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Characterization of intracellular buffering power in human induced pluripotent stem cells and the loss of pluripotency is delayed by acidic stimulation and increase of NHE1 activity
Author(s) -
Lee ShiaoPieng,
Chao ShihChi,
Chou MeiFang,
Huang ShuFu,
Dai NiannTzyy,
Wu GwoJang,
Tsai ChienSung,
Loh ShihHurng,
Tsai YiTing
Publication year - 2021
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.29959
Subject(s) - intracellular ph , extracellular , microbiology and biotechnology , chemistry , intracellular , induced pluripotent stem cell , flow cytometry , downregulation and upregulation , western blot , embryonic stem cell , biochemistry , biology , gene
The homeostasis of intracellular pH (pH i ) affects many cellular functions. Our previous study has established a functional and molecular model of the active pH i regulators in human induced pluripotent stem cells (hiPSCs). The aims of the present study were to further quantify passive pH i buffering power ( β ) and to investigate the effects of extracellular pH and Na + –H + exchanger 1 (NHE1) activity on pluripotency in hiPSCs. pH i was detected by microspectrofluorimetry with pH‐sensitive dye‐BCECF. Western blot, immunofluorescence staining, and flow cytometry were used to detect protein expression and pluripotency. Our study in hiPSCs showed that (a) the value of total ( β tot ), intrinsic ( β i ), and CO 2 ‐dependent ( β C O 2 ) buffering power all increased while pH i increased; (b) during the spontaneous differentiation for 4 days, the β values of β tot and β C O 2changed in a tendency of decrease, despite the absence of statistical significance; (c) an acidic cultured environment retained pluripotency and further upregulated expression and activity of NHE1 during spontaneous differentiation; (d) inhibition on NHE1 activity promoted the loss of pluripotency. In conclusion, we, for the first time, established a quantitative model of passive β during differentiation and demonstrated that maintenance of NHE1 at a higher level was of critical importance for pluripotency retention in hiPSCs.