Project description:Mice on a reference (RD) or western diet (WD) supplemented with olive oil or omega-3 fatty acids (eicosapentaenoic acid [EPA] and/or docosahexaenoic acid [DHA])
Project description:BackgroundNonalcoholic fatty liver disease (NAFLD) is a global health problem. Identification of factors contributing to the onset and progression of NAFLD have the potential to direct novel strategies to combat NAFLD.MethodsWe examined the time course of western diet (WD)-induced NAFLD and its progression to nonalcoholic steatohepatitis (NASH) in age-matched female and male Ldlr-/- mice, with time-points at 1, 4, 8, 20 and 40 weeks on the WD. Controls included Ldlr-/- mice maintained on a purified low-fat diet (LFD) for 1 and 40 weeks. The approach included quantitation of anthropometric, plasma and liver markers of disease, plus hepatic histology, lipids, oxylipins, gene expression and selected metabolites.ResultsOne week of feeding the WD caused a significant reduction in hepatic essential fatty acids (EFAs: 18:2, ω6, 18:3, ω3) which preceded the decline in many C20-22 ω3 and ω6 polyunsaturated fatty acids (PUFA) and PUFA-derived oxylipins after 4 weeks on the WD. In addition, expression of hepatic inflammation markers (CD40, CD44, Mcp1, Nlrp3, TLR2, TLR4, Trem2) increased significantly in both female & male mice after one week on the WD. These markers continued to increase over the 40-week WD feeding study. WD effects on hepatic EFA and inflammation preceded all significant WD-induced changes in body weight, insulin resistance (HOMA-IR), oxidative stress status (GSH/GSSG ratio) and histological and gene expression markers of macrosteatosis, extracellular matrix remodeling and fibrosis.ConclusionsOur findings establish that feeding Ldlr-/- mice the WD rapidly lowered hepatic EFAs and induced key inflammatory markers linked to NASH. Since EFAs have an established role in inflammation and hepatic inflammation plays a major role in NASH, we suggest that early clinical assessment of EFA status and correcting EFA deficiencies may be useful in reducing NASH severity.
Project description:Hepatic transcriptome of junctional adhesion molecule A knockout, F11r–/– mice fed a Western diet (WD) for eight weeks. A cohort of WD-fed mice were treated with IgG or α4β7 mAb for four weeks starting at week four following initiation of the WD.
Project description:Macrophages are considered as a homogeneous population in the heart. We used single cell RNA sequencing (scRNA-seq) to analyze thediversity of macrophages in control diet (CD) mouse, high fat diet (HFD) mouse and Western diet (WD) mouse heart.
Project description:BackgroundNonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, particularly in obese and type 2 diabetic individuals. NAFLD ranges in severity from benign steatosis to nonalcoholic steatohepatitis (NASH); and NASH can progress to cirrhosis, primary hepatocellular carcinoma (HCC) and liver failure. As such, NAFLD has emerged as a major public health concern. Herein, we used a lipidomic and transcriptomic approach to identify lipid markers associated with western diet (WD) induced NASH in female mice.MethodsFemale mice (low-density lipoprotein receptor null (Ldlr -/-) were fed a reference or WD diet for 38 and 46 weeks. Transcriptomic and lipidomic approaches, coupled with statistical analyses, were used to identify associations between major NASH markers and transcriptomic & lipidomic markers.ResultsThe WD induced all major hallmarks of NASH in female Ldlr -/- mice, including steatosis (SFA, MUFA, MUFA-containing di- and triacylglycerols), inflammation (TNFα), oxidative stress (Ncf2), and fibrosis (Col1A). The WD also increased transcripts associated with membrane remodeling (LpCat), apoptosis & autophagy (Casp1, CtsS), hedgehog (Taz) & notch signaling (Hey1), epithelial-mesenchymal transition (S1004A) and cancer (Gpc3). WD feeding, however, suppressed the expression of the hedgehog inhibitory protein (Hhip), and enzymes involved in triglyceride catabolism (Tgh/Ces3, Ces1g), as well as the hepatic abundance of C18-22 PUFA-containing phosphoglycerolipids (GpCho, GpEtn, GpSer, GpIns). WD feeding also increased hepatic cyclooxygenase (Cox1 & 2) expression and pro-inflammatory ω6 PUFA-derived oxylipins (PGE2), as well as lipid markers of oxidative stress (8-iso-PGF2α). The WD suppressed the hepatic abundance of reparative oxylipins (19, 20-DiHDPA) as well as the expression of enzymes involved in fatty epoxide metabolism (Cyp2C, Ephx).ConclusionWD-induced NASH in female Ldlr -/- mice was characterized by a massive increase in hepatic neutral and membrane lipids containing SFA and MUFA and a loss of C18-22 PUFA-containing membrane lipids. Moreover, the WD increased hepatic pro-inflammatory oxylipins and suppressed the hepatic abundance of reparative oxylipins. Such global changes in the type and abundance of hepatic lipids likely contributes to tissue remodeling and NASH severity.
Project description:Here we investigated whether sterile triggers of inflammation induce trained immunity and thereby influence innate immune responses. Western diet (WD) feeding of Ldlr-/- mice induced systemic inflammation, which was undectable in serum soon after mice were shifted back to chow diet (CD). In contrast, myeloid cell responses towards innate stimuli remained broadly augmented. WD induced transcriptomic and epigenomic reprogramming of myeloid progenitor cells, leading to increased proliferation as well as enhanced innate immune and interferon responses towards in vivo LPS challenge. QTL analysis in human monocytes trained with oxidized low-density lipoprotein (oxLDL) and stimulated with LPS suggested inflammasome-mediated trained immunity. Consistently, Nlrp3-/-/Ldlr-/--deficient mice lacked WD-induced systemic inflammation or myeloid progenitor proliferation and reprogramming. Hence, NLRP3 mediates trained immunity following WD and could thereby arbitrate the potentially deleterious effects of trained immunity in inflammatory diseases.
Project description:Here we investigated whether sterile triggers of inflammation induce trained immunity and thereby influence innate immune responses. Western diet (WD) feeding of Ldlr-/- mice induced systemic inflammation, which was undectable in serum soon after mice were shifted back to chow diet (CD). In contrast, myeloid cell responses towards innate stimuli remained broadly augmented. WD induced transcriptomic and epigenomic reprogramming of myeloid progenitor cells, leading to increased proliferation as well as enhanced innate immune and interferon responses towards in vivo LPS challenge. QTL analysis in human monocytes trained with oxidized low-density lipoprotein (oxLDL) and stimulated with LPS suggested inflammasome-mediated trained immunity. Consistently, Nlrp3-/-/Ldlr-/--deficient mice lacked WD-induced systemic inflammation or myeloid progenitor proliferation and reprogramming. Hence, NLRP3 mediates trained immunity following WD and could thereby arbitrate the potentially deleterious effects of trained immunity in inflammatory diseases.
Project description:Here we investigated whether sterile triggers of inflammation induce trained immunity and thereby influence innate immune responses. Western diet (WD) feeding of Ldlr-/- mice induced systemic inflammation, which was undectable in serum soon after mice were shifted back to chow diet (CD). In contrast, myeloid cell responses towards innate stimuli remained broadly augmented. WD induced transcriptomic and epigenomic reprogramming of myeloid progenitor cells, leading to increased proliferation as well as enhanced innate immune and interferon responses towards in vivo LPS challenge. QTL analysis in human monocytes trained with oxidized low-density lipoprotein (oxLDL) and stimulated with LPS suggested inflammasome-mediated trained immunity. Consistently, Nlrp3-/-/Ldlr-/--deficient mice lacked WD-induced systemic inflammation or myeloid progenitor proliferation and reprogramming. Hence, NLRP3 mediates trained immunity following WD and could thereby arbitrate the potentially deleterious effects of trained immunity in inflammatory diseases.