Mice exposed in gestation to maternal high fat/high sucrose (HF/HS) diet develop altered bile acid (BA) homeostasis. We hypothesized that these reflect an altered microbiome and asked if microbiota transplanted from HF/HS offspring change hepatic BA and lipid metabolism to determine the directionality of effect. Female mice were fed HF/HS or chow (CON) for 6 weeks and bred with lean males. 16S sequencing was performed to compare taxa in offspring. Cecal microbiome transplantation (CMT) was performed from HF/HS or CON offspring into antibiotic treated mice fed chow or high fructose. BA, lipid metabolic, and gene expression analyses performed in recipient mice. Gut microbiomes from HF/HS offspring segregated from CON offspring, with increased Firmicutes to Bacteriodetes ratios and Verrucomicrobial abundance. Following CMT, HF/HS recipient mice had larger BA pools, and increased intrahepatic muricholic acid and decreased deoxycholic acid species. HF/HS recipient mice exhibited downregulated hepatic Mrp2, increased hepatic Oatp1b2, and decreased ileal Asbt mRNA expression. HF/HS recipient mice exhibited decreased cecal butyrate and increased hepatic expression of Il6. HF/HS recipient mice had larger livers, and increased intrahepatic triglyceride versus CON recipient mice after fructose feeding, with increased hepatic mRNA expression of lipogenic genes including Srebf1, Fabp1, Mogat1, and Mogat2. CMT from HF/HS offspring increased BA pool and shifted the composition of the intrahepatic BA pool. CMT from HF/HS donor offspring increased fructose-induced liver triglyceride accumulation. These findings support a causal role for vertical transfer of an altered microbiome in hepatic BA and lipid metabolism in HF/HS offspring.

Maternal obesity programs risk for development of non-alcoholic fatty liver disease (NAFLD) in offspring. Maternal exercise is a potential intervention to prevent developmentally programmed phenotypes. We hypothesized that maternal exercise would protect from progression of NAFLD in offspring previously exposed to maternal obesogenic diet. Female mice were fed chow (CON) or HFFC and bred with lean males. A subset had an exercise wheel introduced 4 weeks after starting diet to allow for voluntary exercise. The offspring were weaned to HFFC diet for 7 weeks to induce NAFLD. Serum, adipose, and liver tissue were collected for metabolic, histologic, and gene expression analyses. Cecal contents were collected for 16S sequencing. Global metabolomics was performed on liver. Female mice fed HFFC diet had increased body weight prior to adding an exercise wheel. Female mice fed HFFC diet had an increase in exercise distance relative to CON during the pre-conception period. Exercise distance was similar between groups during pregnancy and lactation. CON-Active and HFFC-Active offspring exhibited decreased inflammation compared to offspring from sedentary dams. Fibrosis increased in offspring from HFFC-sedentary dams compared to CON-sedentary. Offspring from exercised HFFC dams exhibited less fibrosis than offspring from sedentary HFFC dams. While maternal diet significantly affected the microbiome of offspring, the effect of maternal exercise was minimal. Metabolomics analysis revealed shifts in multiple metabolites including several involved in bile acid, one-carbon, histidine, and acylcarnitine metabolism. This study provides pre-clinical evidence that maternal exercise is a potential approach to prevent developmentally programmed liver disease progression in offspring.

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Background Non‐alcoholic fatty liver disease (NAFLD) affects approximately one‐quarter of the global population with increasing prevalence in the pediatric population. There is currently no standard medical therapy and no diagnostic study capable of predicting which patients will develop severe disease. Recent evidence in both humans and animal models show that maternal obesity is a risk factor for the development of NAFLD and progression to NASH. We have shown in a murine model of maternal obesity the offspring develop periportal fibrosis and inflammation with associated changes in bile acid (BA) homeostasis. In this study we define the mechanisms of changes in BA homeostasis. Methods Female C57Bl6 mice were fed chow (CON) or HF/HS diet for 6 weeks to induce obesity and bred with lean males. Offspring were fed chow diet from the time of weaning until tissue collection. BA pool size and levels of specific intrahepatic bile acid species were measured. RT‐PCR was performed to evaluate gene expression of factors involved in bile acid metabolism and signaling. 16S sequencing was performed for evaluation of offspring microbiome. Levels of stool BAs were quantified and timed BA excretion performed. Results Offspring from the maternal HF/HS (mHF/HS) lineage exhibited an increase in total BA pool size with associated changes in expression of genes involved in bile acid metabolism (increased Cyp7a1, Cyp27a1). Measurement of specific bile acids in liver showed a shift in the intrahepatic BA pool composition (decreased deoxycholic acid, increased muricholic acid) in offspring from the mHF/HS lineage. Decreased BA excretion was observed in mHF/HS lineage offspring. Fecal microbiome analysis showed a decrease in alpha diversity and shifts in the abundance of particular phyla (increased Bacteroidetes, decreased Proteobacteria) and genera (increased Barnesiella, decreased Clostridium). Measurement of cecal BA levels showed an increase in abundance of muricholic acid (FXR antagonist) and a decrease in abundance of deoxycholic acid (FXR agonist) in mHF/HS lineage offspring. Conclusions Maternal HF/HS diet exposure leads to pathologic changes in the offspring including periportal fibrosis and inflammation, which is associated with changes in BA homeostasis. Several factors are involved in the BA homeostasis changes including BA metabolism and excretion. Vertical transmission of gut dysbiosis may be a primary factor in driving changes in BA homeostasis in offspring exposed to maternal obesogenic diet.

Background Non‐alcoholic fatty liver disease (NAFLD) affects approximately one‐quarter of the global population, with up to 20–25% developing progressive liver disease. Recent evidence in both humans and animal models show that maternal obesity is a risk factor for the development of NAFLD and progression to NASH. We have shown in a murine model of maternal obesity the offspring develop altered bile acid homeostasis and a varied response to a western diet which is passed by female offspring across generations. In this study we tested the hypothesis that male offspring exposed to maternal obesogenic diet pass an altered bile acid homeostasis phenotype and susceptibility to western diet induced liver disease to their offspring. Methods Female C57Bl6 mice were fed chow (CON) or HF/HS diet for 6 weeks to induce obesity and bred with lean males. Male F1 offspring were then bred with lean females to create a paternal second generation (PF2C from maternal CON lineage, PF2H from maternal HF/HS lineage). Tissues were collected from PF2 offspring to measure bile acid pool size and hepatic bile acid species profile. Additional PF2 offspring were fed high trans‐fat, cholesterol, fructose (HTFC) diet for 16 weeks to induce progressive NAFLD. Metabolic and histopathologic analyses were performed. Results In chow fed PF2 offspring from the maternal HF/HS (mHF/HS) lineage, total BA pool size was increased. No change in intrahepatic BA composition was observed. After HTFC diet, PF2H offspring showed decreased liver weight and liver weight to body weight ratio compared to PF2C offspring. PF2H offspring exhibited lower levels of intrahepatic triglyceride and free fatty acids. Conversely, PF2H offspring liver showed increased Sirius red staining. Conclusions Male offspring exposed to maternal obesogenic diet transmit a phenotype of altered BA homeostasis to their offspring. After exposure to a western diet, PF2H offspring exhibited worse fibrosis despite having less steatosis. Passage of these phenotypes through male offspring would suggest an epigenetic phenomenon as a mechanistic etiology. Future studies will evaluate the mechanism for transmission of maternal obesity driven changes in the liver across generations in the male lineage.