Multi-Modal Analysis of human Hepatic Stellate Cells identifies novel therapeutic targets for Metabolic Dysfunction-Associated Steatotic Liver Disease

Background and aims

Metabolic dysfunction-associated steatotic liver disease (MASLD) ranges from Metabolic dysfunction-associated steatotic liver (MASL) to Metabolic dysfunction-associated steatohepatitis (MASH) with fibrosis. Activation of Hepatic Stellate Cells (HSCs) into fibrogenic myofibroblasts plays a critical role in the pathogenesis of MASH liver fibrosis. We compared transcriptome and chromatin accessibility of human HSCs from NORMAL, MASL, and MASH livers at single cell resolution. We aimed to identify genes that are upregulated in activated HSCs and to determine which of these genes are key in the pathogenesis of MASH fibrosis.

Methods

18 human livers were profiled using single-nucleus (sn)RNA-seq and snATAC-seq. High priority targets were identified, then tested in 2D human HSC cultures, 3D human liver spheroids, and HSC-specific gene knockout mice.

Results

MASH-enriched activated (A) HSC subclusters are the major source of extracellular matrix proteins. We identified a set of concurrently upregulated and more accessible core genes (GAS7, SPON1, SERPINE1, LTBP2, KLF9, EFEMP1) that drive activation of (A) HSC subclusters. Expression of these genes was regulated via crosstalk between lineage-specific (JUNB/AP1), cluster-specific (RUNX1/2) and signal-specific (FOXA1/2) transcription factors. The pathological relevance of the selected targets, such as SERPINE1 (PAI-1), was demonstrated using dsiRNA-based HSC-specific gene knockdown or pharmacological inhibition of PAI-1 in 3D human MASH liver spheroids, and HSC-specific Serpine1 knockout mice.

Conclusion

This study identified novel gene targets and regulatory mechanisms underlying activation of MASH fibrogenic HSCs and demonstrated that genetic or pharmacological inhibition of select genes suppressed liver fibrosis.

Impact and implications

Here we present snRNA-seq and snATAC-seq analysis of human HSCs from NORMAL, MASL, and MASH livers. We identified additional subclusters that were not detected by previous studies and characterized the mechanism by which HSCs activate in the MASH livers, including the transcriptional machinery that activates HSCs into myofibroblasts. For the first time, we described the pathogenic role of activated HSC-derived PAI-1 (a product of SERPINE1 gene) in the development of MASH liver fibrosis. Targeting of RUNX1/2-SERPINE1 axis may provide a novel strategy for treatment of liver fibrosis in patients.