Ben Hsouna A, Ben Saad R, Dhifi W, Mnif W, Brini F. Novel non-specific lipid-transfer protein (TdLTP4) isolated from durum wheat: Antimicrobial activities and anti-inflammatory properties in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.
Microb Pathog 2021;
154:104869. [PMID:
33774106 DOI:
10.1016/j.micpath.2021.104869]
[Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 02/19/2021] [Accepted: 03/15/2021] [Indexed: 01/02/2023]
Abstract
Lipid transfer proteins (LTP) are members of the family of pathogenesis-related proteins (PR-14) that play a key role in plant defense mechanisms. In this study, a novel gene TdLTP4 encoding an antifungal protein from wheat (cv. Om Rabiaa) was cloned, overexpressed in Escherichia coli BL-21 (DE3) and enriched using ammonium sulfate fractionation. The TdLTP4 fusion protein was then tested against a panel of pathogens, food-borne and spoilage bacteria and fungi in order to evaluate the antimicrobial properties. TdLTP4 was applied to 0.5 μg/mL LPS-induced RAW 264.7 macrophages in vitro at different concentrations (5, 10, 20, 50 and 100 μg/mL). Levels of nitric oxide (NO), pro-inflammatory cytokines interleukin (IL)-1β (IL-1 β), interleukin (IL)-6 (IL-6), tumor necrosis factor (TNF-α) and anti-inflammatory cytokine IL-10 in the supernatant fraction were measured using enzyme-linked immunosorbent assay (ELISA). Expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were detected via Western blot. The inhibition zones and minimal inhibitory concentration (MIC) values of bacterial strains were in the range of 14-26 mm and 62.5-250 μg/mL, respectively. Moreover, a remarkable activity against several fungal strains was revealed. TdLTP4 (5-100 μg/mL) decreased the production of NO (IC50 = 4.32 μg/mL), IL-6 (IC50 = 11.52 μg/mL), IL-1β (IC50 = 7.87 μg/mL) and TNF-α (IC50 = 8.66 μg/mL) by lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. TdLTP4 could modulate the macrophages inflammatory mode by causing reduction in iNOS and COX-2. According to these findings, TdLTP4 fusion protein could be used as natural anti-inflammatory and antimicrobial agent in food preservation and human health.
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