In a mouse model of polycystic ovary syndrome, hundreds of messenger RNAs carried altered m6A methylation—and the strongest pathway signal pointed toward insulin signaling. But correlation is not causation. Polycystic ovary syndrome is a common endocrine and metabolic dysfunction condition in women of reproductive age, resulting in irregular menstruation, hyperandrogenism, infertility, and insulin resistance.

Patients with PCOS are at higher risk of diabetes, cardiovascular disease, and endometrial cancer. There is no specific therapy for PCOS, only symptomatic treatment such as lifestyle management, combination oral contraceptives, and insulin sensitizers.

N6-methyladenosine, or m6A, is the most prevalent internal modification of mRNAs. It is reversible and dynamically regulated by methyltransferase complexes, demethylases, and m6A binding proteins. m6A modification regulates post-transcriptional expression of m6A-tagged genes through RNA metabolism, including pre-mRNA splicing, mRNA translation, nuclear export, mRNA decay, and non-coding RNA biogenesis.

The m6A modification level has been reported to increase in PCOS patients, but little attention has been paid to the molecular mechanisms of m6A modification in PCOS. The study investigates the altered m6A modification landscape of mRNAs in the ovaries of PCOS mice using an epitranscriptomic microarray.

It also preliminarily explores potential signal pathways involved in the PCOS process through KEGG analysis. Figure one shows hematoxylin and eosin-stained ovaries from control mice in panel A and PCOS-model mice in panel B. The control ovary displays different stages of follicular development and no large cysts, while the PCOS ovary is swollen and contains multiple cystic, expanded follicles.

These visible morphological differences support the authors’ conclusion that the mouse model of PCOS was successfully established. In the control group, different stages of follicular development were seen in ovaries, and the ovarian morphology was normal without large cysts.

In the PCOS group, the ovaries were swollen with multiple cystic follicles, including cyst-like expanded follicles. The microarray results showed that 307 mRNAs were significantly differentially expressed between the PCOS and control groups, using a fold change of at least one point five and a P value below zero point zero five.

Among them, 226 mRNAs were upregulated and 81 were downregulated in the PCOS group. The ten most significantly differentially regulated mRNAs were listed in Table 1. Figure two summarizes differences between PCOS and control groups at both the mRNA-expression and m-six-A methylation levels.

The expression volcano plot and heatmap identify three hundred seven significantly differentially expressed mRNAs: two hundred twenty-six upregulated and eighty-one downregulated. The methylation panels show one hundred forty-three significantly modified mRNAs, including one hundred thirty-four with higher and nine with lower m-six-A methylation, highlighting widespread epigenetic dysregulation in PCOS.

When mRNA methylation and expression data were integrated, the analysis identified eight hypomethylated and upregulated mRNAs, 415 hypermethylated and downregulated mRNAs, 14 hypermethylated and upregulated mRNAs, and zero hypomethylated and downregulated mRNAs. The functions of these 437 mRNAs were analyzed through GO and KEGG pathway analyses.

The mRNAs were predicted to participate in 24 pathways, and the insulin signaling pathway was the most enriched pathway, involving ten differentially expressed mRNAs with differential methylation. Figure three integrates methylation with gene-expression changes across four panels.

The scatter plot identifies eight hypomethylated and upregulated mRNAs, four hundred fifteen hypermethylated and downregulated mRNAs, fourteen hypermethylated and upregulated mRNAs, and no hypomethylated and downregulated mRNAs. GO and KEGG analyses then organize these genes into enriched functions and pathways, with insulin signaling highlighted as the most enriched pathway; orange marks genes showing both expression and m6A differences.

Figure four compares Skip mRNA methylation between control and PCOS samples, with the bar chart reporting a statistically significant difference at P less than zero point zero one. The authors also used the SRAMP prediction program, shown on the right, which identifies six potential m6A sites with very high confidence: five within the coding sequence and one in the three-prime untranslated region.

Together, these results support Skip mRNA as a specifically methylated transcript for further study. The higher m6A methylation levels of skeletal muscle and kidney-enriched inositol polyphosphate five-phosphatase, or Skip, mRNA were verified via MeRIP-PCR, with P below zero point zero one.

Analysis of Skip mRNA with the SRAMP program predicted six potential m6A sites with very high confidence, including five sites on the coding sequence and one site on the three-prime untranslated region. Figure five uses western blotting to compare control and PCOS samples across PI3K, phosphorylated PI3K, AKT, phosphorylated AKT, and SKIP, with beta-actin as a loading control.

The quantified panels report significantly increased PI3K, phosphorylated PI3K, and SKIP expression in PCOS, alongside decreased AKT and phosphorylated AKT, with significance ranging from one to three asterisks. This matters because it links PCOS with altered PI3K–AKT signaling and elevated SKIP, a PIP3 phosphatase.

The activity levels of the PI3K/AKT signaling pathway were explored by western blotting, as part of the insulin signaling pathway. In the PCOS group, AKT and phosphorylated AKT at serine 473 were significantly decreased, whereas PI3K and phosphorylated PI3K were significantly increased compared with the control group.

SKIP, a phosphatidylinositol three, four, five-trisphosphate phosphatase, was overexpressed in the PCOS group. Several limitations remained. Acknowledged inhibiting factors for the PI3K/AKT pathway, such as phosphatase and tensin homolog and c-Jun N-terminal kinase, were not investigated.

The study did not further validate the hypothesis that hypermethylation of SKIP mRNAs enhances its expression and then inhibits the PI3K/AKT signaling pathway. The altered m6A modification of mRNAs might play a critical role in the PCOS process.

The study emphasized changes in the activity of upstream and downstream factors in the PI3K/AKT signaling pathway. The role of m6A modification of Skip mRNA in the pathogenesis of PCOS warrants further studies. The study links altered m6A modification with disrupted PI3K/AKT signaling in PCOS mice, highlighting Skip as a candidate connection while leaving that causal mechanism for future testing.