Vitamin D differentially regulates Salmonella-induced intestine epithelial autophagy and interleukin-1β expression

Figure 5 1,25D3 up-regulates the vitamin D receptor protein or mRNA expression in Salmonella-infected Caco-2 cells. Caco-2 cells were uninfected (CON) or infected by wild-type S. typhimurium strain SL1344 (SL) at indicated times, in the presence or absence of 1,25D3 (D3). Total RNA was prepared after infection and analyzed by real-time quantitative PCR to estimate amounts of vitamin D receptor (VDR) transcript (A). The amount of VDR mRNA produced, normalized to the corresponding amount of GAPDH transcript, is shown as the fold-increase over uninfected control cells. Results are represented as mean ± SEM for at least three determinations from independent experiments. Immunoblotting was performed on whole cell lysates with an antibody to detect VDR protein expression, or GAPDH for normalization of proteins. Representative immunoblots (B) and densitometric quantification of immunoreactive bands (C) are shown; The relative band intensities of VDR (C) in Caco-2 cells were quantified as fold-increases compared with the control cells. Each value represents the mean ± SEM of three independent experiments. ^aP < 0.05.