Project description:To make the human liver accessible to metabolic treatments, we employed a liver-specific humanized mouse model in which approximately 50% of the mouse hepatocytes were replaced by human ones. For the dietary treatment, the humanized mice were allowed free access to food (AL, n=4 for donor1, n=3 for donor2) or subjected to a twenty-four hours food withdrawal (Fast, n=4 for donor1, n=3 for donor2). For the transcription factor agonist treatments, the humanized mice were injected with DMSO (n=4), fenofibrate (n=4, 50mg/kg, Sigma-Aldrich, Cat. F6020), rosiglitazone (n=4,10mg/kg, Sigma-Aldrich, Cat. R2408) and GW4064 (n=4, 30mg/kg, Sigma-Aldrich, Cat. G5172) by i.p. injection. The livers were collected after 6 hours fasting and stored in liquid nitrogen immediately after mice sacrificed.
Project description:To characterize the dysregulated MSCs in the murine MDS models, we performed a single-cell RNA sequence (scRNA-seq) analysis of FACS-sorted MSCs. The proportions of subclusters comprising MSCs were discrete between controls and MDS, and Osteolineage population was reduced in MDS compared with the control. In addition, Lepr+ mesenchymal population in MDS mice exhibited the remarkable reduction of skeletal stem marker Grem1 and MSC marker genes. This transcriptome analysis suggested that the osteolineage differentiation of MSCs is suppressed in vivo in the presence of MDS cells.
Project description:Loss of function TET2 mutations are frequently seen in myelodysplastic syndrome (MDS) patients. Previous studies have demonstrated that TET2 deficiency enhances maintenance of MDS hematopoietic stem and progenitor cells (HSPCs). Nonetheless, the pathogenic role of TET2 in MDS progression remains elusive. Here, we demonstrate Tet2 knockout (KO) markedly accelerated malignant transformation in Nup98-HoxD13 (NHD13) transgenic mice and promotes leukemogenesis of HoxA9 transduction/transplant mice. Consistently, low TET2 level cooperating with high HOXA9 level predicts poor outcome of MDS patients. Notably, Tet2 KO conferred a clonal advantage to the HSPCs of NHD13 mice. Whole-exome sequencing revealed that Tet2 KO facilitates accumulation of mutations at genes associated with leukemogenesis, including Arih2, whose loss of function promotes MDS cells proliferation. Using 5-hydroxymethylcytosine immunoprecipitation coupled with high-throughput sequencing analysis, we found while Tet2 deletion decreased overall 5hmC levels, it also increased 5hmC distribution at certain mutation loci such as Arih2. Vitamin C treatment, which mimics Tet2/Tet3 restoration, blocked disease progression in Tet2-deficient NHD13 mice. Collectively, our findings demonstrate that TET2 activity governs occurrence of secondary mutations in MDS HSPCs, providing a rationale for enhancing TETs function to block MDS-malignant transformation.
Project description:Background: Chronic exposure to inorganic arsenic (iAs) has been associated with type 2 diabetes (T2D). However, potential sex divergence and the underlying mechanisms remain understudied. iAs is not metabolized uniformly across species, which is a limitation of typical exposure studies in rodent models. The development of a new “humanized” mouse model overcomes this limitation. In this study, we leverage this model to study sex differences in the context of iAs exposure. Objectives: The aim of this study iwas to determine if males and females exhibit different liver and adipose molecular profiles and metabolic phenotypes in the context of iAs exposure. Methods: Our study was performed on wild-type (WT) 129S6/SvEvTac and humanized arsenic +3 methyl transferase (human AS3MT) 129S6/SvEvTac mice treated with 400 ppb of iAs via drinking water ad libitum. After 1 month, mice were sacrificed and the liver and epididymales gonadal adipose depot were harvested for iAs quantification as well as sequencing-based microRNA and gene expression analysis. Serum blood was collected for fasting blood glucose, fasting plasma insulin, and HOMA-IR. Results: We detected sex divergence in liver and adipose markers of diabetes (e.g., insulin signaling pathways, fasting blood glucose, fasting plasma insulin, and HOMA-IR) only in humanized (not WT) male mice. In humanized female mice, numerous genes that promote insulin sensitivity and glucose tolerance in both the liver and adipose are elevated compared to humanized male mice. We also identified Klf11 as a putative master regulator of the sex divergence in gene expression in humanized mice. Discussion: Our study underscoreds the importance of future studies leveraging the humanized mouse model to study iAs-associated metabolic disease. The findings also suggest suggested that humanized females are protected from metabolic dysfunction relative to humanized males in the context of iAs exposure. Future investigations should focus on the detailed mechanisms that underlie the sex divergence, including the potential role of miR-34a and/or Klf11.
Project description:To make the human liver accessible to metabolic treatments, we employed a liver-specific humanized mouse model in which approximately 50% of the mouse hepatocytes were replaced by human ones. To capture transcriptomes reflecting pathophysiology and therapeutic development of metabolic diseases, we subjected the humanized mice to the key metabolic transcriptional factor agonist treatments. We then performed gene expression profiling analysis using data obtained from RNA-seq of these 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. Livers collected at pre-pregnancy, 21 days of pregnancy, and 7 days postpartum from CYP2D6-humanized mice.
Project description:To make the human liver accessible to metabolic treatments, we employed a liver-specific humanized mouse model in which approximately 50% of the mouse hepatocytes were replaced by human ones. To capture transcriptomes reflecting pathophysiology and therapeutic development of metabolic diseases, we subjected the humanized mice to dietary intervention and the key metabolic transcriptional factor agonist treatments. We then performed rna exoression profiling analysis using data obtained from nanopore direct RNA sequencing of these humanized mice.