TY - JOUR
T1 - Marked change in the balance between CYP27A1 and CYP46A1 mediated elimination of cholesterol during differentiation of human neuronal cells
AU - Milagre, Inês
AU - Olin, Maria
AU - Nunes, Maria João
AU - Moutinho, Miguel
AU - Lövgren-Sandblom, Anita
AU - Gama, Maria João
AU - Björkhem, Ingemar
AU - Rodrigues, Elsa
N1 - Funding Information:
We deeply thank Dr. David Russell (Department of Molecular Genetics, University of Texas Southwestern Medical Center, USA) for kindly providing the antibody against CYP46A1. We are also very grateful to Dr. Irina Pikuleva (Department of Ophthalmology and Visual Sciences, Case Western Reserve University and University Hospitals, Cleveland, Ohio, United States) for providing us the antibody against CYP27A1. Supported by Fundaçãopara a Ciência e Tecnologia – Projects PPCDT/SAU-MMO/55919/2004 and PEst-OE/SAU/UI4013/2011 and PhD grants SFRH/BD/27660/2006 (IM) and SFRH/BD/41848/ 2007 (MJN). IB has support from the Swedish Science Council (VR) and Brain Power .
PY - 2012/1
Y1 - 2012/1
N2 - Cholesterol metabolism in the brain is distinct from that in other tissues due to the fact that cholesterol itself is unable to pass across the blood-brain barrier. Elimination of brain cholesterol is mainly dependent on a neuronal-specific cytochrome P450, CYP46A1, catalyzing the conversion of cholesterol into 24(S)-hydroxycholesterol (24OHC), which is able to pass the blood-brain barrier. A suitable model for studying this elimination from human neuronal cells has not been described previously. It is shown here that differentiated Ntera2/clone D1 (NT2) cells express the key genes involved in brain cholesterol homeostasis including CYP46A1, and that the expression profiles of the genes observed during neuronal differentiation are those expected to occur in vivo. Thus there was a decrease in the mRNA levels corresponding to cholesterol synthesis enzymes and a marked increase in the mRNA level of CYP46A1. The latter increase was associated with increased levels of CYP46A1 protein and increased production of 24OHC. The magnitude of the secretion of 24OHC from the differentiated NT2 cells into the medium was similar to that expected to occur under in vivo conditions. An alternative to elimination of cholesterol by the CYP46A1 mechanism is elimination by CYP27A1, and the product of this enzyme, 27-hydroxycholesterol (27OHC), is also known to pass the blood-brain barrier. The CYP27A1 protein level decreased during the differentiation of the NT2 cells in parallel with decreased production of 27OHC. The ratio between 24OHC and 27OHC in the medium from the cultured cells increased, by a factor of 13, during the differentiation process. The results suggest that progenitor cells eliminate cholesterol in the form of 27OHC while neurogenesis induces a change to the CYP46A1 dependent pathway. Furthermore this study demonstrates that differentiated NT2 cells are suitable for studies of cholesterol homeostasis in human neurons.
AB - Cholesterol metabolism in the brain is distinct from that in other tissues due to the fact that cholesterol itself is unable to pass across the blood-brain barrier. Elimination of brain cholesterol is mainly dependent on a neuronal-specific cytochrome P450, CYP46A1, catalyzing the conversion of cholesterol into 24(S)-hydroxycholesterol (24OHC), which is able to pass the blood-brain barrier. A suitable model for studying this elimination from human neuronal cells has not been described previously. It is shown here that differentiated Ntera2/clone D1 (NT2) cells express the key genes involved in brain cholesterol homeostasis including CYP46A1, and that the expression profiles of the genes observed during neuronal differentiation are those expected to occur in vivo. Thus there was a decrease in the mRNA levels corresponding to cholesterol synthesis enzymes and a marked increase in the mRNA level of CYP46A1. The latter increase was associated with increased levels of CYP46A1 protein and increased production of 24OHC. The magnitude of the secretion of 24OHC from the differentiated NT2 cells into the medium was similar to that expected to occur under in vivo conditions. An alternative to elimination of cholesterol by the CYP46A1 mechanism is elimination by CYP27A1, and the product of this enzyme, 27-hydroxycholesterol (27OHC), is also known to pass the blood-brain barrier. The CYP27A1 protein level decreased during the differentiation of the NT2 cells in parallel with decreased production of 27OHC. The ratio between 24OHC and 27OHC in the medium from the cultured cells increased, by a factor of 13, during the differentiation process. The results suggest that progenitor cells eliminate cholesterol in the form of 27OHC while neurogenesis induces a change to the CYP46A1 dependent pathway. Furthermore this study demonstrates that differentiated NT2 cells are suitable for studies of cholesterol homeostasis in human neurons.
KW - Brain cholesterol homeostasis
KW - CYP27A1
KW - CYP46A1
KW - NT2 cell line
KW - Oxysterols
UR - http://www.scopus.com/inward/record.url?scp=84855464848&partnerID=8YFLogxK
U2 - 10.1016/j.neuint.2011.12.003
DO - 10.1016/j.neuint.2011.12.003
M3 - Article
C2 - 22185844
AN - SCOPUS:84855464848
SN - 0197-0186
VL - 60
SP - 192
EP - 198
JO - Neurochemistry International
JF - Neurochemistry International
IS - 2
ER -