Differential Effects of Sodium Butyrate and Lithium Chloride on Rhesus Monkey Trophoblast Differentiation.
Trophoblast differentiation during early placental development is critical for successful pregnancy and aberrant differentiation causes preeclampsia and early pregnancy loss. During the first trimester, cytotrophoblasts are exposed to low oxygen tension (equivalent to~2%-3% O2) and differentiation proceeds along an extravillous pathway (giving rise to invasive extravillous cytotrophoblasts) and a villous pathway (giving rise to multinucleated syncytiotrophoblast). Interstitial extravillous cytotrophoblasts invade the decidua, while endovascular extravillous cytotrophoblasts are involved in re-modelling uterine spiral arteries. We tested the idea that sodium butyrate (an epigenetic modulator) induces trophoblast differentiation in early gestation rhesus monkey trophoblasts through activation of the Wnt/β-catenin pathway. The results show that syncytiotrophoblast formation was increased by butyrate, accompanied by nuclear accumulation of β-catenin, and increased expression of EnvV2 and galectin-1 (two factors thought to be involved in trophoblast fusion). Surprisingly, the expression of GCM1 and syncytin-2 was not affected by sodium butyrate. When trophoblasts were incubated with lithium chloride, a GSK3 inhibitor that mimics Wnt activation, nuclear accumulation of β-catenin also occurred but differentiation into syncytiotrophoblast was not observed. Instead the cells differentiated to mononucleated spindle-shaped cells and showed molecular and behavioral characteristics of endovascular trophoblasts. Another highly specific inhibitor of GSK3, CHIR99021, failed to induce endovascular trophoblast characteristics. These observations suggest that activation of the Wnt/β-catenin pathway correlates with both trophoblast differentiation pathways, but that additional factors determine specific cell fate decisions. Other experiments suggested that the differential effects of sodium butyrate and lithium chloride might be explained by their effects on TNFα production. The results provide valuable tools to manipulate trophoblast differentiation in vitro and to better understand the differentiation pathways that occur during early gestation.
Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States of America.
Priyadarsini
P
Kumar
Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States of America.
Twanda L
TL
Thirkill
Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States of America.
Jennifer
J
Ji
Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States of America.
Louise H
LH
Monte
Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States of America.
Gordon C
GC
Douglas
D000818:Animals; D020148:Butyric Acid / Q000494:pharmacology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D037483:Galectin 1 / Q000235:genetics / Q000378:metabolism; D015686:Gene Products, env / Q000235:genetics / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism; D018021:Lithium Chloride / Q000494:pharmacology*; D008253:Macaca mulatta; D011247:Pregnancy; D014327:Trophoblasts / Q000187:drug effects* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D060449:Wnt Signaling Pathway; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
D037483:Galectin 1; D015686:Gene Products, env; D014409:Tumor Necrosis Factor-alpha; D051176:beta Catenin; D020148:Butyric Acid; D038362:Glycogen Synthase Kinase 3; D018021:Lithium Chloride