Apolipoprotein B is a new target of the GDNF/RET and ET-3/EDNRB signalling pathways.

BACKGROUND: GDNF/RET and Endothelin-3 (ET-3)/EDNRB regulate survival, differentiation, migration, and proliferation of neural crest-derived cells. Although several RET and EDNRB signalling mediators have been characterized, most of the genes targeted by these two pathways are still largely unknown. We focused our study on apolipoprotein B (APOB) as a novel target gene of the RET and EDNRB pathways, based on previous data obtained using a Caenorhabditis elegans strain mutant for the homologue of mammalian ECE1. METHODS: Molecular and cellular studies of Apob were performed in the murine Neuro2a cells, an in vitro model for studying neural crest-derived cell development, along with a mouse knock-in for the Hirschsprung-associated mutation Ret(C620R). Silencing for Apob and Ret has been performed via shRNA. KEY RESULTS: GDNF/RET and ET-3/EDNRB cooperated in inducing neuronal differentiation resulting in Apob activation in Neuro2a cell line. Apob expression was downregulated in mouse embryos homozygous for the Ret(C620R) mutation and presenting a severe Hirschsprung phenotype. Ret silencing prevented Apob expression increase. MAPK P38 kinase activation evoked Apob expression via GDNF/RET signalling in Neuro2a cells. A p53-dependent repressor element in Apob promoter resulted in a reduced Apob expression. Silencing of Apob reduced HuD protein expression. CONCLUSIONS & INFERENCES: Apob is a novel downstream target of the RET/EDNRB pathways with a role in neuronal survival and maintenance, as indicated by its effect on HuD expression. Our data provide a conceptual framework to investigate and establish the role of APOB gene in severe gut dysmotility.

Refinement of the SPG9 locus on chromosome 10q23.3-24.2 and exclusion of candidate genes.

BACKGROUND AND PURPOSE: The hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders, characterized by a progressive spasticity of the lower limbs. So far, 33 different loci (SPGs) have been mapped and the 15 genes responsible have been identified. We mapped a locus responsible for a form of spastic paraplegia, complicated by bilateral cataracts, gastroesophageal reflux with persisting vomiting and amyotrophy to chromosome 10q23.3-q24.2, in an Italian family. The critical region was in a 12 cm chromosomal interval between markers D10S564 and D10S603 (SPG9, MIM601162). In the same region, two other forms of HSP have been recently mapped: SPG27 and SPG33. In the latter case, the gene responsible has been identified. MATERIALS AND METHODS: To better characterize this region, we genotyped individuals from SPG9-linked families using additional markers and reduced the candidate region to a 4.8 Mb, excluding several genes by positional cloning. RESULTS: The refined SPG9 locus is positioned completely within SPG27 and does not include the SPG33 gene. DISCUSSION: Fifty-two transcripts are present in the refined critical region and 25 strong candidates have been excluded as disease causing genes by direct sequencing. Six of them were also excluded as responsible for SPG27.

Phthalazine PDE4 inhibitors. Part 2: the synthesis and biological evaluation of 6-methoxy-1,4-disubstituted derivatives.

This communication describes the synthesis and in vitro evaluation of a novel and potent series of phosphodiesterase type IV (PDE4) inhibitors. The compounds described present substituents in position 4 of the phthalazine ring to replace the commonly observed cyclopentyloxy moiety of rolipram analogues. Preliminary evidences of reduced side effects compared to standards and improved pharmacokinetic properties for selected derivatives are also reported.

The synthesis and biological evaluation of a novel series of phthalazine PDE4 inhibitors I.

This communication describes the synthesis and in vitro evaluation of a novel and potent series of phosphodiesterase type IV (PDE4) inhibitors. The compounds described represent conformationally constrained analogues of RP 73401, Piclamilast. Preliminary evidences of reduced side effects of II compared to standards are also reported.

ONO-5046 (Ono Pharmaceutical).

ONO-5046 (sivelestat) is a competitive inhibitor of human neutrophil elastase from Ono Pharmaceutical, which is awaiting FDA approval for the treatment of pulmonary fibrosis and idiopathic interstitial pneumonia [349488]. An NDA was filed in Japan in September 1998 [299667]. It is in phase II trials for the treatment of acute circulatory failure [171678]. It is also being investigated as a potential treatment of arthritis [230100]. In animal models of asthma, sivelestat decreased the level of hemorrhage and protein extravasation into the bronchoalveolar lavage fluid after the administration of a 40 mg/kg injection of phorbol myristate acetate [188186]. The compound also inhibited the growth of human lung cancer cell lines in SCID mice [269736]. Sivelestat inhibits gastric lesion formation in rats subjected to water immersion restraint stress. Low oral bioavailability in vivo is due to extensive hepatic first-pass metabolism. Endotoxin-induced lung injury in rabbits was attenuated by pretreatment with sivelestat [276401]. In 1996, analysts at Yamaichi estimated sivelestat would be launched in Japan between 1998/9 and peak annual sales would be less than 5 billion yen [216018].

The role of dopaminergic agonists in congestive heart failure.

Congestive Heart Failure is a clinical syndrome characterised by myocardial dysfunction and sympathetic activation. Plasma norepinephrine (NE) levels have been related to the poorest survival. Large-scale clinical trials have proved the clinical benefits of Angiotensin Converting Enzyme inhibitors in reducing the risk of death and hospitalisation. However, mortality remains high in the treated group underlining the need to explore new therapeutic approaches. Specific activation of peripheral dopamine receptors exerts profound hemodynamic effects and neurohormonal control such as peripheral and renal vasodilation, diuresis and natriuresis and inhibition of NE release. Z1046, a mixed D1/D2-like agonist, reduces peripheral and renal vascular resistance increasing renal blood flow. In anaesthetised dogs the compound strongly reduces plasma NE without increasing plasma renin activity and plasma aldosterone. The inhibition of NE could be the basis of Z1046 potent cardioprotective effect observed in a dog model of myocardial ischemia and reperfusion, in which the severity of ventricular arrhythmias was markedly reduced, resulting in higher survival. These findings suggest that chronic oral treatment with specific dopaminergic agonists is able to alleviate the hemodynamic burden on the myocardium, and to suppress the sympatho-adrenal activity.