Dataset Information

Epigallocatechin 3-gallate inhibits the plasma membrane Ca²⁺-ATPase: effects on calcium homeostasis.

ABSTRACT: Flavonoids are natural compounds responsible for the health benefits of green tea. Some of the flavonoids present in green tea are catechins, among which are: epigallocatechin, epicatechin-3-gallate, epicatechin, catechin and epigallocatechin-3-gallate (EGCG). The latter was found to induce apoptosis, reduce reactive oxygen species, in some conditions though in others it acts as an oxidizing agent, induce cell cycle arrest, and inhibit carcinogenesis. EGCG also was found to be involved in calcium (Ca²⁺) homeostasis in excitable and in non-excitable cells. In this study, we investigate the effect of catechins on plasma membrane Ca²⁺-ATPase (PMCA), which is one of the main mechanisms that extrude Ca²⁺ out of the cell. Our studies comprised experiments on the isolated PMCA and on cells overexpressing the pump. Among catechins that inhibited PMCA activity, the most potent inhibitor was EGCG. EGCG inhibited PMCA activity in a reversible way favoring E1P conformation. EGCG inhibition also occurred in the presence of calmodulin, the main pump activator. Finally, the effect of EGCG on PMCA activity was studied in human embryonic kidney cells (HEK293T) that transiently overexpress hPMCA4. Results show that EGCG inhibited PMCA activity in HEK293T cells, suggesting that the effects observed on isolated PMCA occur in living cells.

SUBMITTER: Rinaldi DE

PROVIDER: S-EPMC7930289 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Epigallocatechin 3-gallate inhibits the plasma membrane Ca<sup>2+</sup>-ATPase: effects on calcium homeostasis.

Rinaldi Débora E DE Ontiveros Mallku Q MQ Saffioti Nicolas A NA Vigil Maximiliano A MA Mangialavori Irene C IC Rossi Rolando C RC Rossi Juan P JP Espelt María V MV Ferreira-Gomes Mariela S MS

Heliyon 20210226 2

Flavonoids are natural compounds responsible for the health benefits of green tea. Some of the flavonoids present in green tea are catechins, among which are: epigallocatechin, epicatechin-3-gallate, epicatechin, catechin and epigallocatechin-3-gallate (EGCG). The latter was found to induce apoptosis, reduce reactive oxygen species, in some conditions though in others it acts as an oxidizing agent, induce cell cycle arrest, and inhibit carcinogenesis. EGCG also was found to be involved in calciu ...[more]

PMID: 33681501

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Project description:Intracellular Ca2+ signaling engendered by Ca2+ influx and mobilization in odontoblasts is critical for dentinogenesis induced by multiple stimuli at the dentin surface. Increased Ca2+ is exported by the Na+-Ca2+ exchanger (NCX) and plasma membrane Ca2+-ATPase (PMCA) to maintain Ca2+ homeostasis. We previously demonstrated a functional coupling between Ca2+ extrusion by NCX and its influx through transient receptor potential channels in odontoblasts. Although the presence of PMCA in odontoblasts has been previously described, steady-state levels of mRNA-encoding PMCA subtypes, pharmacological properties, and other cellular functions remain unclear. Thus, we investigated PMCA mRNA levels and their contribution to mineralization under physiological conditions. We also examined the role of PMCA in the Ca2+ extrusion pathway during hypotonic and alkaline stimulation-induced increases in intracellular free Ca2+ concentration ([Ca2+]i). We performed RT-PCR and mineralization assays in human odontoblasts. [Ca2+]i was measured using fura-2 fluorescence measurements in odontoblasts isolated from newborn Wistar rat incisor teeth and human odontoblasts. We detected mRNA encoding PMCA1-4 in human odontoblasts. The application of hypotonic or alkaline solutions transiently increased [Ca2+]i in odontoblasts in both rat and human odontoblasts. The Ca2+ extrusion efficiency during the hypotonic or alkaline solution-induced [Ca2+]i increase was decreased by PMCA inhibitors in both cell types. Alizarin red and von Kossa staining showed that PMCA inhibition suppressed mineralization. In addition, alkaline stimulation (not hypotonic stimulation) to human odontoblasts upregulated the mRNA levels of dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotein (DSPP). The PMCA inhibitor did not affect DMP-1 or DSPP mRNA levels at pH 7.4-8.8 and under isotonic and hypotonic conditions, respectively. We also observed PMCA1 immunoreactivity using immunofluorescence analysis. These findings indicate that PMCA participates in maintaining [Ca2+]i homeostasis in odontoblasts by Ca2+ extrusion following [Ca2+]i elevation. In addition, PMCA participates in dentinogenesis by transporting Ca2+ to the mineralizing front (which is independent of non-collagenous dentin matrix protein secretion) under physiological and pathological conditions following mechanical stimulation by hydrodynamic force inside dentinal tubules, or direct alkaline stimulation by the application of high-pH dental materials.

Dataset Information

Epigallocatechin 3-gallate inhibits the plasma membrane Ca²⁺-ATPase: effects on calcium homeostasis.

Publications

Epigallocatechin 3-gallate inhibits the plasma membrane Ca<sup>2+</sup>-ATPase: effects on calcium homeostasis.

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Epigallocatechin 3-gallate inhibits the plasma membrane Ca2+-ATPase: effects on calcium homeostasis.

Publications

Epigallocatechin 3-gallate inhibits the plasma membrane Ca<sup>2+</sup>-ATPase: effects on calcium homeostasis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Epigallocatechin 3-gallate inhibits the plasma membrane Ca²⁺-ATPase: effects on calcium homeostasis.