Aldosterone increases plasminogen activator inhibitor-1 synthesis in rat cardiomyocytes
Introduction
In the heart, under conditions of high salt intake, aldosterone produced fibrosis and ventricular hypertrophy in several different rat models (Brilla et al., 1990, Rocha et al., 1998, Rocha et al., 2000). In studies of transgenic mice overexpressing 11 β-hydroxysteroid dehydrogenase type 2 in cardiomyocytes, thereby protecting mineralocorticoid receptors (MR) in heart from occupancy by glucocorticoids in favor of aldosterone, fibrosis and hypertrophy developed and eventually heart failure resulting in premature death (Qin et al., 2003). A relationship between aldosterone and cardiac function was evident in two clinical trials of heart failure where treatment with MR antagonists reduced cardiovascular morbidity and mortality (Pitt et al., 1999, Pitt et al., 2003). The mechanism for how aldosterone has these effects on the heart is unknown.
Plasminogen activator inhibitor-1 (PAI-1), an inhibitor of thrombolysis (Saksela and Rifkin, 1988), is known to promote fibrosis (Eddy, 2002, Kaikita et al., 2001, Loskutoff and Quigley, 2000), an effect which could contribute to its known relationship to cardiovascular disease risk (Hamsten et al., 1985, Hamsten et al., 1987, Schneiderman et al., 1992). Angiotensin II (Ang II) stimulates PAI-1 synthesis (Brown et al., 1998, Pahor et al., 2002, Ridker et al., 1993, Vaughan et al., 1995) and there is emerging evidence that aldosterone, whose secretion is stimulated by Ang II, may mediate some of Ang II's effects. Aldosterone and Ang II acted synergistically to increase PAI-1 expression in studies using rat aortic smooth muscle and human umbilical vein endothelium (Brown et al., 2000a). Aldosterone has also been shown to increase PAI-1 synthesis in isolated human neutrophils (Calo et al., 2004). Treatment with spironolactone, an MR antagonist, lowered blood levels of PAI-1 in both animal (Brown et al., 2000b) and human studies (Sawathiparnich et al., 2002). On the other hand, PAI-1 deficient mice [PAI-1 (−/−)] infused with Ang II and in addition treated with the NO synthase inhibitor Ng-nitro-l-arginine methyl ester (l-NAME) were unprotected from myocardial injury whereas spironolactone was protective (Oestreicher et al., 2003). Thus, the role of PAI-1 as a mediator of aldosterone's deleterious effects on the heart remains controversial. Because of the potential for PAI-1 to promote fibrosis, we looked further at its role as a mediator of aldosterone's actions in the heart by exploring for direct influences of aldosterone on PAI-1 expression in myocardial cells.
Section snippets
Cell culture
H9c2 rat heart myocytes were purchased from American Type Culture Collection (Rockville, MD) and maintained in DMEM with 10% FCS. Cell passage was carried out twice a week. Neonatal rat cardiomyocytes were prepared as follows: 1-day-old neonatal Sprague Dawley rats were decapitated and the cardiac ventricles excised, cut into approximately 15 pieces, and washed with Hanks buffer (Gibco) four times. Trypsin digestion buffer (1 mg/ml trypsin, 5 mM HEPES, 0.02 mg/ml DNAse I) was added and then after
The effect of aldosterone on PAI-1 protein and mRNA levels in H9c2 cells
When 80% confluent cells were treated with aldosterone, there was a concentration dependent increase in PAI-1 protein levels when compared with control cells (Fig. 1A and B). Dexamethasone (100 nM), a known inducer of PAI-1 expression (Hamilton et al., 1993), also increased the PAI-1 protein level (data not shown). The effect of aldosterone was blocked by 100 nM spironolactone, consistent with mediation by MR. Spironolactone did not block dexamethasone's effect on PAI-1 (data not shown). To
Discussion
The present study addressed the mechanism for how aldosterone produces myocardial injury, with potential relevance to the known relationship of PAI-1 levels to cardiovascular risk. We found that aldosterone increased PAI-1 synthesis in rat cardiac cells by increasing transcription. Neutralization of TGF-β1 decreased aldosterone-induced PAI-1 expression in neonatal cardiomyocytes consistent with a dependency on the known effect of TGF-β1 to increase PAI-1 expression (Lund et al., 1987).
The
Acknowledgements
We thank Ms. Eun-Young Choi for technical assistance and Mr. George Eckert for statistical analysis. Support was provided by NIH grants R01-HL-35795 and RO1-HL67360, by the U.S. Department of Veterans Affairs, and by a Biomedical Research Grant from Indiana University School of Medicine (T.-Y. Chun).
References (33)
- et al.
Aldosterone modulates plasminogen activator inhibitor-1 and glomerulosclerosis in vivo
Kidney Int.
(2000) - et al.
Spironolactone increases integrin beta3 gene expression in kidney and heart muscle cells
Mol. Cell Endocrinol.
(2002) - et al.
Tissue- and agonist-specific regulation of human and murine plasminogen activator inhibitor-1 promoters in transgenic mice
J. Thromb. Haemost.
(2003) - et al.
Regulation of plasminogen activator inhibitor-1 levels in human monocytes
Cell Immunol.
(1993) - et al.
Plasminogen activator inhibitor in plasma: risk factor for recurrent myocardial infarction
Lancet
(1987) - et al.
Identification of regulatory sequences in the type 1 plasminogen activator inhibitor gene responsive to transforming growth factor beta
J. Biol. Chem.
(1991) - et al.
Remodeling of the rat right and left ventricles in experimental hypertension
Circ. Res.
(1990) - et al.
Effect of activation and inhibition of the renin-angiotensin system on plasma PAI-1
Hypertension
(1998) - et al.
Synergistic effect of adrenal steroids and angiotensin II on plasminogen activator inhibitor-1 production
J. Clin. Endocrinol. Metab.
(2000) - et al.
Effect of aldosterone and glycyrrhetinic acid on the protein expression of PAI-1 and p22(phox) in human mononuclear leukocytes
J. Clin. Endocrinol. Metab.
(2004)
Aldosterone inhibits inducible nitric oxide synthase in neonatal rat cardiomyocytes
Endocrinology
Differential regulation by estrogens of growth and prolactin synthesis in pituitary cells suggests that only a small pool of estrogen receptors is required for growth
Proc. Natl. Acad. Sci. U.S.A.
Plasminogen activator inhibitor-1 and the kidney
Am. J. Physiol. Renal. Physiol.
Increased plasma levels of a rapid inhibitor of tissue plasminogen activator in young survivors of myocardial infarction
N. Engl. J. Med.
Transcriptional regulation of plasminogen activator inhibitor type-1 mRNA in Hep G2 cells by epidermal growth factor
Nucleic Acids Res.
Plasminogen activator inhibitor-1 deficiency prevents hypertension and vascular fibrosis in response to long-term nitric oxide synthase inhibition
Circulation
Cited by (44)
Histone deacetylase inhibitors for cardiovascular conditions and healthy longevity
2021, The Lancet Healthy LongevityCitation Excerpt :The use of valproic acid led to attenuated cardiac hypertrophy and fibrosis in these rats.25 Aldosterone directly increases PAI1 expression in cardiac muscle cells, an effect that is dependent of MR.26 In humans, the administration of MR antagonists prevented the PAI1 increase induced by furosemide.27 Cardiac hypertrophy induced by chronic infusion of angiotensin II or by aortic banding in mice or rats was significantly reduced by valproic acid administration.
Reduced hemostatic effects with drospirenone-based oral contraceptives containing estetrol vs. ethinyl estradiol
2017, ContraceptionCitation Excerpt :DRSP is an antagonist of aldosterone, which induces endothelial inflammation, dysfunction and stiffness [22–25] via mineralocorticoid receptors expressed on the endothelium [26,27]. Both in vivo and in vitro studies have shown that aldosterone activates NF-κB [28], decreases t-PA [29], and increases PAI-1 [29–31], Von Willebrand factor [32], ICAM-1 [33], tissue factor [29], VCAM-1 [34], MCP-1 [34], E-selectin [35], TAT, membrane-bound EPCR [36] and microparticles. That levels of strong reacting variables for the 20 mcg EE/DRSP combination did not return to pretreatment values in the posttreatment sample being around 5 weeks after discontinuation of treatment, is an observation that may provide on retrospect a limitation to our study only employing a 1-month wash-out.
Aldosterone-induced cardiomyocyte growth, and fibroblast migration and proliferation are mediated by TRAF3IP2
2015, Cellular SignallingCitation Excerpt :Chronically elevated levels of Aldo contribute to myocardial hypertrophy, fibrosis and failure through both oxidative stress and inflammatory mechanisms [1,2,4–6,22]. Aldo induces multiple proinflammatory cytokines in the heart that exert negative myocardial inotropic effects [23–25]. Several of these cytokines are oxidative stress responsive, and are regulated by the redox-sensitive nuclear transcription factors NF-κB and AP-1.
The Effect of Aldosterone on Cardiorenal and Metabolic Systems
2023, International Journal of Molecular SciencesMineralocorticoid receptor antagonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease
2023, Nephrology Dialysis TransplantationHypertension and cardiomyopathy associated with chronic kidney disease: epidemiology, pathogenesis and treatment considerations
2023, Journal of Human Hypertension