title: Transcription Factor Brn-3b Overexpression Enhances Neurite Outgrowth in PC12 Cells Under Condition of Hypoxia.
abstract: Transcription factor Brn-3b plays a key role in retinal ganglion cell differentiation, survival, and axon outgrowth during development. However, the precise role of Brn-3b in the normal adult retina as well as during neurodegeneration is unclear. In the current study, the effect of overexpression of Brn-3b was assessed in vitro, in PC12 cells under conditions of normoxia and hypoxia. Immunoblot analysis showed that overexpression of Brn-3b in PC12 cells as well as 661W cells produced significant increase in the growth cone marker, growth-associated protein-43 (GAP-43), and acetylated-tubulin (ac-TUBA). In addition, an increased immunostaining for GAP-43 and ac-TUBA was observed in PC12 cells overexpressing Brn-3b, which was accompanied by a marked increase in neurite outgrowth, compared to PC12 cells overexpressing the empty vector. In separate experiments, one set of PC12 cells transfected either with a Brn-3b expression vector or an empty vector was subjected to conditions of hypoxia for 2 h, while another set of similarly transfected PC12 cells was maintained in normoxic conditions. It was found that the upregulation of GAP-43 and ac-TUBA in PC12 cells overexpressing Brn-3b under conditions of normoxia was sustained under conditions of hypoxia. Immunocytochemical analysis revealed not only an upregulation of GAP-43 and ac-TUBA, but also increased neurite outgrowth in PC12 cells transfected with Brn-3b as compared to PC12 cells transfected with empty vector in both normoxia and hypoxia. The findings have implications for a potential role of Brn-3b in neurodegenerative diseases in which hypoxia/ischemia contribute to pathophysiology of the disease.
authors: Department of Cell Biology and Immunology, North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA.
authors: Nitasha R
authors: NR
authors: Phatak
authors: Dorota L
authors: DL
authors: Stankowska
authors: Raghu R
authors: RR
authors: Krishnamoorthy
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D015687:Cell Hypoxia / Q000235:genetics; D002478:Cells, Cultured; D051379:Mice; D016501:Neurites / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D055495:Neurogenesis / Q000187:drug effects / Q000235:genetics*; D010100:Oxygen / Q000494:pharmacology; D016716:PC12 Cells; D051381:Rats; D050820:Transcription Factor Brn-3B / Q000235:genetics*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D050820:Transcription Factor Brn-3B; D010100:Oxygen