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Orgil BO, Xu F, Munkhsaikhan U, Alberson NR, Bajpai AK, Johnson JN, Sun Y, Towbin JA, Lu L, Purevjav E. Echocardiography phenotyping in murine genetic reference population of BXD strains reveals significant QTLs associated with cardiac function and morphology. Physiol Genomics 2023; 55:51-66. [PMID: 36534598 PMCID: PMC9902221 DOI: 10.1152/physiolgenomics.00120.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
The genetic reference population of recombinant inbred BXD mice has been derived from crosses between C57BL/6J and DBA/2J strains. The DBA/2J parent exhibits cardiomyopathy phenotypes, whereas C57BL/6J has normal heart. BXD mice are sequenced for studying genetic interactions in cardiomyopathies. The study aimed to assess cardiomyopathy traits in BXDs and investigate the quantitative genetic architecture of those traits. Echocardiography, blood pressure, and cardiomyocyte size parameters obtained from 44 strains of BXD family (n > 5/sex) at 4-5 mo of age were associated with heart transcriptomes and expression quantitative trait loci (eQTL) mapping was performed. More than twofold variance in ejection fraction (EF%), fractional shortening (FS%), left ventricular volumes (LVVols), internal dimensions (LVIDs), mass (LVM), and posterior wall (LVPW) thickness was found among BXDs. In male BXDs, eQTL mapping identified Ndrg4 on chromosome 8 QTL to be positively correlated with LVVol and LVID and negatively associated with cardiomyocyte diameter. In female BXDs, significant QTLs were found on chromosomes 7 and 3 to be associated with LVPW and EF% and FS%, respectively, and Josd2, Dap3, and Tpm3 were predicted as strong candidate genes. Our study found variable cardiovascular traits among BXD strains and identified multiple associated QTLs, suggesting an influence of genetic background on expression of echocardiographic and cardiomyocyte diameter traits. Increased LVVol and reduced EF% and FS% represented dilated cardiomyopathy, whereas increased LV mass and wall thickness indicated hypertrophic cardiomyopathy traits. The BXD family is ideal for identifying candidate genes, causal and modifier, that influence cardiovascular phenotypes.NEW & NOTEWORTHY This study aimed to establish a cardiac phenotype-genotype correlation in murine genetic reference population of BXD RI strains by phenotyping the echocardiography, blood pressure, and cardiomyocyte diameter traits and associating each collected phenotype with genetic background. Our study identified several QTLs and candidate genes that have significant association with cardiac hypertrophy, ventricular dilation, and function including systolic hyperfunction and dysfunction.
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Affiliation(s)
- Buyan-Ochir Orgil
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee
| | - Fuyi Xu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee
- School of Pharmacy, Binzhou Medical University, Yantai, China
| | - Undral Munkhsaikhan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Neely R Alberson
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee
| | - Akhilesh Kumar Bajpai
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Jason N Johnson
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee
| | - Yao Sun
- Division of Cardiovascular Diseases, Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Jeffrey A Towbin
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee
- Pediatric Cardiology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Enkhsaikhan Purevjav
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee
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Marceau F, Bachelard H, Charest-Morin X, Hébert J, Rivard GE. In Vitro Modeling of Bradykinin-Mediated Angioedema States. Pharmaceuticals (Basel) 2020; 13:ph13090201. [PMID: 32824891 PMCID: PMC7559923 DOI: 10.3390/ph13090201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/15/2022] Open
Abstract
Kinins (peptides related to bradykinin, BK) are formed from circulating substrates, the kininogens, by the action of two proteases, the kallikreins. The only clinical application of a BK receptor ligand, the B2 receptor antagonist icatibant, is the treatment of the rare hereditary angioedema (HAE) caused by the deficiency of C1-esterase inhibitor (C1-INH). Less common forms of HAE (genetic variants of factor XII, plasminogen, kininogen) are presumably mediated by increased BK formation. Acquired forms of BK-mediated angioedema, such as that associated with angiotensin-I converting enzyme (ACE) inhibition, are also known. Antibody-based analytical techniques are briefly reviewed, and support that kinins are extremely short-lived, prominently cleared by ACE. Despite evidence of continuous activation of the kallikrein–kinin system in HAE, patients are not symptomatic most of the time and their blood or plasma obtained during remission does not generate excessive immunoreactive BK (iBK), suggesting effective homeostatic mechanisms. HAE-C1-INH and HAE-FXII plasmas are both hyperresponsive to fibrinolysis activation. On another hand, we suggested a role for the alternate tissue kallikrein–kinin system in patients with a plasminogen mutation. The role of the BK B1 receptor is still uncertain in angioedema states. iBK profiles under in vitro stimulation provide fresh insight into the physiopathology of angioedema.
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Affiliation(s)
- François Marceau
- Centre de Recherche du CHU de Québec-Université Laval, Québec, QC G1V 4G2, Canada; (H.B.); (X.C.-M.)
- Correspondence:
| | - Hélène Bachelard
- Centre de Recherche du CHU de Québec-Université Laval, Québec, QC G1V 4G2, Canada; (H.B.); (X.C.-M.)
| | - Xavier Charest-Morin
- Centre de Recherche du CHU de Québec-Université Laval, Québec, QC G1V 4G2, Canada; (H.B.); (X.C.-M.)
| | - Jacques Hébert
- Service D’allergie, CHU de Québec-Université Laval, Québec, QC G1V 4G2, Canada;
| | - Georges E. Rivard
- CHU Sainte-Justine, Université de Montréal, Montréal, QC H3T 1C5, Canada;
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Kallikrein-related peptidase 8 is expressed in myocardium and induces cardiac hypertrophy. Sci Rep 2016; 7:20024. [PMID: 26823023 PMCID: PMC4731818 DOI: 10.1038/srep20024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 12/22/2015] [Indexed: 12/13/2022] Open
Abstract
The tissue kallikrein-related peptidase family (KLK) is a group of trypsin- and chymotrypsin-like serine proteases that share a similar homology to parent tissue kallikrein (KLK1). KLK1 is identified in heart and has anti-hypertrophic effects. However, whether other KLK family members play a role in regulating cardiac function remains unknown. In the present study, we demonstrated for the first time that KLK8 was expressed in myocardium. KLK8 expression was upregulated in left ventricle of cardiac hypertrophy models. Both intra-cardiac adenovirus-mediated and transgenic-mediated KLK8 overexpression led to cardiac hypertrophy in vivo. In primary neonatal rat cardiomyocytes, KLK8 knockdown inhibited phenylephrine (PE)-induced cardiomyocyte hypertrophy, whereas KLK8 overexpression promoted cardiomyocyte hypertrophy via a serine protease activity-dependent but kinin receptor-independent pathway. KLK8 overexpression increased epidermal growth factor (EGF) production, which was blocked by the inhibitors of serine protease. EGF receptor (EGFR) antagonist and EGFR knockdown reversed the hypertrophy induced by KLK8 overexpression. KLK8-induced cardiomyocyte hypertrophy was also significantly decreased by blocking the protease-activated receptor 1 (PAR1) or PAR2 pathway. Our data suggest that KLK8 may promote cardiomyocyte hypertrophy through EGF signaling- and PARs-dependent but a kinin receptor-independent pathway. It is implied that different KLK family members can subtly regulate cardiac function and remodeling.
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Sukumar N, Scott E, Dimitromanolakis A, Misiak A, Prassas I, Diamandis EP, Konvalinka A. Mining for single nucleotide variants (SNVs) at the kallikrein locus with predicted functional consequences. Biol Chem 2015; 395:1037-50. [PMID: 25153386 DOI: 10.1515/hsz-2014-0136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 07/03/2014] [Indexed: 12/17/2022]
Abstract
Kallikreins (KLKs) are a group of 15 serine proteases encoded by the KLK locus on chromosome 19. Certain single nucleotide variants (SNVs) within the KLK locus have been linked to human disease. Next-generation sequencing of large human cohorts enables reexamination of genomic variation at the KLK locus. We aimed to identify all KLK-related SNVs and examine their impact on gene regulation and function. To this end, we mined KLK SNVs across Ensembl and Exome Variant Server, with exome-sequencing data from 6503 individuals. PolyPhen-2-based prediction of damaging SNVs and population frequencies of these SNVs were examined. Damaging SNVs were plotted on protein sequence and structure. We identified 4866 SNVs, the largest number of KLK-related SNVs reported. Fourteen percent of noncoding SNVs overlapped with transcription factor binding sites. We identified 602 missense coding SNVs, among which 148 were predicted to be damaging. Nine missense SNVs were common (>1% frequency) and displayed significantly different frequencies between European-American and African-American populations. SNVs predicted to be damaging appeared to alter tertiary structure of KLK1 and KLK6. Similarly, these missense SNVs may affect KLK function, resulting in disease phenotypes. Our study represents a mine of information for those studying KLK-related SNVs and their associations with diseases.
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Waeckel L, Potier L, Richer C, Roussel R, Bouby N, Alhenc-Gelas F. Pathophysiology of genetic deficiency in tissue kallikrein activity in mouse and man. Thromb Haemost 2013; 110:476-83. [PMID: 23572029 DOI: 10.1160/th12-12-0937] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/14/2013] [Indexed: 12/30/2022]
Abstract
Study of mice rendered deficient in tissue kallikrein (TK) by gene inactivation and human subjects partially deficient in TK activity as consequence of an active site mutation has allowed recognising the physiological role of TK and its peptide products kinins in arterial function and in vasodilatation, in both species. TK appears as the major kinin forming enzyme in arteries, heart and kidney. Non-kinin mediated actions of TK may occur in epithelial cells in the renal tubule. In basal condition, TK deficiency induces mild defective phenotypes in the cardiovascular system and the kidney. However, in pathological situations where TK synthesis is typically increased and kinins are produced, TK deficiency has major, deleterious consequences. This has been well documented experimentally for cardiac ischaemia, diabetes renal disease, peripheral ischaemia and aldosterone-salt induced hypertension. These conditions are all aggravated by TK deficiency. The beneficial effect of ACE/kininase II inhibitors or angiotensin II AT1 receptor antagonists in cardiac ischaemia is abolished in TK-deficient mice, suggesting a prominent role for TK and kinins in the cardioprotective action of these drugs. Based on findings made in TK-deficient mice and additional evidence obtained by pharmacological or genetic inactivation of kinin receptors, development of novel therapeutic approaches relying on kinin receptor agonism may be warranted.
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Affiliation(s)
- L Waeckel
- Francois Alhenc-Gelas, INSERM U872, Centre de Recherche des Cordeliers, 15 rue de l'Ecole de Médecine 75006 Paris, France, E-mail:
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Westcott EB, Segal SS. Ageing alters perivascular nerve function of mouse mesenteric arteries in vivo. J Physiol 2013; 591:1251-63. [PMID: 23247111 PMCID: PMC3607869 DOI: 10.1113/jphysiol.2012.244483] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/10/2012] [Indexed: 12/16/2022] Open
Abstract
Abstract Mesenteric arteries (MAs) are studied widely in vitro but little is known of their reactivity in vivo. Transgenic animals have enabled Ca(2+) signalling to be studied in isolated MAs but the reactivity of these vessels in vivo is undefined. We tested the hypothesis that ageing alters MA reactivity to perivascular nerve stimulation (PNS) and adrenoreceptor (AR) activation during blood flow control. First- (1A), second- (2A) and third-order (3A) MAs of pentobarbital-anaesthetized Young (3-6 months) and Old (24-26 months) male and female Cx40(BAC)-GCaMP2 transgenic mice (C57BL/6 background; positive or negative for the GCaMP2 transgene) were studied with intravital microscopy. A segment of jejunum was exteriorized and an MA network was superfused with physiological salt solution (pH 7.4, 37°C). Resting tone was 10% in MAs of Young and Old mice; diameters were ∼5% (1A), 20% (2A) and 40% (3A) smaller (P 0.05) in Old mice. Throughout MA networks, vasoconstriction increased with PNS frequency (1-16 Hz) but was ∼20% less in Young vs. Old mice (P 0.05) and was inhibited by tetrodotoxin (1 μm). Capsaicin (10 μm; to inhibit sensory nerves) enhanced MA constriction to PNS (P 0.05) by ∼20% in Young but not Old mice. Phenylephrine (an α1AR agonist) potency was greater in Young mice (P 0.05) with similar efficacy (∼60% constriction) across ages and MA branches. Constrictions to UK14304 (an α2AR agonist) were less (∼20%; P 0.05) and were unaffected by ageing. Irrespective of sex or transgene expression, ageing consistently reduced the sensitivity of MAs to α1AR vasoconstriction while blunting the attenuation of sympathetic vasoconstriction by sensory nerves. These findings imply substantive alterations in splanchnic blood flow control with ageing.
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Affiliation(s)
- Erika B Westcott
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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Affiliation(s)
- Jerry G. Webb
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina
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Barhoumi T, Jallat I, Berthelot A, Laurant P. Human recombinant erythropoietin alters the flow-dependent vasodilatation of in vitro perfused rat mesenteric arteries with unbalanced endothelial endothelin-1 / nitric oxide ratio. Can J Physiol Pharmacol 2011; 89:435-43. [DOI: 10.1139/y11-032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Chronic use of human recombinant erythropoietin (r-HuEPO) is accompanied by serious vascular side effects related to the rise in blood viscosity and shear stress. We investigated the direct effects of r-HuEPO on endothelium and nitric oxide (NO)-dependent vasodilatation induced by shear stress of cannulated and pressurized rat mesenteric resistance arteries. Intravascular flow was increased in the presence or absence of the NO synthase inhibitor NG-nitro-l-arginine methyl ester (L-NAME; 10−4 mol/L). In the presence of r-HuEPO, the flow-dependent vasodilatation was attenuated, while L-NAME completely inhibited it. The association of r-HuEPO and L-NAME caused a vasoconstriction in response to the rise in intravascular flow. Bosentan (10−5 mol/L), an inhibitor of endothelin-1 (ET-1) receptors, corrected the attenuated vasodilatation observed with r-HuEPO and inhibited the vasoconstriction induced by flow in the presence of r-HuEPO and L-NAME. r-HuEPO and L-NAME exacerbated ET-1 vasoconstriction. At shear stress values of 2 and 14 dyn/cm2 (1 dyn = 10–5 N), cultured EA.hy926 endothelial cells incubated with r-HuEPO, L-NAME, or both released greater ET-1 than untreated cells. In conclusion, r-HuEPO diminishes flow-induced vasodilatation. This inhibitory effect seems to implicate ET-1 release. NO withdrawal exacerbates the vascular effects of ET-1 in the presence of r-HuEPO. These findings support the importance of a balanced endothelial ET-1:NO ratio to avoid the vasopressor effects of r-HuEPO.
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Affiliation(s)
- Tlili Barhoumi
- EA4278, Laboratoire de pharm-écologie cardiovasculaire, Pôle sportif et de recherche universitaire, Université d’Avignon et des Pays de Vaucluse, 15 Boulevard Limbert, 84000 Avignon, France
| | - Isabelle Jallat
- EA3920, Physiopathologie cardiovasculaire et prévention, Université de Franche-Comté, Besançon, France
| | - Alain Berthelot
- EA4267, Sciences séparatives biologiques et pharmaceutiques, Université de Franche-Comté, Besançon, France
| | - Pascal Laurant
- EA4278, Laboratoire de pharm-écologie cardiovasculaire, Pôle sportif et de recherche universitaire, Université d’Avignon et des Pays de Vaucluse, 15 Boulevard Limbert, 84000 Avignon, France
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Nagano H, Wei PZ, Wen CQ, Jomori T, Oku H, Ikeda T, Saito Y, Tano Y. Effects of Kallidinogenase on Ischemic Changes Induced by Repeated Intravitreal Injections of Endothelin-1 in Rabbit Retina. Curr Eye Res 2009; 32:113-22. [PMID: 17364744 DOI: 10.1080/02713680601160602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Repeated intravitreal injections of endothelin-1 (ET-1) lead to alterations in the visually evoked potentials (VEPs) and loss of retinal ganglion cells (RGCs) in rabbits. The purpose of this study was to determine whether kallidinogenase can offset the alterations induced by ET-1. METHODS ET-1 (2.5 x 10(-7) M, 20 microL) was injected into the vitreous of the right eye of rabbits (ET-1-treated eyes, n = 30) twice a week for 4 weeks. The vehicle for ET-1 was injected into the left eye on the same schedule (vehicle treated eyes, n = 30). During this 4 weeks period, kallidinogenase (1.0 unit/kg/day, kallidinogenase-treated group) or saline (saline-injected control group) was continuously delivered intravenously by an implanted osmotic pump. VEPs were recorded before, and 2 weeks and 4 weeks after, the first ET-1 injection, and all rabbits were sacrificed at 4 weeks. The number of RGC cells was counted in hematoxylin- and eosin-stained retinal sections. In the analyses, the ET-1 induced alterations were normalized to the values in the vehicle treated control eyes, i.e., kallidinogenase (K) + ET-1/K+ vehicle or saline (S) +ET-1/S + vehicle. Retinal sections were also examined by immunohistochemistry with antibodies to single-stranded DNA (ssDNA) or to glial fibrillary acidic protein (GFAP). The effect of kallidinogenase on the ONH blood flow was determined by a hydrogen gas clearance flowmeter. RESULTS The significant prolongation of the relative VEP implicit times (ITs) 4 weeks after the ET-1 injection (P < 0.01, paired t test; post-ET-1 vs. pre-ET-1) was significantly decreased by kallidinogenase (P < 0.001, t test, K + ET-1/K+ vehicle vs. S +ET-1/S + vehicle). The relative number of RGCs was decreased in the saline-injected group, and this decrease was also decreased by kallidinogenase (P < 0.05, t test, K + ET-1/K+ vehicle vs. S +ET-1/S + vehicle). ssDNA staining showed fewer apoptotic cells in the retina of kallidinogenase-treated rabbits. Intravitreal injection of ET-1 also decreased the blood flow in the optic nerve head and increased the GFAP immunostaining and axonal degeneration. These changes were also counteracted by kallidinogenase. CONCLUSION These results indicate that kallidinogenase can counter the effects of ET-1 and should be considered for the treatment of ischemic retinal and optic nerve disorders related to abnormal ET-1 production.
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Affiliation(s)
- Hiroshi Nagano
- Pharmaceutical Laboratory, Sanwa Kagaku Kenkyusho Co. Ltd., 363 Shiosaki, Hokusei, Inabe, Mie 511-0406, Japan.
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Pizard A, Richer C, Bouby N, Picard N, Meneton P, Azizi M, Alhenc-Gelas F. Genetic deficiency in tissue kallikrein activity in mouse and man: effect on arteries, heart and kidney. Biol Chem 2008; 389:701-6. [PMID: 18627303 DOI: 10.1515/bc.2008.081] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Tissue kallikrein (KLK1) is a kinin-forming serine protease synthesized in many organs including arteries and kidney. Study of the physiological role of KLK1 has benefited from the availability of mouse and human genetic models of KLK1 deficiency, through engineering of KLK1 mouse mutants and discovery of a major polymorphism in the human KLK1 gene that induces a loss of enzyme activity. Studies in KLK1-deficient mice and human subjects partially deficient in KLK1 have documented its critical role in arterial function in both species. KLK1 is also involved in the control of ionic transport in the renal tubule, an action that may not be kinin-mediated. Studies of experimental diseases in KLK1-deficient mice have revealed cardio- and nephro-protective effects of KLK1 and kinins in acute cardiac ischemia, post-ischemic heart failure, and diabetes. Potential clinical and therapeutic developments are discussed.
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Affiliation(s)
- Anne Pizard
- INSERM U652/U872, Centre de Recherche des Cordeliers, 15 rue de l'Ecole de Médecine, F-75006 Paris, France
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Dietze GJ, Henriksen EJ. Angiotensin-converting enzyme in skeletal muscle: sentinel of blood pressure control and glucose homeostasis. J Renin Angiotensin Aldosterone Syst 2008; 9:75-88. [PMID: 18584583 DOI: 10.3317/jraas.2008.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Recent evidence suggests a coordinated regulation by the local renin-angiotensin system (RAS) and tissue kallikrein-kinin system (TKKS) of blood flow and substrate supply in oxidative red myofibres of skeletal muscle tissue during endurance exercise. The performance of these myofibres is dependent on the increased oxidation of substrates facilitated by augmenting nutritive blood flow and glucose uptake. Humoral factors released by the contracting fibres, such as adenosine and kinins, are suggested to be responsible for this metabolic adjustment. The considerable drain of blood volume and the enormous consumption of glucose during endurance exercise require a control mechanism for the maintenance of blood pressure (BP) and glucose homeostasis. This is achieved by the sympathetic nervous system and its subordinate RAS, which is located in the nutritive vessels and parenchyma of the red myofibres. The angiotensin-converting enzyme (ACE) is the primary enzyme responsible for kinin degradation during exercise, underscoring the important interrelationship between the RAS and the TKKS in the critical role of kinins in the multifactorial regulation of muscle bioenergetics and glucose and BP homeostasis. Importantly, overactivity of the ACE, as occurs in individuals displaying risk factors such as overweight, causes exaggerated BP response and reduced glucose disposal. If they persist over years, compensatory responses to this ACE overactivity, such as hypersecretion of insulin and compliance of the vessel walls, will inevitably be exhausted, leading ultimately to the manifestation of type 2 diabetes and hypertension. This concept also provides a unifying explanation for the beneficial effects of ACE-inhibitors and Angiotensin II receptor antagonists in the treatment of hypertension and insulin resistance.
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Affiliation(s)
- Guenther J Dietze
- Hypertension and Diabetes Research Unit, Max Grundig Clinic, Buehl, Germany
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Madeddu P, Emanueli C, El-Dahr S. Mechanisms of Disease: the tissue kallikrein–kinin system in hypertension and vascular remodeling. ACTA ACUST UNITED AC 2007; 3:208-21. [PMID: 17389890 DOI: 10.1038/ncpneph0444] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Accepted: 01/16/2007] [Indexed: 11/09/2022]
Abstract
The pathogenesis of arterial hypertension often involves a rise in systemic vascular resistance (vasoconstriction and vascular remodeling) and impairment of salt excretion in the kidney (inappropriate salt retention despite elevated blood pressure). Experimental and clinical evidence implicate an imbalance between endogenous vasoconstrictor and vasodilator systems in the development and maintenance of hypertension. Kinins (bradykinin and lys-bradykinin) are endogenous vasodilators and natriuretic peptides known best for their ability to antagonize angiotensin-induced vasoconstriction and sodium retention. In humans, angiotensin-converting enzyme inhibitors, a potent class of antihypertensive agents, lower blood pressure at least partially by favoring enhanced kinin accumulation in plasma and target tissues. The beneficial actions of kinins in renal and cardiovascular disease are largely mediated by nitric oxide and prostaglandins, and extend beyond their recognized role in lowering blood pressure to include cardioprotection and nephroprotection. This article is a review of exciting, recently generated genetic, biochemical and clinical data from studies that have examined the importance of the tissue kallikrein-kinin system in protection from hypertension, vascular remodeling and renal fibrosis. Development of novel therapeutic approaches to bolster kinin activity in the vascular wall and in specific compartments in the kidney might be a highly effective strategy for the treatment of hypertension and its complications, including cardiac hypertrophy and renal failure.
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Affiliation(s)
- Paolo Madeddu
- Experimental Cardiovascular Medicine, Bristol Heart Institute, Bristol University, Bristol, UK.
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Abstract
Transgenic and gene-targeting technologies allowing the generation of genetically altered animal models have greatly advanced our understanding of the function of specific genes. This is also true for the kallikrein-kinin system (KKS), in which some, but not yet all, components have been functionally characterized using such techniques. The first genetically altered animal model for a KKS component was supplied by nature, the brown Norway rat carrying an inactivating mutation in the kininogen gene. Mice deficient in tissue kallikrein, B1 and B2 receptors, some kinin-degrading enzymes, and factor XII followed, together with transgenic rat and mouse strains overexpressing tissue kallikrein, B1 and B2 receptors, and degrading enzymes. There are still no animal models with genetic alterations in plasma kallikrein, kininases I and some other degrading enzymes. The models have confirmed an important role of the KKS in cardiovascular pathology, inflammation, and pain, and have partially elucidated the distinct function of the two receptors. This created the basis for rational decisions concerning the putative use of kinin receptor agonists and antagonists in therapeutic applications. However, a more thorough analysis of the existing models and the generation of new, more sophisticated transgenic models will be necessary to clarify the still elusive issue as to where and by which mechanisms the kinins exert their actions.
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Affiliation(s)
- João B Pesquero
- Department of Biophysics, Universidade Federal de São Paulo, São Paulo, CEP 04023-062, Brazil
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Abstract
In this review, we outline the application and contribution of transgenic technology to establishing the genetic basis of blood pressure regulation and its dysfunction. Apart from a small number of examples where high blood pressure is the result of single gene mutation, essential hypertension is the sum of interactions between multiple environmental and genetic factors. Candidate genes can be identified by a variety of means including linkage analysis, quantitative trait locus analysis, association studies, and genome-wide scans. To test the validity of candidate genes, it is valuable to model hypertension in laboratory animals. Animal models generated through selective breeding strategies are often complex, and the underlying mechanism of hypertension is not clear. A complementary strategy has been the use of transgenic technology. Here one gene can be selectively, tissue specifically, or developmentally overexpressed, knocked down, or knocked out. Although resulting phenotypes may still be complicated, the underlying genetic perturbation is a starting point for identifying interactions that lead to hypertension. We recognize that the development and maintenance of hypertension may involve many systems including the vascular, cardiac, and central nervous systems. However, given the central role of the kidney in normal and abnormal blood pressure regulation, we intend to limit our review to models with a broadly renal perspective.
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Affiliation(s)
- Linda J Mullins
- Molecular Physiology Laboratory, Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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Azizi M, Boutouyrie P, Bissery A, Agharazii M, Verbeke F, Stern N, Bura-Rivière A, Laurent S, Alhenc-Gelas F, Jeunemaitre X. Arterial and renal consequences of partial genetic deficiency in tissue kallikrein activity in humans. J Clin Invest 2005; 115:780-7. [PMID: 15765151 PMCID: PMC1052005 DOI: 10.1172/jci23669] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Accepted: 12/07/2004] [Indexed: 11/17/2022] Open
Abstract
Tissue kallikrein (TK), the major kinin-forming enzyme, is synthesized in several organs, including the kidney and arteries. A loss-of-function polymorphism of the human TK gene (R53H) induces a substantial decrease in enzyme activity. As inactivation of the TK gene in the mouse induces endothelial dysfunction, we investigated the vascular, hormonal, and renal phenotypes of carriers of the 53H allele. In a crossover study, 30 R53R-homozygous and 10 R53H-heterozygous young normotensive white males were randomly assigned to receive both a low sodium-high potassium diet to stimulate TK synthesis and a high sodium-low potassium diet to suppress TK synthesis, each for 1 week. Urinary kallikrein activity was 50-60% lower in R53H subjects than in R53R subjects. Acute flow-dependent vasodilatation and endothelium-independent vasodilatation of the brachial artery were both unaffected in R53H subjects. In contrast, R53H subjects consistently exhibited an increase in wall shear stress and a paradoxical reduction in artery diameter and lumen compared with R53R subjects. Renal and hormonal adaptation to diets was unaffected in R53H subjects. The partial genetic deficiency in TK activity is associated with an inward remodeling of the brachial artery, which is not adapted to a chronic increase in wall shear stress, indicating a new form of arterial dysfunction affecting 5-7% of white people.
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Affiliation(s)
- Michel Azizi
- Centre d'Investigations Cliniques 9201, Assistance Publique des Hôpitaux de Paris and INSERM, Université Paris V, Paris, France.
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Abstract
Remodeling of the arterial wall occurs mainly as a consequence of increased wall stress caused by hypertension. In this issue of the JCI, Azizi et al. report that in humans with a kallikrein gene polymorphism that lowers kallikrein activity, the brachial artery undergoes eutrophic inward remodeling in the absence of hypertension or other hemodynamic changes. It has also been reported that alterations of the kallikrein-kinin system are associated with formation of aortic aneurysms. Conversely, after vascular injury, kinins mediate the beneficial effect of angiotensin-converting enzyme inhibitors that prevent neointima formation. These findings raise the intriguing possibility that decreased kallikrein-kinin system activity may play an important role in the pathogenesis of vascular remodeling and disease, while increased activity may have a beneficial effect.
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Affiliation(s)
- Oscar A Carretero
- Hypertension and Vascular Research Division, Henry Ford Hospital, Detroit, Michigan 48202, USA.
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Azizi M, Boutouyrie P, Bissery A, Agharazii M, Verbeke F, Stern N, Bura-Rivière A, Laurent S, Alhenc-Gelas F, Jeunemaitre X. Arterial and renal consequences of partial genetic deficiency in tissue kallikrein activity in humans. J Clin Invest 2005. [DOI: 10.1172/jci200523669] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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