Institute of Chemical Biology and Fundamental Medicine of the Siberian, Division of Russian Academy of Sciences, Lavrentiev Ave. 8, 630090 Novosibirsk, Russia
Pacific Institute of Bioorganic Chemistry, Far East Division, Russian Academy of Sciences, 690022 Vladivostok, Russia
Int J Mol Sci. 2022 Jul 22;23(15):8102. doi: 10.3390/ijms23158102.
Human milk provides neonates with various components that ensure newborns' growth, including protection from bacterial and viral infections. In neonates, the biological functions of many breast milk components can be very different compared with their functions in the body fluids of healthy adults. Catalytic antibodies-abzymes hydrolyzing peptides, proteins, DNAs, RNAs, and oligosaccharides were detected not only in the blood sera of autoimmune patients but also in human milk. Non-coding microRNAs (18-25 nucleotides) are intra- and extra-cellular molecules of different human fluids. MiRNAs possess many different biological functions, including regulating several hundred genes. Five of them: miR-148a-3p, miR-200c-3p, miR-378a-3p, miR-146b-5p and let-7f-5p were previously found in milk in increased concentrations. Here, we determined number of copies of these miRNAs in 1 mg of analyzed cells, lipid fractions, and plasmas of human milk samples. The relative amount of microRNA decreases in the following order: cells » lipid fraction > plasma. IgGs and sIgAs were isolated from milk plasma, and their activity in the hydrolysis of five microRNAs was compared. In general, sIgAs demonstrated higher miRNA-hydrolyzing activity than IgGs antibodies. The hydrolysis of five microRNAs by sIgAs and IgGs was site-specific. The relative activity of each microRNA hydrolysis was very dependent on the milk preparation. The correlation coefficients between the content of five RNAs in milk plasma and the relative activity of sIgAs than IgGs in their hydrolysis strongly depended on individual microRNA and changed from -0.01 to 0.80. Thus, it was shown that milk contains specific antibodies-abzymes hydrolyzing microRNAs specific for human milk.
人乳为新生儿提供了各种成分，这些成分可确保新生儿的生长，包括防止细菌和病毒感染。在新生儿中，许多母乳成分的生物学功能与健康成人的体液中的功能可能有很大不同。催化抗体-酶切抗体不仅在自身免疫患者的血清中，而且在人乳中也检测到了可以水解肽、蛋白质、DNA、RNA 和寡糖的抗体。非编码 microRNAs（18-25 个核苷酸）是不同人体液体中的细胞内和细胞外分子。miRNAs 具有许多不同的生物学功能，包括调节几百个基因。其中五个：miR-148a-3p、miR-200c-3p、miR-378a-3p、miR-146b-5p 和 let-7f-5p 之前在乳中发现浓度增加。在这里，我们确定了这些 miRNA 在 1mg 分析细胞、脂质部分和人乳样本血浆中的拷贝数。miRNA 的相对数量按以下顺序减少：细胞 > 脂质部分 > 血浆。IgG 和 sIgA 从乳浆中分离出来，并比较了它们对五种 microRNA 水解的活性。一般来说，sIgA 比 IgG 抗体表现出更高的 miRNA 水解活性。sIgA 和 IgG 对五种 microRNA 的水解具有特异性。每种 microRNA 水解的相对活性非常依赖于乳制剂。乳浆中五种 RNA 的含量与 sIgA 比 IgG 水解的相对活性之间的相关系数强烈依赖于个体 microRNA，从-0.01 变化到 0.80。因此，结果表明人乳中含有特异性水解 microRNA 的特异性抗体-酶切抗体。
