Bile acid increases expression of the histamine-producing enzyme, histidine decarboxylase, in gastric cells

Figure 3 Small heterodimer partner is associated with bile acid-induced histidine decarboxylase transactivation. A: Human gastric adenocarcinoma (AGS) cells were cotransfected with the 2.3 kb histidine decarboxylase (HDC)-luc promoter construct and small heterodimer partner (SHP) expression plasmid in the presence of deoxycholic acid (DCA) or chenodeoxycholic acid (CDCA). Cells were analyzed for luciferase activity; B: AGS cells were cotransfected with the 2.3 kb HDC-luc promoter construct and expression plasmids for farnesoid X receptor (FXR)α1/2 and SHP. Cells were analyzed for luciferase activity; C: AGS cells were cotransfected with the 2.3 kb HDC-luc promoter construct and FXRα1/2 expression plasmid in the presence of CDCA. Cells were analyzed for luciferase activity; D: AGS cells were transfected with SHP expression plasmid in the presence of DCA or CDCA. Total RNA was prepared from the cells, after which HDC mRNA levels were determined by reverse transcription-polymerase chain reaction (RT-PCR); E: AGS cells were transfected with expression plasmids for FXRα1/2 and SHP. Total RNA was prepared from the cells, after which HDC mRNA levels were determined by RT-PCR; F: AGS cells were transfected with SHP siRNA construct in the presence of DCA or CDCA. Total RNA was prepared from the cells, after which HDC mRNA levels were determined by RT-PCR.