IL-32 regulates trophoblast invasion through <i>miR-205</i>-<i>NFκB</i>-<i>MMP2/9</i> axis contributing to the pregnancy-induced hypertension

Interleukin-32 is a species-specific cytokine that plays an important role in inflammation, cancer, and other diseases; however, its role in reproductive and pregnancy-related diseases remains unknown. This study aimed to investigate the role of interleukin-32 in reproductive and pregnancy-related diseases. Placental tissues from patients with pregnancy-induced hypertension, healthy pregnant women, and trophoblast lines were analysed. Interleukin-32 expression was quantified via polymerase chain reaction and immunohistochemistry, and functional assays were performed after interleukin-32 modulation. Interleukin-32 was identified only in placental mammals, such as Carnivora, Cetartiodactyla, Chiroptera, Dermoptera, Lagomorpha, Perissodactyla, and Primates via bioinformatics. Immunohistochemistry and polymerase chain reaction revealed that interleukin-32 was highly expressed in human placental villi, poorly expressed in decidua and endometrial tissues, and was not detected in mouse tissues. Second, interleukin-32 upregulates miR-205 expression by increasing DROSHA expression, and miR-205 promotes interleukin-32 expression by targeting its promoter region. Interleukin-32 and miR-205 significantly enhanced the invasion ability of HTR8/SVneo cells (a trophoblast cell line) and the tube formation ability of human umbilical vein endothelial cells. Through quantitative reverse transcription polymerase chain reaction and western blotting, the interleukin-32/miR-205 loop increased MMP2 and MMP9 expression in HTR-8/SVneo cells via the nuclear factor kappa B signaling pathway. Finally, using quantitative reverse transcription polymerase chain reaction, interleukin-32 and miR-205 expression levels were significantly lower in the placentas of patients with pregnancy-induced hypertension than in women with normal pregnancies. In conclusion, interleukin-32 regulates trophoblast invasion through the miR-205-nuclear factor kappa B-MMP2/9 pathway, which is involved in pregnancy-induced hypertension.