MAB3516 Sigma-AldrichAnti-Heat Shock Protein 70 Antibody, clone W27

We sought to determine whether taurine could specifically protect against coronary artery disease during an atherogenic diet and whether taurine affects the lipid profile, metabolites of methionine, and endothelial atherogenic systems. Rabbits were fed one of the following diets for 4 weeks: (1) control diet; (2) 0.5% cholesterol+1.0% methionine; or (3) 0.5% cholesterol+1.0% methionine+2.5% taurine. Endothelial function was examined, and the left main coronary artery atherosclerosis was quantified by stereology and semiquantitative immunohistochemistry to determine the endothelial expression of proteins related to the NO, renin-angiotensin, endoplasmic reticulum, and oxidative stress systems, as well as apoptosis. Taurine normalized hyperhomocysteinemia (Pless than 0.05) and significantly reduced hypermethioninemia (Pless than 0.05) but not lipidemia. The intima:media ratio was reduced by 28% (P=0.034), and atherosclerosis was reduced by 64% (P=0.012) and endothelial cell apoptosis by 30% (Pless than 0.01). Endothelial cell CCAAT/enhancer binding protein homologous protein was normalized (Pless than 0.05). Taurine failed to improve hyperlipidemia, endothelial function, or endothelial proteins related to the NO, renin-angiotensin, and oxidative stress systems. Taurine reduces left main coronary artery wall pathology associated with decreased plasma total homocysteine, methionine, apoptosis, and normalization of CCAAT/enhancer binding protein homologous protein. These results elucidate the antiapoptotic and antiatherogenic properties of taurine, possibly via normalization of endoplasmic reticulum stress.

A physiological atherogenic human diet consists of 0.1% cholesterol, fat, as well as high levels of methionine, which is the precursor to homocysteine. The pathological effects of a diet enriched with physiologically high levels of cholesterol, methionine and fat over a short period on the aorta are unknown. In this regard, we sought to determine the effects of a 0.1% cholesterol diet in combination with a 1% methionine over a 4-week period on endothelial function and artery pathology and the expression of endothelial nitric oxide synthase as well as nitrosative stress by nitrotyrosine (NT), oxidative stress by heat shock protein 70 (HSP70) and endoplasmic reticulum stress by glucose regulated protein 78 (GRP78). Rabbits were fed for 4 weeks a diet supplemented with 1% methionine + 0.1% cholesterol + 5% peanut oil (MC). The endothelial function of the abdominal aorta was examined using organ bath techniques, atherosclerosis determined in each artery by microscopy and eNOS, NT, GRP78 and HSP70 by standard immunohistochemistry. Endothelium dependent relaxation in response to acetylcholine significantly decreased by 63% at 1 muM acetylcholine (P < 0.001) compared with control arteries. There was no evidence of atherosclerosis formation in any artery studied, however, eNOS, NT and GRP78 was clearly present in all arteries studied but HSP70 was not easily detectable. Severe endothelial dysfunction is present in the abdominal aorta of rabbits within 4 weeks of physiological dietary manipulation, possibly due to NT formation and endoplasmic reticulum stress. This model could be used to study the early onset of endothelial dysfunction prior to the initiation of atherosclerosis.

BACKGROUND: E-cadherin, a fundamental component of the adherens junction, is known to mediate aggregation-dependent cell survival. We have previously identified a novel, calpain-dependent proteolytic cleavage of E-cadherin that resulted in the generation of a stable 100-kDa E-cadherin fragment (E-cad(100)) in prostate epithelial cells in response to cell death stimuli. We postulated that the E-cad(100) fragment may play a role in abrogating survival of LNCaP cells following induction of apoptosis. METHODS: Wild-type E-cadherin and E-cad(100) were engineered, tagged with GFP, and stably expressed in LNCaP cells. These cell lines were characterized for E-cadherin-GFP/beta-catenin interactions, endogenous E-cadherin and beta-catenin expression, and sensitivity to apoptosis induced by PKC activation. RESULTS: E-cad(100)-GFP demonstrated a punctuate expression pattern, in contrast to E-cad(120)-GFP, which was membrane-localized. E-cad(100)-GFP, unlike E-cad(120)-GFP, failed to bind to and co-localize with beta-catenin. Transient or stable overexpression of E-cad(100) resulted in the downregulation of endogenous E-cadherin expression at the cell membrane. Activation of PKC in LNCaP cells which overexpressed E-cad(100) potentiated cell death. CONCLUSIONS: Truncated E-cadherin may play a role in the regulation of endogenous E-cadherin expression and epithelial cell survival.