Expression and a role of functionally coupled P2Y receptors in human dendritic cells.
We investigated the physiology and function of P2Y receptors expressed in human dendritic cells (DCs) differentiated in vitro from CD14+ cells (DC-14). These were obtained after a 10 day stimulation period in GM-CSF, IL-4 and monocyte conditioned medium. DC-14 were found to express high amounts of MHC class II, B7, CD40 as well as CD83. The functional analysis, using single cell Ca2+ imaging, demonstrated the expression of at least three subtypes of P2Y receptors. We further found using patch-clamp measurements that ATP evoked a pertussis toxin insensitive non-selective cation current with a peak current amplitude of -276+/-43 pA (holding potential -80 mV, n = 23). This current was not Ca(2+)-activated, since it was still observed under conditions of high intracellular Ca2+ buffering and could be blocked by Gd3+ (0.5 mM). In addition, intracellular application of GTP-gamma-S (0.3 mM) also activated the current. Interestingly, DC-14 redirected the orientation of their dendrites as well as cell shape towards a pipette containing ATP as observed with time lapse microscopy. These data suggest that in human DCs, ATP acts via P2Y receptors and induces chemokine effects.
Liu
Q H
QH
Institute of Neurophysiology, University of Cologne, Germany.
Bohlen
H
H
Titzer
S
S
Christensen
O
O
Diehl
V
V
Hescheler
J
J
Fleischmann
B K
BK
D000255:Adenosine Triphosphate / Q000378:metabolism; D002412:Cations; D003713:Dendritic Cells / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D018048:Receptors, Purinergic P2 / Q000096:biosynthesis / Q000502:physiology*
D002412:Cations; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate