Article

Neuronal Differentiation of P19 Embryonal Carcinoma Cells Modulates Kinin B2 Receptor Gene Expression and Function

University of Leipzig, Leipzig, Saxony, Germany
Journal of Biological Chemistry (Impact Factor: 4.6). 05/2005; 280(20):19576-19586. DOI: 10.1074/jbc.M502513200

ABSTRACT Kinins are vasoactive oligopeptides generated upon proteolytic cleavage of low and high molecular weight kininogens by kallikreins.
These peptides have a well established signaling role in inflammation and homeostasis. Nevertheless, emerging evidence suggests
that bradykinin and other kinins are stored in the central nervous system and may act as neuromediators in the control of
nociceptive response. Here we show that the kinin-B2 receptor (B2BKR) is differentially expressed during in vitro neuronal differentiation of P19 cells. Following induction by retinoic acid, cells form embryonic bodies and then undergo
neuronal differentiation, which is complete after 8 and 9 days. Immunochemical staining revealed that B2BKR protein expression
was below detection limits in nondifferentiated P19 cells but increased during the course of neuronal differentiation and
peaked on days 8 and 9. Measurement of [Ca2+]i in the absence and presence of bradykinin showed that most undifferentiated cells are unresponsive to bradykinin application,
but following differentiation, P19 cells express high molecular weight neurofilaments, secrete bradykinin into the culture
medium, and respond to bradykinin application with a transient increase in [Ca2+]i. However, inhibition of B2BKR activity with HOE-140 during early differentiation led to a decrease in the size of embryonic
bodies formed. Pretreatment of differentiating P19 cells with HOE-140 on day 5 resulted in a reduction of the calcium response
induced by the cholinergic agonist carbamoylcholine and decreased expression levels of M1–M3 muscarinic acetylcholine receptors,
indicating crucial functions of the B2BKR during neuronal differentiation.

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