Tumor development in Dahl S and Dahl R female rats.

<p>The tumor latency (A) and tumor burden index (B) for Dahl S (black bars) and Dahl R (gray bars) female rats are presented. ^*,<i>P</i><0.05 unpaired <i>t</i>-test.</p

QTLs for mammary tumorigenesis susceptibility in F2 (Dahl S x R)-intercross female rats.

<p>QTL, quantitative trait locus; Mts, mammary tumorigenesis susceptibility; Chr, chromosome; %, the amount in % of total trait variance that would be explained by a QTL at these loci; Mbp, mega-base pair; LOD, logarithm of the odds score derived from the likelihood ratio statistic using a factor of 4.6; ↑, S-allele increases trait; ↓, S-allele decreases trait. Significance determined from 2000 permutations on data set: LOD 2.48 significant (S); LOD 1.30 suggestive (Sug).</p>a<p>Overlapping QTL detected in previous study: <i>Mcs</i> = mammary cancer susceptibility.</p>b<p>candidate genes in rat-human syntenic regions; <i>Prlh</i>, prolactin hormone; <i>Anpep</i>, alanyl (membrane) aminopeptidase; <i>Blm</i>, Bloom syndrome homolog; <i>Ece1</i>, endothelin-converting enzyme-1; <i>Smad2</i>, SMAD family member 2.</p

QTLs for mammary tumorigenesis susceptibility (Mts) in F2 [Dahl S x R]-intercross female rats.

<p>Chromosomes with significant and suggestive QTLs were analyzed by interval mapping with bootstrap resampling method to estimate a confidence interval (QTXb19 Map Manager): Panel A, chromosome 9 (<i>Mts-1</i>); B, chromosome 1 (<i>Mts-2</i>); C, chromosome 5 (<i>Mts-3</i>); D, chromosome 18 (<i>Mts-4</i>). Yellow histograms represent the bootstrap-based confidence intervals for the detected QTLs. Orientation of chromosomes: left → right starting from lowest Mbp. Horizontal green lines mark LOD values for significance of linkage, from top to bottom: significant LOD ≥2.48; suggestive LOD ≥1.30; LOD (black line); regression coefficient for additive effect (red line).</p

Genes associated with cancer within mammary tumorigenesis susceptibility QTLs detected in F2 (Dahl S x R)-intercross female rats.

<p>Table legend: Genes and gene locations on rat chromosomes 1, 5, 9 and 18 regions as per RGD. nt, nucleotide; ref, reference.</p

Hematoxylin and Eosin stained digital photomicrographs of representative breast tumor phenotypes in the F2-cohort of radiation-induced breast tumors.

<p>A, Adenoductal carcinoma phenotype, B, fibroadenoma. →, representative duct morphology in each section; *, hyaline (pink) fibrous tissue markedly increased in fibroadenoma.</p

Congenic analysis of <i>Nav-5</i> QTL region on chromosome 17.

<p>On the left of the figure is shown the relevant region of the physical map of rat chromosome 17. Values in parenthesis next to the marker names denote physical locations in base pairs. The mapped <i>Nav-5</i> QTL region of approximately 9.64 Mbp is noted (to the right). Congenic strains are shown as solid bars (representing the Dahl R introgressed fragments) flanked by open bars (representing the putative regions of recombination).</p

Aortic and Carotid Arterial Stiffness and Epigenetic Regulator Gene Expression Changes Precede Blood Pressure Rise in Stroke-Prone Dahl Salt-Sensitive Hypertensive Rats

<div><p>Multiple clinical studies show that arterial stiffness, measured as pulse wave velocity (PWV), precedes hypertension and is an independent predictor of hypertension end organ diseases including stroke, cardiovascular disease and chronic kidney disease. Risk factor studies for arterial stiffness implicate age, hypertension and sodium. However, causal mechanisms linking risk factor to arterial stiffness remain to be elucidated. Here, we studied the causal relationship of arterial stiffness and hypertension in the Na-induced, stroke-prone Dahl salt-sensitive (S) hypertensive rat model, and analyzed putative molecular mechanisms. Stroke-prone and non-stroke-prone male and female rats were studied at 3- and 6-weeks of age for arterial stiffness (PWV, strain), blood pressure, vessel wall histology, and gene expression changes. Studies showed that increased left carotid and aortic arterial stiffness preceded hypertension, pulse pressure widening, and structural wall changes at the 6-week time-point. Instead, differential gene induction was detected implicating molecular-functional changes in extracellular matrix (ECM) structural constituents, modifiers, cell adhesion, and matricellular proteins, as well as in endothelial function, apoptosis balance, and epigenetic regulators. Immunostaining testing histone modifiers Ep300, HDAC3, and PRMT5 levels confirmed carotid artery-upregulation in all three layers: endothelial, smooth muscle and adventitial cells. Our study recapitulates observations in humans that given salt-sensitivity, increased Na-intake induced arterial stiffness before hypertension, increased pulse pressure, and structural vessel wall changes. Differential gene expression changes associated with arterial stiffness suggest a molecular mechanism linking sodium to full-vessel wall response affecting gene-networks involved in vascular ECM structure-function, apoptosis balance, and epigenetic regulation.</p></div

Representative images for pulse wave velocity (PWV) and strain measurements.

<p><b>A</b>, Measurement of distance between two anatomical points along the abdominal aorta: proximal point after superior mesenteric artery branchpoint; distal point at site of crossing of renal vein. <b>B</b>, Representative Doppler frequency at distal point site: where renal vein crosses aorta. Integrated software for cursor-based measurement of distance given in mm (in <b>A</b>) and time in milliseconds from the peak of the ECG-R wave to the foot of the velocity upstroke (in <b>B</b>). <b>C</b>, Representative M-mode image for strain measurement in left carotid artery.</p

Development of high blood pressure in stoke-prone (SP) and non stroke-prone (nSP) Dahl S female rats.

<p>Systolic (<b>A</b>), diastolic (<b>B</b>), mean arterial (<b>C</b>) and pulse (<b>D</b>) pressures in SP Dahl S (n = 4, closed circles) and nSP Dahl S (n = 6, open circles) female rats. Blood pressure parameters were collected at 6 and 16 weeks of age. Values are means ± s.e.m. ***<i>P</i><0.001, (Two Way ANOVA followed by Holm-Sidak Test for multiple comparisons).</p

RT-PCR array profiling in aortas and left common carotid artery (LCCA) of stoke-prone (SP) and non stroke-prone (nSP) Dahl S female rats at six weeks of age.

<p>Pathway-specific RT2-qPCR array comparative analysis of gene expression changes in LCCA (red bars) and aorta (black bars) at 6-weeks of age representing ratio of SP/nSP RNA levels. A) Extracellular matrix (ECM) and matricellular (MC) protein pathway-specific significant gene changes. B) Endothelial Cell (EC) Biology pathway-specific gene changes. C and D) Epigenetic regulator pathway-specific gene changes. SP (0.4% NaCl); nSP (0.23% NaCl) from gestation. Gene expression changes shown are limited to ≥ 2-fold change and p<0.01 in either vessel. Only statistically significant differences are presented (P<0.05, Two Way ANOVA followed by Holm-Sidak Test for multiple comparisons; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107888#pone.0107888.s001" target="_blank">Tables S1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107888#pone.0107888.s006" target="_blank">S6</a>).</p