Identification Of Plant MiRNAs In Maternal-fetal Transport Of Pigs

MicroRNAs (miRNAs) are endogenous organization-time-specific RNAs that play important posttranscriptional gene-regulatory roles in a variety of cellular biological processes within the cell, such as cell proliferation, apoptosis, growth, differentiation and metabolism. Recent studies have shown that plant miRNAs can be digested and absorbed by human, mouse, cow, horse and other animals, in addition, MIR168a could bind to the human/mouse low-density lipoprotein receptor adapter protein1(LDLRAP1) mRNA, inhibit LDLRAP1expression in liver, and consequently decrease LDL removal from mouse plasma. For another, the placenta is an ephemeral materno-fetal organ with chorionic (fetal) villi bathed in maternal blood spaces, which allows restricted transfer of metabolites and nutrients, it was reported that fetal DNA and RNA could be detected in maternal serum which indicated that nucleic acids could pass through the placenta barrier and mediate the communication beteen mother and fetus.In this experiment, we carried out a miScript reverse transcription quantitative PCR for detecting plant miRNAs in porcine samples which containing sow serum and liver;9tissues of pig fetus:heart, liver, spleen, lung,kidney, brain, musle, serum, amniotic fluid; exosomes of sow serum, fetus serum and amniotic fluids, for the purpose of exploring the maternal-fetus miRNA transport characteristics and supplying a new theoretical basis for further study of miRNA cross-kingdom and cross-generation regulation mechanism. The results showed that:(1) Plant miRNAs could be detected in sow serum and liver, MIR164a, MIR390a, MIR319a, MIR167e, MIR408a showed high considerable levels, the average plant miRNA concentraion was about0.06%(liver))å'Œ32.3%(serum) of mammalian miRNAs.(2) Plant miRNAs could be transported from mother to fetus. MIR164a and MIR168a had highest concentraion, while the average plant miRNAs levels differed in different tissues, and that from high to low was spleen, brain, muscle, kidney, liver, lung and heart, respectively, and it was higher in fetus serum than amniotic fluid. The average plant miRNA concentration in liver was about0.4%of endogenous miRNAs but nearly the same in liquid samples.(3) Plant miRNA existed in exosomes of sow serum, fetus serum and amniotic fluids.MIR164a showed the highest ratio of49.9%,52.7%and68.3%compared to the original liquid samples, MIR168a had the second highest level of45.5%and86.8%in fetus serum and amniotic fluid, the result illustrated that exogenous plant miRNA may be transported from mother to fetus by exosome.