MicroRNA let-7i inhibits granulosa-luteal cell proliferation and oestradiol biosynthesis by directly targeting IMP2.
Reprod Biomed Online
; 44(5): 803-816, 2022 05.
Article
en En
| MEDLINE
| ID: mdl-35339367
ABSTRACT
RESEARCH QUESTION Increased granulosa cell division is associated with abnormal folliculogenesis in polycystic ovary syndrome (PCOS). Lethal-7i microRNA (let-7i) may play an important role in the follicular development and granulosa cell growth; therefore is let-7i involved in PCOS pathogenesis? DESIGN:
The expression of let-7i was measured in granulosa-luteal cells (GLC) from women with or without PCOS. A human granulosa cell line, KGN, was used for the functional study. Mimics and inhibitors of let-7i, lentiviruses expressing insulin-like growth factor 2 mRNA binding protein (IMP2), and small-interfering RNAs were transfected into KGN cells. KGN cell proliferation was determined by 5-ethynyl-2'-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assays. The cell cycle and apoptosis were assessed by propidium iodide-annexin V (PI-A) staining and fluorescence-activated cell sorting. Oestradiol concentration was determined by enzyme-linked immunoassay. Bioinformatics analysis and luciferase reporter assay were applied to confirm the let-7i target genes.RESULTS:
The study showed that let-7i was down-regulated in PCOS GLC (Pâ¯=â¯0.001). Mimics of let-7i inhibited KGN proliferation (Pâ¯=â¯0.001), and decreased aromatase expression (Pâ¯=â¯0.030) and oestradiol production (Pâ¯=â¯0.029), whereas let-7i inhibitors had the opposite effect. Bioinformatics analysis and quantitative real-time (qRT) PCR identified IMP2 as a target of let-7i (Pâ¯=â¯0.021). qRT-PCR and western blot analysis indicated that IMP2 was up-regulated in GLC in women with PCOS (Pâ¯=â¯0.001 and Pâ¯=â¯0.044), and IMP2 expression was suppressed by let-7i in KGN cells (P < 0.001). Luciferase reporter assay results (Pâ¯=â¯0.002), combined with the rescue assay, confirmed that let-7i inhibited KGN cell proliferation and reduced oestradiol concentration by directly targeting IMP2.CONCLUSIONS:
let-7i was down-regulated in PCOS GLC. Overexpression of let-7i inhibited KGN cell proliferation and decreased oestradiol production in an IMP2-dependent manner, providing a new molecular mechanism for PCOS.Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Síndrome del Ovario Poliquístico
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MicroARNs
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Células Lúteas
Tipo de estudio:
Prognostic_studies
Límite:
Female
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Humans
Idioma:
En
Revista:
Reprod Biomed Online
Asunto de la revista:
MEDICINA REPRODUTIVA
Año:
2022
Tipo del documento:
Article