Abstract Body (Do not enter title and authors here): Background: The GLP-1 receptor agonist, semaglutide, was shown to be beneficial in obese (STEP HFpEF) and diabetic (STEP HFpEF DM) patients suffering from heart failure with preserved ejection fraction (HFpEF), presumably secondary to anti-obesity effects. Challenging this assumption, we observed that a low dose of semaglutide, which does not impact body weight in a rat model, ameliorates cardiac HFpEF symptoms including diastolic dysfunction, fibrosis and exercise capacity. We sought to determine whether semaglutide could rescue hepatic symptoms of HFpEF, and if so, determine the molecular underpinnings.

Hypothesis: GLP-1 receptor agonism improves the hepatic phenotypes in HFpEF via transcriptional reprogramming of liver.

Methods: Ten-week-old male ZSF1 obese rats (n=6/group), which spontaneously develop HFpEF by 12 weeks, received either vehicle (saline) or semaglutide (30 nmol/kg, SC, biweekly) for 16 weeks, a dose and time course that does not affect body weight. Echocardiography, exercise tolerance testing, invasive hemodynamics, and histopathology were performed. Livers were subjected to single nuclei RNA-seq. Differential gene expression analysis (Wilcoxon rank-sum test) was conducted on distinct populations of cells (significance: absolute log2 fold change > 0.5 and a Bonferroni-corrected p-value < 0.05).

Results: GLP-1 receptor agonism significantly reduced hepatic cholesterol and triglycerides and attenuated lipid droplet accumulation in liver. Single nuclei RNA sequencing identified multiple distinct hepatocyte populations, along with mesenchymal, endothelial, immune and proliferative cells, but no adipocytes (some hepatocytes expressed adipocyte genes). In hepatocytes, semaglutide induced significant downregulation of genes that promote pathologic fibrosis (including Col4a1, Emilin1, Bgn) along with the TGFβ-responsive transcription factor Klf10 (KLF motifs were enriched amongst semaglutide targeted hepatocyte genes). The master regulator of cholesterol metabolism, LXR (Nr1h2, Nr1h3), was decreased following semaglutide, whereas FXR (Nr1h4), which increases fatty acid oxidation, was increased. Semaglutide also upregulated genes associated with amino acid catabolism.

Conclusion: Low dose semaglutide induces a transcriptional response that improves liver metabolism in a HFpEF animal model, independent of weight loss. These data have implications for treatment of metabolic dysfunction associated steatohepatitis (MASH) with GLP1 receptor agonists.