Na Li

Squid ink is a marine-derived bioresource containing diverse bioactive compounds; however, the biological functions of its low-molecular-weight constituents remain largely unexplored. In this study, a novel quinolin derivative, named AEBI, was isolated and identified from squid ink through enzymatic hydrolysis, chromatographic purification, and spectroscopic analysis. The hair growth–promoting activity of AEBI was subsequently evaluated using mouse hair follicle stem cells (HFSCs) and a depilation model established in male Sprague–Dawley (SD) rats. In vitro, AEBI significantly enhanced HFSC viability in a concentration-dependent manner and increased the expression of stem cell- and extracellular matrix-associated proteins, including p63, laminin, and fibronectin. In vivo, topical administration of AEBI markedly accelerated hair regrowth, increased hair follicle density, promoted follicular maturation, and improved hair shaft morphology in depilated rats. Histological analysis revealed that AEBI treatment increased the proportion of mature hair follicles and enhanced subcutaneous adipose tissue development. Furthermore, AEBI treatment upregulated the expression of hair growth–related molecules, including Wnt10b, β-catenin, LEF1, and Ki-67, suggesting that modulation of Wnt/β-catenin-associated signaling may contribute to its hair growth–promoting effects. Notably, high-dose AEBI exhibited comparable or superior effects to 5% minoxidil in several evaluated parameters. Collectively, these findings identify AEBI as a novel squid ink–derived bioactive molecule with potential applications in the development of natural hair growth–promoting agents and provide new insights into the utilization of marine-derived small molecules.

Impaired wound healing is often caused by persistent inflammation, bacterial infection, and insufficient extracellular matrix remodeling. Natural polymer-based hydrogels represent ideal wound dressings but often struggle to balance structural stability and biological activity. Herein, we report a dual-functional network regulation strategy enabled by highly soluble mussel foot protein (HMFP) that acts simultaneously as a structural crosslinking regulator and bioactive effector to fabricate synergistic hydrogels (CS-SH-H) from β-chitosan (CS) and sodium hyaluronate (SH). HMFP homogenizes the porous microstructure, strengthens intermolecular interactions, and significantly improves thermal and structural stability via multivalent non-covalent bonding. In vitro, CS-SH-H shows excellent cytocompatibility, significantly promotes fibroblast proliferation and migration, and exerts potent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In a mouse full-thickness skin defect model, the hydrogel dramatically accelerates wound closure, reducing the residual wound area to 25% on day 7, outperforming the control groups. Immunohistochemistry confirms that HMFP suppresses TNF-α-mediated inflammation and enhances Ki-67-positive cell proliferation, leading to accelerated re-epithelialization and collagen deposition. This study establishes HMFP as a promising marine-derived dual-functional network regulator for designing high-performance hydrogel dressings. This strategy is scalable and translatable for treating infected and inflammatory wounds.

Chronic inflammation is closely associated with various diseases, underscoring the need for natural, biocompatible anti-inflammatory candidates. For this purpose, mussel foot protein could be an excellent candidate due to its diverse biological activities. Hence, this study systematically evaluates the anti-inflammatory effects of a highly soluble mussel foot protein (HMFP) and HMFP-PEG using LPS-stimulated RAW264.7 cells as an in vitro inflammation model. The results reveal that both HMFP and HMFP-PEG markedly reduced intracellular reactive oxygen species (ROS) levels and suppressed the secretion of pro-inflammatory mediators, including IL-1β, TNF-α, and NO, while promoting the production of anti-inflammatory cytokines such as IL-10 and TGF-β. Mechanistically, both agents markedly inhibited the LPS-induced phosphorylation of PI3K, Akt, NF-κB, and IκB, indicating that their anti-inflammatory effects are mediated via suppression of the PI3K/Akt and NF-κB signaling pathways. Furthermore, HMFP and HMFP-PEG downregulated the expression of the inflammatory marker iNOS and markedly upregulated the M2 macrophage marker CD206, suggesting a role in promoting macrophage polarization toward an anti-inflammatory M2 phenotype. Notably, NF-κB signaling was identified as a key mediator in the anti-inflammatory mechanisms of both HMFP and its PEG-modified form. Collectively, these findings demonstrate that HMFP and HMFP-PEG exert significant anti-inflammatory effects through dual inhibition of NF-κB and PI3K/Akt signaling and by promoting M2 macrophage polarization, indicating their potential as promising candidates for the treatment of inflammation-related diseases.

Mussel foot protein is a bioadhesive protein with potential biomedical applications, but its limited solubility and poor biological stability hinder its widespread use. In this study, highly soluble mussel foot protein (HMFP) was successfully extracted using a stepwise selective enzymatic digestion method, with a molecular weight in the range of 11–17 kDa. Furthermore, a dual-functional polyethylene glycol (PEG) derivative of HMFP, designated HMFP-PEG, was synthesized. FTIR analysis confirmed the successful modification of HMFP with PEG, while TGA analysis and SEM observations demonstrated that PEG modification significantly enhanced the stability of the protein. Both HMFP and HMFP-PEG effectively scavenged free radicals, enhanced antioxidant enzyme activity, and reduced MDA levels. Additionally, they activated the PI3K/Akt and Nrf2/HO-1 signaling pathways, inhibiting H₂O₂-induced cell apoptosis. Notably, HMFP-PEG exhibited superior antioxidant and cell-protective effects compared to HMFP, suggesting that PEG modification improves the functional stability of the protein. This study provides theoretical support for the potential application of HMFP in the biomedical and tissue engineering fields.

Protamine is a promising marine-derived bioactive compound that is highly arginine-rich and has demonstrated unique advantages in medical and biological research. This study, for the first time, investigates the molecular mechanisms underlying the immunomodulatory effects of Salmon Protamine Sulfate (SPS), Symplectoteuthis oualaniensis Protamine (SOP), and its polyethylene glycol (PEG) derivative (SOP-PEG) on RAW264.7 macrophages. The results demonstrate that both SOP and SOP-PEG significantly enhance the proliferation of RAW264.7 cells by promoting the secretion of pro-inflammatory cytokines and nitric oxide (NO), increasing ROS production, and improving antioxidant capacity, in comparison to SPS. Elevated ROS levels play a crucial role in enhancing macrophage immune activity, while the enhanced antioxidant defense mechanisms help maintain redox homeostasis and protect against oxidative stress-induced cellular damage. A Western blot analysis reveals that SOP and SOP-PEG notably regulate the expression of key proteins associated with the PI3K/Akt signaling pathway and anti-apoptotic mechanisms. Furthermore, a flow cytometry analysis indicates a significant increase in the G2/M-phase cell population in the treatment groups, which is corroborated by Western blot data showing alterations in critical regulatory proteins. Notably, SOP-PEG exhibits the strongest effects in regulating macrophage immune activity, which can be attributed to the enhanced stability and prolonged bioactivity resulting from the PEGylation of SOP. This comprehensive study reveals how SOP and SOP-PEG enhance macrophage immune function through multiple mechanisms, including PI3K/Akt activation, redox regulation, and cell cycle modulation. It provides valuable insights and a theoretical foundation for their potential applications in immunotherapy and immune regulation.