Dysregulation of GTPase-activating protein-binding protein1 in the pathogenesis of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are two common liver disorders characterized by abnormal lipid accumulation. Our study found reduced levels of GTPase-activating protein-binding protein1（G3BP1）in patients with MASLD and MASH, suggesting its involvement in these liver disorders. Hepatocyte-specific G3BP1 knockout (G3BP1 HKO) mice had more severe MASLD and MASH than their corresponding controls. Intriguingly, the G3BP1 HKO MASLD model mice exhibit dysregulated autophagy, and biochemical analyses demonstrated that G3BP1 promotes autophagosome-lysosome fusion through direct interactions with the SNARE proteins STX17 and VAMP8. We also show that hepatic knockout of G3BP1 promotes de novo lipogenesis, and ultimately found that G3BP1 is required for the nuclear translocation of the well-known liver-lipid-regulating transcription factor TFE3. Taken together, our results suggest that G3BP1 should be investigated as a potential target for developing medical interventions to treat MASLD and MASH. This study investigates the transcriptional changes in the liver of mice with a liver-specific knockout of the G3BP1 gene in response to a high-fat diet (HFD). The study includes a total of six samples derived from two distinct groups of adult male mice, with three biological replicates for each group. Wild-Type (WT) Control Group: This group consists of three mice with a wild-type genotype for the G3BP1 gene, fed a high-fat diet. The genotype is confirmed as G3BP1^flox/flox, which serves as the proper control for the knockout group. G3BP1 Knockout (KO) Group: This group consists of three mice with a liver-specific conditional knockout of the G3BP1 gene, also fed a high-fat diet. The knockout was achieved using the Cre-LoxP system by crossing mice carrying a floxed G3BP1 allele (G3BP1^flox/flox) with mice expressing Cre recombinase under the control of the Albumin promoter (Alb-cre). The resulting genotype is Alb-cre; G3BP1^flox/flox, leading to the specific deletion of G3BP1 in hepatocytes. Total RNA was extracted from the liver tissue of all six mice. Paired-end RNA sequencing libraries were prepared and sequenced on an Illumina HiSeq platform. The raw sequencing data, provided as FASTQ files, was processed to quantify gene expression, followed by differential expression analysis to identify the transcriptional impact of G3BP1 deletion in the context of a high-fat diet.