Echinometrin: A novel mast cell degranulating peptide from the coelomic liquid of Echinometra lucunter sea urchin

Abstract

Echinometra lucunter is an abundant sea urchin found in Brazilian waters. Accidents caused by this animal are common and are characterized by the penetration of the spines in the skin, which raises an inflammatory reaction through mechanical trauma as well as by the presumable action of toxins. Additionally, there have been reports of inflammatory reaction after the consumption of raw sea urchin eggs. In this work, we have isolated a peptide from E. lucunter coelomic fluid that could elicit inflammatory reactions, such as paw edema, leukocyte recruitment and diminishment of the pain threshold. This peptide was termed Echinometrin. Moreover, the peptide administration was able to produce in vivo degranulation of mouse mast cells, in a dose-response manner. The peptide was 'de novo' sequenced by mass spectrometry and its synthetic analog could reproduce all the observed effects. Sequence alignment indicates that this peptide is comprised in vitellogenin, an abundant nutrient protein present in the gametogenic cells of sea urchins, making it possible that echinometrin would be a cryptide with pro-inflammatory effects.

Initial peptidomic profiling of Brazilian sea urchins: Arbacia lixula, Lytechinus variegatus and Echinometra lucunter

“…Interesting biological activities were found for the matched sequences, such as antibiotic, antitumor, phospholipase A 2 inhibitors or neuroprotective. A similarity was also found with a toxin from scorpion venom, which confirms the presence of toxins in sea urchins, as recently described by our group [ 6 , 7 ].…”

“…A. lixula and L. variegatus are also found in reef slopes, but mainly in the sandy bottom [ 5 ]. The composition of their venoms, regarding the molecules actually present in those sea urchin species, has never been not fully described; however, some biological activities have already been reported for E. lucunter sea urchin, clearly signaling for the presence of bioactive molecules [ 6 – 8 ].…”

Marine natural products

“…A short octapeptide echinometrin 1373 (sea urchin Echinometra lucunter) was found to exhibit ability to degranulate mast cells leading to an inammatory reaction. 878 The sequence of the peptide is an internal fragment of vitellogenin, a nutrient protein present in sea urchin gametogenic cells, suggesting the possibility that echinometrin is a cryptide. 879 The rst synthesis of a pyranonaphthazarin pigment isolated from the sea urchin Echinothrix diadema 880 has been reported.…”

Edema and Nociception Induced by Philodryas patagoniensis Venom in Mice: A Pharmacological Evaluation with Implications for the Accident Treatment

“…Other studies have shown that histamine does not participate in the edema induced by Bothrops jararaca or B. asper venom in mice (Perales et al, 1992;Chaves et al, 1995). However, this mediator can participate in the edema induced by other animal venoms, such as viperid venoms (Al-Asmari and Abdo, 2006;Galvão Nascimento et al, 2010;Sebia-Amrane and Laraba-Djebari, 2013), Lonomia caterpillar venom (de Castro Bastos et al, 2004), Potamotrygon motoro stingray venom (Kimura et al, 2015), and Echinometra lucunter sea urchin coelomic fluid (Sciani et al, 2014).…”