Procollagen C-Proteinase Enhancer-1 (PCPE-1) deficiency in mice reduces liver fibrosis but not NASH progression.

BACKGROUND AND AIMS: Nonalcoholic Steatohepatitis (NASH) is a major cause of end-stage liver diseases such as cirrhosis and hepatocellular carcinoma resulting ultimately in increased liver-related mortality. Fibrosis is the main driver of mortality in NASH. Procollagen C-Proteinase Enhancer-1 (PCPE-1) plays a key role in procollagen maturation and collagen fibril formation. To assess its role in liver fibrosis and NASH progression, knock-out mice were evaluated in a dietary NASH model. METHODS: Global constitutive Pcolce-/- and WT male mice were fed with a Choline Deficient Amino acid defined High Fat Diet (CDA HFD) for 8 weeks. Liver triglycerides, steatosis, inflammation and fibrosis were assessed at histological, biochemical and gene expression levels. In addition, human liver samples from control and NASH patients were used to evaluate the expression of PCPE-1 at both mRNA and protein levels. RESULTS: Pcolce gene deficiency prevented diet-induced liver enlargement but not liver dysfunction. Furthermore, liver triglycerides, steatosis and inflammation were not modified in Pcolce-/- male mice compared to WT under CDA HFD. However, a significant decrease in liver fibrosis was observed in Pcolce-/- mice compared to WT under NASH diet, associated with a decrease in total and insoluble collagen content without any significant modifications in the expression of genes involved in fibrosis and extracellular matrix remodeling. Finally, PCPE-1 protein expression was increased in cirrhotic liver samples from both NASH and Hepatitis C patients. CONCLUSIONS: Pcolce deficiency limits fibrosis but not NASH progression in CDA HFD fed mice.

Deficiency of Procollagen C-Proteinase Enhancer 1 in Mice has No Major Impact on Cardiac Collagen and Function Under Basal Conditions.

ABSTRACT: Maturation of fibrillar collagen is known to play a crucial role in the pathophysiology of myocardial fibrosis. Procollagen C-proteinase enhancer 1 (PCPE1) has a key role in procollagen maturation and collagen fibril formation. The phenotype of both male and female PCPE1 knock-out mice was investigated under basal conditions to explore the potential of PCPE1 as a therapeutic target in heart failure. Global constitutive PCPE1-/- mice were generated. Serum procollagen I C-terminal propeptide, organ histology, and cutaneous wound healing were assessed in both wild type (WT) and PCPE1-/- mice. In addition, the cardiac expression of genes involved in collagen metabolism was investigated and the total and insoluble cardiac collagen contents determined. Cardiac function was evaluated by echocardiography. No differences in survival, clinical chemistry, or organ histology were observed in PCPE1-/- mice compared with WT. Serum procollagen I C-terminal propeptide was lower in PCPE1-/- mice. Cardiac mRNA expression of Bmp1, Col1a1, Col3a1, and Loxl2 was similar, whereas Tgfb and Loxl1 mRNA levels were decreased in PCPE1-/- mice compared with sex-matched WT. No modification of total or insoluble cardiac collagen content was observed between the 2 strains. Ejection fraction was slightly decreased in PCPE1-/- male mice, but not in females. Finally, wound healing was not altered in PCPE1-/- mice. PCPE1 deficiency does not trigger any major liabilities and does not affect cardiac collagen content nor its function under basal conditions. Further studies are required to evaluate its role under stressed conditions and determine its suitability as a therapeutic target for heart failure.

S62798, a potent TAFIa inhibitor, accelerates endogenous fibrinolysis in a murine model of pulmonary thromboembolism.

Enhancement of fibrinolysis constitutes a promising approach to treat thrombotic diseases. Venous thrombosis and thromboembolism risks are associated with increased plasma levels of TAFI (Thrombin Activatable Fibrinolysis Inhibitor) as well as its active form TAFIa. A new TAFIa inhibitor, namely S62798 has been identified. Its ability to enhance fibrinolysis was investigated both in vitro and in vivo in a mouse model of pulmonary thromboembolism, as well as its effect on bleeding. S62798 is a highly selective human, mouse and rat TAFIa inhibitor (IC50 = 11; 270; 178 nmol/L, respectively). It accelerates lysis of a human clot in vitro, evaluated by thromboelastometry (EC50 = 27 nmol/L). In a rat tail bleeding model, no effect of S62798 treatment was observed up to 20 mg/kg. Enhancement of endogenous fibrinolysis by S62798 was investigated in a mouse model of Tissue Factor-induced pulmonary thromboembolism. Intravenous administration of S62798 decreased pulmonary fibrin clots with a minimal effective dose of 0.03 mg/kg. Finally, effect of S62798 in combination with heparin was evaluated. When treatment of heparin was done in a curative setting, no effect was observed whereas a significantly decreased pulmonary fibrin deposition was observed in response to S62798 alone or in combination with heparin. This study demonstrates that S62798 is a potent TAFIa inhibitor with minimal risk of bleeding. In vivo, curative S62798 intravenous treatment, alone or associated with heparin, accelerated clot lysis by potentiating endogenous fibrinolysis and thus decreased pulmonary fibrin clots. S62798 is expected to be a therapeutic option for pulmonary embolism patients on top of anticoagulants.