ANP promotes HTR‐8/SVneo cell invasion by upregulating protein kinase N 3 via autophagy inhibition

Abstract

Preeclampsia is a gestational disease characterized by two major pathological changes‐shallow trophoblast invasion and impaired spiral artery remodeling. Atrial natriuretic peptide (ANP) is a kind of peptide hormone that regulates blood pressure, while the lack of active ANP participates in preeclampsia pathogenesis. However, the underlying mechanism of how ANP modulates trophoblasts function remains unclarified. Here, we performed isobaric tags for relative and absolute quantification (iTRAQ) in ANP‐treated HTR‐8/SVneo cells and identified Protein Kinase 3 (PKN3) as the downstream factor of ANP, which was downregulated in preeclamptic placenta. Chromatin immunoprecipitation analysis and luciferase assays showed that NFYA was one of the transcription factors for the PKN3 promoter, which was also regulated by ANP treatment in HTR‐8/SVneo cells. Transmission electron microscopy and Western Blotting in HTR‐8/SVneo cells indicated that ANP inhibited autophagy via AMPK‐mTORC1 signaling, while excess autophagy was observed in preeclamptic placenta. The increased expression of PKN3 and enhanced cell invasion ability in HTR‐8/SVneo cells induced by ANP could be abolished by autophagy activation or transfection with PKN3 shRNA or NFYA shRNA or NPR‐A shRNA via regulating the invasion‐related genes and the epithelial mesenchymal transition molecules. Our results demonstrated that ANP could enhance trophoblast invasion by upregulating PKN3 via NFYA promotion through autophagy inhibition in an AMPK/mTORC1 signaling‐dependent manner.

Natriuretic Peptide Signaling in Uterine Biology and Preeclampsia

“…In supporting this hypothesis, the ANP re NPR-A is expressed in human trophoblasts and decidual stromal cells [16,71]. In cu human trophoblasts, ANP treatment increases intracellular cGMP levels and pro trophoblast invasion in Matrigel assays, whereas NPR-A knockdown suppresses t blast invasion [16,73,134]. Moreover, markedly decreased placental corin and NPR pression and increased levels of pro-ANP are found in preeclamptic women [7 These results indicate that ANP-mediated signaling probably has a role in prom trophoblast invasion, and that defects in ANP signaling may contribute to uterine placental pathology in preeclampsia.…”

“…In supporting this hypothesis, the ANP receptor NPR-A is expressed in human trophoblasts and decidual stromal cells [16,71]. In cultured human trophoblasts, ANP treatment increases intracellular cGMP levels and promotes trophoblast invasion in Matrigel assays, whereas NPR-A knockdown suppresses trophoblast invasion [16,73,134]. Moreover, markedly decreased placental corin and NPR-A expression and increased levels of pro-ANP are found in preeclamptic women [73,134].…”

“…Recent molecular and cellular studies have shown that uterine ANP enhances endometrial decidualization, leading to morphological changes in vascular cells via a TRAIL-dependent mechanism [15]. In trophoblasts, ANP signaling inhibits autophagy and increases PKN3 and metalloproteinase expression, promoting trophoblast invasion [134]. These findings highlight the importance of natriuretic peptide signaling in uterine biology and maternal health, suggesting that defects in ANP and related molecules may be an underlying mechanism in the pathogenesis of gestational hypertension and preeclampsia.…”

“…In the heart, ANP modulates autophagy, a process of regulating cellular function depending on pathophysiological conditions [135,136]. In a recent study in human trophoblasts and chorionic villi, a molecular mechanism has been suggested, in which ANP activates NPR-A and subsequent adenosine 5 -monophosphate-activated protein kinase (AMPK) and the mammalian target of rapamycin complex 1 (mTORC1) signaling to inhibit autophagy and induce protein kinase N3 (PKN3) expression, thereby increasing metalloproteinase expression and trophoblast invasiveness [134] (Figure 4). Autophagy activation or downregulation of PKN3 diminishes the effect of ANP on trophoblast invasion [134].…”

“…Autophagy activation or downregulation of PKN3 diminishes the effect of ANP on trophoblast invasion [134]. Moreover, placentas from preeclamptic women had reduced PKN3 protein levels [134]. These results are intriguing, indicating a potential link between impaired ANP signaling and low PKN3 activity in the pathogenesis of preeclampsia.…”