Paraoxonase-2 agonist vutiglabridin promotes autophagy activation and mitochondrial function to alleviate non-alcoholic steatohepatitis.

BACKGROUND AND PURPOSE: Only limited therapeutic agents have been developed for non-alcoholic steatohepatitis (NASH). Glabridin, a promising anti-obesity candidate, has only limited druggability due to its low in vivo chemical stability and bioavailability. Therefore, we developed vutiglabridin (VUTI), which is based on a glabridin backbone, and investigated its mechanism of action in treating NASH in animal models. EXPERIMENTAL APPROACH: Anti-NASH effects of VUTI were determined in in vitro fatty liver models, spheroids of primary human hepatocytes and L02 normal liver cell lines. To identify VUTI possible cellular target/s, biotin-labelled VUTI was synthesized and underwent chemical proteomic analysis. Further, the evaluation of VUTI therapeutic efficacy was carried out using an amylin-NASH and high-fat (HF) diet-induced obese (DIO) mouse models. This was carried out using transcriptomic, lipidomic and proteomic analyses of the livers from the amylin-NASH mouse model. KEY RESULTS: VUTI treatment markedly reduces hepatic steatosis, fibrosis and inflammation by promoting lipid catabolism, activating autophagy and improving mitochondrial dysfunction, all of which are hallmarks of effective NASH treatment. The cellular target of VUTI was identified as paraoxonase 2 (PON2), a newly proposed protein target for the treatment of NASH, VUTI enhanced PON2 activity. The results using PON2 knockdown cells demonstrated that PON2 is important for VUTI- activation of autophagy, promoting mitochondrial function, decreasing oxidative stress and alleviating lipid accumulation under lipotoxic condition. CONCLUSION AND IMPLICATIONS: Our data demonstrated that VUTI is a promising therapeutic for NASH. Targeting PON2 may be important for improving liver function in various immune-metabolic diseases including NASH.

Effects of meal type on the bioavailability of vutiglabridin, a novel anti-obesity agent, in healthy subjects.

Vutiglabridin, which affects the pharmacokinetics (PKs) of food, is currently under clinical development for the treatment of obesity. This study aimed to evaluate the effects of low- and high-fat meals on PKs of vutiglabridin in healthy male subjects. A randomized, open-label, single-dose, three-period, six-sequence crossover study was conducted. The subjects received a single oral dose of vutiglabridin 480 mg in a fasted state, 30 min after the intake of a low-fat meal (total 500-600 kcal, fat content 100-125 kcal) and high-fat meal (total 800-1000 kcal, fat content 500-600 kcal), with a 21-day washout period. Geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for maximum plasma concentration (Cmax ) and area under the plasma concentration-time curve to the last measurable timepoint (AUClast ) were calculated. After intake of low- and high-fat meals, systemic exposure to vutiglabridin was increased, and the time to reach Cmax (Tmax ) was delayed compared to that in the fasted state. The GMRs (90% CIs) of low-fat meal to fasted state for Cmax and AUClast were 2.14 (1.76-2.60) and 2.15 (1.92-2.42), respectively, and those of high-fat meal to fasted state were 3.07 (2.53-3.72) and 3.00 (2.67-3.37), respectively. The median Tmax was delayed by 1.5 h in both fed states compared with that in the fasted state. The study drug was well-tolerated after administration in both the fed and fasted states. Food ingestion substantially increased the extent of oral vutiglabridin absorption in healthy subjects, and this enhancement increased with the fat content of the meal.

Preclinical Bioavailability Assessment of a Poorly Water-Soluble Drug, HGR4113, Using a Stable Isotope Tracer.

Drug solubility limits intravenous dosing for poorly water-soluble medicines, which misrepresents their bioavailability estimation. The current study explored a method using a stable isotope tracer to assess the bioavailability of drugs that are poorly water-soluble. HGR4113 and its deuterated analog, HGR4113-d7, were tested as model drugs. To determine the level of HGR4113 and HGR4113-d7 in rat plasma, a bioanalytical method using LC-MS/MS was developed. The HGR4113-d7 was intravenously administered to rats that were orally pre-administered HGR4113 at different doses; subsequently, the plasma samples were collected. HGR4113 and HGR4113-d7 were simultaneously determined in the plasma samples, and bioavailability was calculated using plasma drug concentration values. The bioavailability of HGR4113 was 53.3% ± 19.5%, 56.9% ± 14.0%, and 67.8% ± 16.7% after oral dosages of 40, 80, and 160 mg/kg, respectively. By eliminating the differences in clearance between intravenous and oral dosages at different levels, acquired data showed that the current method reduced measurement errors in bioavailability when compared to the conventional approach. The present study suggests a prominent method for evaluating the bioavailability of drugs with poor aqueous solubility in preclinical studies.

Paraoxonase-2 contributes to promoting lipid metabolism and mitochondrial function via autophagy activation.

Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent immuno-metabolic disease that can progress to hepatic cirrhosis and cancer. NAFLD pathogenesis is extremely complex and is characterized by oxidative stress, impaired mitochondrial function and lipid metabolism, and cellular inflammation. Thus, in-depth research on its underlying mechanisms and subsequent investigation into a potential drug target that has overarching effects on these features will help in the discovery of effective treatments for NAFLD. Our study examines the role of endogenous paraoxonase-2 (PON2), a membrane protein with reported antioxidant activity, in an in vitro cell model of NAFLD. We found that the hepatic loss of PON2 activity aggravated steatosis and oxidative stress under lipotoxic conditions, and our transcriptome analysis revealed that the loss of PON2 disrupts the activation of numerous functional pathways closely related to NAFLD pathogenesis, including mitochondrial respiratory capacity, lipid metabolism, and hepatic fibrosis and inflammation. We found that PON2 promoted the activation of the autophagy pathway, specifically the mitophagy cargo sequestration, which could potentially aid PON2 in alleviating oxidative stress, mitochondrial dysfunction, lipid accumulation, and inflammation. These results provide a mechanistic foundation for the prospect of PON2 as a drug target, leading to the development of novel therapeutics for NAFLD.

Safety, tolerability, pharmacokinetic, and pharmacodynamic characteristics of vutiglabridin: A first-in-class, first-in-human study.

This study aimed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of vutiglabridin, a potential anti-obesity treatment under development, for the first time in humans. A randomized, placebo-controlled, single- and multiple-ascending dose study (SAD and MAD, respectively) was performed in healthy Koreans and Whites. Subjects randomly received a single oral dose of 30-720 mg vutiglabridin or placebo at a ratio of 8:2 in the SAD study or 240-480 mg vutiglabridin or placebo once daily for 14 days in the MAD study. Food effect was also evaluated in 240 mg single dose group. Pharmacokinetics were evaluated through plasma concentrations, and pharmacodynamic biomarkers related to obesity or inflammation were analyzed. Safety and tolerability were assessed throughout the study. Single and multiple doses of vutiglabridin were generally well-tolerated. The pharmacokinetic parameters show less than dose-proportionality increase, and plasma concentrations increased more than two-fold after multiple administrations. The mean half-life of Koreans and Whites in the MAD study was 110 and 73 h, respectively. The systemic exposure of vutiglabridin was significantly increased when taken with a high-fat meal, and the systemic exposure was lower in Whites than in Koreans. Vutiglabridin was well-tolerated in healthy Koreans and Whites. The plasma concentration increased less than the dose-proportionality manner. These results justify further investigation of vutiglabridin in patients with obesity.

Discovery and preclinical efficacy of HSG4112, a synthetic structural analog of glabridin, for the treatment of obesity.

BACKGROUND: HSG4112 is a clinical-stage drug candidate for the treatment of obesity. Here, we report its discovery and preclinical efficacy. METHODS: In high-fat diet (HFD)-induced obese male C57BL/6J mice, we tested the weight loss effect of synthetic compounds derived from a structure-activity relationship (SAR) study of glabridin, a natural compound known to reduce body weight and influence energy homeostasis. After selecting HSG4112 as our optimized compound from this discovery method, we characterized its pharmacological effects on parameters related to obesity through in vivo metabolic and biochemical measurements, histology and gene expression analysis, and indirect calorimetry. RESULTS: Through the SAR study, we identified four novel components of glabridin pertinent for its anti-obesity activity, and found that HSG4112, an optimized structural analog of glabridin, markedly supersedes glabridin in weight reduction efficacy and chemical stability. Six-week administration of HSG4112 to HFD-induced obese mice led to dose-dependent normalization of obesity-related parameters, including body weight, muscle and adipose tissue weight, adipocyte size, and serum leptin/insulin/glucose levels. The weight reduction induced by HSG4112 was partially mediated by decreased food intake and mainly mediated by increased energy expenditure, with no change in physical activity. Accordingly, the pattern of transcriptional changes was aligned with increased energy expenditure in the liver and muscles. Following significant body weight reduction, robust amelioration of histopathology and blood markers of fatty liver were also observed. CONCLUSIONS: Our study demonstrates the key chemical components of glabridin pertinent to its weight loss effects and suggests HSG4112 as a promising novel drug candidate for the pharmacological treatment of obesity.

Species Differences in Stereoselective Pharmacokinetics of HSG4112, A New Anti-Obesity Agent.

HSG4112, a racemic drug, is a new anti-obesity agent. In this study, the stereoselective pharmacokinetics of HSG4112 were investigated in rats and dogs, and the underlying mechanism was investigated. The plasma concentrations of HSG4112(S) and HSG4112(R) were quantitated in plasma from rats and beagle dogs after IV and/or oral administration of racemic HSG4112. The concentration of HSG4112(S) was significantly higher than that of HSG4112(R) in rat plasma. Contrarily, the concentration of HSG4112(R) was significantly higher than HSG4112(S) in dog plasma. A metabolic stability test with liver microsomes showed that HSG4112(S) was more stable than HSG4112(R) in rat liver microsomes, but the difference between stereoisomers did not appear in dog liver microsomes. However, the stereoselectivity was observed in dog liver and intestinal microsomes after uridine 5'-diphospho-glucuronic acid was added. Thus, stereoselective metabolism by uridine 5'-diphospho-glucuronosyltransferases is mainly responsible for the stereoselective pharmacokinetics in dogs. These results suggest that the species difference in the stereoselective plasma pharmacokinetics of HSG4112 is due to the stereoselective metabolism.

A Dunnione Compound MB12662 Improves Cisplatin-Induced Tissue Injury and Emesis.

The present study was aimed to investigate the effects of MB12662, a synthetic dunnione compound, on cisplatin-induced vomiting reflexes and intestinal, renal, immune system, and hematopoietic toxicities in ferrets and mice, respectively. Male ICR mice were orally administered MB12662 (5, 10, 25 or 50 mg/kg) for 10 days, during which intraperitoneally challenged with cisplatin (3.5 mg/kg) from day 4 to 7, and sacrificed on day 10 for the pathological examination. Male ferrets were orally administered MB12662 (25, 50 or 100 mg/kg) for 7 days, subcutaneously challenged with cisplatin (5 mg/kg), and monitored for vomiting reflexes and survival of the animals. Four-day injection of cisplatin (3.5 mg/kg) to mice caused body weight loss and degeneration and atrophy of intestinal villi, reducing villi/crypt ratio to a half level of control animals. Cisplatin also induced renal and hepatic toxicities, and depletion of splenocytes and bone marrow progenitor cells. The systemic toxicities including decreased villi/crypt ratio, immune system atrophy, splenocyte depletion, and decreased cellularity in bone marrow were improved by MB12662. Cisplatin (5 mg/kg) induced retching and emetic responses of ferrets, which were remarkably attenuated by MB12662 in a dose-dependent manner. All the ferrets pretreated with MB12662 survived the challenge of cisplatin, in comparison with 40% mortality in vehicle-treated animals, and blood parameters of nephrotoxicity and hepatotoxicity were markedly recovered. It is expected that MB12662 could be a candidate for the body protection against burden, including emesis, of chemotherapeutic agents.

Inhibitory effects of a ß-dunnione compound MB12662 on gastric secretion and ulcers.

The effects of a ß-dunnione compound MB12662 on the gastric secretion and ulcers were investigated in rats. In order to assess the effects of MB12662 on the gastric secretion and acidity, rats were subjected to pylorus ligation operation, and 6 hours later, gastric fluid was collected. Treatment with MB12662 reduced the gastric fluid volume to 47.3% of control level and increased pH. In an alcohol-induced ulcer model, rats were orally administered 3 mL/kg of ethanol, and 1 hour later, the ulcer lesions ware measured under a stereomicroscope. MB12662 reduced ulcer index in a dose-dependent manner which was much stronger than a proton-pump inhibitor pantoprazole. In a stress-induced ulcer model, rats were subjected to water-immersion restraint stress, and 5 hours later, the ulcer lesions ware examined. MB12662 also attenuated the stress-induced gastric lesions, although the efficacy of MB12662 was lower than that of pantoprazole. Therefore, it is suggested that MB12662 could be a candidate compound for the prevention or treatment of gastric ulcers induced by gastric over-secretion and alcoholic hangover.

Pharmacological stimulation of NADH oxidation ameliorates obesity and related phenotypes in mice.

OBJECTIVE: Nicotinamide adenine dinucleotides (NAD+ and NADH) play a crucial role in cellular energy metabolism, and a dysregulated NAD+-to-NADH ratio is implicated in metabolic syndrome. However, it is still unknown whether a modulating intracellular NAD+-to-NADH ratio is beneficial in treating metabolic syndrome. We tried to determine whether pharmacological stimulation of NADH oxidation provides therapeutic effects in rodent models of metabolic syndrome. RESEARCH DESIGN AND METHODS: We used beta-lapachone (betaL), a natural substrate of NADH:quinone oxidoreductase 1 (NQO1), to stimulate NADH oxidation. The betaL-induced pharmacological effect on cellular energy metabolism was evaluated in cells derived from NQO1-deficient mice. In vivo therapeutic effects of betaL on metabolic syndrome were examined in diet-induced obesity (DIO) and ob/ob mice. RESULTS: NQO1-dependent NADH oxidation by betaL strongly provoked mitochondrial fatty acid oxidation in vitro and in vivo. These effects were accompanied by activation of AMP-activated protein kinase and carnitine palmitoyltransferase and suppression of acetyl-coenzyme A (CoA) carboxylase activity. Consistently, systemic betaL administration in rodent models of metabolic syndrome dramatically ameliorated their key symptoms such as increased adiposity, glucose intolerance, dyslipidemia, and fatty liver. The treated mice also showed higher expressions of the genes related to mitochondrial energy metabolism (PPARgamma coactivator-1alpha, nuclear respiratory factor-1) and caloric restriction (Sirt1) consistent with the increased mitochondrial biogenesis and energy expenditure. CONCLUSIONS: Pharmacological activation of NADH oxidation by NQO1 resolves obesity and related phenotypes in mice, opening the possibility that it may provide the basis for a new therapy for the treatment of metabolic syndrome.