Palmitic acid impairs human and mouse placental function by inhibiting trophoblast autophagy through induction of acyl-coenzyme A-binding protein (ACBP) upregulation
Authors: Zhang Yi , Ruan Ling-Ling , Li Ming-Rui , Yao Lu , Li Fang-Fang , Xie You-Long , Tang Jing , Feng Qian , Chen Xiao-Yan , Ding Yu-Bin , Fu Li-Juan 
Published: May 2024

Abstract

STUDY QUESTION
Can exposure to palmitic acid (PA), a common saturated fatty acid, modulate autophagy in both human and mouse trophoblast cells through the regulation of acyl-coenzyme A-binding protein (ACBP)?

SUMMARY ANSWER
PA exposure before and during pregnancy impairs placental development through mechanisms involving placental autophagy and ACBP expression.

WHAT IS KNOWN ALREADY
High-fat diets, including PA, have been implicated in adverse effects on human placental and fetal development. Despite this recognition, the precise molecular mechanisms underlying these effects are not fully understood.

STUDY DESIGN, SIZE, DURATION
Extravillous trophoblast (EVT) cell line HTR-8/SVneo and human trophoblast stem cell (hTSC)-derived EVT (hTSCs-EVT) were exposed to PA or vehicle control for 24 h. Female wild-type C57BL/6 mice were divided into PA and control groups (n = 10 per group) and subjected to a 12-week dietary intervention. Afterward, they were mated with male wild-type C57BL/6 mice and euthanized on Day 14 of gestation. Female ACBPflox/flox mice were also randomly assigned to control and PA-exposed groups (each with 10 mice), undergoing the same dietary intervention and mating with ACBPflox/floxELF5-Cre male mice, followed by euthanasia on Day 14 of gestation. The study assessed the effects of PA on mouse embryonic development and placental autophagy. Additionally, the role of ACBP in the pathogenesis of PA-induced placental toxicity was investigated.

PARTICIPANTS/MATERIALS, SETTING, METHODS
The findings were validated using real-time PCR, Western blot, immunofluorescence, transmission electron microscopy, and shRNA knockdown approaches.

MAIN RESULTS AND THE ROLE OF CHANCE
Exposure to PA-upregulated ACBP expression in both human HTR-8/SVneo cells and hTSCs-EVT, as well as in mouse placenta. PA exposure also induced autophagic dysfunction in HTR-8/SVneo cells, hTSCs-EVT, and mouse placenta. Through studies on ACBP placental conditional knockout mice and ACBP knockdown human trophoblast cells, it was revealed that reduced ACBP expression led to trophoblast malfunction and affected the expression of autophagy-related proteins LC3B-II and P62, thereby impacting embryonic development. Conversely, ACBP knockdown partially mitigated PA-induced impairment of placental trophoblast autophagy, observed both in vitro in human trophoblast cells and in vivo in mice.

LARGE SCALE DATA
N/A.

LIMITATIONS, REASONS FOR CAUTION
Primary EVT cells from early pregnancy are fragile, limiting research use. Maintaining their viability is tough, affecting data reliability. The study lacks depth to explore PA diet cessation effects after 12 weeks. Without follow-up, understanding postdiet impacts on pregnancy stages is incomplete. Placental abnormalities linked to elevated PA diet in embryos lack confirmation due to absence of control groups. Clarifying if issues stem solely from PA exposure is difficult without proper controls.

WIDER IMPLICATIONS OF THE FINDINGS
Consuming a high-fat diet before and during pregnancy may result in complications or challenges in successfully carrying the pregnancy to term. It suggests that such dietary habits can have detrimental effects on the health of both the mother and the developing fetus.

STUDY FUNDING/COMPETING INTEREST(S)
This work was supported in part by the National Natural Science Foundation of China (82171664, 82301909) and the Natural Science Foundation of Chongqing Municipality of China (CSTB2022NS·CQ-LZX0062, cstc2019jcyj-msxmX0749, and cstc2021jcyj-msxmX0236). The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER
N/A.