1
|
Boudreault F, Tan JJ, Grygorczyk R. Propidium uptake and ATP release in A549 cells share similar transport mechanisms. Biophys J 2022; 121:1593-1609. [PMID: 35398020 PMCID: PMC9117937 DOI: 10.1016/j.bpj.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/03/2022] [Accepted: 04/04/2022] [Indexed: 11/02/2022] Open
Abstract
The lipid bilayer of eukaryotic cells' plasma membrane is almost impermeable to small ions and large polar molecules, but its miniscule basal permeability in intact cells is poorly characterized. This report describes the intrinsic membrane permeability of A549 cells toward the charged molecules propidium (Pr2+) and ATP4-. Under isotonic conditions, we detected with quantitative fluorescence microscopy, a continuous low-rate uptake of Pr (∼150 × 10-21 moles (zmol)/h/cell, [Pr]o = 150 μM, 32°C). It was stimulated transiently but strongly by 66% hypotonic cell swelling reaching an influx amplitude of ∼1500 (zmol/h)/cell. The progressive Pr uptake with increasing [Pr]o (30, 150, and 750 μM) suggested a permeation mechanism by simple diffusion. We quantified separately ATP release with custom wide-field-of-view chemiluminescence imaging. The strong proportionality between ATP efflux and Pr2+ influx during hypotonic challenge, and the absence of stimulation of transmembrane transport following 300% hypertonic shock, indicated that ATP and Pr travel the same conductive pathway. The fluorescence images revealed a homogeneously distributed intracellular uptake of Pr not consistent with high-conductance channels expressed at low density on the plasma membrane. We hypothesized that the pathway consists of transiently formed water pores evenly spread across the plasma membrane. The abolition of cell swelling-induced Pr uptake with 500 μM gadolinium, a known modulator of membrane fluidity, supported the involvement of water pores whose formation depends on the membrane fluidity. Our study suggests an alternative model of a direct permeation of ATP (and other molecules) through the phospholipid bilayer, which may have important physiological implications.
Collapse
|
2
|
Mugabo Y, Zhao C, Tan JJ, Ghosh A, Campbell SA, Fadzeyeva E, Paré F, Pan SS, Galipeau M, Ast J, Broichhagen J, Hodson DJ, Mulvihill EE, Petropoulos S, Lim GE. 14-3-3ζ constrains insulin secretion by regulating mitochondrial function in pancreatic β-cells. JCI Insight 2022; 7:156378. [PMID: 35298439 PMCID: PMC9089799 DOI: 10.1172/jci.insight.156378] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
While critical for neurotransmitter synthesis, 14-3-3 proteins are often assumed to have redundant functions due to their ubiquitous expression, but despite this assumption, various 14-3-3 isoforms have been implicated in regulating metabolism. We previously reported contributions of 14-3-3ζ in β cell function, but these studies were performed in tumor-derived MIN6 cells and systemic KO mice. To further characterize the regulatory roles of 14-3-3ζ in β cell function, we generated β cell–specific 14-3-3ζ–KO mice. Although no effects on β cell mass were detected, potentiated glucose-stimulated insulin secretion (GSIS), mitochondrial function, and ATP synthesis were observed. Deletion of 14-3-3ζ also altered the β cell transcriptome, as genes associated with mitochondrial respiration and oxidative phosphorylation were upregulated. Acute 14-3-3 protein inhibition in mouse and human islets recapitulated the enhancements in GSIS and mitochondrial function, suggesting that 14-3-3ζ is the critical isoform in β cells. In dysfunctional db/db islets and human islets from type 2 diabetic donors, expression of Ywhaz/YWHAZ, the gene encoding 14-3-3ζ, was inversely associated with insulin secretion, and pan–14-3-3 protein inhibition led to enhanced GSIS and mitochondrial function. Taken together, this study demonstrates important regulatory functions of 14-3-3ζ in the regulation of β cell function and provides a deeper understanding of how insulin secretion is controlled in β cells.
Collapse
Affiliation(s)
- Yves Mugabo
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Cheng Zhao
- Division of Obstetrics and Gynecology, Department of Clinical Science, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Ju Jing Tan
- Immunopathology Axis, Centre de Recherche du Centre hospitalier de l'Université de Montréal, Montreal, Canada
| | - Anindya Ghosh
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Scott A Campbell
- Cardiometabolic Axis, Centre de Recherche du Centre hospitalier de l'Université de Montréal, Montreal, Canada
| | - Evgenia Fadzeyeva
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, Canada
| | - Frédéric Paré
- Cardiometabolic Axis, Centre de recherche du CHUM (CRCHUM), Montreal, Canada
| | - Siew Siew Pan
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Maria Galipeau
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Julia Ast
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Pro, University of Birmingham, Birmingham, United Kingdom
| | - Johannes Broichhagen
- Department of Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Pro, University of Birmingham, Birmingham, United Kingdom
| | - Erin E Mulvihill
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | | | - Gareth E Lim
- Department of Medicine, Université de Montréal, Montreal, Canada
| |
Collapse
|
3
|
Purinergic signaling is essential for full Psickle activation by hypoxia and by normoxic acid pH in mature human sickle red cells and in vitro-differentiated cultured human sickle reticulocytes. Pflugers Arch 2022; 474:553-565. [PMID: 35169901 DOI: 10.1007/s00424-022-02665-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/03/2021] [Accepted: 01/11/2022] [Indexed: 10/19/2022]
Abstract
Paracrine ATP release by erythrocytes has been shown to regulate endothelial cell function via purinergic signaling, and this erythoid-endothelial signaling network is pathologically dysregulated in sickle cell disease. We tested the role of extracellular ATP-mediated purinergic signaling in the activation of Psickle, the mechanosensitive Ca2+-permeable cation channel of human sickle erythrocytes (SS RBC). Psickle activation increases intracellular [Ca2+] to stimulate activity of the RBC Gardos channel, KCNN4/KCa3.1, leading to cell shrinkage and accelerated deoxygenation-activated sickling.We found that hypoxic activation of Psickle recorded by cell-attached patch clamp in SS RBC is inhibited by extracellular apyrase, which hydrolyzes extracellular ATP. Hypoxic activation of Psickle was also inhibited by the pannexin-1 inhibitor, probenecid, and by the P2 antagonist, suramin. A Psickle-like activity was also activated in normoxic SS RBC (but not in control red cells) by bath pH 6.0. Acid-activated Psickle-like activity was similarly blocked by apyrase, probenecid, and suramin, as well as by the Psickle inhibitor, Grammastola spatulata mechanotoxin-4 (GsMTx-4).In vitro-differentiated cultured human sickle reticulocytes (SS cRBC), but not control cultured reticulocytes, also exhibited hypoxia-activated Psickle activity that was abrogated by GsMTx-4. Psickle-like activity in SS cRBC was similarly elicited by normoxic exposure to acid pH, and this acid-stimulated activity was nearly completely blocked by apyrase, probenecid, and suramin, as well as by GsMTx-4.Thus, hypoxia-activated and normoxic acid-activated cation channel activities are expressed in both SS RBC and SS cRBC, and both types of activation appear to be mediated or greatly amplified by autocrine or paracrine purinergic signaling.
Collapse
|
4
|
Grygorczyk R, Boudreault F, Ponomarchuk O, Tan JJ, Furuya K, Goldgewicht J, Kenfack FD, Yu F. Lytic Release of Cellular ATP: Physiological Relevance and Therapeutic Applications. Life (Basel) 2021; 11:life11070700. [PMID: 34357072 PMCID: PMC8307140 DOI: 10.3390/life11070700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/28/2021] [Accepted: 07/13/2021] [Indexed: 01/01/2023] Open
Abstract
The lytic release of ATP due to cell and tissue injury constitutes an important source of extracellular nucleotides and may have physiological and pathophysiological roles by triggering purinergic signalling pathways. In the lungs, extracellular ATP can have protective effects by stimulating surfactant and mucus secretion. However, excessive extracellular ATP levels, such as observed in ventilator-induced lung injury, act as a danger-associated signal that activates NLRP3 inflammasome contributing to lung damage. Here, we discuss examples of lytic release that we have identified in our studies using real-time luciferin-luciferase luminescence imaging of extracellular ATP. In alveolar A549 cells, hypotonic shock-induced ATP release shows rapid lytic and slow-rising non-lytic components. Lytic release originates from the lysis of single fragile cells that could be seen as distinct spikes of ATP-dependent luminescence, but under physiological conditions, its contribution is minimal <1% of total release. By contrast, ATP release from red blood cells results primarily from hemolysis, a physiological mechanism contributing to the regulation of local blood flow in response to tissue hypoxia, mechanical stimulation and temperature changes. Lytic release of cellular ATP may have therapeutic applications, as exemplified by the use of ultrasound and microbubble-stimulated release for enhancing cancer immunotherapy in vivo.
Collapse
Affiliation(s)
- Ryszard Grygorczyk
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
- Département de Médecine, Université de Montréal, Montréal, QC H2X 0A9, Canada
- Correspondence: (R.G.); (F.Y.)
| | - Francis Boudreault
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Olga Ponomarchuk
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Ju Jing Tan
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Kishio Furuya
- Graduate School of Medicine, Nagoya University, Nagoya 464-8601, Japan;
| | - Joseph Goldgewicht
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - Falonne Démèze Kenfack
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
| | - François Yu
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (F.B.); (O.P.); (J.J.T.); (J.G.); (F.D.K.)
- Département de Radiologie, Radio-Oncologie et Médecine Nucléaire, Université de Montréal, Montréal, QC H2X 0A9, Canada
- Institut de Génie Biomédical, Université de Montréal, Montréal, QC H2X 0A9, Canada
- Correspondence: (R.G.); (F.Y.)
| |
Collapse
|
5
|
Tan JJ, Boudreault F, Adam D, Brochiero E, Grygorczyk R. Type 2 secretory cells are primary source of ATP release in mechanically stretched lung alveolar cells. Am J Physiol Lung Cell Mol Physiol 2019; 318:L49-L58. [PMID: 31596106 DOI: 10.1152/ajplung.00321.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Extracellular ATP and its metabolites are potent paracrine modulators of lung alveolar cell function, including surfactant secretion and fluid transport, but the sources and mechanism of intra-alveolar ATP release remain unclear. To determine the contribution of gas-exchanging alveolar type 1 (AT1) and surfactant-secreting type 2 (AT2) cells to stretch-induced ATP release, we used quantitative real-time luminescence ATP imaging and rat primary alveolar cells cultured on silicon substrate for 2-7 days. When cultured on solid support, primary AT2 cells progressively transdifferentiated into AT1-like cells with ~20% of cells showing AT1 phenotype by day 2-3 (AT2:AT1 ≈ 4:1), while on day 7, the AT2:AT1 cell ratio was reversed with up to 80% of the cells displaying characteristics of AT1 cells. Stretch (1 s, 5-35%) induced ATP release from AT2/AT1 cell cultures, and it was highest on days 2 and 3 but declined in older cultures. ATP release tightly correlated with the number of remaining AT2 cells in culture, consistent with ~10-fold lower ATP release by AT1 than AT2 cells. ATP release was unaffected by inhibitors of putative ATP channels carbenoxolone and probenecid but was significantly diminished in cells loaded with calcium chelator BAPTA. These pharmacological modulators had similar effects on stretch-induced intracellular Ca2+ responses measured by Fura2 fluorescence. The study revealed that AT2 cells are the primary source of stretch-induced ATP release in heterocellular AT2/AT1 cell cultures, suggesting similar contribution in intact alveoli. Our results support a role for calcium-regulated mechanism but not ATP-conducting channels in ATP release by alveolar epithelial cells.
Collapse
Affiliation(s)
- Ju Jing Tan
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Francis Boudreault
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Damien Adam
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Emmanuelle Brochiero
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Ryszard Grygorczyk
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| |
Collapse
|