Faculty Opinions recommendation of Hepatic stellate cells are an important cellular site for β-carotene conversion to retinoid.

Hepatic stellate cells (HSCs) are responsible for storing 90-95% of the retinoid present in the liver. These cells have been reported in the literature also to accumulate dietary -carotene, but the ability of HSCs to metabolize -carotene in situ has not been explored. To gain understanding of this, we investigated whether -carotene-15,15-monooxygensase (Bcmo1) and -carotene-9, 10-monooxygenase (Bcmo2) are expressed in HSCs. Using primary HSCs and hepatocytes purified from wild type and Bcmo1-deficient mice, we establish that Bcmo1 is highly expressed in HSCs; whereas Bcmo2 is expressed primarily in hepatocytes. We also confirmed that HSCs are an important cellular site within the liver for accumulation of dietary -carotene. Bcmo2 expression was found to be significantly elevated for livers and hepatocytes isolated from Bcmo1-deficient compared to wild type mice. This elevation in Bcmo2 expression was accompanied by a statistically significant increase in hepatic apo-12-carotenal levels of Bcmo1-deficient mice.