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

Figure 1 Functional characterization of acid extruders in the HEPES-buffered system. A-D: The top bar shows the buffer system used in perfusion experiments. The application of NH₄Cl and different conditions were respectively shown with the solid and dotted lines above the trace. The trace shown in A showed a typical pH_i recovery slope after NH₄Cl prepulse-induced intracellular acidosis in HEPES-buffered solution as a control. The traces shown in B-D showed the effect of the removal of extracellular Na⁺ (Na⁺-free), addition of 30 μmol/L HOE 694 (H₃₀) and Na⁺-free + 30 μmol/L bafilomycin A1 (Ba₃₀) on the pH_i recovery slope. E: The curve of the pH_i recovery rates for Na⁺-free, H₃₀ and Na⁺-free with Ba₃₀ were collected from 3-6 similar experiments shown in A-D. F: After pre-treatment with NH₄Cl for 5 min, HPS0077 cells were treated with Na⁺-free + Ba₃₀, Na⁺-free + Ba₃₀ + 40 μmol/L SCH-28080 (SCH₄₀) and Na⁺/Cl^--free + Na⁺-free + Ba₃₀ in HEPES-buffered solution, and the change in pH_i was detected by a multimode reader. Error bars represent the mean ± SE.