Intestinal phospholipase A2 from Sparidae species: Functional properties and cytotoxic potential evaluation

A recombinant sPLA2 protein promotes gut mucosal barrier against bacterial infection in fish

Secreted phospholipase A2 family protein (sPLA2) is associated with immune response and plays a critical role in the regulation of gut homeostasis. However, whether sPLA2 is involved in innate immunity in teleost is essentially unknown. For this purpose, we reported the identification of a classical sPLA2 in grass carp (CisPLA2) and elucidated its role in the antibacterial immunity in this study. The result of bioinformatics analysis showed that mammalian sPLA2-IIA is the most similar homologue to CisPLA2. CisPLA2 is expressed in a variety of tissues, including liver and gut, and is significantly upregulated in response to Aeromonas hydrophila infection. Recombinant CisPLA2 protein (rCisPLA2) showed significant antibacterial activity against A. hydrophila by enhancing the phagocytosis of host phagocytes in vitro. Moreover, rCisPLA2 induces significant expression of the antimicrobial molecules and tight junctions in the gut during bacterial infection. Fish administered with rCisPLA2 significantly alleviates the gut permeability and apoptosis. In addition, rCisPLA2 preserves the morphology of the gut mucosa and limits the colonization of A. hydrophila in systemic immune organs. These results indicate that CisPLA2 plays a crucial role in the regulation of gut mucosal barrier, and thus has a potential application for antimicrobial immunity in fish.

Marine Bioactive Peptides: Anti-Photoaging Mechanisms and Potential Skin Protective Effects

Skin photoaging, resulting from prolonged exposure to ultraviolet radiation, is a form of exogenous aging that not only impacts the aesthetic aspect of the skin but also exhibits a strong correlation with the onset of skin cancer. Nonetheless, the safety profile of non-natural anti-photoaging medications and the underlying physiological alterations during the process of photoaging remain inadequately elucidated. Consequently, there exists a pressing necessity to devise more secure interventions involving anti-photoaging drugs. Multiple studies have demonstrated the noteworthy significance of marine biomolecules in addressing safety concerns related to anti-photoaging and safeguarding the skin. Notably, bioactive peptides have gained considerable attention in anti-photoaging research due to their capacity to mitigate the physiological alterations associated with photoaging, including oxidative stress; inflammatory response; the abnormal expression of matrix metalloproteinase, hyaluronidase, and elastase; and excessive melanin synthesis. This review provides a systematic description of the research progress on the anti-photoaging and skin protection mechanism of marine bioactive peptides. The focus is on the utilization of marine bioactive peptides as anti-photoaging agents, aiming to offer theoretical references for the development of novel anti-photoaging drugs and methodologies. Additionally, the future prospects of anti-aging drugs are discussed, providing an initial reference for further research in this field.