Transmigration of Neural Stem Cells across the Blood Brain Barrier Induced by Glioma Cells Mo ´nica Dı´az-Cora ´ nguez 1,4 , Jose ´ Segovia 1 , Adolfo Lo ´ pez-Ornelas 2 , Henry Puerta-Guardo 3 , Juan Ludert 3 , Bibiana Cha ´ vez 3 , Noemi Meraz-Cruz 4,5 , Lorenza Gonza ´ lez-Mariscal 1 * 1 Department of Physiology, Biophysics and Neuroscience, Cinvestav, Mexico City, Mexico, 2 Department of Pharmacology, Cinvestav, Mexico City, Mexico, 3 Department of Infectomics and Molecular Pathogenesis, Cinvestav, Mexico City, Mexico, 4 Faculty of Medicine, UNAM, Mexico City, Mexico, 5 National Institute of Genomic Medicine, Mexico City, Mexico Abstract Transit of human neural stem cells, ReNcell CX, through the blood brain barrier (BBB) was evaluated in an in vitro model of BBB and in nude mice. The BBB model was based on rat brain microvascular endothelial cells (RBMECs) cultured on Millicell inserts bathed from the basolateral side with conditioned media (CM) from astrocytes or glioma C6 cells. Glioma C6 CM induced a significant transendothelial migration of ReNcells CX in comparison to astrocyte CM. The presence in glioma C6 CM of high amounts of HGF, VEGF, zonulin and PGE 2 , together with the low abundance of EGF, promoted ReNcells CX transmigration. In contrast cytokines IFN-a, TNF-a, IL-12p70, IL-1b, IL-6, IL-8 and IL-10, as well as metalloproteinases -2 and -9 were present in equal amounts in glioma C6 and astrocyte CMs. ReNcells expressed the tight junction proteins occludin and claudins 1, 3 and 4, and the cell adhesion molecule CRTAM, while RBMECs expressed occludin, claudins 1 and 5 and CRTAM. Competing CRTAM mediated adhesion with soluble CRTAM, inhibited ReNcells CX transmigration, and at the sites of transmigration, the expression of occludin and claudin-5 diminished in RBMECs. In nude mice we found that ReNcells CX injected into systemic circulation passed the BBB and reached intracranial gliomas, which overexpressed HGF, VEGF and zonulin/prehaptoglobin 2. Citation: Dı ´az-Cora ´nguez M, Segovia J, Lo ´ pez-Ornelas A, Puerta-Guardo H, Ludert J, et al. (2013) Transmigration of Neural Stem Cells across the Blood Brain Barrier Induced by Glioma Cells. PLoS ONE 8(4): e60655. doi:10.1371/journal.pone.0060655 Editor: Joseph Najbauer, University of Pe ´cs Medical School, Hungary Received January 14, 2013; Accepted March 1, 2013; Published April 5, 2013 Copyright: ß 2013 Dı ´az Cora ´nguez, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by the Mexican Council of Science and Technology, CONACYT (Consejo Nacional de Ciencia y Technologia) (URL: http://www. conacyt.mx), grants98448 (LGM) and 127357 (JS) and by a multidisciplinary grant from CINVESTAV (Centro de Investigacio ´ ny de Estudios Avanzados del Instituto Polite ´cnico Nacional) (URL: http://www.cinvestav.mx). Mo ´ nica Dı ´az Cora ´nguez, Adolfo Lo ´ pez -Ornelas and Henry Puerta were recipients of doctoral fellowships from CONACYT (267383, 206882 and 225017). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: lorenza@fisio.cinvestav.mx Introduction Neural stem cells (NSCs) constitute a population that contin- ually self-renews and generates the neurons and glia of the brain. NSCs are highly migratory and appear to be attracted to areas of brain pathology. In particular, endogenous neural precursor cells (NPCs) located in the brain subventricular zone have been found to migrate to glial brain tumors [1], where they exert an age dependent antitumorigenic response [2] mediated in part by the release of endovanilloids [3] and bone morphogenetic protein 7 [4]. This ability renders the possibility of using NSC for replacing neurons in degenerative disorders, to repress the proliferation of tumor cells and to deliver therapeutic genes to diseased regions in the brain including minute brain metastasis after main tumor resection [for review see [5]. Thus, NPCs, when systemically injected reach the cerebral parenchyma, induce recovery in animal models of multiple sclerosis [6], and NSCs when implanted into experimental intracranial gliomas in vivo in adult rodents, distribute extensively throughout the tumor bed, and when implanted intracranially at distant sites from the tumor, migrate through normal tissue to the tumor cells. What is more, when NSCs are implanted outside of the CNS intravascularly, they are capable of targeting intracranial gliomas [7]. Transendothelial migration of NSCs is regulated by inflamma- tion, reactive astrocytosis and angiogenesis. These processes induce the release of numerous chemokines and growth factors that stimulate the directed migration of NSC towards the site of injury. For example, NPCs express receptors of the chemokines IL-8 and CXL13 and migrate in vitro across brain endothelial cells in response to these chemokines [8]. NSC migrate from the contralateral hemisphere towards an infarcted brain area where local astrocytes and endothelium upregulate the expression of stromal cell derived factor 1 (SDF-1)/chemokine CXCL12 [9] and intravenously transplanted NSC migrate to the injured spinal cord in an CXCL12 and hepatocyte growth factor (HGF) dependent manner [10]. In NSC lines, HGH induces the strongest chemotactic response from a variety of multiple tumor-derived growth factors including vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and transforming growth factor alpha (TGF-a) [11]. VEGF, a growth factor that promotes vasculogenesis, is able to induce long-range attraction of trans- planted NSC from distant sites in the brain [12]. Conversely, other factors inhibit NPCs homing. For example, semaphorin 3A/ Vascular endothelial growth factor-165 acts as a repellent guidance cue for migrating NPCs [13] and hyaluronic acid, the major ligand of the adhesion molecule CD44, and anti CD44 PLOS ONE | www.plosone.org 1 April 2013 | Volume 8 | Issue 4 | e60655