title: Human dental pulp stem cells respond to cues from the rat retina and differentiate to express the retinal neuronal marker rhodopsin.
abstract: Human adult dental pulp stem cells (DPSCs) are self-renewing stem cells that originate from the neural crest during development and remain within the dental pulp niche through adulthood. Due to their multi-lineage differentiation potential and their relative ease of access they represent an exciting alternative for autologous stem cell-based therapies in neurodegenerative diseases. In animal models, DPSCs transplanted into the brain differentiate into functional neurons or astrocytes in response to local environmental cues that appear to influence the fate of the surviving cells. Here we tested the hypothesis that DPSCs might be able to respond to factors present in the retina enabling the regenerative potential of these cells. We evaluated the response of DPSCs to conditioned media from organotypic explants from control and chemically damaged rat retinas. To evaluate cell differentiation, we analyzed the expression of glial fibrillary acidic protein (GFAP), early neuronal and retinal markers (polysialic acid-neural cell adhesion molecule (PSA-NCAM); Pax6; Ascl1; NeuroD1) and the late photoreceptor marker rhodopsin, by immunofluorescence and reverse transcription polymerase chain reaction (RT-PCR). Exposure of DPSC cultures to conditioned media from control retinas induced a 39% reduction on the number of DPSCs that expressed GFAP; the expression of Pax6, Ascl1, PSA-NCAM or NeuroD1 was undetectable or did not change significantly. Expression of rhodopsin was not detectable in control or after exposure of the cultures with retinal conditioned media. By contrast, 44% of DPSCs exposed to conditioned media from damaged retinas were immunopositive to this protein. This response could not be reproduced when conditioned media from Müller-enriched primary cultures was used. Finally, quantitative RT-PCR was performed to compare the relative expression of glial cell-derived neurotrophic factor (GDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in DPSC co-cultured with retinal organotypic explants, where BDNF mRNA expression was significantly upregulated in retinal-exposed cultures. Our data demonstrate that DPSC cultures respond to cues from the rat retina and differentiate to express retinal neuronal markers.
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., Mexico; Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del IPN, México D.F., Mexico.
authors.forename: A F
authors.initials: AF
authors.lastname: Bray
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., Mexico.
authors.forename: R R
authors.initials: RR
authors.lastname: Cevallos
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., Mexico.
authors.forename: K
authors.initials: K
authors.lastname: Gazarian
authors.affiliation: Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del IPN, México D.F., Mexico. Electronic address: mlamas@cinvestav.mx.
authors.forename: M
authors.initials: M
authors.lastname: Lamas
mesh_terms: D000328:Adult; D053687:Adult Stem Cells / Q000166:cytology / Q000502:physiology*; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000502:physiology*; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D003782:Dental Pulp / Q000166:cytology / Q000502:physiology*; D063928:Ependymoglial Cells / Q000378:metabolism; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D009414:Nerve Growth Factors / Q000378:metabolism; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020318:Rats, Long-Evans; D012160:Retina / Q000293:injuries / Q000378:metabolism*; D012243:Rhodopsin / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism; D046509:Tissue Culture Techniques; D055815:Young Adult
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D017077:Culture Media, Conditioned; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D039842:Neural Cell Adhesion Molecule L1; D012333:RNA, Messenger; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule; C579455:BDNF protein, human; D012243:Rhodopsin
keywords: Müller glia; dental pulp stem cells; neuronal differentiation; retina