Purification and characterization of a glycoprotein from Sipunculus nudus and its immune-enhancing activity to RAW 264.7 macrophages

Cirsii Herba glycoprotein promotes macrophage M1 polarization through MAPK and NF-κB signaling pathways via interaction with TLR4

The present study aimed to extract and purify the glycoprotein from Cirsii Herba (CHPs), and investigate its immunomodulatory activity and molecular mechanism in RAW264.7 macrophages. The results showed that CHPs contained 14.8% carbohydrates and 80.4% proteins. CHPs were identified as glycoprotein around 70 kDa and contained 17 different amino acids, in which the Glu and Asp were predominant. The carbohydrate chain in CHPs was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose and arabinose with the molecular ratio of 6.387: 24.358: 5.766: 8.877: 12.098: 20.427: 7.090: 14.997. CHPs significantly boosted pinocytic and phagocytic activities, increased the secretions of inflammatory factors (NO, TNF-α and IL-6) and chemokines (CXCL2 and CXCL10), and promoted the expressions of accessory and costimulatory molecules (CD40, CD80, CD86, MHC I and MHC II). RNA-seq analysis identified 721 DEGs, 1575 GO terms and 69 KEGG pathways. The pathway inhibition assay presented that MAPK and NF-κB pathways were essential to macrophage activation by CHPs. TLR4 was revealed as a functional receptor and involved in the early recognition of CHPs. These results indicated that CHPs as a glycoprotein promoted macrophage polarization to M1 phenotype mainly via TLR4-dependent MAPK and NF-κB pathways.

Comprehensive review of extraction, purification, structural characteristics, pharmacological activities, structure-activity relationship and application of seabuckthorn protein and peptides

Seabuckthorn (Hippophae rhamnoides) is an excellent plant that has the concomitant function of both medicine and foodstuff with high nutritional and health-promoting properties. As a pivotal bioactive component mainly existing in the seeds and leaves, seabuckthorn protein and its derived peptides have aroused wide attention owing to their multifaceted pharmacological activities, including anti-hypertensive, hypoglycemic, anti-obesity, anti-freeze, immunomodulatory, anti-inflammatory, sobriety, anti-oxidant and anti-neurodegenerative functions. Despite these promising attributes, the application of seabuckthorn peptides as functional food and medicines are impeded due to lack of a comprehensive understanding of pharmacological activities and intricate structure-activity relationship. Therefore, this review systematically summarizes the latest advancements in the extraction, purification, structural characteristics, pharmacological activities, digestion, absorption and transport, and application of seabuckthorn protein or peptides. Noteworthily, the structure-activity relationship is specifically delved into the hypoglycemic, anti-hypertensive, anti-obesity, anti-neurodegenerative and anti-oxidant peptides. Moreover, the shortcomings of current research and promising prospects are also highlighted. This comprehensive overview will provide a framework for future exploration and application of seabuckthorn protein or peptides in the realms of food and pharmaceuticals, offering a promising horizon for health benefits.

The synergistic immunomodulatory activity of Lycium barbarum glycopeptide and isochlorogenic acid A on RAW264.7 cells

BACKGROUND

Regulation of the immune system to maintain homeostasis in the organism has become a focus of research, and the synergistic effect of multi-component complexes will effectively improve the immunomodulatory activity. The present study aimed to investigate the interaction and synergistic immunomodulatory activity of isochlorogenic acid A (IAA) and Lycium barbarum glycopeptide (LbGp).

RESULTS

The results obtained indicated that non-covalent intermolecular interactions were employed to form the LbGp-IAA complex, with a binding ratio of 135.15 mg g-1. The formation of LbGp-IAA complex altered the conformation of LbGp, and IAA was mainly bound to LbGp by van der Waals forces and hydrogen bonds. In addition, LbGp-IAA promoted the proliferation of RAW264.7 cells. The IAA and LbGp interaction had a synergistic effect on the promotion of phagocytosis and the expression of nitric oxide, tumor necrosis faction-α and interleukin-1β, which improved the immunomodulatory effect of LbGp. Furthermore, the combination of LbGp and IAA synergistically inhibited lipopolysaccharide-induced inflammatory response.

CONCLUSION

In summary, the binding of IAA enhanced the immunomodulatory activity of LbGp and coordinated the immune response, and did not trigger an inflammatory response, which was potentially attributed to the alteration of spatial structure of LbGp through the binding of IAA. The results provide new perspectives for the study of glycopeptide-polyphenol interactions. © 2024 Society of Chemical Industry.

Structural characterization and ferroptosis-related immunomodulatory of a novel exopolysaccharide isolated from marine fungus Aspergillus medius

Marine fungal exopolysaccharides play a crucial role in immunoregulation. In this investigation, a novel polysaccharide was extracted from the culture medium of the marine fungus Aspergillus medius SCAU-236. Compositional analysis revealed a structure composed of glucose units with (1,4)-α-D-Glcp, (1,3,4)-β-D-Glcp, and (1,4,6)-α-D-Glcp, along with side chains of 1-α-D-Glcp linked to carbon 6 of (1,4,6)-α-D-Glcp and carbon 3 of (1,3,4)-β-D-Glcp. Functional evaluations on RAW264.7 macrophage cells demonstrated Aspergillus medius polysaccharide (ASMP)'s effects on cell proliferation, nitric oxide levels, and the secretion of TNF-α, IL-6, and IL-1β cytokines. Additionally, metabolomics indicated ASMP's potential to modulate macrophage immune function by impacting key regulatory molecules, including COX-2, iNOS, Nrf2, SLC7A11, GPX4, and ACSL4. The Nrf2/SLC7A11/GPX4 axis and ACSL4 were suggested to be involved in ASMP-induced ferroptosis, leading to increased reactive oxygen species (ROS) levels and lipid peroxidation. These findings propose a unique mechanism by which ASMP exerts immunomodulatory effects through ferroptosis induction, contributing to the understanding of marine-derived compounds in immunomodulation research.