In Vitro Immune-Enhancing Activity of Ovotransferrin from Egg White via MAPK Signaling Pathways in RAW 264.7 Macrophages

Abstract

Ovotransferrin (OTF) is a well-known protein of the transferrin family with strong iron chelating activity, resulting in its antimicrobial activity. Furthermore, OTF is known to have antioxidant, anticancer, and antihypertensive activities. However, there have been few studies about the immune-enhancing activity of OTF. In current study, we investigated the immune-enhancing activity of OTF using the murine macrophage cells in vitro. The effect of OTF on production of pro-inflammatory mediators and cytokines were determined using Griess assay and quantitative real-time PCR. Using Neutral Red uptake assay, we confirmed the effect of OTF on phagocytic activity of macrophages. Ovotransferrin significantly increased the production of nitric oxide (NO) and secretion of inducible nitric oxide synthase (iNOS) mRNA with no cytotoxic activity. Ovotransferrin (2 mg/mL) stimulated NO production up to 31.9±3.5 μM. Ovotransferrin significantly increased the mRNA expression levels of pro-inflammatory cytokines which are tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), and IL-6: OTF (2 mg/mL) treatment increased the secretion of mRNA for TNF-α, IL-1β, and IL-6 by 22.20-, 37.91-, and 6.17-fold of the negative control, respectively. The phagocytic activity of macrophages was also increased by OTF treatment significantly compared with negative control. Also, OTF treatment increased phosphorylation level of MAPK signaling pathways. These results indicated that OTF has immune-enhancing activity by activating RAW 264.7 macrophages via MAPK pathways.

Improved immune-enhancing activity of egg white protein ovotransferrin after enzyme hydrolysis

“…Some of them are reported to have immunemodulatory activity by stimulating the production of cytokines, activating signaling pathways, and activating immune cells [2,[10][11][12]. Ovotransferrin (OTF) is the second major egg white protein and is reported to account for about 12~13% of egg white protein [13]. OTF has a molecular weight of 78 kDa and has 15 disulfide bonds in a protein structure consisting of 686 amino acids.…”

Enzymatic Hydrolysis of Ovotransferrin and the Functional Properties of Its Hydrolysates

“…The native ovotransferrin displays multiple bioactivities that include antimicrobial activity for a wide spectrum of bacteria, fungi, yeasts, and parasites ( Cooper et al, 2019 ; Ibrahim et al, 1998 ; Ko et al., 2008a ; Ko et al, 2008b ; Moon et al, 2012 ; Valenti et al, 1983 ), antioxidant activity ( Ibrahim et al, 2007 ; Moon et al, 2015 ), anticancer activity against colon and breast cancer ( Ibrahim and Kiyono, 2009 ), and immunomodulatory activity ( Chiurciu et al, 2017 ; Lee et al, 2018 ; Xie et al, 2002 ; Zhang et al, 2020 ; Zhu et al, 2019 ). However, Moon et al (2017) reported that native ovotransferrin does not contain any inhibitory activity against angiotensin-converting enzyme (ACE).…”

Phosphoproteomic analysis of duck egg white and insight into the biological functions of identified phosphoproteins

“…OTF protein has a strong iron‐binding ability, which confers its antimicrobial activity. Due to this ability, it is used as a food additive and an antimicrobial agent (Lee, Ahn, & Paik, 2018). Moreover, OTF also has a wide range of reported bioactivities such as antifungal, antiviral, anticancer, antioxidative, antihypertensive, and immunomodulatory activities (Wu & Acero‐Lopez, 2012).…”