Membrane cholesterol-enriched lipid domains (lipid-rafts) are essential for the structural and functional integrity of neuronal membranes; they have been involved in a variety of different functions (e.g., signal transduction, lipid transport and metabolism, cell growth and migration) and can be modified by aging and certain neurodegenerative diseases. Recently, a new gene termed "selective Alzheimer’s disease indicator 1" (seladin-1) was shown to confer resistance to Alzheimer’s disease-associated neurodegeneration; seladin-1 (Sel-1) is identical to the human gene which encodes for a cholesterol-biosynthetic enzyme 3beta-hydroxysterol delta24-reductase (DHCR24), found to be mutated in the patients affected by desmosterolosis. In the present study we used immortalized neurons derived from post-migratory mature (GT1-7 cell line) and from immature migrating (GN11 cell line) GnRH neurons to investigate the role of Sel-1 on neuronal functions. By real time-PCR technique, we found that GT1-7 cells present 10-100 times higher levels of Sel-1 mRNA compared to GN11 cells. Sel-1 immunoreactivity appears distributed around the nucleus associated by endoplasmic reticulum; transfection of a fluorescent construct of Sel-1 (Sel-1GFP) showed a similar distribution of the protein. The staining of the two cell lines with filipin, a fluorescent polyene antibiotic that detects unesterified cholesterol, revealed a significant accumulation of free cholesterol in vesicular structures. Finally, disruption of lipid rafts by cholesterol-depleting compounds methyl-beta-cyclodextrin, lead to a significant decrease of the in vitro migratory activity of GN11 cells that may be reverted by simultaneous exposure to cholesterol. In conclusion, these data indicate that a) mature and immature GnRH neurons differentially express seladin-1/DHCR24, and b) the membrane cholesterol-rich domains may play a key role in the migration of these neurons. GT1-7 and GN11 cell model represent an useful tool to investigate the role of seladin-1/DHCR24 and of cholesterol in neuronal physiology.
Differential expression of selective Alzheimer disease indicator (seladin-1)/DHCR24 gene in immortalized GnRH neurons / A. Samara, P. Luciani, A. Peri, R. Maggi. - In: JOURNAL OF ENDOCRINOLOGICAL INVESTIGATION. - ISSN 0391-4097. - 28:suppl. 4(2005), pp. 9-9. ((Intervento presentato al 31. convegno National Congress of the Italian Society of Endocrinology tenutosi a Genova nel 2005.
|Titolo:||Differential expression of selective Alzheimer disease indicator (seladin-1)/DHCR24 gene in immortalized GnRH neurons|
SAMARA, ATHINA (Primo)
MAGGI, ROBERTO (Ultimo)
|Parole Chiave:||Alzheimer; DHCR24; cholesterol; GnRH; neurons|
|Settore Scientifico Disciplinare:||Settore BIO/09 - Fisiologia|
Settore MED/13 - Endocrinologia
|Data di pubblicazione:||2005|
|Appare nelle tipologie:||01 - Articolo su periodico|