Preprint: a liver fibrosis model using three human cell types helped select AS191 for testing in mice

Preprint: a liver fibrosis model using three human cell types helped select AS191 for testing in mice

On September 8, the authors posted a preprint describing a human liver organoid, a small three-dimensional tissue model in which liver cells, cells that line blood vessels, and hepatic stellate cells grow together. They induced a fibrotic response in this model, screened 138 compounds to identify seven candidates, and tested one, AS191, in mice with liver injury.

Fibrosis develops when prolonged liver injury causes collagen to accumulate in the tissue and form scars. Hepatic stellate cells produce most of this collagen, and their behavior depends on neighboring liver cells and blood vessel lining cells. In the preprint posted on Research Square on September 8, the authors combined these three components in a single spheroid.

The cells assembled into a spheroid over 16 days. The authors then added TGF-β, a signaling protein that activates hepatic stellate cells during liver injury. After 48 hours, the structure became less compact, and the activity of COL1A1, the gene encoding one of the chains of type I collagen, increased. This increase in COL1A1 provided a measurable readout for subsequent compound screening.

The authors screened 138 compounds by measuring the brightness of a fluorescent COL1A1 label; seven reduced the signal. They selected AS191, an aspirin derivative, for further testing. In organoids treated with AS191, they measured reduced phosphorylation of PI3K, AKT, and GSK3β, meaning that phosphate groups were attached to these proteins less frequently. These proteins belong to a signaling pathway that the authors examined as part of the response to TGF-β.

The authors conducted the final experiment in 23 mice divided into four groups. In three groups, the mice received daily injections of CCl₄, a substance that damages the liver, for 28 days; one of these groups also received AS191 from the first day. In mice given AS191, the authors observed less collagen and fewer inflammatory cells, along with lower blood levels of ALT, AST, and ALP, enzymes used to assess liver injury. Phosphorylation of PI3K and AKT was also reduced in their livers.

Because CCl₄ and AS191 were started on the same day, the mouse experiment tests the candidate during ongoing liver injury.