A metallothionein from disk abalone (Haliotis discus discus): Insights into its functional roles in immune response, metal tolerance, and oxidative stress

• Published in: Fish & shellfish immunology Vol. 150; p. 109645
• Main Authors: Jayasinghe, J.D.H.E., Tharanga, E.M.T., Sirisena, D.M.K.P., Jeyakanesh, Jeganathan Tharshan, Wan, Qiang, Lee, Jehee
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-07-2024
• Subjects: Disk abalone; Heavy metal; Immune response; Metallothionein; Oxidative stress; Oxidative stress; Immune response; Disk abalone; Metallothionein; Heavy metal
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2024.109645

Metallothioneins (MTs) are cysteine-rich metal-binding proteins whose expression is induced by exposure to essential and non-essential metals, making them potential biological markers for assessing metal pollution in various biomonitoring programs. However, the functional properties of these proteins are yet to be comprehensively characterized in most marine invertebrates. In this study, we identified and characterized an MT homolog from the disk abalone (Haliotis discus discus), referred to as disk abalone MT (AbMT). AbMT exhibited the same primary structural features as MTs from other mollusks containing two β-domains (β2β1-form). AbMT protein demonstrated metal-binding and detoxification abilities against Zn, Cu, and Cd, as evidenced by Escherichia coli growth kinetics, metal tolerance analysis, and UV absorption spectrum. Transcriptional analysis revealed that AbMT was ubiquitously expressed in all analyzed tissues and upregulated in gill tissue following challenge with Vibrio parahaemolyticus, Listeria monocytogenes, and viral hemorrhagic septicemia virus (VHSV). Additionally, overexpression of AbMT suppressed LPS-induced NO production in RAW264.7 macrophages, protected cells against H2O2-induced oxidative stress, and promoted macrophage polarization toward the M1 phase. Conclusively, these findings suggest an important role for AbMT in environmental stress protection and immune regulation in disk abalone.
•Disk abalone metallothionein (AbMT) gene was identified and functionally characterized.•AbMT expression was significantly induced by bacterial and viral challenges.•Recombinant AbMT protein demonstrated metal binding activity and heavy metal detoxification abilities.•AbMT suppressed NO production, protected cells against oxidative stress, and promoted macrophage M1 polarization