Botryococcus terribilis Ethanol Extract Exerts Anti-inflammatory Effects on Murine RAW264 Cells

The present study aimed to evaluate the effects of Botryococcus terribilis ethanol extract (BTEE) on lipopolysaccharide (LPS)-induced inflammation in RAW264 cells. BTEE significantly attenuated LPS-induced nitric oxide production and inflammatory cytokines release, including Ccl2, Cox2, and Il6. On the other hand, several anti-inflammatory mediators, such as Pgc1 beta and Socs1, were increased in BTEE-treated cells. Further, we performed an untargeted whole-genome microarray analysis to explore the anti-inflammatory molecular mechanism of BTEE. Enrichment analysis showed BTEE significantly downregulated `response to stimulus', `locomotion', and `immune system response' and upregulated `cell cycle' gene ontologies in both 6- and 17-h post-LPS stimulation conditions. Pathway analysis revealed BTEE could downregulate the expressions of chemokines of the CC and CXC subfamily, and cytokines of the TNF family, TGF beta family, IL1-like, and class I helical. PPI analysis showed AXL receptor tyrosine kinase (Axl), a receptor tyrosine kinase from the TAM family, and its upstream transcription factors were downregulated in both conditions. Node neighborhood analysis showed several Axl coexpressed genes were also downregulated. Further, kinase enrichment and chemical perturbation analyses supported Axl inhibition in BTEE-treated conditions. Altogether, these findings suggest anti-inflammatory effects of BTEE that are mediated via the suppression of pro-inflammatory cytokines and predict its potential as an Axl inhibitor.

Automated summary

The present study investigated the anti-inflammatory effects of Botryococcus terribilis ethanol extract (BTEE) on LPS-induced inflammation in RAW264 cells. BTEE significantly inhibited the production of nitric oxide and inflammatory cytokines, while promoting the expression of anti-inflammatory mediators. Whole-genome microarray analysis revealed that BTEE downregulated genes related to stimulus response, locomotion, and immune system response, and upregulated genes associated with cell cycle. Pathway and protein-protein interaction analyses suggested the potential role of BTEE as an Axl inhibitor. These findings demonstrate the anti-inflammatory properties of BTEE and its potential therapeutic value as an Axl inhibitor.