Enterocytes and hepatocytes synthesize apoA-I, which is secreted in a lipid-poor form and then immediately recruits additional PLs and free cholesterol (FC) via the ABCA1 pathway, forming nascent HDL. Nascent HDL acquires more lipid from other peripheral tissues and from lipoproteins, and LCAT generates CE, forming mature HDL. The liver also synthesizes apoA-II, which results in a subclass of HDL containing both apoA-I and apoA-II.