Citation

Barnwal B, Kini RM. Biochem. J. 2013; 455(2): 239-250.

Copyright

(Copyright © 2013, The Biochemical Society, Publisher Portland Press)

DOI

10.1042/BJ20130599

PMID

23829475

Abstract

Unlike other sea snakes, Aipysurus eydouxii feeds exclusively on fish eggs. This unusual feeding habit prompted us to search for unique transcripts in their venom glands. Here, we expressed a novel cysteine-rich, secretory protein containing 94 amino acid residues that was identified in its cDNA library. As it induced inflammation and writhing in animals, this protein was named as inflamin. It induced two waves of prostanoids production. The first wave peaked at 10 min and 6-keto PGF1α was the major product. The second wave, specifically of 6-keto PGF1α and PGE2, started after 2 h. In RAW264.7 cells, COX-1 activity showed a transient increase at 10 min and is responsible for the first wave, but its expression was unaffected. COX-2 was induced after 3 h and is responsible for the second wave. Using specific inhibitors, we showed that cPLA2, and not sPLA2, iPLA2 or DAG lipase, plays a key role in arachidonate release. The cPLA2 activity showed a transient increase of 62% at 10 min; this increase was due to its phosphorylation and not due to an increase in its expression. Thus, inflamin - the first member of a new family of snake venom proteins, leads to an increase in the cPLA2 and COX-1 activity resulting in inflammation and pain.

Language: en