A novel technique for studying cellular function in human placenta: gestational changes in intracellular pH...

Area of Science:

• Cell Biology
• Physiology
• Reproductive Medicine

Background:

• Human placental syncytiotrophoblast cells are crucial for nutrient and waste exchange.
• Understanding their ionic regulation is vital for healthy pregnancy.
• Previous methods limited detailed study of syncytiotrophoblast cell function.

Purpose of the Study:

• To develop and validate a novel microfluorimetry technique for studying intracellular pH (pHi) in primary human placental syncytiotrophoblast cells.
• To investigate the role of the Na+/H+ antiporter in regulating pHi in these cells.
• To explore the regulation of the Na+/H+ antiporter by phosphorylation.

Main Methods:

• Utilized fluorescent pH-sensitive dye (HPTS) loading in chorionic villous tissue fragments.
• Employed microfluorimetry for real-time pHi monitoring during superfusion.
• Investigated the Na+/H+ antiporter's function in term and first-trimester placental samples.

Main Results:

• Syncytiotrophoblast cells exhibit homeostatic pHi regulation, recovering from acidification.
• The Na+/H+ antiporter is the primary mechanism for pHi recovery in the absence of HCO3-.
• Antiporter activity is allosterically modulated by intracellular protons and regulated by protein kinase C (PKC) phosphorylation.

Conclusions:

• The developed microfluorimetry method is a powerful tool for studying syncytiotrophoblast cell ionic regulation.
• The Na+/H+ antiporter plays a significant role in maintaining placental cell pH balance.
• PKC-mediated phosphorylation is an important regulatory pathway for the Na+/H+ antiporter in the placenta.