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Gap junctions and connexon hemichannels in human embryonic stem cells.
James E Huettner1, Aiwu Lu, Yun Qu
1Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA . huettner@cellbio.wustl.edu
Stem Cells (Dayton, Ohio)
|April 1, 2006
Summary
Human embryonic stem cells exhibit extensive gap junctional communication, crucial for cell survival and differentiation. This intercellular communication is mediated by connexins, forming functional channels between cells.
Area of Science:
- Cell Biology
- Developmental Biology
- Stem Cell Research
Background:
- Gap junctional intercellular communication is vital for embryonic development.
- Previous studies showed coupling in mouse inner cell mass but restrictions with trophectoderm.
- Human embryonic stem cells (hESCs) are derived from the inner cell mass.
Purpose of the Study:
- To investigate gap junctional communication in human embryonic stem cells.
- To identify connexin expression and function in hESCs.
- To explore the role of intercellular communication in hESC pluripotency and differentiation.
Main Methods:
- Reverse transcription-polymerase chain reaction (RT-PCR) for connexin RNA expression.
- Immunofluorescence microscopy to visualize connexin proteins.
- Electron microscopy for ultrastructural gap junction analysis.
- Fluorescent dye and electrical coupling assays.
- Pharmacological inhibition of gap junctional currents.
- Dye uptake studies for hemichannel analysis.
Main Results:
- hESCs express RNA for 18 of 20 known connexins; Cx40, Cx43, and Cx45 are localized at cell contacts.
- Extensive dye and electrical coupling observed within hESC colonies and isolated pairs.
- Minimal coupling between hESCs and mouse embryonic fibroblast (MEF) feeder cells.
- Connexon hemichannels are expressed on the hESC surface.
- Transjunctional currents are inhibited by specific pharmacological agents.
Conclusions:
- Human embryonic stem cells exhibit robust gap junctional communication.
- Connexins play a significant role in hESC intercellular communication.
- hESCs serve as a valuable model for studying human connexin function in pluripotency and differentiation.