Fried U, Kotarsky K, Alling C. Chronic ethanol exposure enhances activating protein-1 transcriptional activity in human neuroblastoma cells.
Alcohol 2001;
24:189-95. [PMID:
11557304 DOI:
10.1016/s0741-8329(01)00151-3]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study demonstrates a method for studying the effects of ethanol on transcription mediated by activating protein-1 (AP-1). The effects of ethanol on AP-1 activity and on the signaling cascades in this process were investigated by using a reporter gene technique with secreted alkaline phosphatase as the reporter gene coupled to nine DNA AP-1-binding elements. Long-term ethanol exposure (48-72 h) dose dependently enhanced AP-1 transcriptional activity in SH-SY5Y cells. Shorter exposure periods with ethanol did not influence AP-1 transcriptional activity compared with findings for control cells. Inhibition of protein kinase C (PKC) dramatically decreased AP-1 activity in both control and ethanol-exposed cells and abolished the ethanol enhancement. This finding suggests a pivotal role for PKC-coupled signaling in AP-1 transcriptional activity. Phorbol ester stimulation of AP-1 transcriptional activity was not influenced by long-term ethanol exposure. This finding indicates that signaling events upstream of PKC are the targets for ethanol. Mitogen-activated protein kinases ERK and p38 may play a role in ethanol-enhanced AP-1 activity because inhibitors of both enzymes partly reduced the enhancement. The inhibitors also partly blocked phorbol ester-induced AP-1 activation, which demonstrates a function of these mitogen-activated protein kinases downstream of PKC.
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