1. Academic Validation
  2. Spike Protein of SARS-CoV-2 Activates Cardiac Fibrogenesis through NLRP3 Inflammasomes and NF-κB Signaling

Spike Protein of SARS-CoV-2 Activates Cardiac Fibrogenesis through NLRP3 Inflammasomes and NF-κB Signaling

  • Cells. 2024 Aug 11;13(16):1331. doi: 10.3390/cells13161331.
Huynh Van Tin 1 Lekha Rethi 2 Satoshi Higa 3 Yu-Hsun Kao 1 4 5 Yi-Jen Chen 1 4 6
Affiliations

Affiliations

  • 1 International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
  • 2 Department of Orthopedics, Shuangho Hospital, Taipei Medical University, Taipei 11031, Taiwan.
  • 3 Cardiac Electrophysiology and Pacing Laboratory, Division of Cardiovascular Medicine, Makiminato Central Hospital, Okinawa 901-2131, Japan.
  • 4 Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
  • 5 Department of Medical Education and Research, Wan Fang Hospital, Taipei Medical University, Taipei 11031, Taiwan.
  • 6 Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei 11031, Taiwan.
Abstract

Background: The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is crucial to viral entry and can cause cardiac injuries. Toll-like Receptor 4 (TLR4) and NOD-, LPR-, and pyrin-domain-containing 3 (NLRP3) inflammasome are critical immune system components implicated in cardiac fibrosis. The spike protein activates NLRP3 inflammasome through TLR4 or angiotensin-converting Enzyme 2 (ACE2) receptors, damaging various organs. However, the role of spike protein in cardiac fibrosis in humans, as well as its interactions with NLRP3 inflammasomes and TLR4, remain poorly understood.

Methods: We utilized scratch assays, Western blotting, and immunofluorescence to evaluate the migration, fibrosis signaling, mitochondrial calcium levels, Reactive Oxygen Species (ROS) production, and cell morphology of cultured human cardiac fibroblasts (CFs) treated with spike (S1) protein for 24 h with or without an anti-ACE2 neutralizing antibody, a TLR4 blocker, or an NLRP3 Inhibitor.

Results: S1 protein enhanced CFs migration and the expressions of collagen 1, α-smooth muscle actin, transforming growth factor β1 (TGF-β1), phosphorylated SMAD2/3, interleukin 1β (IL-1β), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). S1 protein increased ROS production but did not affect mitochondrial calcium content and cell morphology. Treatment with an anti-ACE2 neutralizing antibody attenuated the effects of S1 protein on collagen 1 and TGF-β1 expressions. Moreover, NLRP3 (MCC950) and NF-kB inhibitors, but not the TLR4 Inhibitor TAK-242, prevented the S1 protein-enhanced CFs migration and overexpression of collagen 1, TGF-β1, and IL-1β.

Conclusion: S1 protein activates human CFs by priming NLRP3 inflammasomes through NF-κB signaling in an ACE2-dependent manner.

Keywords

NLRP3 inflammasome; angiotensin-converting enzyme 2; cardiac fibroblasts; spike protein.

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