Human UCN3 blocking peptide

Peptide infusions of peptides the corticotropin releasing factor family, including urocortin 2, stresscopin, and urocortin 3 (UCn3), have favorable acute effects in clinical heart failure (HF), but their short half-lives make them unsuitable for chronic therapy. This study asked whether UCn3 gene transfer, which provides sustained elevation of plasma UCn3 levels, increases the function of the failing heart. HF was induced by transmural left ventricular (LV) cryoinjury in mice. LV function was assessed 3 weeks later by echocardiography. Those with ejection fractions (EF) <40% received intravenous saline or intravenous adeno-associated virus type-8 encoding murine UCn3 (AAV8.mUCn3; 1.9x10(13) genome copies/kg). Five weeks after randomization, repeat echocardiography, assessment of LV function (+dP/dt, -dP/dt), and quantification of Ca2+ transients and sarcomere shortening in isolated cardiac myocytes were conducted, and assessment of LV Ca2+ handling and stress proteins was performed. Three weeks after myocardial infarction, prior to treatment, EFs were reduced (mean 31%, from 63% in sham-operated animals). Mice randomized to receive UCn3 gene transfer showed increased plasma UCn3 (from 0.1 +/- 0.01ng/mL in the saline group to 5.6 +/- 1.1ng/mL; n=12 each group; p<0.0001). Compared to mice that received saline, UCn3 gene transfer was associated with higher values for EF (p=0.0006); LV +dP/dt (p<0.0001), and LV -dP/dt (p<0.0001). Cardiac myocytes from mice that received UCn3 gene transfer showed higher peak Ca2+ transients (p=0.0005), lower time constant of cytosolic Ca2+ decline (tau, p<0.0001), and higher rates of sarcomere shortening (+dL/dt, p=0.03) and lengthening (-dL/dt, p=0.04). LV samples from mice that received UCn3 gene transfer contained higher levels of SERCA2a (p=0.0004 vs. HF) and increased amounts of phosphorylated troponin I (p=0.04 vs. HF). UCn3 gene transfer is associated with improved Ca2+ handling and LV function in mice with HF and reduced EF.

Exogenous administration of substance P (SP) exerts anorexigenic effects in both chicks and rats, but the central mechanism mediating this response is poorly understood. Therefore, this study was designed to elucidate mechanisms of SP-induced anorexia using chicks as models. Chicks that received intracerebroventricular (ICV) injections of SP dose-dependably reduced their food intake with no effect on water intake. Next, the diencephalon was isolated from SP-injected chicks and mRNA expression of neuropeptide Y (NPY), corticotropin releasing factor (CRF), urocortin 3 (UCN 3) and CRF receptors were measured but were not affected. When measured in the hypothalamus, mRNA abundance of these and NPY receptors, urotensin 2 (UTS2) and melanocortin receptor 4 (MCR4) were not affected by SP-injection. Quantification of c-Fos immunoreactivity in appetite-associated hypothalamic nuclei demonstrated that the paraventricular nucleus (PVN) was activated in SP-injected chicks. Finally, in the PVN isolated from SPinjected chicks, there was increased expression of UTS2 mRNA while CRF and UCN3 were not affected. Thus, the anorexigenic effects of SP appear to be mediated by PVN activation and may involve UTS2. (C) 2014 Elsevier Ltd. All rights reserved.