Octominin Inhibits LPS-Induced Chemokine and Pro-inflammatory Cytokine Secretion from RAW 264.7 Macrophages via Blocking TLRs/NF-κB Signal Transduction.

K K Asanka Sanjeewa,Bomi Ryu,Ilson Whang,You-Jin Jeon,Thilina U Jayawardena,D P Nagahawatta,Hye-Won Yang,Jae Young Oh,Mahanama De Zoysa

doi:10.3390/biom10040511

Abstract

Inflammation is a well-organized innate immune response that plays an important role during the pathogen attacks and mechanical injuries. The Toll-like receptors (TLR)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a major signal transduction pathway observed in RAW 264.7 macrophages during the inflammatory responses. Here, we investigated the anti-inflammatory effects of Octominin; a bio-active peptide developed from Octopus minor in RAW 264.7 macrophages in vitro. Octominin was found to inhibit lipopolysaccharides (LPS)-stimulated transcriptional activation of NF-κB in RAW 264.7 cells and dose-dependently decreased the mRNA expression levels of TLR4. Specifically, in silico docking results demonstrated that Octominin has a potential to inhibit TLR4 mediated inflammatory responses via blocking formation of TLR4/MD-2/LPS complex. We also demonstrated that Octominin could significantly inhibit LPS-induced secretion of pro-inflammatory cytokine (interleukin-β; IL-1β, IL-6, and tumor necrosis factor-α) and chemokines (CCL3, CCL4, CCL5, and CXCL10) from RAW 264.7 cells. Additionally, Octominin repressed the LPS-induced pro-inflammatory mediators including nitric oxide (NO), prostaglandin E2, inducible NO synthase, and cyclooxygenase 2 in macrophages. These results suggest that Octominin is a potential inhibitor of TLRs/NF-κB signal transduction pathway and is a potential candidate for the treatment of inflammatory diseases.

Highlights

Octopus minor (Sasaki, 1920) is a member of class Cephalopods and phylum Mollusca; known as the common long-arm octopus
According to in silico docking results, Octominin was buried in the pocket of the TLR4/myeloid differentiation factor 2 (MD-2) complex by interacting with amino acid sites located in the TLR4/MD-2 heterodimer
Our results indicated that Octominin could potently alleviate LPS-activated inflammation through Toll-like receptors (TLR)/NF-κB axis in RAW 264.7 cells

Summary

Introduction

Octopus minor (Sasaki, 1920) is a member of class Cephalopods and phylum Mollusca; known as the common long-arm octopus. Most of the studies conducted on O. minor have been limited to genome studies, co-culture techniques, and nutritional analysis; limited attention have been given to identify its bioactive properties such as anti-inflammatory, anticancer, and antioxidants. It is a well-known fact that the marine ecosystems represent a rich source of structurally unique and novel bioactive compounds from the perspective of potential therapeutic agents [5,6]. The sequence of the peptide, which was designated as Octominin, and was able to act as antimicrobial peptide too

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