IGF2-derived miR-483-3p contributes to macrosomia through regulating trophoblast proliferation by targeting RB1CC1.

STUDY QUESTION: What is the role of insulin-like growth factor 2 (IGF2)-derived miR-483-3p in macrosomia?

SUMMARY ANSWER: IGF2-derived intronic miR-483-3p is overexpressed in macrosomia placentas, and miR-483-3p prompts HTR-8/SVneo extravillous trophoblast cell line proliferation through down-regulation of its target RB1 inducible coiled-coil 1 (RB1CC1).

WHAT IS KNOWN ALREADY: Macrosomia is a common pregnancy-associated disease and causes a number of adverse maternal and perinatal outcomes. The development of macrosomia is reportedly attributable to over proliferation of the placental cells. MicroRNAs (miRNAs) play an important role in the development of fetal and placenta by regulating their target genes. Here, we investigated the role of IGF2-derived intronic miR-483-3p in macrosomia.

STUDY DESIGN, SIZE, DURATION: The expression of IGF2, miR-483-3p and its target gene in placental tissues from 30 pregnant women who had macrosomia was compared to those of 30 gestation-matched healthy pregnant controls. For in vitro studies, the human first trimester extravillous trophoblast cell line, HTR-8/SVneo cell was used.

PARTICIPANTS/MATERIALS, SETTING, METHODS: Placenta tissues were collected from pregnant women who had macrosomia without diabetes or other complications (n = 30) and healthy pregnant controls (n = 30). HTR-8/SVneo cells were transfected with specific miRNA mimics or inhibitors. MiRNA and mRNA isolated from placenta tissues or cells were measured by quantitative real-time PCR. Protein was measured by western blot. Cell proliferation was assayed using a colorimetric proliferation assay method. Cell cycle and apoptosis were analyzed by flow cytometry. The putative targets of miR-483-3p were predicted using the TargetScan, miRanda, miRDB and DIANA algorithms. Dual luciferase reporter assay was used to measure the relationship of miR-483-3p and RB1CC1.

MAIN RESULTS AND THE ROLE OF CHANCE: IGF2-derived miR-483-3p was overexpressed in macrosomia placentas. miR-483-3p promoted proliferation in HTR-8/SVneo cells and had a positive relationship with its host gene IGF2. Subsequently, RB1CC1 was confirmed as a direct target of miR-483-3p, which may be an important mediator of cell growth regulation for miR-483-3p.

LARGE SCALE DATA: N/A.

LIMITATIONS, REASONS FOR CAUTION: The level of IGF2 and its intronic miR-483-3p in the serum of these participants was not investigated. Further studies are required to understand the mechanisms underlying the cause of the increase of IGF2 and miR-483-3p in macrosomia.

WIDER IMPLICATIONS OF THE FINDINGS: These findings give a new insight into the role of intronic miRNA and its host gene in the development of macrosomia. Furthermore, it may offer a new target for prognostic and therapeutic intervention for macrosomia.

STUDY FUNDING/COMPETING INTEREST(S): This work was supported by awards from National Natural Science Foundation of China (Nos. 81401213, 81673217, 81703260), Jiangsu Provincial Medical Youth Talent (No. QNRC2016110), Jiangsu Overseas Visiting Scholar Program for University Prominent Young & Middle-aged Teachers and Presidents, the Priority Academic Program for the Development of Jiangsu Higher Education Institutions (Public Health and Preventive Medicine), the Education Department of Jiangsu Province (No. 16KJB330010), the Science and Technology Department of Jiangsu Province (No. BK20160227), the China Postdoctoral Science Foundation funded project (No. 2016M601892). The authors declare no competing financial interests.