Migratory Capacity of the Cell Line RN33B and the Host Glial Cell Response After Subretinal Transplantation to Normal Adult Rats ANITA BLIXT WOJCIECHOWSKI, 1 * ULRICA ENGLUND, 2 CECILIA LUNDBERG, 2 AND KARIN WARFVINGE 1 1 Wallenberg Retina Center, Department of Ophthalmology, Lund University Hospital, Lund, Sweden 2 Wallenberg Neuroscience Center, Department of Physiological Sciences, Lund University, Lund, Sweden KEY WORDS RN33B; extracellular guidance cues; migration; retinal detachment; reactive gliosis ABSTRACT As previously reported, the brain-derived precursor cell line RN33B has a great capacity to migrate when transplanted to adult brain or retina. This cell line is immortalized with the SV40 large T-antigen and carries the reporter gene LacZ and the green fluorescent protein GFP. In the present study, the precursor cells were transplanted to the subretinal space of adult rats and investigated early after grafting. The purpose was to demonstrate the migration of the grafted cells from the subretinal space into the retina and the glial cell response of the host retina. Detachment caused by the transplantation method was persistent up to 4 days after transplantation, and then reattachment occurred. The grafted cells were shown to migrate in between the photoreceptor cells before entering into the plexiform layers. Molecules involved in migration of immature neuronal cells as the polysialylated neural cell adhesion molecule (PSA-NCAM) and the collapsing response- mediated protein 4 (TUC-4) was found in the plexiform layers of the host retina, but not in the grafted cells. The expression of the intermediate filaments GFAP, vimentin, and nestin was intensely upregulated immediately after transplantation. A less pronounced upregula- tion was observed on sham-operated animals. In summary, the RN33B cell line migrated promptly posttransplantation and settled preferably into the plexiform layers of the retina, the same layers where the migration cues PSA-NCAM and TUC-4 were established. In addition, both the transplantation method per se and the implanted cells caused an intense glial cell response by the host retina. © 2004 Wiley-Liss, Inc. INTRODUCTION In the paths of clinical results from neural grafting to patients suffering from, for example, Parkinson’s dis- ease, the anticipation on transplantation of immature cells in retinal degeneration conditions such as retini- tis pigmentosa (RP) and age-related macular degener- ation (AMD) emerged (Svendsen and Caldwell, 2000; Whittemore and Onifer, 2000; Ostenfeld and Svendsen, 2003). Indeed, transplantation of various neural pre- cursor cells into the retina has been carried out in the normal neonatal and adult host retina (Seigel et al., 1998; Takahashi et al., 1998; Chacko et al., 2000; Warfvinge et al., 2001; Blixt Wojciechowski et al., 2002a, 2004; van Hoffelen et al., 2003), degenerating retina (Young et al., 2000; Mizumoto et al., 2001; Press- mar et al., 2001; Blixt Wojciechowski et al., 2002b; Grant sponsor: the Crown Princess Margareta’s Committee for the Blind; Grant sponsor: the Swedish Association of the Visually Impaired; Grant sponsor: the Swedish Science Council (Medicine); Grant sponsor: Second ONCE Interna- tional Award for New Technologies for the Blind; Grant sponsor: the Lund Faculty of Medicine. Ulrica Englund’s present address is Department of Neurodegenerative Disor- ders, Ottiliavej, Valby, Denmark. *Correspondence to: Anita Blixt Wojciechowski, Department of Ophthalmol- ogy, Lund University Hospital, S-221 84 Lund, Sweden. E-mail: a.blixt@bredband.net Received 19 November 2003; Accepted 14 January 2004 DOI 10.1002/glia.20033 Published online 24 March 2004 in Wiley InterScience (www.interscience. wiley.com). GLIA 47:58 – 67 (2004) © 2004 Wiley-Liss, Inc.