Silencing of TLR4 Inhibits Atrial Fibrosis and Susceptibility to Atrial Fibrillation via Downregulation of NLRP3-TGF- β in Spontaneously Hypertensive Rats

Dis Markers. 2022 Jul 11:2022:2466150. doi: 10.1155/2022/2466150. eCollection 2022.

Abstract

Introduction: This study was aimed at exploring whether silencing of TLR4 could inhibit atrial fibrosis and susceptibility to atrial fibrillation (AF) by regulating NLRP3-TGF-β in hypertensive rats.

Methods: Spontaneously hypertensive rats (SHRs) were transfected with either a virus containing TLR4-shRNA to downregulate TLR4 or an empty virus (vehicle) at the age of 14 weeks. Fibrosis of left atrium and susceptibility to AF were detected, and expression of NLRP3-TGF-β in left atrial tissue at 22 weeks of age was measured. Primary cardiac fibroblasts were transfected with TLR4-shRNA or scrambled vehicle and stimulated with angiotensin (Ang) II. Proliferation of cardiac fibroblasts and expression of NLRP3-TGF-β were detected.

Results: Silencing of TLR4 reduced left atrial fibrosis and susceptibility to AF in SHRs and downregulated expression of NLRP3, TGF-β, and collagen I. In vitro, TLR4 silencing reduced proliferation of cardiac fibroblasts induced by Ang II as well as expression of NLRP3, TGF-β, and collagen I.

Conclusion: Silencing of TLR4 can downregulate NLRP3-TGF-β to reduce atrial fibrosis and susceptibility to AF in SHRs.

MeSH terms

  • Angiotensin II / pharmacology
  • Animals
  • Atrial Fibrillation* / genetics
  • Collagen Type I / genetics
  • Down-Regulation
  • Fibrosis
  • Heart Atria / metabolism
  • Heart Atria / pathology
  • NLR Family, Pyrin Domain-Containing 3 Protein / genetics
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
  • RNA, Small Interfering / metabolism
  • Rats
  • Rats, Inbred SHR
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta1 / genetics

Substances

  • Collagen Type I
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, rat
  • RNA, Small Interfering
  • Tlr4 protein, rat
  • Toll-Like Receptor 4
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • Angiotensin II