Activation of the cardiac ciliary neurotrophic factor receptor reverses left ventricular hypertrophy in leptin-deficient and leptin-resistant obesity

Abstract

Disruption of the leptin signaling pathway within the heart causes left ventricular hypertrophy (LVH). Because human obesity is a syndrome of leptin resistance, which is not amenable to leptin treatment, the identification of parallel signal transduction pathways is of potential therapeutic value. Ciliary neurotrophic factor (CNTF), which acts parallel to leptin in the hypothalamus, is not previously recognized to have cardiac activity. We hypothesized that CNTF receptors are present on cardiomyocytes and their activation reverses LVH in both leptin-deficient ob͞ob and leptinresistant db͞db mice. The localization of CNTF receptors (CNTFR␣) to the sarcolemma in C57BL͞6, ob͞ob and db͞db was confirmed in situ with immunohistochemistry, and immunoblotting (60 and 40 kDa) on isolated myocytes. ob͞ob mice were randomly assigned to receive s.c. recombinant CNTF (CNTF Ax15; 0.1 mg⅐kg ؊1 per day; n ‫؍‬ 11) calorie-restriction (n ‫؍‬ 9), or feeding ad libitum (n ‫؍‬ 11). db͞db mice were allocated to three similar groups (n ‫؍‬ 8, 7, and 8, respectively) plus a leptin group (1 mg⅐kg ؊1 per day; n ‫؍‬ 7). Echocardiography showed that CNTFAx15 reduced cardiac hypertrophy [posterior wall thickness decreased by 29 ؎ 8% (P < 0.01) in ob͞ob and by 21 ؎ 3% in db͞db mice (P < 0.01)], which was consistent with the reduction of myocyte width. Western blotting showed that leptin and CNTF Ax15 activated Stat3 and ERK1͞2 pathway in cultured adult mice cardiomyocytes and cardiac tissue from in ob͞ob and db͞db mice. Together, these findings support the role of a previously undescribed signaling pathway in obesityassociated cardiac hypertrophy and have therapeutic implications for patients with obesity-related cardiovascular disease and other causes of LVH.signal transduction ͉ cardiac remodeling ͉ mouse ͉ heart ͉ Axokine L eft ventricular hypertrophy (LVH) and its subsequent progression to congestive heart failure represents a major cause of morbidity and mortality in the United States (1). Obesity, an important mediator of LVH (2), results from either deficiency of or receptor insensitivity to leptin (3-5), a hormone that regulates appetite and energy metabolism (6). We have previously demonstrated that both leptin deficiency and resistance contribute to LVH in murine models (7). Additionally, we showed regression of LVH with leptin repletion in leptin-deficient ob͞ob mice. However, because the majority of human obesity is associated with hyperleptinemia and leptin resistance (4,8,9) that is unresponsive to leptin treatment, we sought to identify an alternate signaling axis that regulates cardiac architecture. Here we address this issue with ciliary neurotrophic factor (CNTF), which activates a related signaling pathway to leptin and has similar effects on body weight and metabolism (10-12). The CNTF receptor (CNTFR) complex closely resembles the leptin receptor (ObR) structurally and has a similar distribution in the hypothalamic nuclei associated with regulation of feeding and body weight (13, 14). Both receptors are members of the gp...

Magnetic resonance imaging of progressive cardiomyopathic changes in the db/db mouse

“…Our results correlate with those of existing echocardiographic studies on db/db mice (7,8,16,36,45,48,58), although only two such investigations consisted of longitudinal evaluations with multiple time points. Semeniuk et al (58) studied db/db mice at 6 and 12 wk of age.…”

STAT3-induced WNT5A signaling loop in embryonic stem cells, adult normal tissues, chronic persistent inflammation, rheumatoid arthritis and cancer (Review)

“…Leptin deficiency as well as leptin resistance lead to left ventricular hypertrophy and congestive heart failure. CNTF rescues left ventricular hypertrophy associated with leptin resistance through the CNTF-receptor-mediated STAT3-signaling activation (46). Together, these facts indicate that the cytokine-induced WNT5A signaling loop in cardiac myocytes is implicated in the prevention of left ventricular hypertrophy.…”

Long-term functional improvement and gene expression changes after bone marrow-derived multipotent progenitor cell transplantation in myocardial infarction

“…Apart from the monocistronic transcript originating from this locus, a cotranscribed variant composed of ZFP91 and CNTF sequence has been identified. CNTF promotes survival and decreases apoptosis in neurons and islet cells and has also been shown to reverse cardiac hypertrophy in mice (21,22).…”