TY - JOUR
T1 - Transcription Factor Brn-3b Overexpression Enhances Neurite Outgrowth in PC12 Cells Under Condition of Hypoxia
AU - Phatak, Nitasha R.
AU - Stankowska, Dorota L.
AU - Krishnamoorthy, Raghu R.
N1 - Funding Information:
The work was supported by a grant from the Department of Defense (W81XWH-10-2-0003) to Thomas Yorio (P.I.), and Raghu Krishnamoorthy (Co-I.) and partial support from a National Eye Institute grant (1R01EY019952) to Raghu Krishnamoorthy.
Publisher Copyright:
© 2015, Springer Science+Business Media New York.
PY - 2015/8/24
Y1 - 2015/8/24
N2 - 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.
AB - 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.
KW - Hypoxia
KW - Neurite outgrowth
KW - Neurodegeneration
KW - Transcription factor Brn-3b
UR - http://www.scopus.com/inward/record.url?scp=84937520024&partnerID=8YFLogxK
U2 - 10.1007/s10571-015-0171-0
DO - 10.1007/s10571-015-0171-0
M3 - Article
C2 - 25786379
AN - SCOPUS:84937520024
SN - 0272-4340
VL - 35
SP - 769
EP - 783
JO - Cellular and Molecular Neurobiology
JF - Cellular and Molecular Neurobiology
IS - 6
ER -