The cleavage processing of SREBP-1 and -2 as well as expression of their target genes are enhanced in the aorta of diabetic, atherosclerotic pigs.

<p><b>A</b>. The transcriptional regulation of <i>de novo</i> lipogenic enzymes (blue color) by SREBP-1. <b>B</b>. The levels of mature, active form of SREBP-1 and expression of its target lipogenic enzyme, fatty acid synthase (FAS), are increased in the aorta of diabetic and atherosclerotic pigs. Total aortic lysates (100 µg proteins) were resolved by 8% SDS-PAGE and immunoblotted with the specific antibody to recognize both precursor (<b>P</b>, ∼125 kDa) and active mature (<b>M</b>, ∼68 kDa) forms of SREBP-1. Representative immunoblots of aortic tissues from two pigs in each group are shown. <b>C</b>. Densitometric quantification of the mature form of SREBP-1 is normalized to that of β-actin and expressed as relative levels to control pigs. <b>D</b> and <b>E</b>. The transcription of SREBP-1 target genes is elevated in the aorta of diabetic, atherosclerotic pigs. Total RNA was isolated from pig aorta, and mRNA levels of genes encoding stearoyl-CoA desaturase1 (SCD1) (<b>D</b>) and glycerol-3-phosphate acyltransferase (GPAT) (<b>E</b>) were determined by real-time PCR. <b>F</b> and <b>G</b>. The levels of the cleaved form of SREBP-2 protein were quantified by densitometry, normalized to those of β-actin, and expressed as relative levels to normal pigs. <b>H</b> and <b>I</b>. The mRNA amounts of SREBP-2 and its target gene, HMGCoA synthase (HMGCS), are elevated in atherosclerotic pigs. The mRNA levels of SREBP-2 and cholestrogenic genes were determined by real-time PCR, normalized to those of β-actin, and presented as relative levels to control pigs. Data were presented as the mean ± S.E.M., n = 3, *P<0.05, vs control pigs.