Effects Of DPPA On Regulation Of Alzheimer's Disease-related Protein FURIN Promoter Activity And Gene Expression

Precursor protein converting enzyme furin is involved in the maturation of neurotrophic factor, protecting cells from endoplasmic reticulum stress/oxidative stress-induced injury and apoptosis. It may also affect APP metabolism, autophagy and other mechanisms involved in the development and progression of AD. To study the potential roles of furin in AD, we constructed a luciferase reporter plasmid carrying human furin P1 promoter, and stably transfected it into SH-SY5 Y cells. By traditional Chinese medicine monomer high through-put scanning, we found that four kinds of phorbol esters PKC agonists can effectively promote luciferase activity of furin P1 promoter. We selected d PA and dPPA, two of which are not carcinogenic. Our study found that the two agonists can both increase the expression of mRNA and protein levels of furin. By gene regulation analysis, we found neither TGF? signaling pathways nor protein phosphorylation signaling pathways were involved in the regulation of dPA and dPPA to furin. However, PKC inhibitor calphostin C can effectively block the increased levels of furin by co-treating it with dPA or dPPA. This finding suggests that dPA and dPPA mediate furin gene through the interaction of PKC protein. CEBP? and GATA1 elements in the P1 promoter were known to be needed for furin gene expression. Several truncated fragments of furin P1 promoter were transfected in cells and then treated with four PKC agonists. By luciferase activity analysis, we found the highest luciferase expression truncated fragment. And nucleic acid sequence analysis indicated that this fragment may contain the binding site sequences of CEBP? regulatory element. We next suppressed the expression of CEBP? and GATA1 by si-RNA, the results indicated that CEBP? in the P1 promoter is needed for furin gene expression in HEK293 cells and SH-SY5Y cells.