Adiponectin is synthesized and secreted by human and murine cardiomyocytes

Abstract

Adiponectin is thought to play a decisive role in the relationships among obesity, insulin resistance and cardiovascular risk. This study investigated whether cardiomyocytes synthesize and secrete adiponectin, and the effects of this hormone on cardiac cells. RT-PCR showed that mouse, rat and human cardiomyocytes produced mRNA for adiponectin and adiponectin receptors 1 and 2. Immunohistochemistry confirmed the presence of adiponectin in the cytoplasm of cultured cardiomyocytes, and radioimmunoassay showed that these cells secreted adiponectin into the culture medium. Exogenous adiponectin enhanced glucose and fatty acid uptake and induced AMPK phosphorylation in cultured cardiomyocytes. Our results demonstrate that adiponectin is synthesized and secreted by isolated murine and human cardiomyocytes, and suggest that the local production of this hormone by cardiomyocytes could be involved in the regulation of cardiac metabolism and function.

Adiponectin and its receptors are expressed in adult ventricular cardiomyocytes and upregulated by activation of peroxisome proliferator-activated receptor γ

“…It was reported that adiponectin is expressed in bone-forming cells [24] and its expression may be induced in cultured myotubes from skeletal muscle [25]. A recent report revealed that adiponectin can be detected from atrium-derived cardiomyocytes [4]. However, it remains unclear if adiponectin is expressed in ventricular cardiomyocytes, especially those from adult hearts.…”

“…AdipoR1 is abundantly expressed in skeletal muscle, whereas AdipoR2 is predominantly expressed in the liver [3]. Adiponectin and its receptor can be detected in cultured atrial cardiomyocytes [4]. Moreover, left-ventricular pressure-overload induced by transverse aortic banding in adiponectin-deficient mice results in exacerbated concentric cardiac hypertrophy and increased mortality with increased extracellular signal-regulated kinase (ERK) and diminished AMPK signaling in mouse heart [5].…”

Adiponectin as a tissue regenerating hormone: more than a metabolic function

“…In this tissue, the genomic expression and secretion of adiponectin is modulated by cytokines such as tumor necrosis factor-α, interferon-γ, interleukin-6, and leptin [11]. Moreover, isolated murine and human cardiomyocytes produce adiponectin [12]. In murine heart, as well as in microvascular endothelium and white adipose tissue, adiponectin expression occurs through a particular regulation.…”

Regulation of adiponectin release and demonstration of adiponectin mRNA as well as release by the non-fat cells of human omental adipose tissue

“…7,8 Adiponectin was originally described as an adipocytespecific protein. [1][2][3] However, more recently adiponectin mRNA and secretion have been demonstrated in boneforming cells, 9,10 cardiomyocytes, 11 skeletal muscle, 12,13 human liver, 14 human placental syncytiotrophoblasts 15 and human fetal tissues of mesodermic and ectodermal origin. 16 It is unclear whether tissues other than adipose tissue contribute to circulating levels of adiponectin that are some 40-fold higher than those of leptin in obese subjects.…”