Epithelial and Endothelial Adhesion of Immune Cells Is Enhanced by Cardiotonic Steroid Signaling Through Na+/K+-ATPase-α-1.

Abstract

Background Recent studies have highlighted a critical role for a group of natriuretic hormones, cardiotonic steroid (CTS), in mediating renal inflammation and fibrosis associated with volume expanded settings, such as chronic kidney disease. Immune cell adhesion is a critical step in the inflammatory response; however, little is currently understood about the potential regulatory role of CTS signaling in this setting. Herein, we tested the hypothesis that CTS signaling through Na+/K+-ATPase α-1 (NKA α-1) enhances immune cell recruitment and adhesion to renal epithelium that ultimately advance renal inflammation. Methods and Results We demonstrate that knockdown of the α-1 isoform of Na/K-ATPase causes a reduction in CTS-induced macrophage infiltration in renal tissue as well reduces the accumulation of immune cells in the peritoneal cavity in vivo. Next, using functional adhesion assay, we demonstrate that CTS-induced increases in the adhesion of macrophages to renal epithelial cells were significantly diminished after reduction of NKA α-1 in either macrophages or renal epithelial cells as well after inhibition of NKA α-1-Src signaling cascade with a specific peptide inhibitor, pNaKtide in vitro. Finally, CTS-induced expression of adhesion markers in both endothelial and immune cells was significantly inhibited in an NKA α-1-Src signaling dependent manner in vitro. Conclusions These findings suggest that CTS potentiates immune cell migration and adhesion to renal epithelium through an NKA α-1-dependent mechanism; our new findings suggest that pharmacological inhibition of this feed-forward loop may be useful in the treatment of renal inflammation associated with renal disease.

• Authors: Fatimah K Khalaf, Iman Tassavvor, Amal Mohamed, Yiliang Chen, Deepak Malhotra, Zijian Xie, Jiang Tian, Steven T Haller, Kristen Westfall, W H Wilson Tang, David J Kennedy
• Journal: Journal of the American Heart Association (J Am Heart Assoc) Vol. 9 Issue 3 Pg. e013933 (02 04 2020) ISSN: 2047-9980 [Electronic] England
• PMID: 32013704 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Bufanolides
• Cardiotonic Agents
• telocinobufagin
• src-Family Kinases
• ATP1A1 protein, human
• Atp1a1 protein, rat
• Atp1a1 protein, mouse
• Sodium-Potassium-Exchanging ATPase

Topics

• Animals
• Bufanolides (pharmacology)
• Cardiotonic Agents (pharmacology)
• Cell Adhesion (drug effects)
• Cell Movement (drug effects)
• Coculture Techniques
• Endothelial Cells (drug effects, enzymology)
• Epithelial Cells (drug effects, enzymology)
• Humans
• Kidney Tubules, Proximal (drug effects, enzymology)
• LLC-PK1 Cells
• Macrophages, Peritoneal (drug effects, enzymology, immunology)
• Mice, Knockout
• Rats, Inbred Dahl
• Signal Transduction
• Sodium-Potassium-Exchanging ATPase (deficiency, genetics, metabolism)
• Swine
• src-Family Kinases (metabolism)