Recent advances in the identification of genes for human hypertension

Use of data mining to determine changes in the gene expression profiles of rat embryos following prenatal exposure to inflammatory stimulants

Numerous clinical epidemiology and laboratory studies have demonstrated a close association between inflammation or immunity and the occurrence of hypertension. Our group has previously shown that upon intraperitoneal injection of lipopolysaccharide (LPS) or zymosan (Zym) into pregnant rats, the offspring of the experimental group exhibited higher blood pressure levels compared with the control group, and these may be associated with the effects of an accumulation of gene expression changes on female rats during pregnancy. The present study used the Affymetrix GeneChip® Rat Genome 230 2.0 Array to examine gene expression profile changes in the embryos of experimental pregnant rats intraperitoneally injected with LPS or Zym vs. the untreated controls. We discovered that genes associated with DNA replication and mRNA processing were significantly upregulated by the stimuli from analysis using GenMAPP. By contrast, genes involved in the calcium regulatory pathway in cardiac myocytes and the signaling pathway in smooth muscle contraction and relaxation were the most downregulated. Results of the microarray analysis showed that immuno-inflammatory stimuli during pregnancy affected the gene expression profiles of the embryos. These changes in gene expression may affect the developmental and metabolic status of the offspring, thereby increasing their susceptibility to hypertension and obesity.

Microsatellites and SNPs linkage analysis in a Sardinian genetic isolate confirms several essential hypertension loci previously identified in different populations

Background

A multiplicity of study designs such as gene candidate analysis, genome wide search (GWS) and, recently, whole genome association studies have been employed for the identification of the genetic components of essential hypertension (EH). Several genome-wide linkage studies of EH and blood pressure-related phenotypes demonstrate that there is no single locus with a major effect while several genomic regions likely to contain EH-susceptibility loci were validated by multiple studies.

Methods

We carried out the clinical assessment of the entire adult population in a Sardinian village (Talana) and we analyzed 16 selected families with 62 hypertensive subjects out of 267 individuals. We carried out a double GWS using a set of 902 uniformly spaced microsatellites and a high-density SNPs map on the same group of families.

Results

Three loci were identified by both microsatellites and SNP scans and the obtained linkage results showed a remarkable degree of similarity. These loci were identified on chromosome 2q24, 11q23.1–25 and 13q14.11–21.33. Further support to these findings is their broad description present in literature associated to EH or related phenotypes. Bioinformatic investigation of these loci shows several potential EH candidate genes, several of whom already associated to blood pressure regulation pathways.

Conclusion

Our search for major susceptibility EH genetic factors evidences that EH in the genetic isolate of Talana is due to the contribution of several genes contained in loci identified and replicated by earlier findings in different human populations.