Fibroblast growth factor binding protein 1 gene (FGFBP1) and hypertension d from pathway analysis to renal glomerulus
- Authors: Tomaszewski, Maciej , Charchar, Fadi , Barnes, Timothy , Maric, Christine , Zukowska-Szczechowska, Ewa , Samani, Nilesh
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at British Cardiovascular Society Annual Conference 2010, Manchester Central, Manchester, UK : 7th-9th June 2010
- Full Text: false
- Description: Essential hypertension is a complex, multifactorial disease with a strong genetic component. Fibroblast growth factor 1 gene (FGF1) is one of the most relevant candidates having been associated not only with familial susceptibility to hypertension but also with up-regulation within the glomerulus of the human hypertensive kidney/Circulation 2007;116:1915e24/. We have hypothesised that systematic analysis of genes interacting with FGF1 may uncover novel variants underlying essential hypertension. Seventy-nine common (minor allele frequency$0.1) tagging (r2$0.8) and functional single nucleotide polymorphisms (SNPs) spanning eight critical components of the FGF (fibroblast growth factor) pathway (FGF2, FGFR1, FGFR2, FGFR3, FGFR4, FGFBP1, FIBP, SPRY1) were genotyped by MALDI-TOF mass spectrometry in 629 subjects from 207 Polish hypertensive families (Silesian Hypertension Study d SHS). 83.5% of genotyped SNPs that passed quality control filters provided 92.9% genetic coverage of FGF pathway loci. Family-based analysis in SHS revealed that alleles of three SNPs (rs2956724, rs2245964 and rs16892645) in two loci (FGFR1 and FGFBP1) were transmitted to hypertensive offspring more frequently than expected by chance. However, only one association survived correction for multiple testing e major allele of rs16892645 in FGFBP1 was over-transmitted from heterozygous parents to hypertensive offspring more frequently than expected by chance (p¼0.0048, false discovery rate<0.25). The association between rs16892645 and hypertension was replicated in an independent cohort of 807 Polish subjects from Silesian Cardiovascular Study d each major allele copy of rs16892645 increased the odds of hypertension approximately by 1.5 (odds ratio: 1.5; 95% CI: 1.1 to to 2.2, p¼0.04). Association between FGFBP1 and hypertension was also apparent at the protein expression level d compared with normotensive patients, hypertensives from Silesian Renal Tissue Bank showed approximately 1.4-fold higher renal abundance of FGFBP1 in Western blotting (p¼0.001). Immunohistochemical analysis revealed that hypertension-related up-regulation of FGFBP1 was exclusive to renal glomeruli. These data show that FGFBP1da gene that encodes a carrier protein for FGF1 d is associated with human hypertension. We also reveal that up-regulation of FGFBP1 maps to the same histological compartment where FGF1 was shown to be most abundant (renal glomeruli). Our study also proves that systematic genetic analysis of signalling pathways is a strategy with a potential to identify novel molecular mechanisms underlying blood pressure elevation.
Genetic architecture of ambulatory blood pressure in the general population insights from cardiovascular gene-centric array
- Authors: Tomaszewski, Maciej , Debiec, Radoslaw , Braund, Peter , Nelson, Christopher , Hardwick, Robert , Christofidou, Paraskevi , Denniff, Matthew , Codd, Veryan , Rafelt, Suzanne , van der Harst, Pim , Waterworth, Dawn , Song, Kijoung , Vollenweider, Peter , Waeber, Gerard , Zukowska-Szczechowska, Ewa , Burton, Paul , Mooser, Vincent , Charchar, Fadi , Thompson, John , Tobin, Martin , Samani, Nilesh
- Date: 2010
- Type: Text , Journal article
- Relation: Hypertension Vol. 56, no. 6 (2010), p. 1069-U146
- Full Text: false
- Reviewed:
- Description: Genetic determinants of blood pressure are poorly defined. We undertook a large-scale, gene-centric analysis to identify loci and pathways associated with ambulatory systolic and diastolic blood pressure. We measured 24-hour ambulatory blood pressure in 2020 individuals from 520 white European nuclear families (the Genetic Regulation of Arterial Pressure of Humans in the Community Study) and genotyped their DNA using the Illumina HumanCVD BeadChip array, which contains approximate to 50 000 single nucleotide polymorphisms in >2000 cardiovascular candidate loci. We found a strong association between rs13306560 polymorphism in the promoter region of MTHFR and CLCN6 and mean 24-hour diastolic blood pressure; each minor allele copy of rs13306560 was associated with 2.6 mm Hg lower mean 24-hour diastolic blood pressure (P=1.2 x 10(-8)). rs13306560 was also associated with clinic diastolic blood pressure in a combined analysis of 8129 subjects from the Genetic Regulation of Arterial Pressure of Humans in the Community Study, the CoLaus Study, and the Silesian Cardiovascular Study (P=5.4 x 10(-6)). Additional analysis of associations between variants in gene ontology-defined pathways and mean 24-hour blood pressure in the Genetic Regulation of Arterial Pressure of Humans in the Community Study showed that cell survival control signaling cascades could play a role in blood pressure regulation. There was also a significant overrepresentation of rare variants (minor allele frequency: <0.05) among polymorphisms showing at least nominal association with mean 24-hour blood pressure indicating that a considerable proportion of its heritability may be explained by uncommon alleles. Through a large-scale gene-centric analysis of ambulatory blood pressure, we identified an association of a novel variant at the MTHFR/CLNC6 locus with diastolic blood pressure and provided new insights into the genetic architecture of blood pressure.
Whole genome survey of copy number variation in the spontaneously hypertensive rat relationship to quantitative trait loci, gene expression, and blood pressure
- Authors: Charchar, Fadi , Kaiser, Michael , Bingham, Andrew , Fotinatos, Nina , Ahmady, Fahima , Tomaszewski, Maciej , Samani, Nilesh
- Date: 2010
- Type: Text , Journal article
- Relation: Hypertension Vol. 55, no. 5 (2010), p. 1231-1238
- Full Text: false
- Reviewed:
- Description: Copy number variation has emerged recently as an important genetic mechanism leading to phenotypic heterogeneity. The aim of our study was to determine whether copy number variants (CNVs) exist between the spontaneously hypertensive rat (SHR) and its control strain, the Wistar-Kyoto rat, whether these map to quantitative trait loci in the rat and whether CNVs associate with gene expression or blood pressure differences between the 2 strains. We performed a comparative genomic hybridization assay between SHR and Wistar-Kyoto strains using a whole-genome array. In total, 16 CNVs were identified and validated (6 because of a relative loss of copy number in the SHR and 10 because of a relative gain). CNVs were present on rat autosomes 1, 3, 4, 6, 7, 10, 14, and 17 and varied in size from 10.0 kb to 1.6 Mb. Most of these CNVs mapped to chromosomal regions within previously identified quantitative trait loci, including those for blood pressure in the SHR. Transcriptomic experiment! s confirmed differences in the renal expression of several genes (including Ms4a6a, Ndr3, Egln1, Cd36, Sema3a, Ugt2b, and Idi21) located in some of the CNVs between STIR and Wistar-Kyoto rats. In F-2 animals derived from an SHRXWistar-Kyoto cross, we also found a significant increase in blood pressure associated with an increase in copy number in the Egln1 gene. Our findings suggest that, CNVs may play a role in the susceptibility to hypertension and related trails in the SHR. (Hypertension. 2010;55:1231-1238.)
Genetics of human essential hypertension - from single mutations to quantitative trait loci
- Authors: Tomaszewski, Maciej , Brain, Nick , Charchar, Fadi , Dominiczak, Anna
- Date: 2006
- Type: Text , Book chapter
- Relation: Molecular mechanisms in hypertension Chapter p. 241-247
- Full Text: false
- Description: 2003007414
Ethnicity and sympathetic tone: predictors of the blood-pressure response to renal denervation?
- Authors: Wang, Yutang
- Date: 2014
- Type: Text , Letter
- Relation: Nature Reviews Cardiology Vol. 11, no. 638 (2014), p.
- Relation: http://purl.org/au-research/grants/nhmrc/1062671
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Urotensin-II system in genetic control of blood pressure and renal function
- Authors: Debiec, Radoslaw , Christofidou, Paraskevi , Denniff, Matthew , Bloomer, Lisa , Bogdanski, Pawel , Wojnar, Lukasz , Musialik, Katarzyna , Charchar, Fadi , Thompson, John , Waterworth, Dawn , Song, Kijoung , Vollenweider, Peter , Waeber, Gerard , Zukowska-Szczechowska, Ewa , Samani, Nilesh , Lambert, David , Tomaszewski, Maciej
- Date: 2013
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 8, no. 12 (2013), p.
- Full Text:
- Reviewed:
- Description: Urotensin-II controls ion/water homeostasis in fish and vascular tone in rodents. We hypothesised that common genetic variants in urotensin-II pathway genes are associated with human blood pressure or renal function. We performed familybased analysis of association between blood pressure, glomerular filtration and genes of the urotensin-II pathway (urotensin-II, urotensin-II related peptide, urotensin-II receptor) saturated with 28 tagging single nucleotide polymorphisms in 2024 individuals from 520 families; followed by an independent replication in 420 families and 7545 unrelated subjects. The expression studies of the urotensin-II pathway were carried out in 97 human kidneys. Phylogenetic evolutionary analysis was conducted in 17 vertebrate species. One single nucleotide polymorphism (rs531485 in urotensin-II gene) was associated with adjusted estimated glomerular filtration rate in the discovery cohort (p = 0.0005). It showed no association with estimated glomerular filtration rate in the combined replication resource of 8724 subjects from 6 populations. Expression of urotensin-II and its receptor showed strong linear correlation (r = 0.86, p< 0.0001). There was no difference in renal expression of urotensin-II system between hypertensive and normotensive subjects. Evolutionary analysis revealed accumulation of mutations in urotensin-II since the divergence of primates and weaker conservation of urotensin-II receptor in primates than in lower vertebrates. Our data suggest that urotensin-II system genes are unlikely to play a major role in genetic control of human blood pressure or renal function. The signatures of evolutionary forces acting on urotensin-II system indicate that it may have evolved towards loss of function since the divergence of primates. © 2013 Debiec et al.
Birth weight and adult health in historical perspective: Evidence from a New Zealand cohort, 1907-1922
- Authors: Roberts, Evan , Wood, Pamela
- Date: 2014
- Type: Text , Journal article
- Relation: Social Science and Medicine Vol. 107, no. (2014), p. 154-161
- Full Text: false
- Reviewed:
- Description: We provide new historical evidence on the developmental origins of health and disease in a cohort of boys born between 1907 and 1922 in Wellington, New Zealand. Using a dataset of 1523 birth records that include birth weight and length we find 852 (58%) of the adult cohort in World War II records measuring stature, body mass and blood pressure. On average, the boys weighed 3.5kg at birth, similar to Australian and American babies of the era, and nearly identical to full-term New Zealand babies in the 1990s. Using OLS regression models we estimate the effect of birth weight on adult stature and systolic blood pressure. We find an increase in birth weight of 1kg is associated with an increase in stature of 2.6cm (95% confidence interval [CI] 1.6cm-3.6cm), and a decrease in systolic blood pressure of 2.1mm/Hg (95% CI - 5.00 to 0.67). This is the earliest cohort by fifty years for whom the fetal origins hypothesis has been examined in early adulthood. Our estimates of the effect of birth weight on blood pressure are towards the upper end of the range of published estimates in modern cohorts. © 2014 Elsevier Ltd.
Is isolated systolic hypertension an indication for renal denervation?
- Authors: Wang, Yutang
- Date: 2014
- Type: Text , Commentary
- Relation: Frontiers in Physiology Vol. 5, no. 505 (2014), p. 1-2
- Relation: http://purl.org/au-research/grants/nhmrc/1062671
- Full Text:
- Reviewed:
- Description: Ewen et al. recently reported in the journal Hypertension that they investigated, for the first time, the effect of renal denerva tion on blood pressure in 63 patients with isolated systolic hypertension (Ewen et al., 2014). The authors concluded that renal denervation reduced office and ambula- tory blood pressure in patients with iso- lated systolic hypertension (Ewen et al., 2014). However, this conclusion may not be drawn, as renal denervation may not decrease ambulatory blood pressure in these patients. The potential risk of renal denervation may overweigh its benefit in patients with isolated systolic hypertension. Therefore, adjusted drug treatment may be recommended to these patients before renal denervation.
Neurogenic hypertension : Revelations from genome-wide gene expression profiling
- Authors: Marques, Francine , Morris, Brian
- Date: 2012
- Type: Text , Journal article
- Relation: Current Hypertension Reports Vol. 14, no. 6 (2012), p. 485-491
- Full Text: false
- Reviewed:
- Description: There is now good evidence for a role of the sympathetic nervous system in the etiology of essential hypertension in humans. Although genetic variation is expected to underlie the elevated sympathetic outflow in this complex polygenic condition, only limited information has emerged from classic molecular genetic studies. Recently, progress has been made in understanding neurogenic aspects by determination of global alterations in gene expression in key brain regions of animal models of neurogenic hypertension. Such genome-wide expression studies in the hypothalamus and brainstem support roles for factors such as neuronal nitric oxide synthase, inflammation and reactive oxygen species. A role for non-coding RNAs such as microRNAs, and epigenetic alterations await exploration. Ongoing novel approaches should provide a better understanding of the processes responsible for the increased sympathetic outflow in animal models, as well as essential hypertension in humans. Such information may lead to better therapies for neurogenic hypertension in humans. © Springer Science+Business Media, LLC 2012.
- Description: 2003010573
Daily kiwifruit consumption did not improve blood pressure and markers of cardiovascular function in men with hypercholesterolemia
- Authors: Gammon, Cheryl , Kruger, Rozanne , Brown, Stephen , Conlon, Cathryn , von Hurst, Pamela , Stonehouse, Welma
- Type: Text , Journal article
- Relation: Nutrition Research Vol. 34, no. (2014), p.235-240
- Full Text: false
- Reviewed:
- Description: Increasing fruit and vegetable consumption is a key lifestyle modification in the prevention and treatment of hypertension. Kiwifruit has previously been shown to have favorable effects on blood pressure (BP), likely through inhibiting angiotensin I-converting enzyme activity. We hypothesized that the replacement of 2 fruit servings in a healthy diet with 2 green kiwifruit a day would significantly improve BP and other markers of cardiovascular function, including heart rate, stroke volume, cardiac output, and total peripheral resistance, in a group of hypercholesterolemic men. Using a controlled cross-over study design, 85 subjects completed a 4-week healthy diet run-in period before randomization to one of two 4-week intervention sequences in which they either consumed 2 green kiwifruit a day plus a healthy diet (intervention) or consumed a healthy diet alone (control). Blood pressure and other measures of cardiovascular function (using a Finometer MIDI [Finapres Medical Systems B.V, Amsterdam, The Netherlands] and standard oscillometric device) and anthropometric measurements were taken before and at the end of the treatment periods. A physical activity questionnaire was completed during the last visit. Subjects were found to be predominantly normotensive (43.5%) or prehypertensive (50.6%) and quite physically active (>30 minutes of moderate to vigorous physical activity/day in >80% subjects). No significant differences were seen for BP or any of the other markers, including heart rate, stroke volume, cardiac output, and total peripheral resistance. In conclusion, in this hypercholesterolemic, nonhypertensive group, no beneficial effects on BP or other markers of cardiovascular function were seen when consuming 2 kiwifruit a day against the background of a healthy diet.
Signatures of miR-181a on the renal transcriptome and blood pressure
- Authors: Marques, Francine , Romaine, Simon , Denniff, Matthew , Eales, James , Dormer, John , Garrelds, Ingrid , Wojnar, Lukasz , Musialik, Katarzyna , Duda-Raszewska, Barbara , Kiszka, Bartlomiej , Duda, Magdalena , Morris, Brian , Samani, Nilesh , Jan Danser, Jan , Bogdanski, Pawel , Zukowska-Szczechowska, Ewa , Charchar, Fadi , Tomaszewski, Maciej
- Date: 2015
- Type: Text , Journal article
- Relation: Molecular Medicine Vol. 21, no. (2015), p. 739-748
- Full Text: false
- Reviewed:
- Description: MicroRNA-181a binds to the 3’ untranslated region of messenger RNA (mRNA) for renin, a rate-limiting enzyme of the renin-angiotensin system. Our objective was to determine whether this molecular interaction translates into a clinically meaningful effect on blood pressure and whether circulating miR-181a is a measurable proxy of blood pressure. In 200 human kidneys from the TRANScriptome of renaL humAn TissuE (TRANSLATE) study, renal miR-181a was the sole negative predictor of renin mRNA and a strong correlate of circulating miR-181a. Elevated miR-181a levels correlated positively with systolic and diastolic blood pressure in TRANSLATE, and this association was independent of circulating renin. The association between serum miR-181a and systolic blood pressure was replicated in 199 subjects from the Genetic Regulation of Arterial Pressure of Humans In the Community (GRAPHIC) study. Renal immunohistochemistry and in situ hybridization showed that colocalization of miR-181a and renin was most prominent in collecting ducts where renin is not released into the systemic circulation. Analysis of 69 human kidneys characterized by RNA sequencing revealed that miR-181a was associated with downregulation of four mitochondrial pathways and upregulation of 41 signaling cascades of adaptive immunity and inflammation. We conclude that renal miR-181a has pleiotropic effects on pathways relevant to blood pressure regulation and that circulating levels of miR-181a are both a measurable proxy of renal miR-181a expression and a novel biochemical correlate of blood pressure.
Singlet molecular oxygen regulates vascular tone and blood pressure in inflammation
- Authors: Stanley, Christopher , Maghzal, Ghassan , Ayer, Anita , Talib, Jihan , Giltrap, Andrew , Shengule, Sudhir , Wolhuter, Kathryn , Wang, Yutang , Chadha, Preet , Suarna, Cacang , Prysyazhna, Oleksandra , Scotcher, Jenna , Dunn, Louise , Prado, Fernanda , Nguyen, Nghi , Odiba, Jephthah , Baell, Johathan , Stasch, Johannes-Peter , Yamamoto, Yorihiro , Di Mascio, Paolo , Eaton, Philip , Payne, Richard , Stocker, Roland
- Date: 2019
- Type: Text , Journal article , Letter
- Relation: Nature Vol. 566, no. 7745 (2019), p. 548-552
- Full Text:
- Reviewed:
- Description: Singlet molecular oxygen (O-1(2)) has well-established roles in photosynthetic plants, bacteria and fungi(1-3), but not in mammals. Chemically generated O-1(2) oxidizes the amino acid tryptophan to precursors of a key metabolite called N-formylkynurenine(4), whereas enzymatic oxidation of tryptophan to N-formylkynurenine is catalysed by a family of dioxygenases, including indoleamine 2,3-dioxygenase 1(5). Under inflammatory conditions, this haem-containing enzyme is expressed in arterial endothelial cells, where it contributes to the regulation of blood pressure(6). However, whether indoleamine 2,3-dioxygenase 1 forms O-1(2) and whether this contributes to blood pressure control have remained unknown. Here we show that arterial indoleamine 2,3-dioxygenase 1 regulates blood pressure via formation of O-1(2). We observed that in the presence of hydrogen peroxide, the enzyme generates O-1(2) and that this is associated with the stereoselective oxidation of L-tryptophan to a tricyclic hydroperoxide via a previously unrecognized oxidative activation of the dioxygenase activity. The tryptophan-derived hydroperoxide acts in vivo as a signalling molecule, inducing arterial relaxation and decreasing blood pressure; this activity is dependent on Cys42 of protein kinase G1 alpha. Our findings demonstrate a pathophysiological role for O-1(2) in mammals through formation of an amino acid-derived hydroperoxide that regulates vascular tone and blood pressure under inflammatory conditions.
Measurement of absolute copy number variation reveals association with essential hypertension
- Authors: Marques, Francine , Prestes, Priscilla , Pinheiro, Leonardo , Scurrah, Katrina , Emslie, Kerry , Tomaszewski, Maciej , Harrap, Stephen , Charchar, Fadi
- Date: 2014
- Type: Text , Journal article
- Relation: BMC Medical Genomics Vol. 7, no. (2014), p. 1-8
- Full Text:
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- Description: Background: The role of copy number variation (CNV) has been poorly explored in essential hypertension in part due to technical difficulties in accurately assessing absolute numbers of DNA copies. Droplet digital PCR (ddPCR) provides a powerful new approach to CNV quantitation. The aim of our study was to investigate whether CNVs located in regions previously associated with blood pressure (BP) variation in genome-wide association studies (GWAS) were associated with essential hypertension by the use of ddPCR. Methods: Using a "power of extreme" approach, we quantified nucleic acids using ddPCR in white subjects from the Victorian Family Heart Study with extremely high (n = 96) and low (n = 92) SBP, providing power equivalent to 1714 subjects selected at random. Results: A deletion of the CNVs esv27061 and esv2757747 on chromosome 1p13.2 was significantly more prevalent in extreme high BP subjects after adjustment for age, body mass index and sex (12.6% vs. 2.2%; P = 0.013). Conclusions: Our data suggests that CNVs within regions identified in previous GWAS may play a role in human essential hypertension.
Renal Mechanisms of Association between Fibroblast Growth Factor 1 and Blood Pressure
- Authors: Tomaszewski, Maciej , Eales, James , Denniff, Matthew , Myers, Stephen , Chew, Guatsiew , Nelson, Christopher , Christofidou, Paraskevi , Desai, Aishwarya , Büsst, Cara , Wojnar, Lukasz , Musialik, Katarzyna , Jozwiak, Jacek , Debiec, Radoslaw , Dominiczak, Anna , Navis, Gerjan , van Gilst, Wiek , van der Harst, Pim , Samani, Nilesh , Harrap, Stephen , Bogdanski, Pawel , Zukowska-Szczechowska, Ewa , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of the American Society of Nephrology Vol. 26, no. 12 (2015), p. 3151-3160
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: The fibroblast growth factor 1 (FGF1) gene is expressed primarily in the kidney and may contribute to hypertension. However, the biologic mechanisms underlying the association between FGF1 and BP regulation remain unknown. We report that the major allele of FGF1 single nucleotide polymorphism rs152524 was associated in a dose-dependent manner with systolic BP (P=9.65 x10(-5)) and diastolic BP (P=7.61 x10(-3)) in a meta-analysis of 14,364 individuals and with renal expression of FGF1 mRNA in 126 human kidneys (P=9.0x10(-3)). Next-generation RNA sequencing revealed that upregulated renal expression of FGF1 or of each of the three FGF1 mRNA isoforms individually was associated with higher BP. FGF1-stratified coexpression analysis in two separate collections of human kidneys identified 126 FGF1 partner mRNAs, of which 71 and 63 showed at least nominal association with systolic and diastolic BP, respectively. Of those mRNAs, seven mRNAs in five genes (MME, PTPRO, REN, SLC12A3, and WNK1) had strong prior annotation to BP or hypertension. MME, which encodes an enzyme that degrades circulating natriuretic peptides, showed the strongest differential coexpression with FGF1 between hypertensive and normotensive kidneys. Furthermore, higher level of renal FGF1 expression was associated with lower circulating levels of atrial and brain natriuretic peptides. These findings indicate that FGF1 expression in the kidney is at least under partial genetic control and that renal expression of several FGF1 partner genes involved in the natriuretic peptide catabolism pathway, reninangiotensin cascade, and sodium handling network may explain the association between FGF1 and BP.
Epigenetic modifications in essential hypertension
- Authors: Wise, Ingrid
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background: Hypertension (HTN) is a complex, multifactorial, quantitative trait under polygenic control that affects more than one billion people globally. Despite advances in our understanding of the pathophysiology of HTN and the implementation of more effective treatment and prevention strategies, HTN remains one of the world’s great public health problems. The accepted inference from genome-wide association studies (GWAS) is that the genetic code lays the foundation for transcriptomic changes and in turn physiological change. On the other side of the coin, environmental factors (smoking, diet, chemical exposure) can in turn affect DNA itself in genes relevant to blood pressure (BP). Variation in epigenetic forms of modification may thus explain additional phenotypic variation in BP and provide new clues to the physiological processes influencing its regulation. DNA methylation is one of these epigenetic mechanisms responsible for changes to gene expression, activated by interaction with environmental triggers. DNA methylation is a reversible epigenetic modifier of specific dinucleotide sites called CpGs, which consists of a transfer of a methyl group derived from S-adenosyl-L-methionine to position five of a cytosine ring, forming 5mC. Pathophysiologically, the kidney is known as the key organ of BP regulation and one of the most important contributors to HTN. According to the hypothesis put forward by Guyton, over 40 years ago, the control of BP in the steady-state and longer-term is critically dependent on renal mechanisms. In fact, almost all monogenic forms of HTN are driven by rare mutations in genes involved in salt handling in the distal nephron. It is therefore crucial to understand kidney DNA methylation changes that may drive gene expression in kidney and lead to HTN. Hypothesis: The central hypothesis underpinning this PhD thesis is that alterations in kidney specific DNA methylation plays a fundamental role in modulating gene expression changes involved in the regulation of BP and pathophysiology of EH. Aims: This PhD thesis focuses on characterising the role of DNA methylation in the hypertensive kidney using array and RNA-sequencing methods. Three major aims are addressed: • Aim 1: To characterise blood and kidney global DNA methylation dynamics and its functional role in the hypertensive population (Chapter 3). • Aim 2: To determine the role of genome-wide, loci specific DNA methylation in the hypertensive human kidney (Chapter 4). • Aim 3: To understand the relationship between DNA methylation and differential expression of genes associated with BP and HTN in the human kidney (Chapter 5). Results: In Aim 1 global DNA methylation changes were characterised in peripheral blood leukocyte and kidney DNA of the hypertensive (HT) population using he ELISA method. We found no association between HTN diagnosis and global methylation percentage in either peripheral blood leukocytes or kidney DNA. However, a negative correlation was found between global methylation and diastolic blood pressure (DBP), yet this relationship was not evident after adjustment for the effect of antihypertensive medication. Furthermore, we investigated the sensitivity of ELISA-based global methylation detection by calculating the percentage of global methylation in kidney using array based methods; the results were similar, demonstrating no association between HTN diagnosis and median kidney methylation
- Description: Doctor of Philosophy
MicroRNAs in essential hypertension and blood pressure regulation
- Authors: Marques, Francine , Charchar, Fadi
- Date: 2015
- Type: Text , Book chapter
- Relation: Advances in Experimental Medicine and Biology p. 215-235
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text: false
- Reviewed:
- Description: Unravelling the complete genetic predisposition to high blood pressure (BP) has proven to be challenging. This puzzle and the fact that coding regions of the genome account for less than 2 % of the entire human DNA support the hypothesis that mechanisms besides coding genes are likely to contribute to BP regulation. Non-coding RNAs, especially microRNAs, are emerging as key players of transcription regulation in both health and disease states. They control basic functions in virtually all cell types relevant to the cardiovascular system and, thus, a direct involvement with BP regulation is highly probable. Here we review the literature about microRNAs associated with regulation of BP and hypertension, highlighting investigations, methodology and difficulties arising in the field. These molecules are being studied for exploitation in diagnostics, prognostics and therapeutics in many diseases. There have been some studies that examined biological fl uid microRNAs as biomarkers for hypertension, but most remain inconclusive due to the small sample sizes and differences in methodological standardisation. Fewer studies have analysed tissue microRNA levels in vascular smooth muscle cells and the kidney. Others focused on the interaction between single nucleotide polymorphisms and microRNA binding sites. Studies in animals have shown that angiotensin II, high- salt diet and exercise change microRNA levels in hypertension. Treatment of spontaneously hypertensive rats with a miR-22 inhibitor and treatment of hypertensive Schlager BPH/2J mice with a miR-181a mimic decreased their BP. This supports the use of microRNAs as therapeutic targets in hypertension, and future studies should test the use of other microRNAs found in human association studies. In conclusion, there is a clear need of increased pace of human, animal and functional studies to help us understand the multifaceted roles of microRNAs as critical regulators of the development and physiology of BP. © Springer International Publishing Switzerland 2015. Funding Details: APP1052659, NHMRC, National Heart Foundation of Australia Funding Details: PF12M6785, National Heart Foundation of Australia
High intensity interval training (HIIT) improves resting blood pressure, metabolic (MET) capacity and heart rate reserve without compromising resting myocardial function in sedentary aging men
- Authors: Grace, Fergal , Herbert, Peter , Elliott, Adrian , Beaumont, Alexander , Richards, Jo , Sculthorpe, Nicholas
- Date: 2017
- Type: Text , Journal article
- Relation: Experimental Gerontology Vol.109, no. (2018), p.75-81
- Full Text:
- Reviewed:
- Description: Background This study examined a programme of pre-conditioning exercise with subsequent high intensity interval training (HIIT) on blood pressure, echocardiography, cardiac strain mechanics and maximal metabolic (MET) capacity in sedentary (SED) aging men compared with age matched masters athletes (LEX). Methods Using a STROBE compliant observational design, 39 aging male participants (SED; n = 22, aged 62.7 ± 5.2 yrs) (LEX; n = 17, aged = 61.1 ± 5.4 yrs) were recruited to a study that necessitated three distinct assessment phases; enrolment (Phase A), following pre-conditioning exercise in SED (Phase B), then following 6 weeks of HIIT performed once every five days by both groups before reassessment (Phase C). Hemodynamic, echocardiographic and cardiac strain mechanics were obtained at rest and maximal cardiorespiratory and chronotropic responses were obtained at each measurement phase. Results The training intervention improved systolic, mean arterial blood pressure, rate pressure product and heart rate reserve (each P < 0.05) in SED and increased MET capacity in both SED and LEX (P < 0.01) which was amplified by HIIT. Echocardiography and cardiac strain measures were unremarkable apart from trivial increase to intra-ventricular septum diastole (IVSd) (P < 0.05) and decrease to left ventricular internal dimension diastole (LVId) (P < 0.05) in LEX following HIIT. Conclusions A programme of preconditioning exercise with HIIT induces clinically relevant improvements in blood pressure, rate pressure product and encourages recovery of heart rate reserve in SED, while improving maximal MET capacity in both SED and LEX without inducing any pathological cardiovascular remodeling. These data add to the emerging repute of HIIT as a safe and promising exercise prescription to improve cardiovascular function and metabolic capacity in sedentary aging.
Genetics of blood pressure : Time to curate the collection
- Authors: Harrap, Stephen , Charchar, Fadi
- Date: 2017
- Type: Text , Journal article , Editorial
- Relation: Journal of Hypertension Vol. 35, no. 7 (2017), p. 1360-1362
- Full Text: false
- Reviewed:
- Description: The genetics of blood pressure (BP) is all about discovery and understanding, but it is certainly not for the faint hearted. Despite heroic effort, the question we posed nearly 15 years ago [1] regarding the whereabouts of BP genes remains largely unanswered.
Single-sided renal denervation may be not suitable for patients with significant renal artery stenosis
- Authors: Wang, Yutang
- Date: 2014
- Type: Text , Journal article , Letter
- Relation: Clinical Research in Cardiology Vol. 103, no. 11 (2014), p. 950-951
- Relation: http://purl.org/au-research/grants/nhmrc/1062671
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Renal denervation promotes atherosclerosis in hypertensive apolipoprotein E-Deficient mice infused with angiotensin II
- Authors: Wang, Yutang , Dinh, Tam , Nield, Alex , Krishna, Smriti , Denton, Kate , Golledge, Jonathan
- Date: 2017
- Type: Text , Journal article
- Relation: Frontiers in Physiology Vol. 8, no. (2017), p. 1-9
- Relation: http://purl.org/au-research/grants/nhmrc/1062671
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- Description: Objective: To determine the effect of renal denervation (RDN) on the severity of atherosclerosis and aortic aneurysm in hypertensive mice. Methods: Hypertension, atherosclerosis and aortic aneurysm were induced by subcutaneous infusion of angiotensin II (1 μg/kg/min) for 28 days in apolipoprotein E-deficient mice. RDN was conducted using combined surgical and local chemical denervation. The norepinephrine concentration in the kidney was measured by high-performance liquid chromatography. Blood pressure was measured by the tail-cuff method. Atherosclerosis was assessed by Sudan IV staining of the aortic arch. The aortic diameter was measured by the morphometric method. The mRNA expression of genes associated with atherosclerosis and aortic aneurysm were analyzed by quantitative PCR. Results: RDN decreased the median norepinephrine content in the kidney by 93.4% (n = 5-7, P = 0.003) 5 days after the procedure, indicating that the RDN procedure was successful. RDN decreased systolic blood pressure in apolipoprotein E-deficient mice. Mice that had RDN had more severe aortic arch atherosclerosis (median percentage of Sudan IV positive area: 13.2% in control mice, n = 12, and 25.4% in mice having RDN, n = 12, P = 0.028). The severity of the atherosclerosis was negatively correlated with the renal norepinephrine content (spearman r = -0.6557, P = 0.005). RDN did not affect the size of aortic aneurysms formed or the incidence of aortic rupture in mice receiving angiotensin II. RDN significantly increased the aortic mRNA expression of matrix metalloproteinase-2 (MMP-2). Conclusion: RDN promoted atherosclerosis in apolipoprotein E-deficient mice infused with angiotensin II associated with upregulation of MMP-2. The higher MMP-2 expression could be the results of the greater amount of atheroma in the RDN mice. The findings suggest further research is needed to assess potentially deleterious effects of RDN in patients. © 2017 Wang, Dinh, Nield, Krishna, Denton and Golledge.