Persistent activation of DNA damage response in the liver after MASLD reversal

Background and aims

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its more advanced form, metabolic dysfunction-associated steatohepatitis, have emerged as the most prevalent liver diseases worldwide. Currently, lifestyle modification is the foremost guideline-recommended management strategy for MASLD. However, it remains unclear which detrimental signals persist in MASLD even after disease remission. Thus, we aimed to examine the persistent changes in liver transcriptomic profiles following this reversal.

Methods

Male C57BL/6J mice were divided into three groups: Western diet (WD) feeding, chow diet (CD) feeding, or diet reversal from WD to CD. After 16 weeks of feeding, RNA sequencing was performed on the mice's livers to identify persistent alterations characteristic of MASLD. Additionally, RNA sequencing databases containing high-fat diet-fed P53-knockout mice and human MASLD samples were utilized.

Results

WD-induced MASLD triggered persistent activation of the DNA damage response (DDR) and its primary transcription factor, P53, long after the resolution of the hepatic phenotype through dietary reversal. Elevated levels of P53 might promote apoptosis, thereby exacerbating metabolic dysfunction-associated steatohepatitis, as they strongly correlated with hepatocyte ballooning, an indicator of apoptosis activation. Moreover, P53 knockout in mice led to downregulated expression of apoptosis signaling in the liver. Mechanistically, P53 may regulate apoptosis by transcriptionally activating the expression of apoptosis-enhancing nuclease (AEN). Consistently, P53, AEN, and the apoptosis process all exhibited persistently elevated expression and showed a strong inter-correlation in the liver following dietary reversal.

Conclusions

The liver demonstrated upregulation of DDR signaling and the P53-AEN-apoptosis axis both during and after exposure to WD. Our findings provide new insights into the mechanisms of MASLD relapse, highlighting DDR signaling as a promising target to prevent MASLD recurrence.