Altered distribution of caveolin-1 in early liver steatosis.
BACKGROUND
Caveolin-1, the main structural protein of caveolae, is involved in cholesterol homoeostasis, transcytosis, endocytosis and signal transduction and thought to play an important role in lipidogenesis. Little is known about the pathophysiological role of caveolin-1 in nonalcoholic fatty liver disease (NAFLD), a condition frequently associated with the metabolic syndrome and characterized by abnormal accumulation of intrahepatic triglycerides with a potentially harmful risk of evolution to liver fibrosis, cirrhosis and hepatocellular carcinoma.


METHODS
Liver steatosis (micro/macrovesicular) was induced in adult rats fed a choline-deficient diet for 14days and compared with a control normal diet. The expression and subcellular distribution of caveolin-1 was assessed using light and electron microscopy by immunohistochemical and immunocytochemical techniques and by Western blotting.


RESULTS
Caveolin-1 was mainly associated with the hepatocyte basolateral plasma membrane. Fatty hepatocytes were characterized by a significant increase in the expression of caveolin-1 around and within the lipid droplets as well as in the inner membrane of mitochondria.


CONCLUSIONS
Our data suggest the involvement of caveolin-1 in the case of abnormal lipogenesis and mitochondrial function typical of steatotic hepatocytes in NAFLD. Addressing the role played by caveolin-1 in liver membranes in NAFLD may help future therapeutic choices in a frequent metabolic liver disease.
Department of Animal and Environmental Biology, Aldo Moro University, Bari, Italy. m.mastrodonato@biologia.uniba.it
Maria
M
Mastrodonato
Giuseppe
G
Calamita
Roberta
R
Rossi
Donatella
D
Mentino
Leonilde
L
Bonfrate
Piero
P
Portincasa
Domenico
D
Ferri
Giuseppa E
GE
Liquori
D000818:Animals; D051242:Caveolin 1 / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D004032:Diet; D005234:Fatty Liver / Q000378:metabolism* / Q000473:pathology; D015151:Immunoblotting; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013223:Statistics as Topic
D051242:Caveolin 1; D002794:Choline