Muscle LIM protein of Macrobrachium nipponense (MnMLP) involved in immune and stress response

The muscle LIM protein (MLP) is a member of the cysteine and glycine-rich protein (CSRP) family, composed of CSRP1, CSRP2 and CSRP3/MLP. MLP is involved in a multitude of functional roles, including cytoskeletal organization, transcriptional regulation, and signal transduction. However, the molecular mechanisms underlying its involvement in immune and stress responses remain to be elucidated. This study identified an MnMLP in the freshwater crustacean Macrobrachium nipponense. The isothermal titration calorimetry assay demonstrated that recombinant MnMLP was capable of coordinating with Zn²⁺. Upon challenge by Aeromonas veronii or WSSV, and exposure to CdCl₂, up-regulation was recorded in the muscle and intestinal tissues, suggesting its involvement in immune and anti-stress responses. MnMLP protein was predominantly expressed in the cytoplasm of the transfected HEK-293T cells, but after treatment with LPS, Cd²⁺ or H₂O₂, the MnMLP was observed to be transferred into the nucleus. The comet assay demonstrated that the overexpression of MnMLP could mitigate the DNA damage induced by H₂O₂ in HEK-293T cells, suggesting the potential involvement of MnMLP in the DNA repair process. These findings suggest that DNA repair may represent a possible mechanism by which MnMLP may be involved in the host's defense against pathogens and stress.