title: Mechanisms of cardioprotection resulting from Brown Norway chromosome 16 substitution in the salt-sensitive Dahl rat.
abstract: The SS-16(BN)/Mcwi consomic rat was produced by the introgression of chromosome 16 from the Brown Norway (BN/NHsdMcwi) rat onto the genetic background of the Dahl salt-sensitive (SS/Mcwi) rat by marker-assisted breeding. We have previously shown that the normotensive SS-16(BN)/Mcwi consomic strain is better protected from developing left ventricular dysfunction and fibrosis with aging than the hypertensive SS/Mcwi parental strain; however, the mechanism of this protection was not clear since the SS-16(BN)/Mcwi had both lowered blood pressure and an altered genetic background compared with SS/Mcwi. Microarray analysis of SS-16(BN)/Mcwi and SS/Mcwi left ventricle tissue and subsequent protein pathway analysis were used to identify alterations in gene expression in signaling pathways involved with the observed cardioprotection on the SS background. The SS-16(BN)/Mcwi rats exhibited much higher mRNA levels of expression of transcription factor JunD, a gene found on chromosome 16. Additionally, high levels of differential gene expression were found in pathways involved with angiogenesis, oxidative stress, and growth factor signaling. We tested the physiological relevance of these pathways by experimentally determining the responsiveness of neonatal cardiomyocytes to factors from identified pathways and found that cells isolated from SS-16(BN)/Mcwi rats had a greater growth response to epidermal growth factor and endothelin-1 than those from parental SS/Mcwi. We also demonstrate that the SS-16(BN)/Mcwi is better protected from developing fibrosis with surgically elevated afterload than other normotensive strains, indicating that gene-gene interactions resulting from BN chromosomal substitution confer specific cardioprotection. When combined with our previous findings, these data suggest that that SS-16(BN)/Mcwi may have an increased angiogenic potential and better protection from oxidative stress than the parental SS/Mcwi strain. Additionally, the early transient idiopathic left ventricular hypertrophy in the SS-16(BN)/Mcwi may be related to altered myocyte sensitivity to growth factors.
authors: Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. agreene@mcw.edu
authors: Alison J
authors: AJ
authors: Kriegel
authors: Daniela N
authors: DN
authors: Didier
authors: Peigang
authors: P
authors: Li
authors: Jozef
authors: J
authors: Lazar
authors: Andrew S
authors: AS
authors: Greene
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002316:Cardiotonic Agents / Q000378:metabolism*; D033481:Chromosomes, Mammalian / Q000235:genetics*; D019332:Endothelin-1 / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D006984:Hypertrophy; D008297:Male; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D011914:Rats, Inbred BN; D020303:Rats, Inbred Dahl; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002316:Cardiotonic Agents; D019332:Endothelin-1; D042461:Vascular Endothelial Growth Factor A; D004815:Epidermal Growth Factor