• Yang Yu, Ethan Chen, Robert M Weiss, Robert B Felder, and Shun-Guang Wei.
• Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, United States.
• Neuroscience. 2022 Feb 10; 483: 132313-23.

AbstractActivation of epidermal growth factor receptor (EGFR) tyrosine kinase is associated with increased extracellular signal-regulated kinase (ERK) 1/2 signaling in the hypothalamic paraventricular nucleus (PVN), which contributes to the sympathetic excitation in heart failure (HF). Transforming growth factor (TGF)-α is a major endogenous ligand for EGFR. The present study sought to determine whether TGF-α increases in the PVN in HF and promotes the activation of EGFR to increase ERK1/2 activity. Male rats received bilateral PVN microinjections of an EGFR siRNA or a scrambled siRNA followed by an intracerebroventricular (ICV) injection of TGF-α or vehicle one week later. In rats pretreated with the scrambled siRNA, ICV TGF-α increased phosphorylated (p-) EGFR and upregulated the expression of p-ERK1/2 and mRNA levels of proinflammatory cytokines (PICs) and renin-angiotensin system (RAS) components in the PVN, when compared with the untreated age-matched control rats. These responses to ICV TGF-α were significantly attenuated in rats pretreated with the EGFR siRNA. Furthermore, bilateral PVN microinjection of a TGF-α siRNA in HF rats significantly decreased the elevated levels of TGF-α, p-EGFR, p-ERK1/2 and the mRNA expression of PICs and RAS components in the PVN, compared with the HF rats treated with a scrambled siRNA. The TGF-α siRNA-treated HF rats also exhibited lower plasma norepinephrine levels and improved peripheral manifestations of HF. These data suggest that TGF-α expression is upregulated in the PVN in HF and induces the activation of EGFR-mediated ERK1/2 signaling to augment the inflammation and RAS activity that drives sympathetic excitation in HF.Copyright © 2021 IBRO. Published by Elsevier Ltd. All rights reserved.

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