Female sex and estrogen receptor-β attenuate cardiac remodeling and apoptosis in pressure overload

2010 ◽  
Vol 298 (6) ◽  
pp. R1597-R1606 ◽  
Author(s):  
Daniela Fliegner ◽  
Carola Schubert ◽  
Adam Penkalla ◽  
Henning Witt ◽  
George Kararigas ◽  
...  
Keyword(s):  
Heart Failure ◽  
Estrogen Receptor ◽  
Cardiac Fibrosis ◽  
Pressure Overload ◽  
Transcriptional Response ◽  
Left Ventricular ◽  
Estrogen Receptor Β ◽  
Female Sex ◽  
Microarray Profiling ◽  
Eccentric Hypertrophy

We investigated sex differences and the role of estrogen receptor-β (ERβ) on myocardial hypertrophy in a mouse model of pressure overload. We performed transverse aortic constriction (TAC) or sham surgery in male and female wild-type (WT) and ERβ knockout (ERβ−/−) mice. All mice were characterized by echocardiography and hemodynamic measurements and were killed 9 wk after surgery. Left ventricular (LV) samples were analyzed by microarray profiling, real-time RT-PCR, and histology. After 9 wk, WT males showed more hypertrophy and heart failure signs than WT females. Notably, WT females developed a concentric form of hypertrophy, while males developed eccentric hypertrophy. ERβ deletion augmented the TAC-induced increase in cardiomyocyte diameter in both sexes. Gene expression profiling revealed that WT male hearts had a stronger induction of matrix-related genes and a stronger repression of mitochondrial genes than WT female hearts. ERβ−/− mice exhibited a different transcriptional response. ERβ−/−/TAC mice of both sexes exhibited induction of proapoptotic genes with a stronger expression in ERβ−/− males. Cardiac fibrosis was more pronounced in male WT/TAC than in female mice. This difference was abolished in ERβ−/− mice. The number of apoptotic nuclei was increased in both sexes of ERβ−/−/TAC mice, most prominent in males. Female sex offers protection against ventricular chamber dilation in the TAC model. Both female sex and ERβ attenuate the development of fibrosis and apoptosis, thus slowing the progression to heart failure.

Abstract P130: Estrogen Receptor β Mediates the Rescue of Cardiac Function in Advanced Heart Failure by Promoting Neoangiogenesis and Reducing Fibrosis

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Andrea Iorga ◽  
Rod Partow-Navid ◽  
Humann Matori ◽  
Jingyuan Li ◽  
Soban Umar ◽  
...  
Keyword(s):  
Heart Failure ◽  
Estrogen Receptor ◽  
Estrogen Receptor Alpha ◽  
Cardiac Fibrosis ◽  
Biological Effects ◽  
Estrogen Receptor Beta ◽  
Pressure Overload ◽  
Decompensated Heart Failure ◽  
Beta Agonist ◽  
Receptor Beta

Estrogen can act via the estrogen receptor alpha (ERa) or estrogen receptor beta (ERb) to exert its biological effects, and both of these receptors are present in the heart. We have previously shown that short-term estrogen (E2) treatment can rescue pressure overload-induced decompensated heart failure (HF) in mice, and that this rescue is achieved mainly through the ERb. Furthermore, E2 has been shown to regulate angiogenesis in different tissues. Because HF has been associated with decreased angiogenesis and increased fibrosis, here we investigated whether the E2-induced rescue of HF by the selective ERb agonist DPN can regulate cardiac fibrosis and neoangiogenesis. We used transaortic constriction to induce HF, and once the ejection fraction (EF) reached ∼30%, one group of animals was sacrificed (HF group), and the other three groups received either 17b-estradiol via a subcutaneous pellet implant (0.012mg/pellet, n=16), selective ERa agonist (PPT, 0.625mg/kg/day), or selective ERb agonist (DPN, 0.625mg/kg/day) for 10 days. Serial echocardiography was performed to monitor cardiac structure and function. As expected, E2 rescued HF by restoring EF from 33.17±1.12% to 53.05±1.29%. Mice treated with DPN had a significant EF improvement from 33.17±1.12% to 45.25±2.1% (n=7), while the EF of PPT-treated mice did not improve (31.09±2.3%, n=6). Similarly, only the fractional shortening of DPN-treated mice improved from 15.7±0.58% in HF to 21.95±1.65% with DPN treatment vs. 14.72±1.24% with PPT. Next, we examined whether promotion of cardiac neoangiogenesis and suppression of fibrosis by the selective ERb agonist are possible mechanisms in the rescue action of HF by DPN. DPN treatment was able to reverse the interstitial and perivascular fibrosis observed in HF, while PPT had no effect. The selective ERb agonist also stimulated neoangiogenesis, as the capillary density was increased from 0.46±0.04 microvessels/cardiomyocyte in HF to 0.67±0.07 with DPN treatment, whereas PPT treatment had no effect (0.43±0.03). Our data strongly suggests that upregulation of cardiac neoangiogenesis and reversal of fibrosis are pivotal mechanisms in rescuing advanced HF by the estrogen receptor beta agonist DPN.

Cardiac response to pressure overload in 129S1/SvImJ and C57BL/6J mice: temporal- and background-dependent development of concentric left ventricular hypertrophy

2007 ◽  
Vol 292 (5) ◽  
pp. H2119-H2130 ◽  
Author(s):  
Cordelia J. Barrick ◽  
Mauricio Rojas ◽  
Robert Schoonhoven ◽  
Susan S. Smyth ◽  
David W. Threadgill
Keyword(s):  
Heart Failure ◽  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Cardiac Response ◽  
Dependent Manner ◽  
Geometric Patterns ◽  
Concentric Hypertrophy ◽  
Eccentric Hypertrophy

Left ventricular hypertrophy (LVH), a risk factor for cardiovascular morbidity and mortality, is commonly caused by essential hypertension. Three geometric patterns of LVH can be induced by hypertension: concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Clinical studies suggest that different underlying etiologies, genetic modifiers, and risk of mortality are associated with LVH geometric patterns. Since pressure overload-induced LVH can be modeled experimentally using transverse aortic constriction (TAC) and since C57BL/6J (B6) and 129S1/SvImJ (129S1) strains, which have different baseline cardiovascular phenotypes, are commonly used, we conducted serial echocardiographic studies to assess cardiac function up to 8 wk of post-TAC in male B6, 129S1, and B6129F1 (F1) mice. B6 mice had an earlier onset and more pronounced impairment in contractile function, with corresponding left and right ventricular dilatation, fibrosis, change in expression of hypertrophy marker, and increased liver weights at 5 wk of post-TAC. These observations suggest that B6 mice had eccentric hypertrophy with systolic dysfunction and right-sided heart failure. In contrast, we found that 129S1 and F1 mice delayed transition to decompensated heart failure, with 129S1 mice exhibiting preserved systolic function until 8 wk of post-TAC and relatively mild alterations in histology and markers of hypertrophy at 5 wk post-TAC. Consistent with concentric hypertrophy, our results show that these strains manifest different cardiac responses to pressure overload in a time-dependent manner and that genetic susceptibility to initial concentric hypertrophy is dominant to eccentric hypertrophy. These results also imply that genetic background differences can complicate interpretation of TAC studies when using mixed genetic backgrounds.

scholarly journals A Porcine Model of Heart Failure With Preserved Ejection Fraction Induced by Chronic Pressure Overload Characterized by Cardiac Fibrosis and Remodeling

2021 ◽  
Vol 8 ◽  
Author(s):  
Weijiang Tan ◽  
Xiang Li ◽  
Shuang Zheng ◽  
Xiaohui Li ◽  
Xiaoshen Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Ejection Fraction ◽  
Cardiac Fibrosis ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Pathological Examination ◽  
Type I ◽  
Preserved Ejection Fraction

Heart failure is induced by multiple pathological mechanisms, and current therapies are ineffective against heart failure with preserved ejection fraction (HFpEF). As there are limited animal models of HFpEF, its underlying mechanisms have not yet been elucidated. Here, we employed the descending aortic constriction (DAC) technique to induce chronic pressure overload in the left ventricles of Tibetan minipigs for 12 weeks. Cardiac function, pathological and cellular changes, fibrotic signaling activation, and gene expression profiles were explored. The left ventricles developed concentric hypertrophy from weeks 4 to 6 and transition to dilation starting in week 10. Notably, the left ventricular ejection fraction was maintained at >50% in the DAC group during the 12-week period. Pathological examination, biochemical analyses, and gene profile analysis revealed evidence of inflammation, fibrosis, cell death, and myofilament dephosphorylation in the myocardium of HFpEF model animals, together with gene expression shifts promoting cardiac remodeling and downregulating metabolic pathways. Furthermore, we noted the activation of several signaling proteins that impact cardiac fibrosis and remodeling, including transforming growth factor-β/SMAD family members 2/3, type I/III/V collagens, phosphatidylinositol 3-kinase, extracellular signal-regulated kinase, matrix metalloproteinases 2 and 9, tissue inhibitor of metalloproteinases 1 and 2, interleukins 6 and 1β, and inhibitor of κBα/nuclear factor-κB. Our findings demonstrate that this chronic pressure overload-induced porcine HFpEF model is a powerful tool to elucidate the mechanisms of this disease and translate preclinical findings.

scholarly journals Moderate Loss of the Extracellular Matrix Proteoglycan Lumican Attenuates Cardiac Fibrosis in Mice Subjected to Pressure Overload

Cardiology ◽  
2020 ◽  
Vol 145 (3) ◽  
pp. 187-198 ◽  
Author(s):  
Naiyereh Mohammadzadeh ◽  
Arne Olav Melleby ◽  
Sheryl Palmero ◽  
Ivar Sjaastad ◽  
Shukti Chakravarti ◽  
...  
Keyword(s):  
Heart Failure ◽  
Extracellular Matrix ◽  
Diastolic Dysfunction ◽  
Cardiac Fibrosis ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Cross Linking ◽  
Myocardial Remodeling ◽  
Functional Changes ◽  
Collagen Cross Linking

Introduction: The heart undergoes myocardial remodeling during progression to heart failure following pressure overload. Myocardial remodeling is associated with structural and functional changes in cardiac myocytes, fibroblasts, and the extracellular matrix (ECM) and is accompanied by inflammation. Cardiac fibrosis, the accumulation of ECM molecules including collagens and collagen cross-linking, contributes both to impaired systolic and diastolic function. Insufficient mechanistic insight into what regulates cardiac fibrosis during pathological conditions has hampered therapeutic so­lutions. Lumican (LUM) is an ECM-secreted proteoglycan known to regulate collagen fibrillogenesis. Its expression in the heart is increased in clinical and experimental heart failure. Furthermore, LUM is important for survival and cardiac remodeling following pressure overload. We have recently reported that total lack of LUM increased mortality and left ventricular dilatation, and reduced collagen expression and cross-linking in LUM knockout mice after aortic banding (AB). Here, we examined the effect of LUM on myocardial remodeling and function following pressure overload in a less extreme mouse model, where cardiac LUM level was reduced to 50% (i.e., moderate loss of LUM). Methods and Results: mRNA and protein levels of LUM were reduced to 50% in heterozygous LUM (LUM+/–) hearts compared to wild-type (WT) controls. LUM+/– mice were subjected to AB. There was no difference in survival between LUM+/– and WT mice post-AB. Echocardiography revealed no striking differences in cardiac geometry between LUM+/– and WT mice 2, 4, and 6 weeks post-AB, although markers of diastolic dysfunction indicated better function in LUM+/– mice. LUM+/– hearts revealed reduced cardiac fibrosis assessed by histology. In accordance, the expression of collagen I and III, the main fibrillar collagens in the heart, and other ECM molecules central to fibrosis, i.e. including periostin and fibronectin, was reduced in the hearts of LUM+/– compared to WT 6 weeks post-AB. We found no differences in collagen cross-linking between LUM+/– and WT mice post-AB, as assessed by histology and qPCR. Conclusions: Moderate lack of LUM attenuated cardiac fibrosis and improved diastolic dysfunction following pressure overload in mice, adding to the growing body of evidence suggesting that LUM is a central profibrotic molecule in the heart that could serve as a potential therapeutic target.

scholarly journals Phosphodiesterase 2 inhibition preferentially promotes NO/guanylyl cyclase/cGMP signaling to reverse the development of heart failure

2018 ◽  
Vol 115 (31) ◽  
pp. E7428-E7437 ◽  
Author(s):  
Reshma S. Baliga ◽  
Michael E. J. Preedy ◽  
Matthew S. Dukinfield ◽  
Sandy M. Chu ◽  
Aisah A. Aubdool ◽  
...  
Keyword(s):  
Heart Failure ◽  
Guanylyl Cyclase ◽  
Cardiac Fibrosis ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Treatment Modalities ◽  
Pharmacodynamic Profile ◽  
Cgmp Signaling ◽  
Synthase Inhibitor ◽  
And Function

Heart failure (HF) is a shared manifestation of several cardiovascular pathologies, including hypertension and myocardial infarction, and a limited repertoire of treatment modalities entails that the associated morbidity and mortality remain high. Impaired nitric oxide (NO)/guanylyl cyclase (GC)/cyclic guanosine-3′,5′-monophosphate (cGMP) signaling, underpinned, in part, by up-regulation of cyclic nucleotide-hydrolyzing phosphodiesterase (PDE) isozymes, contributes to the pathogenesis of HF, and interventions targeted to enhancing cGMP have proven effective in preclinical models and patients. Numerous PDE isozymes coordinate the regulation of cardiac cGMP in the context of HF; PDE2 expression and activity are up-regulated in experimental and human HF, but a well-defined role for this isoform in pathogenesis has yet to be established, certainly in terms of cGMP signaling. Herein, using a selective pharmacological inhibitor of PDE2, BAY 60-7550, and transgenic mice lacking either NO-sensitive GC-1α (GC-1α−/−) or natriuretic peptide-responsive GC-A (GC-A−/−), we demonstrate that the blockade of PDE2 promotes cGMP signaling to offset the pathogenesis of experimental HF (induced by pressure overload or sympathetic hyperactivation), reversing the development of left ventricular hypertrophy, compromised contractility, and cardiac fibrosis. Moreover, we show that this beneficial pharmacodynamic profile is maintained in GC-A−/− mice but is absent in animals null for GC-1α or treated with a NO synthase inhibitor, revealing that PDE2 inhibition preferentially enhances NO/GC/cGMP signaling in the setting of HF to exert wide-ranging protection to preserve cardiac structure and function. These data substantiate the targeting of PDE2 in HF as a tangible approach to maximize myocardial cGMP signaling and enhancing therapy.

Minoxidil accelerates heart failure development in rats with ascending aortic constriction

1998 ◽  
Vol 76 (6) ◽  
pp. 613-620 ◽  
Author(s):  
Marian Turcani ◽  
Ruthard Jacob
Keyword(s):  
Heart Failure ◽  
Myocardial Contractility ◽  
Pressure Overload ◽  
Volume Overload ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Aortic Constriction ◽  
Lung Weight ◽  
Eccentric Hypertrophy ◽  
Hemodynamic Overload

To test the ability of the heart to express characteristic geometric features of concentric and eccentric hypertrophy concurrently, constriction of the ascending aorta was performed in 4-week-old rats. Simultaneously, these rats were treated with an arteriolar dilator minoxidil. An examination 6 weeks after induction of the hemodynamic overload revealed no signs of congestion in systemic or pulmonary circulation in rats with aortic constriction or minoxidil-treated sham-operated rats. The magnitude of hemodynamic overload caused by aortic constriction or minoxidil treatment could be considered as equivalent, because the same enlargement of left ventricular pressure-volume area was necessary to compensate for either pressure or volume overload. Myocardial contractility decreased in rats with aortic constriction, and the compensation was achieved wholly by the marked concentric hypertrophy. Volume overload in minoxidil-treated rats was compensated partially by the eccentric hypertrophy and partially by the increased myocardial contractility. In contrast, increased lung weight and pleural effusion were found in all minoxidil-treated rats with aortic constriction. Unfavorable changes in left ventricular mass and geometry, relatively high chamber stiffness, and depressed ventricular and myocardial function were responsible for the massive pulmonary congestion.Key words: cardiac hypertrophy, heart failure, pressure overload, volume overload, minoxidil.

scholarly journals Sotagliflozin, a Dual SGLT1/2 Inhibitor, Improves Cardiac Outcomes in a Normoglycemic Mouse Model of Cardiac Pressure Overload

2021 ◽  
Vol 12 ◽  
Author(s):  
Sophia L. Young ◽  
Lydia Ryan ◽  
Thomas P. Mullins ◽  
Melanie Flint ◽  
Sarah E. Steane ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Cardiac Injury ◽  
Pressure Overload ◽  
Tween 80 ◽  
Left Ventricular ◽  
Normal Diet ◽  
Whole Body ◽  
High Fat ◽  
Cardiac Outcomes

Selective SGLT2 inhibition reduces the risk of worsening heart failure and cardiovascular death in patients with existing heart failure, irrespective of diabetic status. We aimed to investigate the effects of dual SGLT1/2 inhibition, using sotagliflozin, on cardiac outcomes in normal diet (ND) and high fat diet (HFD) mice with cardiac pressure overload. Five-week-old male C57BL/6J mice were randomized to receive a HFD (60% of calories from fat) or remain on ND for 12 weeks. One week later, transverse aortic constriction (TAC) was employed to induce cardiac pressure-overload (50% increase in right:left carotid pressure versus sham surgery), resulting in left ventricular hypertrophic remodeling and cardiac fibrosis, albeit preserved ejection fraction. At 4 weeks post-TAC, mice were treated for 7 weeks by oral gavage once daily with sotagliflozin (10 mg/kg body weight) or vehicle (0.1% tween 80). In ND mice, treatment with sotagliflozin attenuated cardiac hypertrophy and histological markers of cardiac fibrosis induced by TAC. These benefits were associated with profound diuresis and glucosuria, without shifts toward whole-body fatty acid utilization, increased circulating ketones, nor increased cardiac ketolysis. In HFD mice, sotagliflozin reduced the mildly elevated glucose and insulin levels but did not attenuate cardiac injury induced by TAC. HFD mice had vacuolation of proximal tubular cells, associated with less profound sotagliflozin-induced diuresis and glucosuria, which suggests dampened drug action. We demonstrate the utility of dual SGLT1/2 inhibition in treating cardiac injury induced by pressure overload in normoglycemic mice. Its efficacy in high fat-fed mice with mild hyperglycemia and compromised renal morphology requires further study.

scholarly journals Regulation and impact of cardiac lymphangiogenesis in pressure-overload-induced heart failure

2021 ◽  
Author(s):  
C Heron ◽  
A Dumesnil ◽  
M Houssari ◽  
S Renet ◽  
A Lebon ◽  
...  
Keyword(s):  
Heart Failure ◽  
Dilated Cardiomyopathy ◽  
Cardiac Fibrosis ◽  
Immune Cell ◽  
Pressure Overload ◽  
Wall Stress ◽  
Myocardial Edema ◽  
Selective Inhibition ◽  
Left Ventricular ◽  
Ventricular Dilation

AbstractRationaleLymphatics are essential for cardiac health, and insufficient lymphatic expansion (lymphangiogenesis) contributes to development of heart failure (HF) after myocardial infarction. However, the regulation and impact of lymphatics in non-ischemic cardiomyopathy induced by pressure-overload remains to be determined.ObjectiveInvestigate cardiac lymphangiogenesis following transverse aortic constriction (TAC) in adult male or female C57Bl/6J or Balb/c mice, and in patients with end-stage HF.Methods & ResultCardiac function was evaluated by echocardiography, and cardiac hypertrophy, lymphatics, inflammation, edema, and fibrosis by immunohistochemistry, flow cytometry, microgravimetry, and gene expression analysis, respectively. Treatment with neutralizing anti-VEGFR3 antibodies was applied to inhibit cardiac lymphangiogenesis in mice.The gender- and strain-dependent mouse cardiac hypertrophic response to TAC, especially increased ventricular wall stress, led to lymphatic expansion in the heart. Our experimental findings that ventricular dilation triggered cardiac lymphangiogenesis was mirrored by observations in clinical HF samples, with increased lymphatic density found in patients with dilated cardiomyopathy. Surprisingly, the striking lymphangiogenesis observed post-TAC in Balb/c mice, linked to increased cardiac Vegfc, did not suffice to resolve myocardial edema, and animals progressed to dilated cardiomyopathy and HF. Conversely, selective inhibition of the essentially Vegfd-driven capillary lymphangiogenesis observed post-TAC in male C57Bl/6J mice did not significantly aggravate cardiac edema. However, cardiac immune cell levels were increased, notably myeloid cells at 3 weeks and T lymphocytes at 8 weeks. Moreover, while the TAC-triggered development of interstitial cardiac fibrosis was unaffected by anti-VEGFR3, inhibition of lymphangiogenesis increased perivascular fibrosis and accelerated the development of left ventricular dilation and cardiac dysfunction.ConclusionsWe demonstrate for the first time that endogenous cardiac lymphangiogenesis limits pressure-overload-induced cardiac inflammation and perivascular fibrosis, thus delaying HF development. While these findings remain to be confirmed in a larger study of HF patients, we propose that under settings of pressure-overload poor cardiac lymphangiogenesis may accelerate HF development.

Abstract 99: IL10-inhibits Fibroblast Progenitor Cell-mediated Cardiac Fibrosis in Pressure-overloaded Myocardium

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Suresh K Verma ◽  
Venkata N Garikipati ◽  
Prasanna Krishnamurthy ◽  
Cindy Benedict ◽  
Emily Nickoloff ◽  
...  
Keyword(s):  
Heart Failure ◽  
Bone Marrow ◽  
Cardiac Fibrosis ◽  
Critical Role ◽  
Pressure Overload ◽  
Interleukin 10 ◽  
Left Ventricular ◽  
Lv Function ◽  
Wild Type ◽  
Mirna Array

Background: Activated fibroblasts (myoFBs) play critical role in cardiac fibrosis, however, their origin in diseased heart remains uncertain. Recent studies suggest the contribution of bone marrow fibroblasts progenitor cells (BM-FPC) in pressure overload (PO)-induced cardiac fibrosis. Previously we have shown that interleukin-10 suppress PO-induced cardiac fibrosis, however, its role on inhibition of BM-FPC-mediated fibrosis is not known. Thus, we hypothesized that IL-10 inhibits PO-induced homing and transition of BM-FPC to myoFBs and therefore, attenuates cardiac fibrosis. Methods and Results: Cardiac fibrosis was induced in Wild-type (WT) and IL-10-knockout (KO) mice by transverse aortic constriction (TAC). TAC-induced left ventricular (LV) dysfunction and fibrosis were further exaggerated in KO mice. Systemic recombinant IL-10 administration markedly improved LV function and inhibited PO-induced cardiac fibrosis. PO-enhanced FPC (Prominin1 + cells) mobilization and homing in IL-10 KO mice compared to WT mice. Furthermore, bone marrow transplantation (BMT) experiment was performed wherein WT marrow from GFP mice was repopulated in IL-10 KO mice. FPC mobilization was significantly reduced in BMT-IL10 KO mice compared to IL-10 KO mice after TAC. Furthermore, immunofluorescence result in BMT mice showed that subsets of myoFBs are derived from BM after TAC. To identify the molecular mechanism, wild type BM-FPC were treated with TGFβ 2 with or without IL10. IL10 treatment significantly inhibits TGFβ 2 -induced FPC to myoFBs transition. As miRNAs are key players in cardiac fibrosis, next we performed fibrosis-associated miRNA profiling using miRNA array kit. TGFβ 2 -induced miR-208, 155, 21 and 145 expression was markedly inhibited by IL-10. Conclusion: Taken together, our findings suggest that both reduced homing to heart and transition of FPC to myofibroblasts mediate anti-fibrotic effect of IL10 during PO-induced heart failure. Ongoing investigations using molecular approaches will provide a better understanding on the mechanistic and therapeutic aspects of IL10 on PO-induced cardiac fibrosis and heart failure.

scholarly journals Decreased metalloprotease 9 induction, cardiac fibrosis, and higher autophagy after pressure overload in mice lacking the transcriptional regulator p8

2011 ◽  
Vol 301 (5) ◽  
pp. C1046-C1056 ◽  
Author(s):  
Serban P. Georgescu ◽  
Mark J. Aronovitz ◽  
Juan L. Iovanna ◽  
Richard D. Patten ◽  
John M. Kyriakis ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Ventricular Remodeling ◽  
Left Ventricular Remodeling ◽  
Pressure Overload ◽  
Transcriptional Regulator ◽  
Left Ventricular ◽  
Cardiomyocyte Hypertrophy ◽  
Causative Role

Left ventricular remodeling, including the deposition of excess extracellular matrix, is key to the pathogenesis of heart failure. The stress-inducible transcriptional regulator p8 is increased in failing human hearts and is required both for agonist-stimulated cardiomyocyte hypertrophy and for cardiac fibroblasts matrix metalloprotease-9 (MMP9) induction. In the heart, upregulation of autophagy is an adaptive response to stress and plays a causative role in cardiomyopathies. We have recently shown that p8 ablation in cardiac cells upregulates autophagy and that, in vivo, loss of p8 results in a decrease of cardiac function. Here we investigated the effects of p8 genetic deletion in mediating adverse myocardial remodeling. Unstressed p8−/− mouse hearts manifested complex alterations in the expression of fibrosis markers. In addition, these mice displayed elevated autophagy and apoptosis compared with p8+/+ mice. Transverse aortic constriction (TAC) induced left ventricular p8 expression in p8+/+ mice. Pressure overload caused left ventricular remodeling in both genotypes, however, p8−/− mice showed less cardiac fibrosis induction. Consistent with this, although MMP9 induction was attenuated in the p8−/− mice, induction of MMP2 and MMP3 were strikingly upregulated while TIMP2 was downregulated. Left ventricular autophagy increased after TAC and was significantly higher in the p8−/− mice. Thus p8-deletion results in reduced collagen fibrosis after TAC, but in turn, is associated with a detrimental higher increase in autophagy. These findings suggest a role for p8 in regulating in vivo key signaling pathways involved in the pathogenesis of heart failure.

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