GABA(A) and GABA(B) receptors of distinct properties affect oppositely the proliferation of mouse embryonic stem cells through synergistic elevation of intracellular Ca(2+).
Gamma-amminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system of vertebrates, serves as an autocrine/paracrine signaling molecule during development, modulating a number of calcium (Ca(2+))-dependent processes, including proliferation, migration, and differentiation, acting via 2 types of GABA receptors (GABARs): ionotropic GABA(A)Rs and metabotropic GABA(B)Rs. Here, we demonstrate that mouse embryonic stem cells (mESCs), which possess the capacity for virtually unlimited self-renewal and pluripotency, synthesize GABA and express functional GABA(A)Rs and GABA(B)Rs, as well as voltage-gated calcium channels (VGCCs), ryanodine receptors (RyRs), and inwardly rectifying potassium (GIRK) channels. On activation, both GABAR types triggered synergistically intracellular calcium rise. Muscimol (a GABA(A)R agonist) induced single Ca(2+) transients involving both VGCC-mediated Ca(2+) influx and intracellular stores, while baclofen (a GABA(B)R agonist) evoked Ca(2+) transients followed by intercellular Ca(2+) waves and oscillations that were resistant to antagonists and entirely dependent on Ca(2+) release from intracellular stores. Prolonged treatment with muscimol slightly inhibited, while baclofen or SR95531 (a GABA(A)R antagonist) significantly facilitated, mESC proliferation. GABA(A)R-specific ligands also induced morphological and gene expression changes indicating a differentiation shift. Our data suggest that the interplay between GABARs and downstream (coupled) effectors differentially modulates mESC proliferation/differentiation through selective activation of second messenger signaling cascades.-Schwirtlich, M., Emri, Z., Antal, K., Máté, Z., Katarova, Z., Szabó, G. GABA(A) and GABA(B) receptors of distinct properties affect oppositely the proliferation of mouse embryonic stem cells through synergistic elevation of intracellular Ca(2+).
Schwirtlich
Marija
M
Laboratory of Molecular Biology and Genetics, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
Emri
Zsuzsa
Z
Antal
Károly
K
Máté
Zoltán
Z
Katarova
Zoya
Z
Szabó
Gábor
G
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels / Q000378:metabolism; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D005786:Gene Expression Regulation / Q000187:drug effects; D051379:Mice; D009118:Muscimol / Q000494:pharmacology; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D011724:Pyridazines / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000378:metabolism*; D018080:Receptors, GABA-B / Q000378:metabolism*; D013997:Time Factors
D015220:Calcium Channels; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018755:GABA Agonists; D018756:GABA Antagonists; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D011724:Pyridazines; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D009118:Muscimol; C049853:gabazine; D001418:Baclofen; D002118:Calcium