The Intracellular Interaction of Porcine β-Defensin 2 with VASH1 Alleviates Inflammation via Akt Signaling Pathway.

Abstract

Defensins are a major class of antimicrobial peptides that facilitate the immune system to resist pathogen infection. To date, only β-defensins have been identified in pigs. In our previous studies, porcine β-defensin 2 (PBD-2) was shown to have both bactericidal activity and modulatory roles on inflammation. PBD-2 can interact with the cell surface TLR4 and interfere with the NF-κB signaling pathway to suppress the inflammatory response. In this study, the intracellular functions of PBD-2 were investigated. The fluorescently labeled PBD-2 could actively enter mouse macrophage cells. Proteomic analysis indicated that 37 proteins potentially interacted with PBD-2, among which vasohibin-1 (VASH1) was further tested. LPS, an inflammation inducer, suppressed the expression of VASH1, whereas PBD-2 inhibited this effect. PBD-2 inhibited LPS-induced activation of Akt, expression and release of the inflammatory mediators vascular endothelial growth factor and NO, and cell damage. A follow-up VASH1 knockdown assay validated the specificity of the above observations. In addition, PBD-2 inhibited LPS-induced NF-κB activation via Akt. The inhibition effects of PBD-2 on LPS triggered suppression of VASH1 and activation of Akt, and NF-κB and inflammatory cytokines were also confirmed using pig alveolar macrophage 3D4/21 cells. Therefore, the data indicate that PBD-2 interacts with intracellular VASH1, which inhibits the LPS-induced Akt/NF-κB signaling pathway, resulting in suppression of inflammatory responses. Together with our previous findings, we conclude that PBD-2 interacts with both the cell surface receptor (TLR4) and also with the intracellular receptor (VASH1) to control inflammation, thereby providing insights into the immunomodulatory roles of defensins.

• Authors: Chao Huang, Yufan Sun, Xiuxiu Qiu, Jing Huang, Antian Wang, Qiuhong Zhang, Siqi Pang, Qi Huang, Rui Zhou, Lu Li
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 208 Issue 12 Pg. 2795-2805 (06 15 2022) ISSN: 1550-6606 [Electronic] United States
• PMID: 35688466 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2022 by The American Association of Immunologists, Inc.

Chemical References

• Cell Cycle Proteins
• Lipopolysaccharides
• NF-kappa B
• Toll-Like Receptor 4
• Vascular Endothelial Growth Factor A
• beta-Defensins
• Proto-Oncogene Proteins c-akt

Topics

• Animals
• Cell Cycle Proteins (metabolism)
• Inflammation
• Lipopolysaccharides (pharmacology)
• Mice
• NF-kappa B (metabolism)
• Proteomics
• Proto-Oncogene Proteins c-akt (metabolism)
• Signal Transduction
• Swine
• Toll-Like Receptor 4
• Vascular Endothelial Growth Factor A (pharmacology)
• beta-Defensins (pharmacology)