Mechanisms of nerve growth factor release from a human urothelial cell line

Abstract

Nerve growth factor (NGF) has been recently implicated in urinary bladder dysfunction, but the cellular source and mechanisms controlling its release have not been characterized yet. We studied NGF release and underlying signal transduction pathways in a human urothelial cell line UROtsa.UROtsa expressed NGF at mRNA and protein level, as determined by Real‐time PCR and immunocytochemistry, respectively. NGF was constitutively released to the medium (11.5 ± 1.4 pg NGF/mg protein/h), as measured by ELISA. Down‐regulation of proteinkinase C by pre‐incubation with phorbol ester PMA reduced NGF release down to 71±3 % of the baseline within 24 hours. In contrast, NGF release was enhanced by stimulation with bradykinin, thrombin or brain‐derived nerve factor by 121±9, 127±9, 135±8 %, respectively. In case of bradykinin, enhanced NGF release was associated with elevated mRNA expression.These data suggest that urothelial cells are able to release NGF, potentially modifiable by several G‐protein coupled and tyrosine kinase receptor ligands. Targeting these modulatory urothelial receptors may provide a novel strategy in the treatment of urinary bladder overactivity.Supported by EU grant HEALTH‐F2‐2008‐223234.