Regulation of proliferation of LLC-MK2 cells by nucleosides and nucleotides: the role of ecto-enzymes

Lemmens, Raf; Vanduffel, Luc; Teuchy, H.; Čulić, Ognjen

doi:10.1042/bj3160551

Cited by 33 publications

(13 citation statements)

References 51 publications

(60 reference statements)

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“…We have previously shown that DIDS inhibits T. cruzi epimastigote cell growth (Bernardes et al 2000), and that this inhibition is supposed to be related to ectoenzymes involved in cell proliferation (Berreˆdo-Pinho et al 2001). ATP and other nucleotides stimulate the proliferation of different cell types, while the inhibition of the ecto-ATPase, 5¢ nucleotidase and alkaline phosphatase moderate the stimulatory effect of ATP (Lemmens et al 1996). Figure 4 shows that the Mg 2+ -dependent ATPase activity decreased during the time course of cell growth.…”

Section: Resultsmentioning

confidence: 91%

A Mg-dependent ecto-ATPase is increased in the infective stages of Trypanosoma cruzi

et al. 2004

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In this work, we describe the ability of living epimastigotes of Trypanosoma cruzi to hydrolyze extracellular ATP. In these intact parasites, there was a low level of ATP hydrolysis in the absence of any divalent metal (2.42 +/- 0.31 nmol Pi/h x 10(8) cells). ATP hydrolysis was stimulated by MgCl2, and the Mg-dependent ecto-ATPase activity was 27.15 +/- 2.91 nmol Pi/h x 10(8) cells. The addition of MgCl2 to the extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. This stimulatory activity was also observed when MgCl2 was replaced by MnCl2, but not by CaCl2 or SrCl2. The apparent Km for Mg-ATP2- was 0.61 mM, and free Mg2+ did not increase the ecto-ATPase activity. This ecto-ATPase activity was insensitive to the inhibitors of other ATPase and phosphatase activities. To confirm that this Mg-dependent ATPase was an ecto-ATPase, we used an impermeant inhibitor, DIDS (4, 4'.diisothiocyanostylbene 2'-2'-disulfonic acid) as well as suramin, an antagonist of P2 purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg2+-dependent ATPase activity in a dose-dependent manner. A comparison among the Mg2+-ecto-ATPase activities of the three forms of T. cruzi showed that the noninfective epimastigotes were less efficient at hydrolyzing ATP than the infective trypomastigote and amastigote stages.

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Section: Resultsmentioning

confidence: 91%

A Mg-dependent ecto-ATPase is increased in the infective stages of Trypanosoma cruzi

et al. 2004

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“…The physiological role of the ecto-ATPases is still unknown, but a possible involvement in cell proliferation has been proposed (Lemmens et al 1996;Bernardes et al 2000;Berreˆdo-Pinho et al 2001). The trypanosomatidae family includes species that cannot synthesize purines de novo and thus are dependent on exogenous sources of these essential nutrients (Cohn and Gottlieb 1997;Gero 1998).…”

Section: Resultsmentioning

confidence: 99%

Ectonucleotide diphosphohydrolase activity in Crithidia deanei

Lemos

Pinheiro

Berrêdo-Pinho

et al. 2002

Parasitology Research

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In this work we describe the ability of living Crithidia deanei to hydrolyze extracellular ATP. In intact cells at pH 7.2, a low level of ATP hydrolysis was observed in the absence of any divalent metal (0.41+/-0.13 nmol P(i) h(-1) 10(7) cells(-1)). The ATP hydrolysis was stimulated by MgCl(2) and the Mg(2+)-dependent ecto-ATPase activity was 4.05+/-0.17 nmol P(i) h(-1) 10(7) cells(-1). Mg(2+)-dependent ecto-ATPase activity increased linearly with cell density and with time for at least 60 min. The addition of MgCl(2) to extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. At 5 mM ATP, half-maximal stimulation of ATP hydrolysis was obtained with 0.93+/-0.26 mM MgCl(2). This stimulatory activity was also observed when MgCl(2) was replaced by MnCl(2), but not CaCl(2) or SrCl(2). The apparent K(m) for Mg-ATP(2-) was 0.26+/-0.03 mM. ATP was the best substrate for this enzyme; other nucleotides, such as ITP, GTP, UTP and CTP, produced lower reaction rates. In the pH range from 6.6 to 8.4, in which the cells were viable, the acid phosphatase activity also present in this cell decreased, while the Mg(2+)-dependent ATPase activity did not change. This ecto-ATPase activity was insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin A(1), ouabain, vanadate, molybdate, sodium fluoride and tartrate. To confirm that this Mg(2+)-dependent ATPase was an ecto-ATPase, we used the impermeant inhibitor 4, 4'-diisothiocyanostylbene 2'-2'-disulfonic acid as well as suramin, an antagonist of P(2) purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg(2+)-dependent ATPase activity in a dose-dependent manner. The cell surface location of the ATP-hydrolyzing site was also confirmed by cytochemical analysis.

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“…30,31 In comparison with ATP or uridine 5Ј-triphosphate, 5Ј-mononucleotides usually have much lower agonist activity for the nucleotide receptors. 32,33 However, it has been found that AMPS is a weak agonist of a novel P2 receptor on undifferentiated HL-60 cells. Its pharmacological profile is very similar to that of the P2Y11 receptor identified in 2 different cell lines: the 1321N1 astrocytoma and the Chinese hamster over K1 cell line.…”

Section: Discussionmentioning

confidence: 99%

The mononucleotide-dependent, nonantisense mechanism of action of phosphodiester and phosphorothioate oligonucleotides depends upon the activity of an ecto-5′-nucleotidase

Koziołkiewicz

Gendaszewska

Maszewska

et al. 2001

Blood

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Regulation of proliferation of LLC-MK2 cells by nucleosides and nucleotides: the role of ecto-enzymes

Cited by 33 publications

References 51 publications

A Mg-dependent ecto-ATPase is increased in the infective stages of Trypanosoma cruzi

A Mg-dependent ecto-ATPase is increased in the infective stages of Trypanosoma cruzi

Ectonucleotide diphosphohydrolase activity in Crithidia deanei

The mononucleotide-dependent, nonantisense mechanism of action of phosphodiester and phosphorothioate oligonucleotides depends upon the activity of an ecto-5′-nucleotidase

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