| Objective: Studies have shown that pearl powder has anti-inflammatory,antioxidant,wound healing and skin whitening properties.Most of researches are still based on the use of pearl or a mixture of pearl powder,water-soluble matrix(WSM),acid-soluble matrix(ASM)or acid-insoluble matrix(AIM)compounds as experimental materials to investigate its biological properties,while the material basis for its biological functions is still unclear.In this study,the anti-UV and whitening functions of pearl powder extracts were firstly investigated.Secondly,the protein composition of pearl powder was determined by liquid chromatography-tandem mass spectrometry(LC-MS/MS),and its biomineralization and various medicinal functions including wound healing,osteogenesis,antioxidant,neuromodulatory,skin whitening,antiinflammatory and anti-apoptotic effects,and other immunomodulatory effects were analyzed.Finally,the function of the complement control protein domain CCP was explored.Methods:(1)Total extract and protein extract of pearl powder were prepared and acted on UV-irradiated A375 cells.Cell proliferation activity was determined by MTT method,tyrosinase activity was determined by L-dopa oxidation method,and melanin synthesis content was determined by Na OH lysis method.(2)The matrix proteins of freshwater seedless pearl powder were detected using liquid chromatography-tandem mass spectrometry(LC-MS/MS)respectively,and identified against the transcriptomic database of the pearl sac.(3)After analysis of selected peptide CCP acting on human A375 melanoma cells,cell proliferation activity was determined by MTT method and changes in human C3(complement component 3)and human C4(complement component 4)concentrations were measured by enzyme-linked immunosorbent assay(ELISA).Results:(1)The tyrosinase activity and melanin content in A375 cells increased significantly under UV irradiation(P<0.05).However,the total extract of pearl powder increased the activity of tyrosinase in A375 cells(P<0.05),but did not affect the content of melanin in cells.Protein extract of pearl powder did not change cell tyrosinase activity,but inhibited melanin production(P<0.05).It indicated that the total extract of pearl powder can protect A375 melanoma cells from UV damage,and its protein extract had whitening effect under the action of UV.(2)A total of 190 proteins were identified in pearl proteomics,and was divided into eight categories by their potential biomineralization functions.The composition of pearl matrix proteins and the high frequency conserved domains like carbonic anhydrase,von Willebrand factor type A(VWA),tyrosinase and chitin binding 2(Cht BD2)in protein sequences suggested the“chitin-silk fibroin gel proteins–acidic macromolecules” model of pearl biomineralization pattern.Meanwhile,ninety-one of pearl matrix proteins were classified into seven categories by their potential medical functions including wound healing,osteogenic property,antioxidant activity,neuro-regulation effects,skin lightening effect,anti-inflammatory and anti-apoptotic effects and other immunomodulatory property.(3)Peptide CCP had no significant effect on the proliferative activity of A375 cells(P>0.05),but increased the concentrations of human C3 and C4 in A375 cells(P<0.05),indicating that peptide CCP has an effect on the cellular complement system and could be a target drug for the treatment of immune system diseases.Conclusion: Through proteomic analysis,it was found that there are many proteins with different biological functions in the organic matter of pearl powder.Further studies on its functional domains and cellular assays showed that pearl powder has anti-UV and whitening effects as well as enhancing human immune function at the cellular level,which can provide basic information and basis for the medicinal development of pearl powder. |
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