Activation of the β-adrenergic receptor exacerbates lipopolysaccharide-induced wasting of skeletal muscle cells by increasing interleukin-6 production

PLoS One. 2021 May 18;16(5):e0251921. doi: 10.1371/journal.pone.0251921. eCollection 2021.

Abstract

The skeletal muscle mass has been shown to be affected by catecholamines, such as epinephrine (Epi), norepinephrine (NE), and isoproterenol (ISO). On the other hand, lipopolysaccharide (LPS), one of the causative substances of sepsis, induces muscle wasting via toll-like receptors expressed in skeletal muscle. Although catecholamines are frequently administered to critically ill patients, it is still incompletely understood how these drugs affect skeletal muscle during critical illness, including sepsis. Herein, we examined the direct effects of catecholamines on LPS-induced skeletal muscle wasting using the C2C12 myoblast cell line. Muscle wasting induced by catecholamines and/or LPS was analyzed by the use of the differentiated C2C12 myotubes, and its underlying mechanism was explored by immunoblotting analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and the TransAM kit for p-65 NF-κB. Epi augmented myosin heavy chain (MHC) protein loss and reduction of the myotube diameter induced by LPS. LPS induced C/EBPδ protein, Atrogin-1 and inteleukin-6 (IL-6), and these responses were potentiated by Epi. An IL-6 inhibitor, LMT28, suppressed the potentiating effect of Epi on the LPS-induced responses. NF-κB activity was induced by LPS, but was not affected by Epi and recombinant IL-6, and the NF-κB inhibitor, Bay 11-7082, abolished Atrogin-1 mRNA expression induced by LPS with or without Epi. NE and ISO also potentiated LPS-induced IL-6 and Atroign-1 mRNA expression. Carvedilol, a nonselective β-adrenergic receptor antagonist, suppressed the facilitating effects of Epi on the Atrogin-1 mRNA induction by LPS, and abolished the effects of Epi on the MHC protein loss in the presence of LPS. It was concluded that Epi activates the β-adrenergic receptors in C2C12 myotubes and the IL-6-STAT3 pathway, leading to the augmentation of LPS-induced activation of the NF-κB- C/EBPδ-Atrogin-1 pathway and to the exacerbation of myotube wasting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CCAAT-Enhancer-Binding Protein-delta / genetics*
  • Carvedilol / pharmacology
  • Epinephrine / metabolism
  • Epinephrine / pharmacology
  • Gene Expression Regulation / drug effects
  • Humans
  • Interleukin-6 / antagonists & inhibitors
  • Interleukin-6 / genetics
  • Isoproterenol / metabolism
  • Isoproterenol / pharmacology
  • Lipopolysaccharides / toxicity
  • Mice
  • Muscle Proteins / genetics*
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / pathology
  • Muscular Atrophy / chemically induced
  • Muscular Atrophy / drug therapy*
  • Muscular Atrophy / genetics
  • Muscular Atrophy / pathology
  • Myoblasts / drug effects
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / genetics
  • Nitriles / pharmacology
  • Norepinephrine / metabolism
  • Norepinephrine / pharmacology
  • Oxazolidinones / pharmacology
  • Receptors, Adrenergic, beta / genetics
  • SKP Cullin F-Box Protein Ligases / genetics*
  • STAT3 Transcription Factor / genetics*
  • Sulfones / pharmacology

Substances

  • 3-(4-methylphenylsulfonyl)-2-propenenitrile
  • Cebpd protein, mouse
  • Interleukin-6
  • LMT-28
  • Lipopolysaccharides
  • Muscle Proteins
  • NF-kappa B
  • Nitriles
  • Oxazolidinones
  • Receptors, Adrenergic, beta
  • STAT3 Transcription Factor
  • Stat3 protein, mouse
  • Sulfones
  • Carvedilol
  • CCAAT-Enhancer-Binding Protein-delta
  • Fbxo32 protein, mouse
  • SKP Cullin F-Box Protein Ligases
  • Isoproterenol
  • Norepinephrine
  • Epinephrine

Grant support

The study was supported by Grants-in-Aid for Young Scientists from the Japan Society for the Promotion of Science (grant numbers 18K16447 to SK, and 17K16729 to HS), and Research Grants from The Nakatomi Foundation (203180700108) (https://www.nakatomi.or.jp/en/) to SK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.