VEGF-A related SNPs: a cardiovascular context.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Currently, cardiovascular disease risk algorithms play a role in primary prevention. However, this is complicated by a lack of powerfully predictive biomarkers that could be observed in individuals before the onset of overt symptoms. A key potential biomarker for heart disease is the vascular endothelial growth factor (VEGF-A), a molecule that plays a pivotal role in blood vessel formation. This molecule has a complex biological role in the cardiovascular system due to the processes it influences, and its production is impacted by various CVD risk factors. Research in different populations has shown single nucleotide polymorphisms (SNPs) may affect circulating VEGF-A plasma levels, with some variants associated with the development of CVDs, as well as CVD risk factors. This minireview aims to give an overview of the VEGF family, and of the SNPs reported to influence VEGF-A levels, cardiovascular disease, and other risk factors used in CVD risk assessments.

Genetic variation in the renin-angiotensin-aldosterone system is associated with cardiovascular risk factors and early mortality in established coronary heart disease.

This study examined renin-angiotensin-aldosterone (RAAS) system gene variants for associations with cardiovascular risk factors and outcomes in coronary heart disease. Coronary disease patients (n=1186) were genotyped for 21 single-nucleotide polymorphisms (SNPs) within angiotensinogen (AGT), angiotensin-converting enzyme (ACE), angiotensin-II type-1 receptor (AGTR1) and aldosterone synthase (CYP11B2). Associations with all-cause mortality and cardiovascular readmissions were assessed over a median of 3.0 years. The AGT M235T 'T' allele was associated with a younger age of clinical coronary disease onset (P=0.006), and the AGT rs2478545 minor allele was associated with lower circulating natriuretic peptides (P=0.0001-P=0.001) and E/E(1) (P=0.018). Minor alleles of AGT SNPs rs1926723 and rs11122576 were associated with more frequent history of renal disease (P0.04) and type-2 diabetes (P0.02), higher body mass index (P0.02) and greater mortality (P0.007). AGT rs11568054 minor allele carriers had more frequent history of renal disease (P=0.04) and higher plasma creatinine (P=0.033). AGT rs6687360 minor allele carriers exhibited worse survival (P=0.02). ACE rs4267385 was associated with older clinical coronary disease onset (P=0.008) and hypertension (P=0.013) onset, increased plasma creatinine (P=0.01), yet greater mortality (P=0.044). Less history of hypertension was observed with the AGTR1 rs12685977 minor allele (P=0.039). Genetic variation within the RAAS was associated with cardiovascular risk factors and accordingly poorer survival.

Differential expression of a gene homologous to a G-alpha protein gene in neonatal mouse skin during development of hair follicles.

The development of mouse hair follicles depends on the proliferation, differentiation and migration of epithelial matrix cells in the follicle bulb. In particular, induction of the proliferation of epithelial cells is thought to be signalled by the dermal papilla at the base of the bulb. Neonatal mouse skin is useful for studying changes in gene expression during development of the follicles, as the mitotic activity of skin cells changes shortly after birth. Using RNA differential display, a 248-bp message has been identified, which is expressed in the skin, specifically on day 2 and day 3 but not on day 4 after birth. Confirmation of expression of this gene by ribonuclease protection assay showed that strong expression is seen on day 2 and day 3, but weak expression is also shown on day 1, day 4 and day 5. In situ hybridization data revealed that it is mainly localized in the dermal papilla. Analysis of its nucleotide sequence showed 99% identity between nucleotide 2 and 232 of the mouse uncoupled S49 cell mRNA for stimulatory GTP-binding protein (G(S)) alpha subunit, suggesting it is a segment of G(S)alpha. As the G(S)alpha subunit is involved in transducing extracellular signals across the cell, the finding of its expression in the papilla suggests it may be a molecular signal to the induction of epithelial proliferation in the follicle bulb. Evidence of strong expression on day 2, at the time when the mitotic activity of epithelial matrix cells starts to increase, also suggests that the G(S)alpha is a potential candidate for involvement in the initiation of follicle growth.

Single nucleotide polymorphisms in an intron of the ovine calpastatin gene.

Calpastatin is the specific inhibitor of the ubiquitous calcium-dependent proteases mu-calpain and m-calpain. Enzyme assay data from sheep and cattle inversely correlates post-mortem muscle calpastatin levels with ultimate meat tenderness. Genetic markers of meat quality may therefore be found linked to the calpastatin gene (CAST). A three-allele system detected by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) has been observed in the ovine CAST. The three allele amplimers have been fully nucleotide sequenced and their differences in terms of single nucleotide polymorphism (SNPs) in the intron region of the amplimer are reported and compared to a consensus sequence of the orthologous region of the cattle CAST. A PCR-RFLP for more rapid CAST genotyping of all three ovine alleles was also developed.

A delivery system for olfactory stimuli.

This paper describes the design of a new method for controlling and administering olfactory stimuli--namely, the hood system. The hood system involves a stream of vaporized odor (at known concentrations) mixed with odorless air and pumped (at a constant flow rate) into an oxygen therapy hood. It is designed to be used with odorants in solution, such as essential oils, as the olfactory stimulus. The use of oxygen therapy hoods allows for the precise control of a constant concentration of odorized air over time, while allowing subjects to breathe normally. The hood system provides a natural administration of olfactory stimuli and the exact determination of the stimulus concentration. The use of this system will allow experimental conditions to be completely defined and results and replication studies to be accurately interpreted. The hood system is portable, cost effective, and constructed from readily available components. It is proposed that the hood system could be adopted to suit a wide range of olfactory research, particularly that in which the effects of chronic exposure to olfactory stimuli on cognition are examined.

Insulin-like growth factor 1 and hair growth.

Insulin-like growth factor 1 (IGF-1) has been identified as an important growth factor in many biological systems.[1] It shares considerable structural homology with insulin and exerts insulin-like effects on food intake and glucose metabolism. Recently it has been suggested to play a role in regulating cellular proliferation and migration during the development of hair follicles. [2,3] To exert its biological effects, the IGF-1 is required to activate cells by binding to specific cell-surface receptors. The type I IGF receptor (IGF-1R) is the only IGF receptor to have IGF-mediated signaling functions.[1] In circulation, this growth factor mediates endocrine action of growth hormone (GH) on somatic growth and is bound to specific binding proteins (BPs). The latter control IGF transport, efflux from vascular compartments and association with cell surface receptors.[4] In tissues, IGF-1 is produced by mesenchymal type cells and acts in a paracrine and autocrine fashion by binding to the IGF-1R. This binding activates the receptor tyrosine kinase (RTK) that triggers the downstream responses and finally stimulates cell division.[5] IGF-1 may therefore be able to stimulate the proliferation of hair follicle cells through cellular signaling pathways of its receptors. Local infusion of IGF-1 into sheep has been reported to be capable of stimulating protein synthesis in the skin.[6] It may also increase the production of wool keratin. Recently, transgenic mice overexpressing IGF-1 in the skin have been shown to have earlier hair follicle development than controls.[7] In addition, this growth factor plays an important role in many cell types as a survival factor to prevent cell death.[8] This anti-apoptotic function of IGF-1 may be important to the development of follicle cells as follicles undergo a growth cycle where the regressive, catagen phase is apoptosis driven. In this review, the effects of IGF-1 on follicle cell proliferation and differentiation are discussed. In particular, the paracrine versus endocrine action of IGF-1 on hair growth and the targeting of expression of the growth factor to the follicles of transgenic animals will be emphasized. The anti-apoptotic role of IGF-1 in hair follicles is also reviewed. Prospects for future studies on hair and fiber growth by IGF-1 are discussed.

The dam and dcm strains of Escherichia coli--a review.

The construction of a variety of strains deficient in the methylation of adenine and cytosine residues in DNA by the methyltransferases (MTases) Dam and Dcm has allowed the study of the role of these enzymes in the biology of Escherichia coli. Dam methylation has been shown to play a role in coordinating DNA replication initiation, DNA mismatch repair and the regulation of expression of some genes. The regulation of expression of dam has been found to be complex and influenced by five promoters. A role for Dcm methylation in the cell remains elusive and dcm- cells have no obvious phenotype. dam- and dcm- strains have a range of uses in molecular biology and bacterial genetics, including preparation of DNA for restriction by some restriction endonucleases, for transformation into other bacterial species, nucleotide sequencing and site-directed mutagenesis. A variety of assays are available for rapid detection of both the Dam and Dcm phenotypes. A number of restriction systems in E. coli have been described which recognise foreign DNA methylation, but ignore Dam and Dcm methylation. Here, we describe the most commonly used mutant alleles of dam and dcm and the characteristics of a variety of the strains that carry these genes. A description of several plasmids that carry dam gene constructs is also included.

DNA methylation alters the pattern of spontaneous mutation in Escherichia coli cells (mutD) defective in DNA polymerase III proofreading.

We have shown previously that dam mutants of Escherichia coli have a weak mutator phenotype which generates mostly transition mutations in the P22 mnt gene. In contrast, in mutD5 cells, which have a strong mutator phenotype, transversion mutations were the most prevalent. A dam-16 mutD5 strain, defective in both DNA polymerase III associated-proofreading and Dam-directed mismatch repair exhibits a strong mutator phenotype but, surprisingly, its mutation spectrum is similar to that of the dam rather than the mutD parent. The most likely explanation is that Dam-directed mismatch repair in the mutD5 strain corrects most of the potential transition mutations (therefore yielding transversions) in the newly synthesised strand. When the dam-16 allele is present together with mutD5 a reduced efficiency of repair as well as loss of strand discrimination and misdirected repair results in the appearance of transition mutations at high frequency.