Summary
A bioRxiv preprint links the mitochondrial protein OPA1 to liver fibrosis through human MASLD analyses and experiments in mice. The mouse findings connect loss of OPA1 in liver cells with stellate-cell activation and fibrosis.
A bioRxiv preprint reports that the mitochondrial protein OPA1 is associated with liver fibrosis in analyses of human metabolic dysfunction-associated steatotic liver disease (MASLD), and that removing OPA1 from liver cells caused fibrotic changes in mice. The findings connect disrupted mitochondrial maintenance with signals that can activate scar-forming cells in the liver.
The study combines large-scale genomic analyses with experiments in mice. In the human analyses, the authors identified a strong association between fibrosis and OPA1, a protein involved in mitochondrial fusion. OPA1 transcripts and protein abundance in liver epithelial cells also became progressively dysregulated as fibrosis advanced. The abstract does not specify a single direction of change in those levels.
From mitochondrial damage to fibrosis
Mitochondria are structures inside cells that carry out key functions including energy production. OPA1 helps regulate their fusion, one part of the processes that maintain mitochondrial shape and function. When hepatocytes—the main functional cells of the liver—are injured, they can release mitochondrial damage-associated molecular patterns, or mito-DAMPs. These signals can contribute to tissue responses associated with fibrosis.
Fibrosis develops as scar tissue accumulates in the liver. Hepatic stellate cells are among the cells that can become activated and contribute to that scar formation. The authors’ results place OPA1 within a proposed chain linking mitochondrial dysfunction, mito-DAMP release, stellate-cell activation and fibrosis.
In mice, loss of OPA1 specifically in hepatocytes was sufficient to induce stellate-cell activation and fibrosis in zone 3 of the liver. The authors also report that this loss promoted the release of mito-DAMPs into the circulation and worsened fibrosis in an experimental model of metabolic dysfunction-associated steatohepatitis (MASH), the inflammatory form of MASLD.
What the evidence means
The human analyses show associations: they connect OPA1 measures with fibrosis but do not by themselves establish that changes in OPA1 cause human liver disease. The mouse experiments provide a causal test in that model, showing that hepatocyte-specific OPA1 loss can drive fibrotic changes. Together, these findings suggest a mechanism by which impaired mitochondrial quality control may contribute to liver scarring.
The work is a bioRxiv preprint, so it has not yet undergone peer review. Its causal findings come from mice, while the human evidence is genomic and tissue-based. OPA1 is therefore a mechanistic lead for further research, rather than an established treatment target or a demonstrated way to prevent fibrosis in people.