Francoise Jeanne Gellibert

Inhibition of TGF-β signaling by an ALK5 inhibitor protects rats from dimethylnitrosamine-induced liver fibrosis

1 Chronic liver disease is characterized by an exacerbated accumulation of matrix, causing progressive fibrosis, which may lead to cirrhosis. Transforming growth factor beta (TGF‐β), a well‐known profibrotic cytokine, transduces its signal through the ALK5 ser/thr kinase receptor, and increases transcription of different genes including PAI‐1 and collagens. The identification of GW6604 (2‐phenyl‐4‐(3‐pyridin‐2‐yl‐1H‐pyrazol‐4‐yl)pyridine), an ALK5 inhibitor, allowed us to evaluate the therapeutic potential of inhibiting TGF‐β pathway in different models of liver disease. 2 A cellular assay was used to identify GW6604 as a TGF‐β signaling pathway inhibitor. This ALK5 inhibitor was then tested in a model of liver hepatectomy in TGF‐β‐overexpressing transgenic mice, in an acute model of liver disease and in a chronic model of dimethylnitrosamine (DMN)‐induced liver fibrosis. 3 In vitro, GW6604 inhibited autophosphorylation of ALK5 with an IC50 of 140 nM and in a cellular assay inhibited TGF‐β‐induced transcription of PAI‐1 (IC50: 500 nM). In vivo, GW6604 (40 mg kg−1 p.o.) increased liver regeneration in TGF‐β‐overexpressing mice, which had undergone partial hepatectomy. In an acute model of liver disease, GW6604 reduced by 80% the expression of collagen IA1. In a chronic model of DMN‐induced fibrosis where DMN was administered for 6 weeks and GW6604 dosed for the last 3 weeks (80 mg kg−1 p.o., b.i.d.), mortality was prevented and DMN‐induced elevations of mRNA encoding for collagen IA1, IA2, III, TIMP‐1 and TGF‐β were reduced by 50–75%. Inhibition of matrix genes overexpression was accompanied by reduced matrix deposition and reduction in liver function deterioration, as assessed by bilirubin and liver enzyme levels. 4 Our results suggest that inhibition of ALK5 could be an attractive new approach to treatment of liver fibrotic diseases by both preventing matrix deposition and promoting hepatocyte regeneration.

Identification of a novel series of BET family bromodomain inhibitors: binding mode and profile of I-BET151 (GSK1210151A).

A novel series of quinoline isoxazole BET family bromodomain inhibitors are discussed. Crystallography is used to illustrate binding modes and rationalize their SAR. One member, I-BET151 (GSK1210151A), shows good oral bioavailability in both the rat and minipig as well as demonstrating efficient suppression of bacterial induced inflammation and sepsis in a murine in vivo endotoxaemia model.

From ApoA1 upregulation to BET family bromodomain inhibition: discovery of I-BET151.

The discovery, synthesis and biological evaluation of a novel series of 7-isoxazoloquinolines is described. Several analogs are shown to increase ApoA1 expression within the nanomolar range in the human hepatic cell line HepG2.

Design of novel quinazoline derivatives and related analogues as potent and selective ALK5 inhibitors

Starting from quinazoline 3a, we designed potent and selective ALK5 inhibitors over p38MAP kinase from a rational drug design approach based on co-crystal structures in the human ALK5 kinase domain. The quinazoline 3d exhibited also in vivo activity in an acute rat model of DMN-induced liver fibrosis when administered orally at 5mg/kg (bid).

Inhibition of ALK5 Signaling Induces Physeal Dysplasia in Rats

TGF-|β|, and its type 1 (ALK5) receptor, are critical to the pathogenesis of fibrosis. In toxicologic studies of 4 or more days in 10-week-old Sprague–Dawley rats, using an ALK5 inhibitor (GW788388), expansion of hypertrophic and proliferation zones of femoral physes were noted. Subphyseal hyperostosis, chondrocyte hypertrophy/hyperplasia, and increased matrix were present. Physeal zones were laser microdissected from ALK5 inhibitor-treated and control rats sacrificed after 3 days of treatment. Transcripts for TGF-|β|1, TGF-|β|2, ALK5, IHH, VEGF, BMP-7, IGF-1, bFGF, and PTHrP were amplified by real-time PCR. IGF and IHH increased in all physis zones with treatment, but were most prominent in prehypertrophic zones. TGF-|β|2, bFGF and BMP7 expression increased in proliferative, pre- and hypertrophic zones. PTHrP expression was elevated in proliferative zones but decreased in hypertrophic zones. VEGF expression was increased after treatment in pre- and hypertrophic zones. ALK5 expression was elevated in prehypertrophic zones. Zymography demonstrated gelatinolytic activity was reduced after treatment. Apoptotic markers (TUNEL and caspase-3) were decreased in hypertrophic zones. Proliferation assessed by Topoisomerase II and Ki67 was increased in multiple zones. Movat stains demonstrated that proteoglycan deposition was altered. Physeal changes occurred at doses well above those resulting in fibrosis. Interactions of factors is important in producing the physeal dysplasia phenotype.

(Chloro-phenylthio-methylene)dimethylammonium chloride (CPMA) an efficient reagent for selective chlorination and bromination of primary alcohols

Abstract (Chloro-phenylthio-methylene)dimethylammonium chloride reacts smoothly with a variety of alcohols, to afford the corresponding alkyl chloride in good yields. In the presence of tetrabuthylammonium bromide the corresponding bromide is obtained. Selective halogenation of primary hydroxyl groups in the presence of an unprotected secondary one is described. The mild reaction conditions involved are compatible with the major alcohol protecting groups as well as with acid sensitive functions like epoxides.

Naphthyridines as Novel Bet Family Bromodomain Inhibitors.

Bromodomains (BRDs) are small protein domains found in a variety of proteins that recognize and bind to acetylated histone tails. This binding affects chromatin structure and facilitates the localisation of transcriptional complexes to specific genes, thereby regulating epigenetically controlled processes including gene transcription and mRNA elongation. Inhibitors of the bromodomain and extra‐terminal (BET) proteins BRD2–4 and T, which prevent bromodomain binding to acetyl‐modified histone tails, have shown therapeutic promise in several diseases. We report here the discovery of 1,5‐naphthyridine derivatives as potent inhibitors of the BET bromodomain family with good cell activity and oral pharmacokinetic parameters. X‐ray crystal structures of naphthyridine isomers have been solved and quantum mechanical calculations have been used to explain the higher affinity of the 1,5‐isomer over the others. The best compounds were progressed in a mouse model of inflammation and exhibited dose‐dependent anti‐inflammatory pharmacology.

Comparison of Soluble Guanylate Cyclase Stimulators and Activators in Models of Cardiovascular Disease Associated with Oxidative Stress

Soluble guanylate cyclase (sGC), the primary mediator of nitric oxide (NO) bioactivity, exists as reduced (NO-sensitive) and oxidized (NO-insensitive) forms. We tested the hypothesis that the cardiovascular protective effects of NO-insensitive sGC activation would be potentiated under conditions of oxidative stress compared to those of NO-sensitive sGC stimulation. The cardiovascular effects of the NO-insensitive sGC activator GSK2181236A [a low, non-depressor dose, and a high dose which lowered mean arterial pressure (MAP) by 5–10 mmHg] and those of equi-efficacious doses of the NO-sensitive sGC stimulator BAY 60-4552 were assessed in (1) Sprague Dawley rats during coronary artery ischemia/reperfusion (I/R) and (2) spontaneously hypertensive stroke prone rats (SHR-SP) on a high salt/fat diet (HSFD). In I/R, neither compound reduced infarct size 24 h after reperfusion. In SHR-SP, HSFD increased MAP, urine output, microalbuminuria, and mortality, caused left ventricular hypertrophy with preserved ejection fraction, and impaired endothelium-dependent vasorelaxation. The low dose of BAY 60-4552, but not that of GSK2181236A, decreased urine output, and improved survival. Conversely, the low dose of GSK2181236A, but not that of BAY 60-4552, attenuated the development of cardiac hypertrophy. The high doses of both compounds similarly attenuated cardiac hypertrophy and improved survival. In addition to these effects, the high dose of BAY 60-4552 reduced urine output and microalbuminuria and attenuated the increase in MAP to a greater extent than did GSK2181236A. Neither compound improved endothelium-dependent vasorelaxation. In SHR-SP isolated aorta, the vasodilatory responses to the NO-dependent compounds carbachol and sodium nitroprusside were attenuated by HSFD. In contrast, the vasodilatory responses to both GSK2181236A and BAY 60-4552 were unaltered by HSFD, indicating that reduced NO-bioavailability and not changes in the oxidative state of sGC is responsible for the vascular dysfunction. In summary, GSK2181236A and BAY 60-4552 provide partial benefit against hypertension-induced end-organ damage. The differential beneficial effects observed between these compounds could reflect tissue-specific changes in the oxidative state of sGC and might help direct the clinical development of these novel classes of therapeutic agents.

(Chloro-phenylthio-methylene)dimethylammonium chloride (CPMA): a new coupling reagent for the formation of ester and amide bond

CPMA is an efficient agent for the formation of esters and amides from carboxylic acids. It is compatible with substrates that are sensitive to basic conditions or oxophilic reagents. The reaction proceeds without racemization of chirally labile carboxylic acids. All these advantages make CPMA a valuable adjunct to the existing arsenal of coupling reagents.