Einleitung Glycosylphosphatidylinositol-anchored proteins (GPI-APs)
are anchored at the outer leaflet of plasma membranes (PM) by a carboxy-terminal GPI
glycolipid, and fulfill multiple functions at the cell surface. GPI-APs with the
complete GPI anchor can be transferred between donor and acceptor cells, the
physiological role of which remains unclear.
Methoden Differentiated human adipocytes with reduced expression of
GPI-APs at PM were used as acceptor cells and incubated with GPI-APs, prepared from
primary rat adipocytes and embedded in micelle-like complexes, or with
erythroleukemia (EL) cells and human adipocytes with normal expression of GPI-APs
as
donor cells in transwell co-cultures.
Ergebnisse Upregulation of GPI-APs detected at PM of adipocytes and
lipid synthesis was observed which followed similar time courses and was abrogated
by serum, albumin and depletion of total, but not selected GPI-APs. Adipocytes of
low size were shown to act as lipid-synthesizing acceptor cells with higher efficacy
compared to large lipid-filled adipocytes which are more productive as donor cells
for GPI-APs.
Schlussfolgerung Full-length GPI-APs are transferred between blood
cells and adipocytes resulting in stimulation of lipid synthesis under control of
serum factors. This argues for the (patho)physiological relevance of intercellular
transfer of GPI-APs in (dys)regulation of lipid metabolism, and raises the
possibility for use of transfer of GPI-APs as target for the therapy of obesity.
