Cloning of human preprotachykinin-I promoter and the role of cyclic adenosine 5 '-monophosphate response elements in its expression by IL-1 and stem cell factor

Pregrotachykinin-I gene (PPT-I) encodes several peptides with organ-specifi c functions that link the neuroendocrine-immunehemopoietic axis. We cloned upstream of the initiation site of human PPT-I promoter and identified cons ensus sequences for two cAMP response elements (CRE), PPT-I is induced by c ytokines including those that signal through the cAMP pathway. Therefore, w e studied the role of the two CRE in IL-1 alpha and stem cell factor (SCF) stimulation of bone marrow stroma because both cytokines induce endogenous PPT-I in these cells and activate the cAMP pathway. Furthermore, bone marro w stroma expresses the transcription factors regulated by the cAMP pathways such as the repressor (ICERII gamma) and activator (CREM pi). Mutagenesis of the two CRE and/or cotransfection with vectors that express ICERII gamma or CREM pi indicated that the two CRE have major roles in PPT-I expression . The two CRE are also required for optimal promoter activity by SCF and IL -la. A particular cytokine could concomitantly induce PPT-I and the high af finity G protein-coupled receptor for PPT-I peptides, NK-IR, We showed that SCF, a representative cytokine, induced PPT-I and NK-IR leading to autocri ne and/or paracrine cell activation, Because NK-1R activates cAMP through t he G protein, the results suggest that the presence of CRE sequences within PPT-I promoter could be important in the regulation of PPT-I expression by cytokines, irrespective of their ability to signal through cAMP, As PPT-I is implicated in hemopoietic regulation, immune responses, breast cancer, a nd other neural functions, these studies add to the basic biology of these processes and could provide targets for drug development. The Journal of Im munology, 2001, 166: 2553-2561.