title: Leptin stimulates sympathetic axon outgrowth.
abstract: The neurohormone leptin regulates energy homeostasis. Circulating levels of leptin secreted by adipose tissue act on hypothalamic neurons in the brain leading to decreased appetite and increased energy expenditure. Although leptin signaling in the central nervous system (CNS) is fundamental to its ability to regulate the body's metabolic balance, leptin also has a variety of effects in many peripheral tissues including the heart, the liver, and the sympathetic nervous system. Leptin stimulation of the hypothalamus can stimulate glucose uptake via the sympathetic nervous system in heart, muscle, and brown adipose tissue. Leptin receptors (Ob-Rb) are also expressed by peripheral sympathetic neurons, but their functional role is not clear. In this study, we found that leptin stimulates axonal growth of both adult and neonatal sympathetic neurons in vitro. Leptin stimulates acute activation of the transcription factor STAT3 via phosphorylation of tyrosine 705. STAT3 phosphorylation is required for leptin-stimulated sympathetic axon outgrowth. Thus, circulating levels of leptin may enhance sympathetic nerve innervation of peripheral tissues.
authors.affiliation: Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, USA. Electronic address: pellegri@ohsu.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pellegrino
authors.affiliation: Trauma Research Institute of Oregon, Division of Trauma, Critical Care & Acute Care Surgery, Department of Surgery, Oregon Health & Science University, Portland, OR 97239, USA. Electronic address: houghtob@ohsu.edu.
authors.forename: Belinda H
authors.initials: BH
authors.lastname: McCully
authors.affiliation: Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, USA. Electronic address: habecker@ohsu.edu.
authors.forename: Beth A
authors.initials: BA
authors.lastname: Habecker
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000502:physiology*; D020738:Leptin / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D010766:Phosphorylation; D017207:Rats, Sprague-Dawley; D050796:STAT3 Transcription Factor / Q000378:metabolism; D017783:Superior Cervical Ganglion / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D020738:Leptin; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat
keywords: Axon outgrowth; Cardiac arrhythmia; Leptin; Obesity; STAT3