Farnesoid X receptor antagonist exacerbates dyslipidemia in mice

Background

The effects of farnesoid X receptor (FXR) antagonists on plasma lipid profile in mice have not been investigated thus far. The aim of this study was to investigate the antidyslipidemic effects of an FXR antagonist in dyslipidemic mice, and to clarify the mechanisms underlying the lipid modulatory effect.

Farnesoid X receptor modulators: a patent review

Importance of the field: The farnesoid X receptor (FXR) is a key regulator of cholesterol homeostasis, triglyceride synthesis and lipogenesis. Given some patients' inability to tolerate existing medications, such as the statins, for cholesterol reduction, there is a pressing need for additional medicines to treat dyslipidemia. FXR agonists have emerged in discovery and preclinical efforts to show great potential for the treatment of these and other life-impairing and life-threatening conditions.

Areas covered in this review: Recent advances in the search for novel FXR modulators are reviewed, with a particular focus on patent applications and peer-reviewed publications disclosed in the past 5 years.

What the reader will gain: A total of 72 patent applications and peer-reviewed articles, containing 16 generic structure classes with nearly 5000 novel synthesized structures are reviewed. Where possible, the structure–activity relationship of these structure classes is surveyed, new insights into in vitro and in vivo efficacy of FXR agonists are disclosed, and potential new and promising therapeutic applications are revealed.

Take home message: FXR agonists have proven their efficacy and safety in primates and have significant potential as therapeutic agents for the treatment of dyslipidemia and potentially an array of other disease areas.     

Farnesoid X receptor contributes to oleanolic acid-induced cholestatic liver injury in mice

Farnesoid X receptor (FXR) is a nuclear receptor involved in the metabolism of bile acid. However, the molecular signaling of FXR in bile acid homeostasis in cholestatic drug-induced liver injury remains unclear. Oleanolic acid (OA), a natural triterpenoid, has been reported to produce evident cholestatic liver injury in mice after a long-term use. The present study aimed to investigate the role of FXR in OA-induced cholestatic liver injury in mice using C57BL/6J (WT) mice and FXR knockout (FXR^−/−) mice. The results showed that a significant alleviation in OA-induced cholestatic liver injury was observed in FXR^−/− mice as evidenced by decreases in serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase as well as reduced hepatocyte necrosis. UPLC-MS analysis of bile acids revealed that the contents of bile acids decreased significantly in liver and serum, while increased in the bile in FXR^−/− mice compared with in WT mice. In addition, the mRNA expressions of hepatic transporter Bsep, bile acid synthesis enzymes Bacs and Baat, and bile acids detoxifying enzymes Cyp3a11, Cyp2b10, Ephx1, Ugt1a1, and Ugt2b5 were increased in liver tissues of FXR^−/− mice treated with OA. Furthermore, the expression of membrane protein BSEP was significantly higher in livers of FXR^−/− mice compared with WT mice treated with OA. These results demonstrate that knockout of FXR may alleviate OA-induced cholestatic liver injury in mice by decreasing accumulation of bile acids both in the liver and serum, increasing the export of bile acids via the bile, and by upregulation of bile acids detoxification enzymes.     

Farnesoid X receptor modulators 2014-present: a patent review

Introduction. The nuclear receptor FXR regulates the expression of genes involved in bile acids, glucose and lipid homeostasis. For its role as guardian of metabolism, FXR has been identified a promising pharmacological target in liver bile acid and lipid accumulation, such as cholestasis and non-alcoholic fatty liver disease (NAFLD). The field of FXR research is extremely competitive with a large number of patents and articles published in the last decades identifying promising hit compounds.

Areas covered. The present review summarizes recent patent activity (2014-to date) filing for synthetic and natural FXR ligands, including bile acid derivatives and non-steroidal compounds, alongside their in vitro and in vivo efficacy as well as their therapeutic applications.

Expert opinion. While the first FXR agonist, obeticholic acid, has gained approval, significant safety issues have been emerged. Today is unclear whether these safety issues are class related or restricted to the bile acid scaffold of this agent. Despite the significant number of patent applications claiming steroidal and non-steroidal FXR agonists, several questions on their therapeutic potential in cholestasis and NASH remain open leaving a space for the development of novel compounds.     

Farnesoid X receptor agonism -- a new approach to the treatment of cholesterol gallstone disease

Gallstone disease is very common among native Americans and Hispanics, and approximately 20 million patients are treated for this disease annually in the US. The nuclear farnesoid X receptor (FXR) is the receptor for bile acids, and GW4064 is a synthetic agonist at the FXR. FXR(-/-) mice fed a lithogenic diet (high fat, cholesterol and cholic acid) are more susceptible to gallstone disease than wild-type mice with the same mixed background, thus establishing that the ablation of FXR is associated with this disease. The C57L mouse is susceptible to gallstone formation. When C57L mice are fed a lithogenic diet for a week, the bile contains large aggregates of cholesterol precipitates, and two of five C57L mice had macroscopic cholesterol crystals. In contrast, when C57L mice were fed the lithogenic diet and administered GW4064 100 mg/kg/day by oral gavage, there was no precipitation of cholesterol. Treatment with this agent also increased bile salt and phospholipid concentration, and prevented gallbladder epithelium damage. As FXR agonism with GW4064 has been shown to be useful in a mouse model of cholesterol gallstone disease, it should undergo further development for the treatment of this condition.     

Protection against nonalcoholic steatohepatitis through targeting IL-18 and IL-1alpha by luteolin

BackgroundThe management of nonalcoholic steatohepatitis (NASH) is still a crosstalk so the current study was designed to evaluate the effect of different luteolin doses on an experimental model of NASH and to elucidate novel anti-inflammatory pathways underlying its effect.MethodsAdult male Wistar rats (200–220 g; n = 60) were used. Rats were fed a high carbohydrate/high fat diet (? 30% carbohydrate and 42% fat) daily for 12 weeks to induce NASH. Luteolin (10, 25, 50 or 100 mg/kg/day) was administered as a suspension (10% w/v in 0.9% NaCl) using an oral gavage. Histopathological changes (necrosis, inflammation and steatosis) were evaluated. Biomarkers for liver function, lipid peroxidation, extracellular matrix deposition and anti-oxidant activity were measured. Levels of IFN-γ, TNF-α and IL-1α and IL-18 were measured.ResultsObtained results showed ability of luteolin to reduce activity of ALT and AST and to decrease levels of bilirubin, hyaluronic acid and malondialdehyde significantly (p < 0.05). Also, luteolin showed an anti-oxidant activity as indicated by the significant (p < 0.05) increase in reduced glutathione. Finally, a significant (p < 0.05) decrease in IFN-γ, TNF-α, IL-1α and IL-18 levels was observed most notably in groups that received high doses of luteolin (50 and 100 mg/kg).ConclusionsLuteolin can protect against non-alcoholic steatohepatitis through targeting the pro-inflammatory IL-1 and Il-18 pathways in addition to an antioxidant effect.     

Farnesoid X receptor: a master regulator of hepatic triglyceride and glucose homeostasis

Non-alcoholic fatty liver disease (NAFLD) is characterized by the aberrant accumulation of triglycerides in hepatocytes in the absence of significant alcohol consumption, viral infection or other specific causes of liver disease. NAFLD has become a burgeoning health problem both worldwide and in China, but its pathogenesis remains poorly understood. Farnesoid X receptor (FXR), a member of the nuclear receptor (NR) superfamily, has been demonstrated to be the primary sensor for endogenous bile acids, and play a crucial role in hepatic triglyceride homeostasis. Deciphering the synergistic contributions of FXR to triglyceride metabolism is critical for discovering therapeutic agents in the treatment of NAFLD and hypertriglyceridemia.     

非酒精性脂肪性肝炎52例临床病理特征

目的观察非酒精性脂肪性肝炎的临床病理特征。方法对临床与病理确诊的非酒精性脂肪性肝炎的肝组织进行光镜观察,并对相应的临床资料进行分析。结果大部分患者有乏力、纳差、右上腹胀满不适及丙氨酸转氨酶、天冬氨酸转氨酶、γ-谷氨酰转肽酶、胆固醇、甘油三酯升高,肥胖与非酒精性脂肪性肝炎相关,肝组织病理分析,G125例、G218例、G37例、G42例,其中S112例、S24例、S31例、S41例,有肝组织病理改变,光镜下可见到位于Ⅲ带的大泡性或大泡性为主的脂肪变性,肝细胞核位于细胞的边缘,汇管区无界面性炎;邻近的肝细胞从肿胀变性至气球样变;肝纤维化程度多较轻微,可观察到腺泡3区的窦周纤维化,少数病例可见汇管区周围细短纤维间隔,典型的M llory小体少见。结论非酒精性脂肪性肝炎是一种较为常见的、具有一定临床与病理特点的慢性肝病,肝穿活检有助于早期明确诊断。     

G protein-coupled receptor 35 attenuates nonalcoholic steatohepatitis by reprogramming cholesterol homeostasis in hepatocytes

Nonalcoholic fatty liver disease(NAFLD) is the most common chronic liver disease worldwide.Fat accumulation "sensitizes" the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35(GPR35) is involved in metabolic stresses,but its role in NAFLD is unknown.We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis.Specifically,we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose(HFC...     

Altered cisplatin pharmacokinetics during nonalcoholic steatohepatitis contributes to reduced nephrotoxicity

Disease-mediated alterations to drug disposition constitute a significant source of adverse drug reactions. Cisplatin (CDDP) elicits nephrotoxicity due to exposure in proximal tubule cells during renal secretion. Alterations to renal drug transporter expression have been discovered during nonalcoholic steatohepatitis (NASH), however, associated changes to substrate toxicity is unknown. To test this, a methionine- and choline-deficient diet-induced rat model was used to evaluate NASH-associated changes to CDDP pharmacokinetics, transporter expression, and toxicity. NASH rats administered CDDP (6 mg/kg, i.p.) displayed 20% less nephrotoxicity than healthy rats. Likewise, CDDP renal clearance decreased in NASH rats from 7.39 to 3.83 mL/min, renal secretion decreased from 6.23 to 2.80 mL/min, and renal CDDP accumulation decreased by 15%, relative to healthy rats. Renal copper transporter-1 expression decreased, and organic cation transporter-2 and ATPase copper transporting protein-7b increased slightly, reducing CDDP secretion. Hepatic CDDP accumulation increased 250% in NASH rats relative to healthy rats. Hepatic organic cation transporter-1 induction and multidrug and toxin extrusion protein-1 and multidrug resistance-associated protein-4 reduction may contribute to hepatic CDDP sequestration in NASH rats, although no drug-related toxicity was observed. These data provide a link between NASH-induced hepatic and renal transporter expression changes and CDDP renal clearance, which may alter nephrotoxicity.     

Promising therapies for treatment of nonalcoholic steatohepatitis

Introduction: Non-alcoholic fatty liver disease (NAFLD) has become the most common etiology for abnormal aminotransferase levels and chronic liver disease. Its growing prevalence is largely linked to the presence of metabolic syndrome, particularly diabetes and insulin resistance. It is estimated that 60–80% of the type 2 diabetic population has NAFLD. NAFLD encompasses a range of conditions ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). A subset of patients with hepatic steatosis progress to NASH, while 15–20% of patients with NASH develop cirrhosis. This progression is thought to be multifactorial, and there are currently no FDA-approved medications for the treatment of NASH.

Areas covered: We review drugs currently in Phase II and III clinical trials for treatment of NAFLD and NASH, including their mechanisms of action, relationship to the pathophysiology of NASH, and rationale for their development.

Expert opinion: The treatment of NASH is complex and necessitates targeting a number of different pathways. Combination therapy, preferably tailored toward the disease stage and severity, will be needed to achieve maximum therapeutic effect. With multiple agents currently being developed, there may soon be an ability to effectively slow or even reverse the disease process in many NAFLD/NASH patients.     

法尼酯X受体调控因素及配体的研究进展

法尼酯X受体（Farnesoid X Receptor,FXR）属于核激素受体超家族中的一员,作为一种胆汁酸受体和胆汁酸生物合成的生物感受器,参与机体多种生理活动。因此揭示FXR转录表达的调控因素以及寻找具有选择性和高活性的FXR配体,为新药研发提供新思路具有重要的意义。因而对FXR表达调控和配体的最新研究进行综述。     

枯否细胞在非酒精性脂肪肝炎中的发病机制

非酒精性脂肪肝炎(NASH)是一种代谢综合性肝病,是在肝脏细胞脂肪变性基础上进一步诱发炎性反应及纤维化.枯否细胞(KCs)是一种肝巨噬细胞,NASH进展过程中,KCs能够在脂质、内毒素、氧化应激等刺激作用下分泌炎性因子,引发肝细胞炎性反应,损伤肝脏.该文就KCs激活分泌的炎症因子在NASH发病机制中的作用进行详细论述.     

Farnesoid X receptor agonist for the treatment of liver and metabolic disorders: focus on 6-ethyl-CDCA

6-ethyl-chedeoxycholic acid (6E-CDCA) is a farnesoid X receptor (FXR) ligand endowed with agonistic activity under development for treatment of cholestatic liver diseases including primary biliary cirrhosis (PBC) and liver-related metabolic disorders including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). FXR is a bile sensor that acts in coordination with other nuclear receptors to regulate essential steps of bile acid uptake, metabolism and excretion. 6E-CDCA has been investigated in preclinical models of cholestasis, liver fibrosis and diet-induced atherosclerosis. In a phase II clinical trial in patients with PBC, 6E-CDCA met the primary endpoint of a reduction in alkaline phosphatase levels but safety data indicated that the drug exacerbated pruritus, one of the main symptoms of PBC, suggesting that 6E-CDCA or FXR are mediators of pruritus in humans. Treatment of patients with diabetes and liver steatosis resulted in amelioration of insulin sensitivity despite a reduction a slight reduction in HDL and increased levels of LDL were observed. These side effects on bile acids and lipid metabolism were all predicted by pre-clinical studies, suggesting that potent FXR ligands hold promise but potential side effects might limit their development.