The Trp64Arg polymorphism of the beta3-adrenergic receptor is not increased in women with preeclampsia

β3-Adrenoceptor agonists for overactive bladder syndrome: Role of translational pharmacology in a repositioning clinical drug development project

β3-Adrenoceptor agonists were originally considered as a promising drug class for the treatment of obesity and/or type 2 diabetes. When these development efforts failed, they were repositioned for the treatment of the overactive bladder syndrome. Based on the example of the β3-adrenoceptor agonist mirabegron, but also taking into consideration evidence obtained with ritobegron and solabegron, we discuss challenges facing a translational pharmacology program accompanying clinical drug development for a first-in-class molecule. Challenges included generic ones such as ligand selectivity, species differences and drug target gene polymorphisms. Challenges that are more specific included changing concepts of the underlying pathophysiology of the target condition while clinical development was under way; moreover, a paucity of public domain tools for the study of the drug target and aspects of receptor agonists as drugs had to be addressed. Nonetheless, a successful first-in-class launch was accomplished. Looking back at this translational pharmacology program, we conclude that a specifically tailored and highly flexible approach is required. However, several of the lessons learned may also be applicable to translational pharmacology programs in other indications.

The Human Obesity Gene Map: The 2004 Update

This paper presents the eleventh update of the human obesity gene map, which incorporates published results up to the end of October 2004. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTLs) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2004, 173 human obesity cases due to single-gene mutations in 10 different genes have been reported, and 49 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 166 genes which, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 221. The number of human obesity QTLs derived from genome scans continues to grow, and we have now 204 QTLs for obesity-related phenotypes from 50 genome-wide scans. A total of 38 genomic regions harbor QTLs replicated among two to four studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably with 358 findings of positive associations with 113 candidate genes. Among them, 18 genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, >600 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful publications and genomic and other relevant sites can be found at http://obesitygene.pbrc.edu.

Haplotype-based case-control study of estrogen receptor alpha (ESR1) gene and pregnancy-induced hypertension

Hypotheses about pregnancy-induced hypertension (PIH) have been proposed to explain the vascular damage that characterizes this disease. Reports indicate that estrogens and estrogen receptors play important physiological roles in cardiovascular diseases. There have been studies examining the association between coronary artery disease and the estrogen receptor alpha (ESR1) gene. The aim of the present work was to assess the association between PIH and single-nucleotide polymorphisms (SNPs) in the human ESR1 gene, by conducting a haplotype-based case-control study. Based on a database search at the web site of the National Center of Biotechnology Information, we chose five SNPs in the human ESR1 gene, and performed an association study using 95 PIH patients and 200 age-matched non-PIH subjects. The frequency of rs2881766 genotypes and alleles differed significantly between the two groups. There was no significant difference in overall distribution of genotypes or alleles of the other four SNPs. The T allele of rs2881766 was significantly more prevalent in the PIH group than in the non-PIH group. Haplotype-based case-control analysis revealed that there was a significant difference in overall distribution of the combinations rs2881766-rs1643821-rs988328 and rs2881766-rs1643821 between the PIH group and the non-PIH group (all or body mass index [BMI]-matched). One susceptibility haplotype for PIH and two resistance haplotypes for PIH were revealed by comparison between the PIH group and the non-PIH (BMI-matched) control group. In conclusion, the T allele of rs2881766 could be a useful genetic marker of PIH. The G-A-T haplotype of rs2881766-rs1643821-rs988328 and the G-A haplotype of rs2881766-rs1643821 appear to be resistance markers of PIH.

Searching for genetic clues to the causes of pre-eclampsia

Pre-eclampsia and its related syndromes are significant causes of maternal and fetal death, but much remains unclear about the underlying disease mechanisms. Epidemiological research has consistently demonstrated a familial predisposition to pre-eclampsia, which has encouraged genetic research in this area. The goal is the discovery of susceptibility genes which will inform understanding of the pathophysiology of pre-eclampsia, and may prove to be targets for therapeutic or preventative strategies. This review examines the application of molecular technologies to the search for genetic clues in pre-eclampsia and emphasizes the importance of integrative approaches. The results of recent genome-wide linkage studies have been particularly encouraging, identifying a number of loci which merit closer examination. Candidate gene studies have proved less fruitful, generating conflicting and inconclusive results. Possible explanations and remedies for this deficiency are discussed with a view to stimulating closer collaboration between researchers in this field.

Stimulation of the ADRB3 adrenergic receptor induces relaxation of human placental arteries: influence of preeclampsia

Preeclampsia, which complicates 3-8% of pregnancies, is one of the leading causes of neonatal morbidity and mortality. Its pathophysiology remains unclear. The aim of the present study was to investigate the presence and the role of beta2- and beta2-adrenergic receptors (ADRB2 and ADRB3, respectively) in human placental arteries and to assess the influence of preeclampsia on ADRB responsiveness. SR 59119A, salbutamol, and isoproterenol (ADRB3, ADRB2, and nonselective ADRB agonists, respectively) induced a concentration-dependent relaxation of placental artery rings obtained from women with uncomplicated or preeclamptic pregnancies. SR 59119A-induced relaxation was unaffected by the blockade of ADRB1 and ADRB2 by 0.1 microM propranolol but was significantly decreased by the blockade of ADRB1, ADRB2, and ADRB3 by 10 microM propranolol. Both SR 59119A and salbutamol were associated with a significant increase in cAMP production that was significantly inhibited by pretreatment with 0.1 microM propranolol only for salbutamol. SR 59119A-induced relaxation (E(max) = 28% +/- 5% vs. 45% +/- 4%, respectively) and cAMP production (2.7 +/- 0.5 vs. 4.9 +/- 0.4 pmol/mg of protein, respectively; P < 0.01) were decreased in arteries obtained from preeclamptic compared to normotensive women. Both ADRB2 and ADRB3 transcripts were expressed at the same level between arteries from normotensive and preeclamptic women. Western blot analysis, however, revealed a decreased expression of the ADRB3 immunoreactive protein in arteries from preeclamptic compared to normotensive women. We suggest the presence of functional ADRB2 and ADRB3 in human placental arteries. Even if preeclampsia is associated with an impairment of the ADRB3 responsiveness, ADRB3 agonists may have future pharmaceutical implications in the management of pregnancy-related disorders.

Association study using single nucleotide polymorphisms in the estrogen receptor beta (ESR2) gene for preeclampsia

The pathophysiology of preeclampsia (PE) remains uncertain despite many research efforts. Actual hypotheses seek to explain the vascular damage that characterizes the disease. Recently, it was reported that the mouse disrupted estrogen receptor beta (ESR2) gene was associated with abnormal vascular function and hypertension. Moreover, some investigators have reported that subjects with a family history of hypertension have a statistically significant increased risk for PE. Thus, it is thought that the pathophysiology of PE overlaps that for hypertension. The aim of the present study was to investigate the relationships between single nucleotide polymorphisms (SNPs) in the human ESR2 gene and PE in Japanese subjects, and to assess the involvement of a family history of hypertension in these relationships. Based on a database search on the web site of the National Center of Biotechnology Information (NCBI), we chose four SNPs in the human ESR2 gene, and performed an association study in 84 PE patients and 160 age-matched non-PE subjects. The overall distribution in each SNP did not differ significantly between the two groups. However, after dividing the groups into subjects with and without a family history of hypertension, the allelic distribution of one of the SNPs (rs928554) revealed a positive association. Thus, a possible mutation linked to a SNP may prescribe a genetic predisposition for patients with a family history of hypertension in PE.