Project description:While microbiome and pregnancy are known to alter drug disposition, the interplay of the two physiological factors to impact expression and/or activity of drug processing genes (DPGs) has yet to be elucidated. This study aimed to investigate the effects of microbiome on host hepatic DPGs during pregnancy using conventional (CV) and germ-free (GF) mice. Four groups of female mice were used, namely CV non-pregnant (CVNP), GF non-pregnant (GFNP), CV pregnant (CVP), and GF pregnant (GFP) mice. Pregnant mice examined were on gestation day 15. Transcriptomic and targeted proteomics of hepatic DPGs were profiled using a multi-omics approach. Plasma bile acid and steroid hormone levels were quantified using LC-MS/MS. Cyp3a activities were measured by mouse liver microsome incubations. While the overall trend in pregnancy-induced changes in the expression or activity of hepatic DPGs in CV and GF mice was similar, significant differences in the magnitude of changes were observed. For certain genes, we noticed opposite effects of pregnancy on mRNA and protein expression of DPGs in both CV and GF mice. For instance, the mRNA levels of Cyp3a11, the murine homolog of human CYP3A4, were decreased by 1.7-fold and 3.3-fold by pregnancy in CV and GF mice, respectively. However, the protein levels of Cyp3a11 were increased similarly ~2-fold by pregnancy in both CV and GF mice. Yet, microsome incubations revealed a marked induction of Cyp3a activity by pregnancy that was >5-fold greater in CV mice than that in GF mice. Plasma bile acid and steroid hormone levels were also significantly altered by microbiome and pregnancy, respectively, which may contribute to the differential effects of pregnancy in CV and GF mice. This is the first study to show that microbiome can alter hepatic DPGs in pregnancy.
Project description:Hepatic drug metabolism plays a key role in determining drug response and safety. Studies of drug metabolism generate valuable information about regulation of genes encoding drug-metabolizing enzymes and enzyme functions that are critical in developing dosing guideline. However, current knowledge is insufficient to support dosing guideline for pregnant women. Specifically, substrates of a major drug-metabolizing enzyme CYP2D6 show increased elimination during pregnancy, but the underlying mechanisms are completely unknown largely due to a lack of experimental models. Here, we introduce CYP2D6-humanized (Tg-CYP2D6) mice as an animal model where hepatic CYP2D6 expression is increased during pregnancy, recapitulating the clinically reported changes in CYP2D6-mediated drug metabolism. In these mice, pregnancy had minimal effects on the expression of hepatocyte nuclear factor (HNF) 4a, the transcription factor controlling basal CYP2D6 expression. Krüppel-like factor (KLF) 9 and small heterodimer partner (SHP) were found up- and down-regulated in Tg-CYP2D6 mouse livers during pregnancy, respectively. KLF9 enhanced HNF4a-mediated transactivation of the CYP2D6 promoter whereas SHP repressed it. Retinoic acid (RA), an endogenous compound that induces SHP, exhibited decreased hepatic levels during pregnancy. These results indicate that interplay among hepatic transcription factors HNF4a, SHP, and KLF9 underlies CYP2D6 induction during pregnancy, and that retinoic acid is a potential trigger. This is the first report on the mechanisms underlying CYP2D6 induction and illustrates the utility of humanized mice as an in vivo model to study altered drug disposition during pregnancy. Livers collected at pre-pregnancy, 21 days of pregnancy, and 7 days postpartum from CYP2D6-humanized mice.
Project description:Hepatic drug metabolism plays a key role in determining drug response and safety. Studies of drug metabolism generate valuable information about regulation of genes encoding drug-metabolizing enzymes and enzyme functions that are critical in developing dosing guideline. However, current knowledge is insufficient to support dosing guideline for pregnant women. Specifically, substrates of a major drug-metabolizing enzyme CYP2D6 show increased elimination during pregnancy, but the underlying mechanisms are completely unknown largely due to a lack of experimental models. Here, we introduce CYP2D6-humanized (Tg-CYP2D6) mice as an animal model where hepatic CYP2D6 expression is increased during pregnancy, recapitulating the clinically reported changes in CYP2D6-mediated drug metabolism. In these mice, pregnancy had minimal effects on the expression of hepatocyte nuclear factor (HNF) 4a, the transcription factor controlling basal CYP2D6 expression. Krüppel-like factor (KLF) 9 and small heterodimer partner (SHP) were found up- and down-regulated in Tg-CYP2D6 mouse livers during pregnancy, respectively. KLF9 enhanced HNF4a-mediated transactivation of the CYP2D6 promoter whereas SHP repressed it. Retinoic acid (RA), an endogenous compound that induces SHP, exhibited decreased hepatic levels during pregnancy. These results indicate that interplay among hepatic transcription factors HNF4a, SHP, and KLF9 underlies CYP2D6 induction during pregnancy, and that retinoic acid is a potential trigger. This is the first report on the mechanisms underlying CYP2D6 induction and illustrates the utility of humanized mice as an in vivo model to study altered drug disposition during pregnancy.
Project description:Purpose: Next-generation sequencing (NGS) has been utilized for systems-based analysis of all liver samples. The goals of this study were to compare the hepatic transcriptome and PBDE metabolism between conventional (CV) and germ-free (GF) mice. Methods: Livers from vehicle (corn oil), BDE-47, or BDE-99 treated adult male CV and GF mice were used for RNA-Seq (biological replicates: n=3 for CV corn oil, n=4 for CV BDE-47, n=2 for CV BDE-99, n=3 for GF corn oil, n=3 for GF BDE-47, and n=3 for BDE-99) using a HiSeq 2000 sequencer. The sequence reads that passed quality filters were mapped to the mouse reference genome (mm10) using HISAT v 0.1.6 beta; transcript abundance and differential expression were determined using Cufflinks (CuffDiff) v 2.2.1. Results: Using an optimized data analysis workflow,RNA-Seq generated approximately 47 to 68 million reads per sample, among which approximately 40 to 60 million reads were uniquely mapped to the mouse reference genome (NCBI GRCm/38/mm10). And we identified 393 drug processing genes in the livers of WT and hCAR-TG with with HISAT workflow. RNA-seq data confirmed that among all the 393 DPGs with known important functions in xenobiotic biotransformation, 90 DPGs were not expressed in livers of any groups (threshold: average FPKM < 1 in all treatment groups); whereas a total of 303 genes were expressed in livers of at least one groups, among which 258 DPGs were differentially regulated by mCAR or hCAR activation in either Day 5 or Day 60 (FDR-BH<0.05), and 45 genes were stably expressed among all treatment groups. Conclusions: Our study has unveiled a novel interaction between gut microbiome and the hepatic biotransformation of PBDEs, demonstrating that germ-free conditions modified the hepatic oxidation of PBDEs as well as the expression of relevant drug-processing genes in liver.
Project description:All subjects were enrolled from Grady Memorial and Emory Midtown Hospitals. Subjects provided blood samples at two timepoints during pregnancy.
Project description:Caloric Restriction (CR) extends lifespan and delays the onset of age-related disorders in diverse species. Metabolic regulatory pathways have been implicated in the mechanisms of CR, but the molecular details have not been elucidated. Here we show that CR engages RNA processing of genes associated with a highly integrated reprogramming of hepatic metabolism. We conducted molecular profiling of liver biopsies collected from adult male rhesus monkeys (Macaca mulatta) at baseline and after 2 years on control or CR (30% restricted) diet. Quantitation of over 20,000 molecules from the hepatic transcriptome, proteome, and metabolome, indicated that metabolism and RNA processing are major features of the response to CR. Predictive models identified lipid, branched chain amino acid, and short-chain carbon metabolic pathways, with alternate transcript use for over half of the genes in the CR network. We conclude that RNA-based mechanisms are central to the CR response and integral in metabolic reprograming.
Project description:To capture the global gene changes associated with pregnancy experience, uterine tissues were collected on day 8 of pregnancy from mice during the first pregnancy and second pregnancy, respectively. Transcriptomes were determined by RNA-seq. Identifying global gene changes associated with pregnancy experience
Project description:All subjects were enrolled from Grady Memorial and Emory Midtown Hospitals. Subjects provided blood samples at two timepoints during pregnancy. Medical record abstraction was used to determine the presence of fetal intolerance of labor.