Fish oil supplementation reverses the effect of cholesterol on apoptotic gene expression in smooth muscle cells.
BACKGROUND
Nutritional control of gene regulation guides the transformation of smooth muscle cells (SMC) into foam cells in atherosclerosis. Oxidative stress has been reported in areas of lipid accumulation, activating proliferation genes. Suppression of oxidative stress by antioxidant administration reduces this activation and the progression of lesions. We hypothesized that fish oil consumption may protect against atherosclerotic vascular disease. The study objective was to determine the effects of dietary cholesterol and fish-oil intake on the apoptotic pathways induced by 25-hydroxycholesterol (25-HC) in SMC cultures.


METHODS
An in vivo/in vitro cell model was used, culturing SMC isolated from chicks exposed to an atherogenic cholesterol-rich diet with 5% of cholesterol (SMC-Ch) alone or followed by an anti-atherogenic fish oil-rich diet with 10% of menhaden oil (SMC-Ch-FO) and from chicks on standard diet (SMC-C). Cells were exposed to 25-HC, studying apoptosis levels by flow cytometry (Annexin V) and expressions of caspase-3, c-myc, and p53 genes by quantitative real-time reverse transcriptase-polymerase chain reaction.


RESULTS
Exposure to 25-HC produced apoptosis in all three SMC cultures, which was mediated by increases in caspase-3, c-myc, and p53 gene expression. Changes were more marked in SMC-Ch than in SMC-C, indicating that dietary cholesterol makes SMC more susceptible to 25-HC-mediated apoptosis. Expression of p53 gene was elevated in SMC-Ch-FO. This supports the proposition that endogenous levels of p53 protect SMC against apoptosis and possibly against the development of atherosclerosis. Fish oil attenuated the increase in c-myc levels observed in SMC-C and SMC-Ch, possibly through its influence on the expression of antioxidant genes.


CONCLUSIONS
Replacement of a cholesterol-rich diet with a fish oil-rich diet produces some reversal of the cholesterol-induced changes, increasing the resistance of SMC to apoptosis.
Perales
Sonia
S
Department of Biochemistry and Molecular Biology I, Faculty of Sciences, Campus Universitario de Fuentenueva Avenida Severo Ochoa s/n 18071 University of Granada, Spain.
Alejandre
Ma José
MJ
Morales
Rogelio Palomino
RP
Torres
Carolina
C
Linares
Ana
A
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D001013:Aorta, Thoracic / Q000166:cytology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D050197:Atherosclerosis / Q000378:metabolism* / Q000517:prevention & control; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002645:Chickens; D002791:Cholesterol, Dietary / Q000009:adverse effects*; D004036:Diet, Atherogenic; D019587:Dietary Supplements; D005395:Fish Oils / Q000008:administration & dosage*; D005487:Foam Cells / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006888:Hydroxycholesterols / Q000633:toxicity*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism / Q000502:physiology
D017304:Annexin A5; D051017:Apoptosis Regulatory Proteins; D002791:Cholesterol, Dietary; D005395:Fish Oils; D006888:Hydroxycholesterols; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; C033266:Menhaden oil; C007997:25-hydroxycholesterol; D053148:Caspase 3