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Excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents.

ABSTRACT: Although many animal studies indicate insulin has cardioprotective effects, clinical studies suggest a link between insulin resistance (hyperinsulinemia) and heart failure (HF). Here we have demonstrated that excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents. Chronic pressure overload induced hepatic insulin resistance and plasma insulin level elevation. In contrast, cardiac insulin signaling was upregulated by chronic pressure overload because of mechanical stretch-induced activation of cardiomyocyte insulin receptors and upregulation of insulin receptor and Irs1 expression. Chronic pressure overload increased the mismatch between cardiomyocyte size and vascularity, thereby inducing myocardial hypoxia and cardiomyocyte death. Inhibition of hyperinsulinemia substantially improved pressure overload-induced cardiac dysfunction, improving myocardial hypoxia and decreasing cardiomyocyte death. Likewise, the cardiomyocyte-specific reduction of insulin receptor expression prevented cardiac ischemia and hypertrophy and attenuated systolic dysfunction due to pressure overload. Conversely, treatment of type 1 diabetic mice with insulin improved hyperglycemia during pressure overload, but increased myocardial ischemia and cardiomyocyte death, thereby inducing HF. Promoting angiogenesis restored the cardiac dysfunction induced by insulin treatment. We therefore suggest that the use of insulin to control hyperglycemia could be harmful in the setting of pressure overload and that modulation of insulin signaling is crucial for the treatment of HF.

SUBMITTER: Shimizu I

PROVIDER: S-EPMC2860916 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

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Excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents.

Shimizu Ippei I Minamino Tohru T Toko Haruhiro H Okada Sho S Ikeda Hiroyuki H Yasuda Noritaka N Tateno Kaoru K Moriya Junji J Yokoyama Masataka M Nojima Aika A Koh Gou Young GY Akazawa Hiroshi H Shiojima Ichiro I Kahn C Ronald CR Abel E Dale ED Komuro Issei I

The Journal of clinical investigation 20100419 5

Although many animal studies indicate insulin has cardioprotective effects, clinical studies suggest a link between insulin resistance (hyperinsulinemia) and heart failure (HF). Here we have demonstrated that excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents. Chronic pressure overload induced hepatic insulin resistance and plasma insulin level elevation. In contrast, cardiac insulin signaling was upregulated by chronic pressure overload ...[more]

PMID: 20407209

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Project description:Background Chronic sustained pressure overload induces cardiac remodeling, which often leads to heart failure. Cardiac macrophages (cMacs) are heterogeneous cell populations, and their elimination has been shown to exacerbate pressure overload-induced heart failure. CD163, a macrophage-specific scavenger receptor expressed in a subset of cMacs, has been linked to cardiovascular events through its serum soluble form. This study aimed to elucidate the functional role of the CD163+ cMacs subset in pressure overload-induced heart failure. Methods Transverse aortic constriction (TAC) was performed on wild-type and CD163-deficient (Cd163-/-) mice to investigate the role of CD163 in pressure overload-induced cardiac remodeling and heart failure. Echocardiography was used to assess heart structure and function. Transcriptomic analysis and transmission electron microscopy were employed to observe mitochondrial structure in cardiomyocytes. Flow cytometry was used to quantify cMacs and cytokine-expressing cMacs in the heart. Additionally, serum samples from hypertensive patients with and without heart failure were analyzed to explore the relationship between CD163 and heart failure. Results TAC-induced left ventricular systolic dysfunction, including reduced ejection fraction and fractional shortening, was significantly aggravated in Cd163-/- mice post-surgery. Genes differentially expressed due to CD163 deficiency were enriched in pathways related to mitochondrial bioenergetics and homeostasis. Transmission electron microscopy revealed an increase in dysfunctional mitochondria in cardiomyocytes of Cd163-/- mice post-TAC. Additionally, decreased serum interleukin (IL)-10 levels and reduced IL-10 expression in cMacs were observed in Cd163-/- mice post-TAC. IL-10 supplementation significantly reversed TAC-induced reductions in left ventricular systolic function and improved mitochondrial bioenergetics and homeostasis in Cd163-/- mice. Conclusions The protective functions of CD163 in cMacs are associated with IL-10 expression during pressure overload-induced heart failure.

Project description:Background SENP1 (sentrin/small ubiquitin-like modifier-specific protease 1) has emerged as a significant modulator involved in the pathogenesis of a variety of human diseases, especially cancer. However, the regulatory roles of SENP1 in cardiovascular biology and diseases remain controversial. Our current study aims to clarify the function and regulation of SENP1 in pressure overload-induced cardiac remodeling and dysfunction. Methods and Results We used a preclinical mouse model of transverse aortic constriction coupled with in vitro studies in neonatal rat cardiomyocytes to study the role of SENP1 in cardiac hypertrophy. Gene delivery system was used to knockdown or overexpress SENP1 in vivo. Here, we observed that SENP1 expression was significantly augmented in murine hearts following transverse aortic constriction as well as neonatal rat cardiomyocytes treated with phenylephrine or angiotensin II. Cardiac-specific SENP1 knockdown markedly exacerbated transverse aortic constriction-induced cardiac hypertrophy, systolic dysfunction, fibrotic response, and cellular apoptosis. In contrast, adenovirus-mediated SENP1 overexpression in murine myocardium significantly attenuated cardiac remodeling and dysfunction following chronic pressure overload. Mechanistically, JAK2 (Janus kinase 2) and STAT3 (signal transducer and activator of transcription 3) acted as new interacting partners of SENP1 in this process. SENP1-JAK2/STAT3 interaction suppressed STAT3 nuclear translocation and activation, ultimately inhibiting the transcription of prohypertrophic genes and the initiation of hypertrophic response. Furthermore, cardiomyocyte-specific STAT3 knockout mice were generated to validate the underlying mechanisms, and the results showed that STAT3 ablation blunted the cardiac hypertrophy-promoting effects of SENP1 deficiency. Additionally, pharmacological inhibition of SENP1 by Momordin Ic amplified cardiac remodeling post-transverse aortic constriction. Conclusions Our study provided evidence that SENP1 protected against pressure overload-induced cardiac remodeling and dysfunction via inhibiting STAT3 signaling. SENP1 supplementation might constitute a new promising treatment against cardiac hypertrophy. Notably, cardiovascular side effects should be seriously considered while applying systemic SENP1 blockers to suppress tumors.

Dataset Information

Excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents.

Publications

Excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents.

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