Differentially expressed microRNAs and affected signaling pathways in placentae of transgenic cloned cattle

Placental deficiencies are related to the developmental abnormalities of transgenic cattle produced by somatic cell nuclear transfer, but the concrete molecular mechanism is not very clear. Studies have shown that placental development can be regulated by microRNAs (miRNAs) in normal pregnancy. Thus, this study screened differentially expressed miRNAs by the next-generation sequencing technology to reveal the relationship between miRNAs expression and aberrant development of placentae produced by the transgenic-clone technology. Expressions of miRNAs and mRNAs in different placentae were compared, the placentae derived from one natural pregnancy counterpart (PNC), one natural pregnancy of a cloned offspring as a mother (PCM), and two transgenic (human beta-defensin-3) cloned pregnancy: one offspring was alive after birth (POL) and the other offspring was dead in 2 days after birth (POD). Further, signaling pathway analysis was conducted. The results indicated that 694 miRNAs were differentially expressed in four placental samples, such as miR-210, miR-155, miR-21, miR-128, miR-183, and miR-145. Signaling pathway analysis revealed that compared with PNC, significantly upregulated pathways in POL, POD, and PCM mainly included focal adhesion, extracellular matrix-receptor interaction, pathways in cancer, regulation of actin cytoskeleton, endosytosis, and adherens junction, and significantly downregulated pathways mainly included malaria, nucleotide binding oligomerization domain-like receptor signaling, cytokine-cytokine receptor interaction, Jak-STAT signaling pathway. In conclusion, this study confirmed alterations of the expression profile of miRNAs and signaling pathways in placentae from transgenic (hBD-3) cloned cattle (PTCC), which could lead to the morphologic and histologic deficiencies of PTCC. This information would be useful for the relative research in future.