出版社：American Society for Biochemistry and Molecular Biology
摘要：The astrocytes prepared by 1 week secondary culture after 1month primary culture of rat brain cells (M/W cells) synthesizedand secreted apolipoprotein E (apoE) and cholesterol more thanthe astrocytes prepared by conventional 1 week primary and 1week secondary culture (W/W cells) (Ueno, S., J. Ito, Y. Nagayasu,T. Furukawa, and S. Yokoyama. 2002. An acidic fibroblast growthfactor-like factor secreted into the brain cell culture mediumupregulates apoE synthesis, HDL secretion and cholesterol metabolismin rat astrocytes. Biochim. Biophys. Acta. 1589: 261–272).M/W cells also highly expressed fibroblast growth factor-1 (FGF-1)mRNA. FGF-1 was identified in the cell lysate of both cell types,but M/W cells released more of it into the medium. Immunostainingof FGF-1 and apoE revealed that both localized in the cellsthat produce glial fibrillary acidic protein. The conditionedmedia of M/W cells and FGF-1 stimulated W/W cells to releaseapoE and cholesterol to generate more HDL. Pretreatment witha goat anti-FGF-1 antibody or heparin depleted the stimulatoryactivity of M/W cell-conditioned medium. The presence of theanti-FGF-1 antibody in the medium suppressed apoE secretionby M/W cells. Differential inhibition of signaling pathwayssuggested that FGF-1 stimulates apoE synthesis via the phosphoinositide3-OH kinase for PI3K/Akt pathway. Thus, astrocytes release FGF-1,which promotes apoE-HDL production by an autocrine mechanism.
These results are consistent with our in vivo observation thatastrocytes produce FGF-1 before the increase of apoE in thepostinjury lesion of the mouse brain (Tada, T., J. Ito, M. Asai,and S. Yokoyama. 2004. Fibroblast growth factor 1 is producedprior to apolipoprotein E in the astrocytes after cryo-injuryof mouse brain. Neurochem. Int. 45: 23–30).Abbreviations: apoE, apolipoprotein E; DPBS, Dulbecco's phosphate-buffered saline; FCS, fetal calf serum; FGF-1, fibroblast growth factor-1; GFAP, glial fibrillary acidic protein; PI3K, phosphoinositide 3-OH kinase; TBS, salined 0.02 Tris-Hcl buffer
Supplementary key words apolipoprotein E • fibroblast growth factor-1 • high density lipoprotein • brain damage • cholesterol
