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β‐Carotene 15,15′‐oxygenase 1 (BCO1) is expressed in both hepatocytes and non‐parenchymal cells in rat liver and enriched in stellate cells and endothelial cells
Author(s) -
Raghuvanshi Shiva,
Reed Vanessa M,
Blaner William S,
Harrison Earl H
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.333.1
β‐Carotene 15,15′‐oxygense 1 (BCO1) catalyzes the first step in the synthesis of vitamin A (retinoids) and hepatic stellate cells (HSCs) in liver are the major vitamin A storage site in the body. Hepatocytes and stellate cells function in coordination in the metabolism of vitamin A in liver. Hepatocytes take up the chylomicron remnant retinyl esters from the circulation and then transfer them to HSCs for storage in lipid droplets. We recently showed the relatively high expression of BCO1 mRNA and protein in a non‐parenchymal, HSC‐enriched fraction of mouse liver as compared to the hepatocyte cell fraction (Shmarakov, et al., 2010, Arch. Biochem. Biophys. 504: 3–10). Here we investigated the localization of BCO1 in normal rat liver using immunohistochemistry. Antibodies specific for BCO1 were used to study the distribution of BCO1 in liver sections and compare it with the markers of hepatocytes (esterase 4) and HSCs (desmin). We observed that BCO1 is uniformly distributed in the cytoplasm of the hepatocytes in parenchyma. However, more intense BCO1 labeling was observed in non‐parenchymal cells corresponding with the location of desmin‐positive HSCs and in endothelial cells lining the hepatic artery and hepatic portal vein. The enrichment of BCO1 in HSCs and endothelial cells may indicate multiple roles for the enzyme in hepatic retinoid and carotenoid metabolism.