Inflammation-induced PFKFB3-mediated glycolysis promoting myometrium contraction through the PI3K-Akt-mTOR pathway in preterm birth mice.

Inflammation is a significant risk factor for preterm birth. Inflammation enhances glycolytic processes in various cell types and contributes to the development of myometrial contractions. However, the potential of inflammation to activate glycolysis in pregnant murine uterine smooth muscle cells (mUSMCs) and its role in promoting inflammatory preterm birth remain unexplored. In this study, lipopolysaccharide was employed to establish both cell and animal inflammation models. We found that inflammation of mUSMCs during late pregnancy could initiate glycolysis and promote cell contraction. Subsequently, the inhibition of glycolysis using the glycolysis inhibitor 2-deoxyglucose can reverse inflammation-induced cell contraction. The expression of 6-phosphofructokinase 2 kinase (PFKFB3) was significantly upregulated in mUSMCs following lipopolysaccharide stimulation. In addition, lactate accumulation and enhanced contraction were observed. Inhibition of PFKFB3 reversed the lactate accumulation and enhanced contraction induced by inflammation. We also found that inflammation activated the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt)-mammalian target of the rapamycin (mTOR) pathway, leading to the upregulation of PFKFB3 expression. The PI3K-Akt pathway inhibitor LY294002 and the mTOR pathway inhibitor rapamycin effectively inhibited the upregulation of PFKFB3 protein expression, lactate production, and the enhancement of cell contraction induced by lipopolysaccharide. This study indicates that inflammation regulates PFKFB3 through the PI3K-Akt-mTOR pathway, which enhances the glycolytic process in pregnant mUSMCs, ultimately leading to myometrial contraction. Expression of PFKFB3, a key enzyme in glycolysis, was significantly upregulated both in the mUSMCs and myometrium of mice during late pregnancy after lipopolysaccharide stimulation. Activation of the PI3K-Akt-mTOR pathway enhanced PFKFB3 expression, which is involved in the initiation of glycolysis. Inflammation-activated PFKFB3 via the PI3K-Akt-mTOR pathway, which enhances the cellular glycolytic process and thus promotes myometrium contraction in pregnancy.