Identification of a functional receptor for granulocyte colony-stimulating factor on platelets.
Since granulocyte colony-stimulating factor (G-CSF) is thought to be a granulocyte lineage-specific cytokine, G-CSF receptors on blood cells other than those of granulocyte or monocyte lineage have not been well investigated. We now report that G-CSF receptors are present on platelets. The expression of G-CSF receptors on platelets was demonstrated by flow cytometry and radioreceptor assay. The mean number of G-CSF-binding sites per cell was 41 and the binding affinity was high (Kd 300 pM), similar to the affinity observed on granulocytes. Cross-linking assay revealed that G-CSF receptors were present on a single subunit protein of approximately 150 kD on the platelets. To clarify whether or not G-CSF might produce some direct functional influence on platelet response, the effects on platelet aggregation were studied. Although G-CSF itself did not affect platelet aggregation in vitro, preincubation with G-CSF augmented a secondary aggregation of platelets induced by low concentrations of adenosine diphosphate (ADP). There was a dose-response relationship for this G-CSF activity at concentrations of up to 10 ng/ml. Furthermore, the augmented ADP-induced secondary aggregation of platelets on G-CSF receptors was completely abrogated in the presence of anti-G-CSF polyclonal antibodies. These results indicate that platelets possess functional G-CSF receptors.
Shimoda
K
K
Cancer Center, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Okamura
S
S
Harada
N
N
Kondo
S
S
Okamura
T
T
Niho
Y
Y
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001792:Blood Platelets / Q000648:ultrastructure*; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects; D011869:Radioligand Assay; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000502:physiology*
D016188:Receptors, Granulocyte Colony-Stimulating Factor; D016179:Granulocyte Colony-Stimulating Factor; D000244:Adenosine Diphosphate