1
|
Lee SP, Chao SC, Chou MF, Huang SF, Dai NT, Wu GJ, Tsai CS, Loh SH, Tsai YT. 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. J Cell Physiol 2020; 236:1515-1528. [PMID: 32841374 DOI: 10.1002/jcp.29959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/18/2020] [Accepted: 07/07/2020] [Indexed: 11/07/2022]
Abstract
The homeostasis of intracellular pH (pHi ) affects many cellular functions. Our previous study has established a functional and molecular model of the active pHi regulators in human induced pluripotent stem cells (hiPSCs). The aims of the present study were to further quantify passive pHi buffering power (β) and to investigate the effects of extracellular pH and Na+ -H+ exchanger 1 (NHE1) activity on pluripotency in hiPSCs. pHi 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 (βtot ), intrinsic (βi ), and CO2 -dependent ( β C O 2 ) buffering power all increased while pHi increased; (b) during the spontaneous differentiation for 4 days, the β values of βtot and β C O 2 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.
Collapse
Affiliation(s)
- Shiao-Pieng Lee
- Department of Dentistry, School of Dentistry, Division of Oral and Maxillofacial Surgery, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan
| | - Shih-Chi Chao
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Mei-Fang Chou
- Department of Pharmacy Practice, Tri-Service General Hospital, Taipei, Taiwan
| | - Shu-Fu Huang
- Department of Pharmacy Practice, Tri-Service General Hospital, Taipei, Taiwan
| | - Niann-Tzyy Dai
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Tri-Service General Hospital, Taipei, Taiwan
| | - Gwo-Jang Wu
- Department of Obstetrics and Gynecology, Tri-Service General Hospital, Taipei, Taiwan
| | - Chien-Sung Tsai
- Department of Surgery, Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- Department of Pharmacology, National Defense Medical Center, Taipei, Taiwan
- Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Shih-Hurng Loh
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Department of Pharmacy Practice, Tri-Service General Hospital, Taipei, Taiwan
- Department of Surgery, Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Ting Tsai
- Department of Surgery, Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| |
Collapse
|
2
|
Koch A, Schwab A. Cutaneous pH landscape as a facilitator of melanoma initiation and progression. Acta Physiol (Oxf) 2019; 225:e13105. [PMID: 29802798 DOI: 10.1111/apha.13105] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/22/2018] [Accepted: 05/22/2018] [Indexed: 12/15/2022]
Abstract
Melanoma incidence is on the rise and currently causes the majority of skin cancer-related deaths. Yet, therapies for metastatic melanoma are still insufficient so that new concepts are essential. Malignant transformation of melanocytes and melanoma progression are intimately linked to the cutaneous pH landscape and its dysregulation in tumour lesions. The pH landscape of normal skin is characterized by a large pH gradient of up to 3 pH units between surface and dermis. The Na+ /H+ exchanger NHE1 is one of the major contributors of acidity in superficial skin layers. It is also activated by the most frequent mutation in melanoma, BRAFV 600E , thereby causing pH dysregulation during melanoma initiation. Melanoma progression is supported by an extracellular acidification and/or NHE1 activity which promote the escape of single melanoma cells from the primary tumour, migration and metastatic spreading. We propose that viewing melanoma against the background of the acid-base physiology of the skin provides a better understanding of the pathophysiology of this disease and allows the development of novel therapeutic concepts.
Collapse
Affiliation(s)
- A. Koch
- Institute of Physiology II; University of Münster; Münster Germany
| | - A. Schwab
- Institute of Physiology II; University of Münster; Münster Germany
| |
Collapse
|