Functional and molecular mechanism of intracellular pH regulation in human inducible pluripotent stem cells

Chao, Shih-Chi; Wu, Gwo-Jang; Huang, Shu-Fu; Dai, Niann‐Tzyy; Huang, Hsu-Kai; Chou, Mei-Fang; Tsai, Yi‐Ting; Lee, Shiao-Pieng; Loh, Shih‐Hurng

doi:10.4252/wjsc.v10.i12.196

Cited by 10 publications

(21 citation statements)

References 66 publications

(97 reference statements)

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“…This could be due to the intracellular pH being not the same as the pH value of buffer solutions, especially for the cells in alkaline and acidic environments. As reported in previous studies, the intracellular pH in mammalian cells is maintained within an optimal narrow range through the combined operation of transmembrane transporters and the intracellular buffering capacity [59,60]. The alkaline or acidic buffer solutions changed the intracellular pH, but the intracellular buffering and acid extrusion/loading systems trend to maintain intracellular pH neutral.…”

Section: Cds Ph Response In Living Cellsmentioning

confidence: 59%

Carbon Dots for Intracellular pH Sensing with Fluorescence Lifetime Imaging Microscopy

et al. 2020

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The monitoring of intracellular pH is of great importance for understanding intracellular trafficking and functions. It has various limitations for biosensing based on the fluorescence intensity or spectra study. In this research, pH-sensitive carbon dots (CDs) were employed for intracellular pH sensing with fluorescence lifetime imaging microscopy (FLIM) for the first time. FLIM is a highly sensitive method that is used to detect a microenvironment and it can overcome the limitations of biosensing methods based on fluorescence intensity. The different groups on the CDs surfaces changing with pH environments led to different fluorescence lifetime values. The CDs aqueous solution had a gradual change from 1.6 ns to 3.7 ns in the fluorescence lifetime with a pH range of 2.6–8.6. Similar fluorescence lifetime changes were found in pH buffer-treated living cells. The detection of lysosomes, cytoplasm, and nuclei in living cells was achieved by measuring the fluorescence lifetime of CDs. In particular, a phasor FLIM analysis was used to improve the pH imaging. Moreover, the effects of the coenzymes, amino acids, and proteins on the fluorescence lifetime of CDs were examined in order to mimic the complex microenvironment inside the cells.

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Section: Cds Ph Response In Living Cellsmentioning

confidence: 59%

Carbon Dots for Intracellular pH Sensing with Fluorescence Lifetime Imaging Microscopy

et al. 2020

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“…Therefore, it is postulated that in PSCs there may also exist a specific pH i regulating mechanism similar to that of cancer cells. Indeed, in our previous study, we found that in hiPSCs the steady-state pH i values were found to be 7.5 ± 0.01 and 7.68 ± 0.01 in HEPES and 5% CO 2 /HCO 3 − -buffered systems, respectively, which were much higher than that in normal adult cells (pH i~7 .2) and similar to that of cancer cells (Chao et al, 2018).…”

Section: And the Acid-loading Transporters Includementioning

confidence: 64%

“…According to our previous study, the expression and activity of acidextruders were decreased during the loss of pluripotency in hiPSCs (Chao et al, 2018). Therefore, we consider that the retaining effect of F I G U R E 4 The acidic environment retained the pluripotency and up-regulate expression of NHE1 in hiPSCs.…”

Section: The Reversed Ph Gradient Upregulated the Acid-extruder Nhe1mentioning

confidence: 85%

“…K3012010) was used. Western blot analysis was performed as described previously (Chao et al, 2018) with the following antibodies: NHE1 (1:1,000; Origene; TA328914), OCT4…”

Section: Immunoblottingmentioning

confidence: 99%

“…For immunocytochemistry, staining was performed as described previously (Chao et al, 2018) with the following antibodies: OCT4…”

Section: Immunocytochemistry Stainingmentioning

confidence: 99%

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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

Lee

Chao

Chou

et al. 2020

Journal Cellular Physiology

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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 CO2) buffering power all increased while pH i increased; (b) during the spontaneous differentiation for 4 days, the β values of β tot and β CO2 changed 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.

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Machine Learning‐Driven Bioelectronics for Closed‐Loop Control of Cells

Selberg

Jafari

Mathews

et al. 2020

Advanced Intelligent Systems

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Life is built upon closed-loop feedback and regulation systems that maintain a delicate balance of environmental and metabolic conditions that support cellular function. [1] Bioelectronic devices interface electronic devices with biology with potential for sensing and actuation. [2-5] A challenge for bioelectronic devices is translating between ionic and biochemical signals that dominate biology into electronic currents in the devices and vice versa. Iontronics addresses this challenge by modulating ions directly at the device level rather than electron and holes as in traditional semiconductors. [6] Electrophoretic ion pumps mediate the delivery of ions and charged molecules with an induced electric field [7] to treat epilepsy, [6] chronic pain, [8] inflammation, [9] and to actuate movement in plants. [10] In addition, bioprotonic devices can sense and actuate the flow of H þ in field effect transistors (H þ-FETs), [11,12] enzymatic logic gates, [12] and ion channels. [13] A cell's resting potential, V mem , is an electrical control signal that occurs between the interior of the cell and the extracellular environment regulated by ion channels. [14] In nonexcitable cells, [15] V mem affects cell physiology and functions such as proliferation, differentiation, migration, and apoptosis, as well as cell-cell communication and large-scale morphogenesis. [16] Recently, optically actuated

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Functional and molecular mechanism of intracellular pH regulation in human inducible pluripotent stem cells

Cited by 10 publications

References 66 publications

Carbon Dots for Intracellular pH Sensing with Fluorescence Lifetime Imaging Microscopy

Carbon Dots for Intracellular pH Sensing with Fluorescence Lifetime Imaging Microscopy

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

Machine Learning‐Driven Bioelectronics for Closed‐Loop Control of Cells

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