مقالات پذیرفته شده در هفتمین کنگره بین المللی زیست پزشکی
Echinometrin peptide as biomarker of chronically salt-exposed sea urchin Echinometra mathaei. Toward an understanding of red cell degranulation under stressful condition
Echinometrin peptide as biomarker of chronically salt-exposed sea urchin Echinometra mathaei. Toward an understanding of red cell degranulation under stressful condition
Introduction: Peptides are promising molecules that fill gaps in current therapeutic approaches, between small organic molecules (0.4–2 kDa) and protein drugs. It is thought that peptides signify a group of potential fascinating biotechnological molecules to be developed, regarding their specificity and high potency versus the (comparative) small size. Problems concerning their bio distribution and enzymatic degradation had dispirited their development as medicines, but these problems can now be avoided by using new constructions, encapsulation and/or injectable-solution. The marine echinoderms has previously provided molecules with therapeutic potential; therefore, they contain a good source of molecules that has been poorly discovered. Marine invertebrates produce/secrete/develop molecules for some purposes, including chemical defense against predators, oxidative stress and even ingestion, establishing a broad inventory waiting to be explored. Echinometra mathaei can be found throughout the Persian Gulf coast and are testified to be one of the major causes of marine coincidences on the shoreline. Although not lethal, these accidents are described to be exceedingly painful. Sea urchins have a large quantity of perivisceral coelomic fluid by which the internal organs seem to be protected. The survival of urchins in the contaminated marine environment is dependent on their ability to defend themselves against xenobiotics, micro biota and oxidative damages. These organisms have developed defense responses mainly based on immune cells and humoral elements contained in the coelomic fluid.
Methods: Sea urchins Echinometra mathaei were collected from Qeshm Island, Persian Gulf. The coelomic fluid (about 2 mL) was extracted from the sea urchin by puncturing the peristomial membrane and hypodermic needle. Mass spectrometry analyses were performed by a liquid chromatograph-triple quadrupole mass spectrometer (LC-QqQ-MS, Agilent G6410). The coelomic fluid of specimens was diluted in a 50% ACN containing 0.5% formic acid, and was directly introduced in the spectrometer, at a flow rate of 50 µL min−1, in positive ionization mode and mass spectra collected in the 50–2000 m/z range. The results were automatically processed by MS data, and then manually verified.
Results: In positive ionization mode, we detected dominant second order peptide ions of m/z = 353 [M+3H] 3+and m/z = 265 [M+4H] 4+, for molecular mass of 1054 Da, then the daughter ions spectra were explored and manually verified for accuracy and precision. The deduced sequence of the eight-residue peptide was LRKLMLQR.
Conclusion: The ion signal of m/z 1054 was attributed to protonated Echinometrin [M+2H] +2 besides it had been sequenced as LRKLMLQR. Echinometrin was firstly isolated from the peristomial coelomic fluid of Echinometra lucunter sea urchin, interestingly we deciphered Echinometrin in samples from outlet of Desalination plant. As mentioned earlier, we also observed pro-inflammatory reactions, such as red spherules recruitment or PHNQs release in some stressed specimens (personal observation). This cell recruitment may be caused by the presence and increased content of activated mediators, such as Echinometrin. Echinometrin as a cryptide peptide was primarily isolated from the peristomial coelomic fluid of E. lucunter, which is thought to be involved in stimulating the adaptive immune process related to stress by inflammatory feedbacks, such as , promoting histamine release, foot edema, white cell recruitment and depletion of the pain threshold. Likewise, it has been proved that Echinometrin from E. lucunter activate the in vivo degranulation of mouse mesenchymal MCs in a dose exposure mode, with pro-inflammatory effects.