Sirtuin 1 is a potential therapeutic candidate gene for fetal growth restriction via insulin-like 4

Abstract

Objective

Insufficient placental development causes various obstetric complications, including fetal growth restriction (FGR). The Sirtuin 1 (SIRT1) and insulin-like 4 (INSL4) protein-coding genes have been demonstrated to play an important role in placental development. However, no treatment for FGR is available due to placental dysfunction. Therefore, this study aimed to examine the potential of the SIRT1–INSL4 axis as a treatment candidate for FGR caused by insufficient placental development.

Methods

Twenty patients were enrolled, including 10 with FGR and 10 full-term controls. FGR and control placental samples were collected. Quantitative real-time polymerase chain reaction, immunohistochemical analysis, and western blotting were used to analyze INSL4 and SIRT1 expression. An in-vitro loss-of-function approach with the human choriocarcinoma cell line BeWo was applied for functional analyses of SIRT1 in placental development. BeWo cells were differentiated into syncytiotrophoblasts by silencing SIRT1 using small interfering RNA. SIRT1 activator was added during differentiation of SIRT1-knockdown BeWo cells into syncytiotrophoblasts.

Results

The FGR samples had lower INSL4 and SIRT1 mRNA and protein expression levels than the control samples. Immunohistochemistry showed that both SIRT1 and INSL4 were expressed mainly in syncytiotrophoblasts. In-vitro analyses showed that SIRT1 knockdown decreased INSL4 expression; however, SIRT1 activator restored SIRT1 expression in SIRT1-silenced BeWo cells.

Conclusions

SIRT1 and INSL4 are downregulated in the placenta of FGR, and INSL4 is regulated by SIRT1. These findings indicate that the SIRT1–INSL4 axis may be a potential therapeutic target for FGR.

Keywords:

• Fetal growth restriction
• sirtuin 1
• insulin-like 4
• insulin-like growth factor

Acknowledgments

We would like to thank the members of our department for their support.

Disclosure statement

The authors report that there are no competing interests to declare.

Data availability statement

The data that support the findings of this study are available from the corresponding author, Masanori Ono, upon reasonable request.

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research [grant No. 22K16866].