Mexican Ganoderma lucidum extracts decrease lipogenesis modulating transcriptional metabolic networks and gut microbiota in C57BL/6 mice fed with a high-cholesterol diet from early Drosophila embryo

Background: Prevention of hyperlipidemia and associated diseases is a health priority. Complementary medicine based on scientific evidence has recently recognized the potential of natural products for modulating lipid metabolism, such as the medicinal mushroom Ganoderma lucidum (Gl), which possesses hypocholesterolemic, prebiotic and antidiabetic properties. Methods: Whole-transcriptomic changes in liver and kidney from a mouse model (C57BL/6), under a high-cholesterol diet and standardized Gl extracts (Gl-1, Gl-2) or simvastatin administration, were analyzed to determine Gl hypocholesterolemic activity. Further effects of Gl extracts on lipid metabolism were evaluated using an in vitro hepatic-like macrophage model. Additionally, correlations among hepatic gene expression, microbiota and serum lipid profiles in vivo established by Gl extracts were evaluated. Results: Based on the hepatic and renal mRNA profiles of mice treated with Gl extracts and high-cholesterol diet, we identified relevant metabolic pathways modulated by Gl involving the restriction of lipid biosynthesis and the enrichment of lipid degradation and secretion. We further showed that Gl extracts induce a significant decrease of macrophage lipid storage and cholesterol biosynthesis, which occurs concomitantly by the down-modulation of Fasn and Elovl6. We also determined that prebiotic effects of Gl extracts modulating gut microbiota are correlated with the gene expression portraits. Conclusions: Our high-throughput analysis allowed to identify key transcriptomic nodes established by Gl extracts and their interaction with microbiome composition related to lipid catabolic signaling. Our results indicated that our Gl extracts have a robust potential to be used as transcriptome modulators and prebiotic agents to prevent metabolic disorders associated to hypercholesterolemia. We used male 7-week-old C57BL/6 mice (26 g ± 0.5 g of weight) purchased from the animal facility of the INCMNSZ. Animals were housed (4/cage) in a 12-h light–dark cycle at a constant temperature (23 ± 2 °C) and relative humidity (45-55%). Mice were assigned to one of following experimental groups (N=40, n=8 per experimental group) in a complete randomization strategy: 1) Control: Control diet (AIN-93); 2) HCD: High-cholesterol diet (0.5% cholesterol) (Sigma-Aldrich, New Zealand); 3) HCD+Sim: High-cholesterol diet (0.5%) plus simvastatin (0.03 g/100 g); 4) HCD+Gl-1: High-cholesterol diet (0.5%) plus the Gl-1 extract (1.0%); 5) HCD+Gl-2: High-cholesterol diet (0.5%) plus the Gl-2 extract (1.0%). Sample size was calculated in accordance with the 3R's model with G*power software (two tail test, power = 0.95 and effect size=2). Allocation and treatment was performed with a not blinded strategy. Animals were fed with AIN-93 standard diet (average intake: 3.47 g/day of 9.5 g available per mouse) and water ad libitum. Each treatment (Simvastatin and lyophilized Gl extracts) were added to food pellet daily. At day 43, mice were deprived of food and water for 8 h and blood samples from the portal vein were collected for serological analysis. Mice were sacrificed at this end point, and liver and kidney tissues were collected and stored at -80ºC for further processing. Confounders were not controlled on this experiment.