (PLVAP) was increased in endothelial cells in the presence of VEGF. This in vitro model is the first co-culture model of the BRB that mimicks in vivo VEGF-dependent changes occurring in DME. © 2011 Elsevier Ltd.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: HEALTH.2012.2.4.5-1 | Award Amount: 6.55M | Year: 2012
Dysregulation of cGMP is a pathological hallmark of inherited retinal degenerations (RD) affecting photoreceptors, the sensory cells of the retina. These RDs, including Retinitis Pigmentosa, Lebers Congenital Amaurosis, and Achromatopsia, are major causes of blindness, affecting approximately one in every 2000 individuals worldwide, and remain without effective treatment. In photoreceptors, cGMP is produced by retinal guanylyl cyclase (GC). The two main cGMP targets are cyclic nucleotide gated ion channels (CNGC) and cGMP-dependent protein kinase (PKG). Since attenuation of PKG and CNGC activity can reduce photoreceptor cell death, both proteins constitute potential targets to prevent RD. Recent data suggest that blocking retinal GC may also constitute a viable therapeutic approach. This consortium will study and develop targeted compounds and delivery systems aimed at preventing photoreceptor damage in preclinical disease models. Towards this goal, two SMEs have teamed up with three academic research groups focused on retinal degeneration: the German company BIOLOG specializes on development of cyclic nucleotide based drugs targeting PKG, CNGC, and GC; the Dutch company to-BBB develops systems to deliver drugs across the blood brain/retinal barrier (BBB, BRB, resp.); the groups of V. Marigo (Modena, Italy), P. Ekstrm (Lund, Sweden), and F. Paquet-Durand (Tbingen, Germany) have a strong and joint collaborative track record of studying photoreceptor degenerative mechanisms as well as on testing and evaluating drug treatment effects. Manufacturing of the most promising drugs fitted to a suitable delivery system will be scaled up towards clinical-size batches and studied towards efficacy, toxicology and off-target effects in model animals. The results of the project will allow the SMEs to further co-develop these drugs towards translation into clinical studies, addressing the high needs of RD patients and the high economic benefit of such therapies.
Reijerkerk A.,To BBB technologies BV |
Appeldoorn C.C.M.,To BBB technologies BV |
Rip J.,To BBB technologies BV |
de Boer M.,To BBB technologies BV |
Gaillard P.J.,To BBB technologies BV
Investigative Ophthalmology and Visual Science | Year: 2014
Purpose. Ocular inflammation is associated with the loss of visual acuity and subsequent blindness. Since their development, glucocorticoids have been the mainstay of therapy for ocular inflammatory diseases. However, the clinical benefit is limited by side effects due to the chronic use and generally high dosage that is required for effective treatment. We have developed the G-Technology to provide a means for sustained drug delivery, increased drug half-life, and reduced bodily drug exposure. Glutathione PEGylated liposomal methylprednisolone (2B3-201) has been developed as treatment for neuroinflammatory conditions and was evaluated in ocular inflammation. Methods. The efficacy of 2B3-201 was investigated in rats with experimental autoimmune uveitis (EAU). Rats received 10 mg/kg of 2B3-201 intravenously at disease onset and at peak of the disease. The same dose of free methylprednisolone served as control treatment. Clinical signs of ocular inflammation were assessed by slit-lamp and immunohistochemistry. Results. Whereas free methylprednisolone was ineffective, two doses of 2B3-201 almost completely abolished clinical signs of EAU. This was corroborated further by immunohistochemical analyses of isolated eyes. Treatment with 2B3-201 significantly reduced the infiltration of inflammatory cells and subsequent destruction of the retina cell layers. Conclusions. In this study, we show that systemic treatment with 2B3-201, a glutathione PEGylated liposomal methylprednisolone formulation, resulted in a superior efficacy in rats with EAU. Altogether, our findings hold promise for the development of a safe and more convenient systemic treatment for uveitis. © 2014 The Association for Research in Vision and Ophthalmology, Inc.
Mizee M.R.,VU University Amsterdam |
Nijland P.G.,VU University Amsterdam |
van der Pol S.M.A.,VU University Amsterdam |
Drexhage J.A.R.,VU University Amsterdam |
And 6 more authors.
Acta Neuropathologica | Year: 2014
Multiple sclerosis (MS) lesions are characterized by the presence of activated astrocytes, which are thought to actively take part in propagating lesion progression by secreting pro-inflammatory mediators. Conversely, reactive astrocytes may exert disease-dampening effects through the production of trophic factors and anti-inflammatory mediators. Astrocytic control of the blood–brain barrier (BBB) is crucial for normal brain homeostasis and BBB disruption is a well-established early event in MS lesion development. Here, we set out to unravel potential protective effects of reactive astrocytes on BBB function under neuroinflammatory conditions as seen in MS, where we focus on the role of the brain morphogen retinoic acid (RA). Immunohistochemical analysis revealed that retinaldehyde dehydrogenase 2 (RALDH2), a key enzyme for RA synthesis, is highly expressed by reactive astrocytes throughout white matter lesions compared to control and normal appearing white matter. In vitro modeling of reactive astrocytes resulted in increased expression of RALDH2, enhanced RA synthesis, and a protective role for astrocyte-derived RA on BBB function during inflammation-induced barrier loss. Furthermore, RA induces endothelial immune quiescence and decreases monocyte adhesion under inflammatory conditions. Finally, we demonstrated that RA attenuated oxidative stress in inflamed endothelial cells, through activation of the antioxidant transcription factor nuclear factor E2 related factor 2. In summary, RA synthesis by reactive astrocytes represents an endogenous protective response to neuroinflammation, possibly aimed at protecting the BBB against inflammatory insult. A better understanding of RA signaling in MS pathophysiology may lead to the discovery of novel targets to halt disease progression. © 2014, Springer-Verlag Berlin Heidelberg.
Gaillard P.J.,To BBB Technologies BV |
Visser C.C.,To BBB Technologies BV |
Appeldoorn C.C.M.,To BBB Technologies BV |
Rip J.,To BBB Technologies BV
Drug Discovery Today: Technologies | Year: 2012
The blood-brain barrier presents a significant hurdle in CNS drug development. Blood-to-brain delivery by effectively crossing this barrier allows therapeutics to reach a large area of the brain. Over the past decades several drug delivery technologies have been developed, some more successful than others, which we hold against 10 key development criteria. Adhering to these criteria will allow a more successful development of therapeutics for patients with devastating brain diseases. © 2011 Elsevier Ltd. All rights reserved.
Rip J.,To BBB Technologies BV |
Chen L.,To BBB Technologies BV |
Hartman R.,Leiden University |
Van Den Heuvel A.,To BBB Technologies BV |
And 8 more authors.
Journal of Drug Targeting | Year: 2014
Partly due to poor blood-brain barrier drug penetration the treatment options for many brain diseases are limited. To safely enhance drug delivery to the brain, glutathione PEGylated liposomes (G-Technology®) were developed. In this study, in rats, we compared the pharmacokinetics and organ distribution of GSH-PEG liposomes using an autoquenched fluorescent tracer after intraperitoneal administration and intravenous administration. Although the appearance of liposomes in the circulation was much slower after intraperitoneal administration, comparable maximum levels of long circulating liposomes were found between 4 and 24 h after injection. Furthermore, 24 h after injection a similar tissue distribution was found. To investigate the effect of GSH coating on brain delivery in vitro uptake studies in rat brain endothelial cells (RBE4) and an in vivo brain microdialysis study in rats were used. Significantly more fluorescent tracer was found in RBE4 cell homogenates incubated with GSH-PEG liposomes compared to non-targeted PEG liposomes (1.8-fold, p < 0.001). In the microdialysis study 4-fold higher (p < 0.001) brain levels of fluorescent tracer were found after intravenous injection of GSH-PEG liposomes compared with PEG control liposomes. The results support further investigation into the versatility of GSH-PEG liposomes for enhanced drug delivery to the brain within a tolerable therapeutic window. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted.
Rotman M.,Leiden University |
Welling M.M.,Leiden University |
Bunschoten A.,Leiden University |
De Backer M.E.,To BBB Technologies BV |
And 6 more authors.
Journal of Controlled Release | Year: 2015
Treatment of neurodegenerative disorders such as Alzheimer's disease is hampered by the blood-brain barrier (BBB). This tight cerebral vascular endothelium regulates selective diffusion and active transport of endogenous molecules and xenobiotics into and out of the brain parenchyma. In this study, glutathione targeted PEGylated (GSH-PEG) liposomes were designed to deliver amyloid-targeting antibody fragments across the BBB into the brain. Two different formulations of GSH-PEG liposomes based on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and egg-yolk phosphatidylcholine (EYPC) were produced. Both formulations encapsulate 15 kDa amyloid beta binding llama single domain antibody fragments (VHH-pa2H). To follow the biodistribution of VHH-pa2H rather than the liposome, the antibody fragment was labeled with the radioisotope indium-111. To prolong the shelf life of the construct beyond the limit of radioactive decay, an active-loading method was developed to efficiently radiolabel the antibody fragments after encapsulation into the liposomes, with radiolabeling efficiencies of up to 68% after purification. The radiolabeled liposomes were administered via a single intravenous bolus injection to APPswe/PS1dE9 double transgenic mice, a mouse model of Alzheimer's disease, and their wildtype littermates. Both GSH-PEG DMPC and GSH-PEG EYPC liposomes significantly increased the standard uptake values (SUV) of VHH-pa2H in the blood of the animals compared to free VHH-pa2H. Encapsulation in GSH-PEG EYPC liposomes resulted in the highest increase in SUV in the brains of transgenic animals. Overall, these data provide evidence that GSH-PEG liposomes may be suitable for specific delivery of single domain antibody fragments over the BBB into the brain. © 2015 Elsevier B.V. All rights reserved.
Gaillard P.J.,To BBB Technologies BV |
Appeldoorn C.C.M.,To BBB Technologies BV |
Dorland R.,To BBB Technologies BV |
Van Kregten J.,To BBB Technologies BV |
And 7 more authors.
PLoS ONE | Year: 2014
Brain cancer is a devastating disease affecting many people worldwide. Effective treatment with chemotherapeutics is limited due to the presence of the blood-brain barrier (BBB) that tightly regulates the diffusion of endogenous molecules but also xenobiotics. Glutathione pegylated liposomal doxorubicin (2B3-101) is being developed as a new treatment option for patients with brain cancer. It is based on already marketed pegylated liposomal doxorubicin (Doxil®/Caelyx®), with an additional glutathione coating that safely enhances drug delivery across the BBB. Uptake of 2B3-101 by human brain capillary endothelial cells in vitro was time-, concentration- and temperature-dependent, while pegylated liposomal doxorubicin mainly remained bound to the cells. In vivo, 2B3-101 and pegylated liposomal doxorubicin had a comparable plasma exposure in mice, yet brain retention 4 days after administration was higher for 2B3-101. 2B3-101 was overall well tolerated by athymic FVB mice with experimental human glioblastoma (luciferase transfected U87MG). In 2 independent experiments a strong inhibition of brain tumor growth was observed for 2B3-101 as measured by bioluminescence intensity. The effect of weekly administration of 5 mg/kg 2B3-101 was more pronounced compared to pegylated liposomal doxorubicin (p<0.05) and saline (p<0.01). Two out of 9 animals receiving 2B3-101 showed a complete tumor regression. Twice-weekly injections of 5 mg/kg 2B3-101 again had a significant effect in inhibiting brain tumor growth (p<0.001) compared to pegylated liposomal doxorubicin and saline, and a complete regression was observed in 1 animal treated with 2B3-101. In addition, twice-weekly dosing of 2B3-101 significantly increased the median survival time by 38.5% (p<0.001) and 16.1% (p<0.05) compared to saline and pegylated liposomal doxorubicin, respectively. Overall, these data demonstrate that glutathione pegylated liposomal doxorubicin enhances the effective delivery of doxorubicin to brain tumors and could become a promising new therapeutic option for the treatment of brain malignancies. © 2014 Gaillard et al.