Insights into the molecular mechanisms of Spirulina platensis against rheumatoid arthritis through integrative serum pharmacochemistry and network pharmacology analysis

Abstract

Spirulina platensis traditionally and increasingly consumed as a premium food and complementary medicine in many Asian countries on account of its nutritive and pharmacological attributes. So far, Spirulina holds promise as a potential therapeutic agent for RA alleviation. However, the mechanistic basis of S. platensis against RA remains poorly clarified.The research strategy featuring serum pharmacochemistry and network pharmacology was constructed to pinpoint the potential bioactive components and efficiency mechanisms of S. platensis against RA. Firstly, a rat model of RA was established using Complete Freund's Adjuvant (CFA). Secondly, serum migrating components following Spirulina administration were profiled and relatively quantified as monitoring indexes for Spirulina bioavailability. Using network pharmacology strategy, potential target genes of transitional components and associated pathways were predicted. Lastly, the control mechanisms of S. platensis in CFA model were verified through a series of serum and synovial biochemical markers along with master RA-related pathways by western blotting. Nineteen circulating compounds, including four prototypes and fifteen metabolites were profiled and selected as candidate efficacy compounds successfully absorbed and maintained considerable concentrations in Spirulina-treated sera creating a great opportunity to exert the anti-RA potential. Among which, fatty acids and their conjugated metabolites represented the most relevant and abundant circulating metabolites. Regarding network pharmacology findings, the top predictive targets highly correlated with RA were NFKB, NLRP3, TNF, MMP-9, TLR4 and VEGFA. Relatedly, KEGG analysis dissected PI3K-Akt signaling pathway, MAPK signaling pathway, osteoclasts (OCs) differentiation and VEGF signaling pathway as the top-ranked RA pathways. Our efficacy experimental findings emphasized that Spirulina markedly downregulated the inflammatory mediators (IL-1, IL-6, IL-17, TNF-α and MMP-9) levels. Following Spirulina treatment, western blotting detected significant alterations in RA master proteins as TLR4, NLRP3, VEGF, Pro caspases-1, Caspase-1, and NF-κB p65. This integrated work illuminates the molecular mechanisms and efficacy constituents of S. platensis as referenced templates against RA. In the light of the above, systematized information on the metabolic fate of the absorbable Spirulina metabolites should be expanded through in-depth pharmacokinetics research for highly targeted drugs. In a broader sense, future investigations and adequate evidence should be explored to broaden the therapeutic strategies scenario in the era of personalized medicine to achieve a comprehensive “treat-to-target” approach which, undoubtedly, is of a great significance in the clinical settings.