Transcriptomic and functional analysis of a polysaccharide from Caulerpa lentillifera with immunostimulatory and antioxidant properties

This study investigates the immunomodulatory and antioxidative potential of SGP 31 , a sulfated polysaccharide derived from the seaweed Caulerpa lentillifera . Transcriptomic profiling of RAW 264.7 macrophages treated with SGP 31 indicated dose-dependent modulation of genes associated with immune responses and oxidative stress regulation. Key genes, including Tnf, Il6, Hmox1, and Txnrd1 were differentially expressed, suggesting activation of inflammatory and antioxidant pathways. Pathway enrichment analysis highlighted signaling networks, including cytokine–cytokine receptor interaction and AGE–RAGE signaling, which may contribute to the observed cellular responses. To validate these transcriptomic findings, qRT-PCR analysis was conducted on selected genes. SGP 31 significantly increased the expression of Tnf and Il6 relative to the untreated control, although expression levels remained considerably lower than those induced by LPS, suggesting a moderate immunostimulatory effect. The antioxidant-related gene Hmox1 was markedly upregulated at higher SGP 31 concentrations, whereas Nqo1 expression decreased in a concentration-dependent manner. Functional assays revealed no cytotoxicity across the tested concentrations, with cell viability remaining above 88 %. SGP 31 also increased nitric oxide (NO) production in a dose-dependent manner, consistent with its immunostimulatory potential. Collectively, these findings suggest that SGP 31 can influence both inflammatory cytokines and antioxidant genes in macrophages, supporting its promise as a natural bioactive compound for immune and antioxidant modulation. SGP 31 , a sulfated polysaccharide purified from Caulerpa lentillifera , was applied to RAW 264.7 macrophages. Transcriptomic profiling and qRT-PCR validation revealed its immunomodulatory and antioxidant effects. • SGP 31 is a sulfated polysaccharide purified from Caulerpa lentillifera. • RNA-seq revealed immunomodulatory and antioxidant gene activation. • Key genes regulated include Tnf , Il6 , and Hmox1. • Pathways enriched: cytokine signaling and AGE-RAGE interaction. • SGP 31 is a well-characterized algal bioproduct with therapeutic potential.