The new-generation pan-peroxisome proliferator-activated receptor agonist IVA337 protects the liver from metabolic disorders and fibrosis

Abstract

IVA337 is a pan-peroxisome proliferator-activated receptor (PPAR) agonist with moderate and well-balanced activity on the three PPAR isoforms (α, γ, δ). PPARs are regulators of lipid metabolism, inflammation, insulin resistance, and fibrogenesis. Different single or dual PPAR agonists have been investigated for their therapeutic potential in nonalcoholic steatohepatitis (NASH), a chronic liver condition in which steatosis coexists with necroinflammation, potentially leading to liver fibrosis and cirrhosis. Clinical results have demonstrated variable improvements of histologically assessed hepatic lesions depending on the profile of the tested drug, suggesting that concomitant activation of the three PPAR isoforms would translate into a more substantial therapeutic outcome in patients with NASH. We investigated the effects of IVA337 on several preclinical models reproducing the main metabolic and hepatic features associated with NASH. These models comprised a diet-induced obesity model (high-fat/high-sucrose diet); a methionine- and choline-deficient diet; the foz/foz model; the CCl4-induced liver fibrosis model (prophylactic and therapeutic) and human primary hepatic stellate cells. IVA337 normalized insulin sensitivity while controlling body weight gain, adiposity index, and serum triglyceride increases; it decreased liver steatosis, inflammation, and ballooning. IVA337 demonstrated preventive and curative effects on fibrosis in the CCl4 model and inhibited proliferation and activation of human hepatic stellate cells, the key cells driving liver fibrogenesis in NASH. Moreover, IVA337 inhibited the expression of (pro)fibrotic and inflammasome genes while increasing the expression of β-oxidation-related and fatty acid desaturation-related genes in both the methionine- and choline-deficient diet and the foz/foz model. For all models, IVA337 displayed an antifibrotic efficacy superior to selective PPARα, PPARδ, or PPARγ agonists. Conclusion: The therapeutic potential of IVA337 for the treatment of patients with NASH is supported by our data. (Hepatology Communications 2017;1:524-537).

Figures

Figure 1

IVA337 dose dependently decreases adiposity index and normalizes glucose and insulinemia in a diet‐induced obesity model. (A) The adipose index (total WAT/body weight) was calculated in mice under a chow diet (ND controls) and mice under an HF/HS diet treated or not with IVA337 at 3, 10, and 30 mg/kg (n = 10 per group). (B‐E) Plasma analyses were performed at sacrifice for nonfasting glucose, insulin, triglycerides, and adiponectin levels. (F) An OGTT was carried out at 5 weeks. Data represented as mean ± SEM. **P <  0.01, ***P <  0.001 versus ND controls; *P <  0.05, **P <  0.01, ***P <  0.001 versus HF/HS diet + vehicle. Abbreviations: OGTT, oral glucose tolerance test; WAT, white adipose tissue.

Figure 2

IVA337 improves steatosis, inflammation, fibrosis, and ALT in the MCD model. (A,B) Steatosis and (C,D) inflammation were histologically measured at magnification ×20 in mice under an MCD diet for 3 weeks receiving or not IVA337 at 10 and 30 mg/kg (n = 10 per group). (E) ALT level was measured in the blood, and (F) the expression of fibrotic genes was evaluated by RT‐qPCR in the liver. Data represented as mean ± SEM. *P <  0.05, **P <  0.01, ***P <  0.001 versus MCD diet + vehicle. Abbreviations: ALT, alanine aminotransferase; col1, collagen type I; RT‐qPCR, real time polymerase chain reaction.

Figure 3

IVA337 normalizes hyperglycemia and reduces steatosis, ballooning, and inflammation in the foz/foz model. During the 12‐week experiment, mice under ND (n = 8), HFD (n = 10), HFD + IVA337 at 10 mg/kg (n = 10), or HFD + IVA337 at 30 mg/kg (n = 12) were followed for (A) body weight and (B) glycemia evaluation once a week. After sacrifice, (C) circulating adiponectin was measured and (D‐F) histologic analyses at magnification ×20 of the liver were performed to quantify steatosis, ballooning, and inflammation foci. Data represented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001 versus HFD + vehicle.

Figure 4

IVA337 inhibits Inflammasome‐related genes and NF‐κB expression and induces lipid metabolism‐related gene expression in the MCD and foz/foz models. Gene analyses were performed on the liver of mice from (A‐C) the MCD model (n = 10 per group) and (D‐E) the foz/foz model (n = 8‐12 per group). (A,D) Liver inflammasome‐related genes, (B,E) lipid metabolism genes, and (C,F) inflammatory genes. Data represented as mean ± SEM. *P <  0.05, **P <  0.01, ***P <  0.001 versus MCD + vehicle (A‐C) or HFD + vehicle (D‐F). Abbreviations: ASC, apoptosis‐associated speck‐like protein containing a CARD; CCL5, chemokine (C‐C motif) ligand 5; CCR2, C‐C chemokine receptor type 2; mRNA, messenger RNA.

Figure 5

IVA337 reverses fibrosis in a curative CCl4‐induced liver fibrosis model. (A) Liver histologic pictures (magnification × 20) from a 6‐week CCl4 study, (B) liver hydroxyproline content, and (C) PicroSirius Red analysis in mice treated or not with IVA337 10 and 30 mg/kg (n = 8 per group). Data represented as mean ± SEM. ***P < 0.001.

Figure 6

IVA337 reversion of fibrosis in the CCl4 model, comparison with selective PPAR agonists. (A) Liver histologic pictures from a 6‐week CCl4 study, (B) liver hydroxyproline content, and (C) PicroSirius Red analysis in mice treated or not with IVA337 (15 and 30 mg/kg), rosiglitazone (5 mg/kg), GW501516 (10 mg/kg) or fenofibrate (100 mg/kg) (n = 8 per group). Data represented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001. Abbreviation: PSR, PicroSirius Red.

Figure 7

IVA337 inhibits PDGF‐induced proliferation, stiffness‐induced activation, and TGF‐β1‐induced profibrotic gene expression; comparison with selective PPAR agonists. (A) Effects of IVA337, rosiglitazone, GW501516, and fenofibrate in a dose range (3 nM to 30 µM, with a semi‐log dilution scale) on PDGF (10 ng/mL)‐induced hHSC proliferation. (B) hHSCs plated on plastic differentiated into myofibroblasts after 7 days in culture. Effect of IVA337 (3 µM), rosiglitazone (3 µM), GW501516 (3 µM), and fenofibric acid (30 µM) were evaluated. (C‐F) TGF‐β1‐induced profibrotic gene expression after 24 hours. Data represented as mean ± SEM. ***P <  0.001 versus DMSO; **P <  0.01, ***P <  0.001 versus TGF‐β1. Abbreviations: col1α1, collagen type Iα1; CTGF, connective tissue growth factor; DMSO, dimethyl sulfoxide; EdU, 5‐ethynyl‐2′‐deoxyuridine; mRNA, messenger RNA; PAI‐1, plasminogen activator inhibitor 1.