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

Authors

H.-W. Lin
C.-W. Liu
D.-J. Yang
C.-C. Chen
S.-Y. Chen
J.-K. Tseng
T.-J. Chang
Y.-Y. Chang

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. © 2017

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ScienceDirect Link

10.1016/j.jfda.2016.11.018

Recommended Citation

Lin, H.-W.; Liu, C.-W.; Yang, D.-J.; Chen, C.-C.; Chen, S.-Y.; Tseng, J.-K.; Chang, T.-J.; and Chang, Y.-Y. (2017) "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," Journal of Food and Drug Analysis: Vol. 25 : Iss. 4 , Article 7.
Available at: https://doi.org/10.1016/j.jfda.2016.11.018

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https://www.sciencedirect.com/science/article/pii/S1021949817300303/pdfft?md5=eb5df59218231a3954fac633c34a7847&pid=1-s2.0-S1021949817300303-main.pdf