Dataset Information

Aldose reductase is involved in the development of murine diet-induced nonalcoholic steatohepatitis.

ABSTRACT: Hepatic aldose reductase (AR) expression is known to be induced in liver diseases, including hepatitis and hepatocellular carcinoma. However, the role of AR in the development of these diseases remains unclear. We performed this current study to determine whether and how AR might be involved in the development of diet-induced nonalcoholic steatohepatitis. Our results showed that the level of AR protein expression was significantly higher in db/db mice fed the methionine-choline-deficient (MCD) diet than in mice fed the control diet. In parallel with the elevation in AR, steatohepatitis was observed in MCD diet-fed mice, and this diet-induced steatohepatitis was significantly attenuated by lentiviral-mediated knock-down of the AR gene. This suppressive effect of AR knock-down was associated with repressed levels of serum alanine aminotransferase and hepatic lipoperoxides, reduced mRNA and protein expression of hepatic cytochrome P450 2E1 (CYP2E1), and decreased mRNA expression of pro-inflammatory tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6). Moreover, AR-induced elevations on the level of CYP2E1 expression, reactive oxygen species, mRNA expression of TNF-? and IL-6 were confirmed in AML12 hepatocytes. Further, lentiviral-mediated knock-down of AR ameliorated MCD diet-induced collagen deposition in the livers of db/db mice. With the improvement in liver fibrosis, the mRNA levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and matrix metalloproteinase-2 (MMP-2), two genes involved in hepatic fibrogenesis, were found to be significantly suppressed, while TIMP-2 and MMP-13 were unaffected. Together these data indicate that inhibition of AR alleviates the MCD diet-induced liver inflammation and fibrosis in db/db mice, probably through dampening CYP2E1 mediated-oxidative stress and ameliorating the expression of pro-inflammatory cytokines.

SUBMITTER: Qiu L

PROVIDER: S-EPMC3774689 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Aldose reductase is involved in the development of murine diet-induced nonalcoholic steatohepatitis.

Qiu Longxin L Lin Jianhui J Ying Miao M Chen Weiqiang W Yang Jinmei J Deng Tiantian T Chen Jinfeng J Shi Duanyu D Yang James Y JY

PloS one 20130916 9

Hepatic aldose reductase (AR) expression is known to be induced in liver diseases, including hepatitis and hepatocellular carcinoma. However, the role of AR in the development of these diseases remains unclear. We performed this current study to determine whether and how AR might be involved in the development of diet-induced nonalcoholic steatohepatitis. Our results showed that the level of AR protein expression was significantly higher in db/db mice fed the methionine-choline-deficient (MCD) d ...[more]

PMID: 24066058

Similar Datasets

Project description:BackgroundNonalcoholic fatty liver disease (NAFLD) is a major public health burden in western societies. The progressive form of NAFLD, nonalcoholic steatohepatitis (NASH), is characterized by hepatosteatosis, inflammation, oxidative stress, and hepatic damage that can progress to fibrosis and cirrhosis; risk factors for hepatocellular carcinoma. Given the scope of NASH, validating treatment protocols (i.e., low fat diets and weight loss) is imperative.MethodsWe evaluated the efficacy of two diets, a non-purified chow (NP) and purified (low-fat low-cholesterol, LFLC) diet to reverse western diet (WD)-induced NASH and fibrosis in Ldlr-/- mice.ResultsMice fed WD for 22-24 weeks developed robust hepatosteatosis with mild fibrosis, while mice maintained on the WD an additional 7-8 weeks developed NASH with moderate fibrosis. Returning WD-fed mice to the NP or LFLC diets significantly reduced body weight and plasma markers of metabolic syndrome (dyslipidemia, hyperglycemia) and hepatic gene expression markers of inflammation (Mcp1), oxidative stress (Nox2), fibrosis (Col1A, LoxL2, Timp1) and collagen crosslinking (hydroxyproline). Time course analyses established that plasma triglycerides and hepatic Col1A1 mRNA were rapidly reduced following the switch from the WD to the LFLC diet. However, hepatic triglyceride content and fibrosis did not return to normal levels 8 weeks after the change to the LFLC diet. Time course studies further revealed a strong association (r2 ≥ 0.52) between plasma markers of inflammation (TLR2 activators) and hepatic fibrosis markers (Col1A, Timp1, LoxL2). Inflammation and fibrosis markers were inversely associated (r2 ≥ 0.32) with diet-induced changes in hepatic ω3 and ω6 polyunsaturated fatty acids (PUFA) content.ConclusionThese studies establish a temporal link between plasma markers of inflammation and hepatic PUFA and fibrosis. Low-fat low-cholesterol diets promote reversal of many, but not all, features associated with WD-induced NASH and fibrosis in Ldlr-/- mice.

Project description:BackgroundThe mechanisms triggering nonalcoholic steatohepatitis (NASH) remain poorly defined.ResultsKupffer cells are the first responding cells to hepatocyte injuries, leading to TNF? production, chemokine induction, and monocyte recruitment. The silencing of TNF? in myeloid cells reduces NASH progression.ConclusionIncrease of TNF?-producing Kupffer cells is crucial for triggering NASH via monocyte recruitment.SignificanceMyeloid cells-targeted silencing of TNF? might be a tenable therapeutic approach. Nonalcoholic steatohepatitis (NASH), characterized by lipid deposits within hepatocytes (steatosis), is associated with hepatic injury and inflammation and leads to the development of fibrosis, cirrhosis, and hepatocarcinoma. However, the pathogenic mechanism of NASH is not well understood. To determine the role of distinct innate myeloid subsets in the development of NASH, we examined the contribution of liver resident macrophages (i.e. Kupffer cells) and blood-derived monocytes in triggering liver inflammation and hepatic damage. Employing a murine model of NASH, we discovered a previously unappreciated role for TNF? and Kupffer cells in the initiation and progression of NASH. Sequential depletion of Kupffer cells reduced the incidence of liver injury, steatosis, and proinflammatory monocyte infiltration. Furthermore, our data show a differential contribution of Kupffer cells and blood monocytes during the development of NASH; Kupffer cells increased their production of TNF?, followed by infiltration of CD11b(int)Ly6C(hi) monocytes, 2 and 10 days, respectively, after starting the methionine/choline-deficient (MCD) diet. Importantly, targeted knockdown of TNF? expression in myeloid cells decreased the incidence of NASH development by decreasing steatosis, liver damage, monocyte infiltration, and the production of inflammatory chemokines. Our findings suggest that the increase of TNF?-producing Kupffer cells in the liver is crucial for the early phase of NASH development by promoting blood monocyte infiltration through the production of IP-10 and MCP-1.

Project description:Nonalcoholic fatty liver disease (NAFLD) is characterized by lipid accumulation in the liver that may progress to hepatic fibrosis and nonalcoholic steatohepatitis (NASH). Mechanisms underlying NAFLD and NASH are not yet fully understood. Dietary cholesterol was recently shown to be a risk factor for the development of NASH, suggesting a role for intestinal handling of cholesterol. One important regulator of cholesterol homeostasis is the sterol response element-binding protein-2 (SREBP-2) transcription factor. We tested the hypothesis that the overactivation of intestinal SREBP-2 increases the susceptibility to diet-induced NASH. A transgenic mouse model with intestine-specific overexpression of active SREBP-2 (ISR2 mice) driven by villin promoter was used. ISR2 mice and their wild-type littermates were fed a regular chow diet or a high-fat, high-cholesterol (HFHC) diet (15% fat, 1% cholesterol) for 15 wk. Results showed that HFHC feeding to ISR2 mice caused hepatic inflammation with increased levels of proinflammatory cytokines. Histological examination demonstrated extensive fibrosis after a HFHC diet associated with a perivascular as well as pericellular collagen deposits in ISR2 mice compared with wild-type littermates. The severe hepatic inflammation and advanced fibrosis in ISR2 mice was not associated with a difference in lipid accumulation in ISR2 mice compared with wild type littermates after HFHC feeding. These data indicate that overactivation of intestinal SREBP2 promotes diet-induced hepatic inflammation with features of human NASH resulting in rapid severe fibrosis and provide a novel link between regulatory processes of intestinal cholesterol and progression of fatty liver.NEW & NOTEWORTHY The current study highlights the role of overactivation of intestinal SREBP-2 transcription factor in the progression of hepatic fibrosis associated with diet-induced NASH. Mice with intestine-specific overexpression of SREBP-2 demonstrated more inflammation and severe fibrosis in the liver in response to 15 wk of being fed a high-cholesterol, high-fat diet as compared with their wild-type littermates. These data demonstrate a novel link between intestinal regulatory processes of cholesterol metabolism and the pathogenesis of fatty liver diseases.

Dataset Information

Aldose reductase is involved in the development of murine diet-induced nonalcoholic steatohepatitis.

Publications

Aldose reductase is involved in the development of murine diet-induced nonalcoholic steatohepatitis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets