Physiol Genomics [journal]
- ESR1 and PGR Polymorphisms Affect Estrogen and Progesterone Receptor Expression in Breast Tumors. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Aug 19.:physiolgenomics.00065.2016.
Hormone receptor positive (HR+) breast cancers express the estrogen (ERα) and/or progesterone (PgR) receptors. Inherited single nucleotide polymorphisms (SNPs) in ESR1, the gene encoding ERα, have been reported to predict tamoxifen effectiveness. We hypothesized that these associations could be attributed to altered tumor gene/protein expression of ESR1/ERα, and that SNPs in the PGR gene predict tumor PGR/PgR expression.Formalin-fixed paraffin-embedded breast cancer tumor specimens were were analyzed for ESR1 and PGR gene transcript expression using the reverse transcription polymerase chain reaction (RT-PCR) based Oncotype DX assay, and for ERα and PgR protein expression using immunohistochemistry (IHC) and an automated quantitative immunofluorescence assay (AQUA). Germline genotypes for SNPs in ESR1 (n=41) and PGR (n=8) were determined using allele specific Taqman assays.One SNP in ESR1 (rs9322336) was significantly associated with ESR1 gene transcript expression (p=0.006) but not ERα protein expression (p>0.05). A PGR SNP (rs518162) was associated with decreased PGR gene transcript expression (p=0.003) and PgR protein expression measured by IHC (p=0.016), but not AQUA (p=0.054). There were modest, but statistically significant correlations between gene and protein expression for ESR1/ERα and PGR/PgR and for protein expression measured by IHC and AQUA (Pearson correlation=0.32-0.64, all p<0.001).Inherited ESR1 and PGR genotypes may affect tumor ESR1/ERα and PGR/PgR expression, respectively, which are moderately correlated. This work supports further research into germline predictors of tumor characteristics and treatment effectiveness, which may someday inform selection of hormonal treatments for patients with HR+ breast cancer.
- Corrigendum. [Journal Article]
- Physiol Genomics 2016 Aug 1; 48(8):650.
- Differential roles of caveolin-1 in ouabain-induced Na+/K+-ATPase cardiac signaling and contractility. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Aug 12.:physiolgenomics.00042.2016.
Binding of ouabain to cardiac Na(+)/K(+)-ATPase initiates cell signaling and causes contractility in cardiomyocytes. It is widely accepted that caveolins, structural proteins of caveolae, have been implicated in signal transduction. It is known that caveolae play a role in Na(+)/K(+)-ATPase functions. Regulation of caveolin-1 in ouabain-mediated cardiac signaling and contractility has never been reported. The aim of this study is to compare ouabain-induced cardiac signaling and contractility in wild-type (WT) and cav-1 knockout (cav-1 KO) mice. In contrast with WT cardiomyocytes, ouabain-induced signaling (activation of phosphoinositide 3-kinase(PI3K) α /Akt and extracellular signal-regulated kinases (ERK) 1/2) and hypertrophic growth were significantly reduced in cav-1 KO cardiomyocytes. Interactions of the Na(+)/K(+)-ATPase α1 subunit with caveolin-3 and the Na(+)/K(+)-ATPase α1 subunit with PI3K α were also decreased in cav-1 KO cardiomyocytes. The results from cav-1 KO mouse embryonic fibroblasts also proved that cav-1 significantly attenuated ouabain-induced ERK1/2 activation without alteration in protein and cholesterol distribution in caveolae/lipid rafts. Intriguingly, the effect of ouabain induced positive inotropy in vivo (via transient infusion of ouabain (0.48 nmol/g b.w.)) was not attenuated in cav-1 KO mice. Furthermore, ouabain (1-100μM) induced dose- dependent contractility in isolated working hearts from WT and cav-1 KO mice. The effects of ouabain on contractility between WT and cav-1 KO mice were not significantly different. These results demonstrated differential roles of cav-1 in the regulation of ouabain signaling and contractility. Signaling by ouabain, in contrast to contractility, may be a redundant property of Na+/K+-ATPase.
- RNA Expression Profile of Calcified Bicuspid, Tricuspid and Normal Human Aortic Valves by RNA Sequencing. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Aug 5.:physiolgenomics.00041.2016.
The molecular mechanisms leading to premature development of aortic valve stenosis (AS) in individuals with a bicuspid aortic valve are unknown. The objective of this study was to identify genes differentially expressed between calcified bicuspid aortic valves (BAVc) and tricuspid valves with (TAVc) and without (TAVn) AS using RNA sequencing (RNA-Seq). Ten human BAVc and nine TAVc were collected from male who underwent primary aortic valve replacement. Eight TAVn were obtained from male who underwent heart transplantation. mRNA levels were measured by RNA-Seq and compared between valve groups. Two genes were up-regulated and none were down-regulated in BAVc compared to TAVc, suggesting a similar gene expression response to AS in individuals with bicuspid and tricuspid valves. There were 462 genes up-regulated and 282 down-regulated in BAVc compared to TAVn. In TAVc compared to TAVn, 329 genes were up- and 170 were down-regulated. A total of 273 up-regulated and 147 down-regulated genes were concordantly altered between BAVc vs. TAVn and TAVc vs. TAVn, which represent 56% and 84% of significant genes in the first and second comparisons, respectively. This indicates that extra genes and pathways were altered in BAVc. Shared pathways between calcified (BAVc and TAVc) and normal (TAVn) aortic valves were also more extensively altered in BAVc. The top pathway enriched for genes differentially expressed in calcified compared to normal valves was fibrosis, which support the remodeling process as a therapeutic target. These findings are relevant to understand the molecular basis of AS in patients with bicuspid and tricuspid valves.
- Circadian variation of the pancreatic islet transcriptome. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Aug 5.:physiolgenomics.00019.2016.
Pancreatic islet failure is a characteristic feature of impaired glucose control in diabetes mellitus. Circadian control of islet function is essential for maintaining proper glucose homeostasis. Circadian variations in transcriptional pathways have been described in diverse cell types and shown to be critical for optimization of cellular function in vivo. In the current study, we utilized Short Time Series Expression Miner (STEM) analysis to identify diurnally-expressed transcripts and biological pathways from mouse islets isolated at 4 h intervals throughout the 24 h LD cycle. STEM analysis identified 19 distinct chronological model profiles, and genes belonging to each profile were subsequently annotated to significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathways. Several transcriptional pathways essential for proper islet function (e.g. Insulin secretion, Oxidative phosphorylation), cell survival (e.g. Insulin Signaling, Apoptosis) and cell proliferation (DNA replication, Homologous recombination) demonstrated significant time-dependent variations. Notably, KEGG pathway analysis revealed "Protein processing in Endoplasmic Reticulum - mmu04141" as one of the most enriched time-dependent pathways in islets. This study provides unique data set on time-dependent diurnal profiles of islet gene expression and biological pathways, and suggests that diurnal variation of the islet transcriptome is an important feature of islet homeostasis, which should be taken into consideration for optimal experimental design and interpretation of future islet studies.
- Angiotensin type 1a receptors in the paraventricular nucleus of the hypothalamus control cardiovascular reactivity and anxiety-like behavior in male mice. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Jul 28.:physiolgenomics.00029.2016.
This study tested the hypothesis that deletion of angiotensin type 1a receptors (AT(1a)) from the paraventricular nucleus of hypothalamus (PVN) attenuates anxiety-like behavior, hypothalamic-pituitary-adrenal (HPA) axis activity, and cardiovascular reactivity. We used the Cre/LoxP system to generate male mice with AT(1a) specifically deleted from the PVN. Deletion of the AT(1a)from the PVN reduced anxiety-like behavior as indicated by increased time spent in the open arms of the elevated plus maze. In contrast, PVN AT(1a) deletion had no effect on HPA axis activation subsequent to an acute restraint challenge but did reduce hypothalamic mRNA expression for corticotropin-releasing hormone (CRH). To determine whether PVN AT(1a) deletion inhibits cardiovascular reactivity, we measured systolic blood pressure, heart rate, and heart rate variability (HRV) using telemetry and found that PVN AT(1a) deletion attenuated restraint-induced elevations in systolic blood pressure and elicited changes in HRV indicative of reduced sympathetic nervous activity. Consistent with the decreased HRV, PVN AT(1a) deletion also decreased adrenal weight, suggestive of decreased adrenal sympathetic outflow. Interestingly, the altered stress responsivity of mice with AT(1a) deleted from the PVN was associated with decreased hypothalamic microglia and pro-inflammatory cytokine expression. Collectively, these results suggest that deletion of AT(1a) from the PVN attenuates anxiety, CRH gene transcription, and cardiovascular reactivity and reduced brain inflammation may contribute to these effects.
- The properties of skeletal muscle in the teleost Sternopygus macrurus are unaffected by short-term electrical inactivity. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Jul 22.:physiolgenomics.00068.2016.
Skeletal muscle is distinguished from other tissues on the basis of its shape, biochemistry, and physiological function. Based on mammalian studies, fiber size, fiber types, and gene expression profiles are regulated, in part, by the electrical activity exerted by the nervous system. To address whether similar adaptations to changes in electrical activity in skeletal muscle occur in teleosts, we studied these phenotypic properties of ventral muscle in the electric fish Sternopygus macrurus following two and five days of electrical inactivation by spinal transection. Our data show that morphological and biochemical properties of skeletal muscle remained largely unchanged after these treatments. Specifically, the distribution of type I and type II muscle fibers, and the cross-sectional areas of these fiber types observed in control fish remained unaltered after each spinal transection survival period. This response to electrical inactivation was generally reflected at the transcript level using real-time PCR and RNA-seq data by showing little effect on the transcript levels of genes associated with muscle fiber type differentiation and plasticity, the sarcomere complex, and pathways implicated in the regulation of muscle fiber size. Data from this first study characterizing the neural influence on muscle mass and sarcomere gene expression in a teleost is discussed in the context of comparative studies in mammalian model systems and vertebrate species from different lineages.
- Early steatohepatitis in hyperlipidemic mice with endothelial-specific gain of TRPC3 function precedes changes in aortic atherosclerosis. [Journal Article]
- Physiol Genomics 2016 Aug 1; 48(8):644-9.
Nonalcoholic fatty liver disease (NAFLD) and its more advanced form nonalcoholic steatohepatitis (NASH) are the most common chronic liver diseases in developed countries. Moreover, NAFLD and NASH are considerable risk factors for atherosclerosis, the most frequent vascular pathology in these and other metabolic diseases. Despite this strong connection, current knowledge of the relationship between NAFLD/NASH and atherosclerosis is scarce. Recently, we studied hyperlipidemic Apoe knockout mice with endothelial-specific gain of transient receptor potential canonical 3 channel function (TgESTRPC3/ApoeKO) and found that these animals had increased burden of advanced aortic atherosclerosis (16 wk on high-fat diet) compared with nontransgenic ApoeKO littermate controls (non-Tg/ApoeKO), whereas early lesions (10 wk on high-fat diet) were not different. Here, we report that at the early stage when differences in aortic atherosclerosis are not yet manifest, the livers of TgESTRPC3/ApoeKO mice show steatosis, fibrosis, and altered hepatic enzymes compared with non-Tg/ApoeKO animals. Because differences in liver pathology were noticeable long before differences in atherosclerosis were evident, our studies suggest that TRPC3-related endothelial mechanisms that promote steatohepatitis may also contribute to atherosclerosis progression. In vitro, downregulation of TRPC3 in liver sinusoid endothelial cells reduces their susceptibility to endoplasmic reticulum stress-induced apoptosis, suggesting that a proapoptotic effect of TRPC3 may add to other fibrogenic factors in vivo. These novel findings show a positive association between augmented expression of an endothelial TRPC channel, development of early steatohepatitis, and atherosclerotic burden in a hyperlipidemic mouse model of NAFLD fed conventional Western-type diet.
- Deep transcriptomic profiling reveals the similarity between endothelial cells cultured under static and oscillatory shear stress conditions. [JOURNAL ARTICLE]
- Physiol Genomics 2016 Jul 22.:physiolgenomics.00025.2016.
Atherosclerosis is a multifactorial disease that preferentially develops in specific regions in the arterial tree. This characteristic is mainly attributed to the unique pattern of hemodynamic shear stress in vivo. High laminar shear stress (LS) found in straight lumen exerts athero-protective effects. Low or oscillatory shear stress (OS) present in regions of lesser curvature predisposes arterial intima to atherosclerosis. Shear stress-regulated endothelial function plays an important role in the process of atherosclerosis. Here, we profiled the whole transcriptome of primary human coronary arterial endothelial cellss (HCAECs) under different shear stress conditions using RNA sequencing. Among 16, 313 well-expressed genes we detected, 8,177 were differentially expressed in OS vs. LS conditions and 9,369 in ST vs. LS conditions. Notably, only 1,618 were differentially expressed in OS vs. ST conditions. Hierarchical clustering of ECs demonstrated a strong similarity between ECs under OS and ST conditions at transcriptome level. Subsequent pairwise heat mapping and principal component analysis further weighed on the similarity. At individual gene level, expressional analysis of representative well-known genes as well as novel genes showed a comparable amount at mRNA and protein levels in ECs under ST and OS conditions. In conclusion, the present work compared the whole transcriptome of HCAECs under different shear stress conditions. We found that cultured ECs are significantly different from those under LS condition. Given the revealed high similarities of endothelial transcriptome under OS and ST conditions, it may be helpful to understand the underlying mechanisms of OS-induced endothelial dysfunction from static cultured endothelial studies.
- Transcriptome meta-analysis of three follicular compartments and its correlation with ovarian follicle maturity and oocyte developmental competence in cows. [Journal Article]
- Physiol Genomics 2016 Aug 1; 48(8):633-43.
Oocyte developmental competence in superstimulated cows is dependent in part on the duration of the FSH coasting. FSH coasting refers to superstimulation with FSH (2 days of endogenous FSH following follicle ablation and 3 days of FSH injections) followed by no FSH for a specific duration. The optimal duration varies among individuals. FSH coasting appears to modulate the transcriptome of different follicular compartments, which cooperate as a single functional unit. However, the integrative effects of FSH coasting on different follicular compartments remain ambiguous. Meta-analysis of three independent transcriptome studies, each focused on a single cell type (granulosa, cumulus, and oocyte) during FSH coasting, allowed the identification of 12 gene clusters with similar time-course expression patterns in all three compartments. Network analysis identified HNF4A (involved in metabolic functions) and ELAVL1 (an RNA-binding protein) as hub genes regulated respectively upward and downward in the clusters enriched at the optimal coasting time, and APP (involved in mitochondrial functions) and COPS5 (a member of the COP9 signalosome) as hub genes regulated respectively upwards and downwards in the clusters enriched progressively throughout the coasting period. We confirmed the effects on HNF4A downstream targets (TTR, PPL) and other hub genes (ELAVL1, APP, MYC, and PGR) in 30 cows with RT-quantitative PCR. The correlation of hub gene expression levels with FSH coasting indicated that a combination of these genes could predict oocyte competence with 83% sensitivity, suggesting that they are potential biomarkers of follicle differentiation. These findings could be used to optimize FSH coasting on an individual basis.