Dunaliella salina alga extract inhibits the production of interleukin-6, nitric oxide, and reactive oxygen species by regulating nuclear factor-κB/Janus kinase/signal transducer and activator of transcription in virus-infected RAW264.7 cells

Hui Wen Lin, Cheng Wei Liu, Deng Jye Yang, Ching Chung Chen, Shih Yin Chen, Jung Kai Tseng*, Tien Jye Chang, Yuan Yen Chang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Recent investigations have demonstrated that carotenoid extract of Dunaliella salina alga (Alga) contains abundant β-carotene and has good anti-inflammatory activities. Murine macrophage (RAW264.7 cells) was used to establish as an in vitro model of pseudorabies virus-induced reactive oxygen species (ROS) response. In this study, antioxidant activities of Alga were measured based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, trolox equivalent antioxidant capacity assays, reducing power, and virus-induced ROS formation in RAW264.7 cells. Anti-inflammatory activities of Alga were assessed by its ability to inhibit the production of interleukin-6 and nitric oxide (NO) using enzyme-linked immunosorbent assay, then the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway was investigated by measuring the inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor-κB (p50 and p65), JAK, STAT-1/3, and suppressor of cytokine signaling 3 (SOCS3) by Western blotting. In addition, Alga inhibited virus replication by plaque assay. Our results showed that the Alga had high antioxidant activity, significantly reduced the virus-induced accumulation of ROS, and inhibited the levels of nitric oxide and interleukin-6. Further studies revealed that Alga also downregulated the gene and protein expressions of iNOS, COX-2, nuclear factor-κB (p50 and p65), and the JAK/STAT pathway. The inhibitory effects of Alga were similar to pretreatment with specific inhibitors of JAK and STAT-3 in pseudorabies virus -infected RAW264.7 cells. Alga enhanced the expression of SOCS3 to suppress the activity of the JAK/STAT signaling pathway in pseudorabies virus-infected RAW264.7 cells. In addition, Alga has decreased viral replication (p < 0.005) at an early stage. Therefore, our results demonstrate that Alga inhibits ROS, interleukin6, and nitric oxide production via suppression of the JAK/STAT pathways and enhanced the expression of SOCS3 in virus-infected RAW264.7 cells.

Original languageEnglish
Pages (from-to)908-918
Number of pages11
JournalJournal of Food and Drug Analysis
Volume25
Issue number4
DOIs
StatePublished - Oct 2017

Keywords

  • anti-inflammatory
  • Dunaliella salina
  • pseudorabies virus
  • reactive oxygen species

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