Evi J.C. Koene1, Elva Wong2, Sander Kersten2,3, Florian Haans4, Vera B. Schrauwen-Hinderling4,5, Martijn C.G.J. Brouwers6, Patrick Schrauwen5,7
1Department of Nutrition and Movement Sciences, NUTRIM institute, Maastricht University, Maastricht, Netherlands. 2Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA. 3Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, Netherlands. 4Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, Netherlands. 5Institute for Clinical Diabetology, German Diabetes Center, Düsseldorf, Germany. 6Department of Internal Medicine, Division of Endocrinology and Metabolic Disease, CARIM research institute, Maastricht University Medical Center, Maastricht+, Netherlands. 7Clinical Epidemiology, Leiden University Medical Center, Leiden, Netherlands
e.koene@maastrichtuniversity.nl
Background: Fructose intake is associated with metabolic dysfunction-associated steatotic liver disease (MASLD) and development of type 2 diabetes. We previously showed that pharmacological inhibition of fructose metabolism with a ketohexokinase (KHK) inhibitor, PF-06835919, decreased liver fat and markedly improved insulin sensitivity in participants with MASLD, which surprisingly was mainly due to an improvement in skeletal muscle insulin sensitivity. Since KHK is not widely expressed in muscle, indirect mechanisms must be underlying this improvement. To understand involved mechanisms, we here aimed to elucidate changes in skeletal muscle transcriptome after treatment with PF-06835919.
Methods: We used muscle biopsies taken at day 42 from twelve overweight/obese individuals with MASLD who participated in the randomized double-blind, placebo-controlled cross-over trial. They were treated with PF-06835919 (300 mg, once/day) and placebo for six weeks with a 5-week wash-out period. Total RNA was isolated from skeletal muscle biopsies using TRIzol. PolyA-library preparation and sequencing was done in Maastricht with the NovaSeq 6000 sequencing system. Pathway analyses were performed using gene-set enrichment analysis and Enric.
Results: After adjusting for multiple comparisons, three genes (FABP4, BMP6, NAV2) were significantly upregulated and four genes (SLC45A4, RGS10, LGALS9, MSTN) were significantly downregulated after treatment with PF-06835919 (Padj<0.05). Pathway analysis revealed that gene sets involved in mitochondrial respiration, lipid oxidation and regulation of plasma lipoprotein particle levels, as well as the PPAR signalling pathway were upregulated after KHK inhibition. Conversely, gene sets involved in chemokine signalling pathways and activation and regulation of leukocyte mediated immune response were downregulated.
Conclusion: Six weeks of KHK inhibition upregulated oxidative pathways, and downregulated inflammatory pathways at mRNA level. Metabolomic analysis is currently ongoing to further deepen our understanding of the molecular changes in skeletal muscle upon inhibition of hepatic fructose metabolism.