This Program Project Grant (PPG) renewal describes a series of experiments designed to answer highly relevant questions concerning the mechanisms for sympatho-excitation in chronic heart failure (CHF). There has been a long history of interaction among the Pi's in this PPG. We have contributed substantially to the literature in this area and are now proposing new studies that probe deeper into the origins of sympathetic regulation in CHF. Overall, we believe that sympathetic activation is mediated by a combination of increased sympatho-excitatory reflexes, blunted sympatho-inhibitory reflexes and changes in signaling molecules in the central nervous system and in the periphery. Four projects are proposed. In Project I the focus will be on the mechanism by which the ATiR is upregulated in the RVLM of animals with heart failure. This unique property of a GPCR to be upregulated in the face of increased agonist (Ang II) suggests a pivotal role for this receptor in the pathogenesis of sympatho-excitation in CHF. We will determine alterations in transcriptional regulation of the ATiR and the roles of ACE, ACE2, ROS and exercise training. Project II will focus on the role of the PVN in sympathetic regulation. Building on studies showing abnormalities in the GABA-glutamate systems in the PVN, this project now proposes that an ascending noradrenergic pathway modulated, in part, by aldosterone plays an important role in sympatho-excitation in CHF. The interactions between aldosterone and nNOS will be examined in this project. Finally, the role of exercise training on nNOS and aldosterone in CHF will be investigated. Project III concentrates on the sensitized carotid chemoreflex in CHF. This project has clearly shown chemoreceptor and chemoreflex sensitization in CHF and an important role for K* channel modulation in glomus cells by Ang II and NO in response to hypoxia. This project now focuses on the role of altered carotid body blood flow as a mediator of chemoreflex sensitivity. These studies will investigate the role of a novel transcription factor, KLF2, in mediating transduction between endothelial shear stress and mediators of K* channel function. The role of Ang (1-7) will also be investigated in this project. Project IV will investigate the role of skeletal muscle reflexes on sympatho-excitation in CHF. Specifically, this project will determine if ROS play an important role in altering the sensitivity of both chemically sensitive group III afferents and mechanically sensitive group IV afferents. The role of exercise training in modulating ROS generation and antioxidant enzymes in animals with CHF will also be investigated in this project.
Chronic heart failure is a growing concern as the aging population of the United States increases. New Strategies in the treatment of heart failure must be developed. This PPG is important and highly relevant to the heart failure epidemic in that it addresses a relatively neglected area of patho-physiology, namely sympathetic nerve, activation. These studies will uncover new mechanisms and new potential targets for therapy in the heart failure state.
|Zheng, Hong; Liu, Xuefei; Sharma, Neeru M et al. (2016) Urinary Proteolytic Activation of Renal Epithelial Na+ Channels in Chronic Heart Failure. Hypertension 67:197-205|
|Zheng, Hong; Patel, Kaushik P (2016) Integration of renal sensory afferents at the level of the paraventricular nucleus dictating sympathetic outflow. Auton Neurosci :|
|Patel, Kaushik P; Xu, Bo; Liu, Xuefei et al. (2016) Renal Denervation Improves Exaggerated Sympathoexcitation in Rats With Heart Failure: A Role for Neuronal Nitric Oxide Synthase in the Paraventricular Nucleus. Hypertension 68:175-84|
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|Schiller, Alicia M; Pellegrino, Peter Ricci; Zucker, Irving H (2016) Eppur Si Muove: The dynamic nature of physiological control of renal blood flow by the renal sympathetic nerves. Auton Neurosci :|
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|Stern, Javier E; Son, Sookjin; Biancardi, Vinicia C et al. (2016) Astrocytes Contribute to Angiotensin II Stimulation of Hypothalamic Neuronal Activity and Sympathetic Outflow. Hypertension 68:1483-1493|
|Ardell, J L; Andresen, M C; Armour, J A et al. (2016) Translational neurocardiology: preclinical models and cardioneural integrative aspects. J Physiol 594:3877-909|
|PÃ¼gge, Carolin; Mediratta, Jai; Marcus, Noah J et al. (2016) Exercise training normalizes renal blood flow responses to acute hypoxia in experimental heart failure: role of the Î±1-adrenergic receptor. J Appl Physiol (1985) 120:334-43|
|Sharma, Neeru M; Cunningham, Craig J; Zheng, Hong et al. (2016) Hypoxia-Inducible Factor-1Î± Mediates Increased Sympathoexcitation via Glutamatergic N-Methyl-d-Aspartate Receptors in the Paraventricular Nucleus of Rats With Chronic Heart Failure. Circ Heart Fail 9:|
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