P2X1 receptor-mediated inhibition of the proliferation of human coronary smooth muscle cells involving the transcription factor NR4A1

Abstract

Adenine nucleotides acting at P2X 1 receptors are potent vasoconstrictors. Recently, we demonstrated that activation of adenosine A 2B receptors on human coronary smooth muscle cells inhibits cell proliferation by the induction of the nuclear receptor subfamily 4, group A, member 1 (NR4A1; alternative notation Nur77). In the present study, we searched for long-term effects mediated by P2X 1 receptors by analyzing receptor-mediated changes in cell proliferation and in the expression of NR4A1. Cultured human coronary smooth muscle cells were treated with selective receptor ligands. Effects on proliferation were determined by counting cells and measuring changes in impedance. The induction of transcription factors was assessed by qPCR. The P2X receptor agonist α,β-methylene-ATP and its analog β,γ-methylene-ATP inhibited cell proliferation by about 50 % after 5 days in culture with half-maximal concentrations of 0.3 and 0.08 μM, respectively. The effects were abolished or markedly attenuated by the P2X 1 receptor antagonist NF449 (carbonylbis-imino-benzenetriylbis-(carbonylimino)tetrakis-benzene-1,3-disulfonic acid; 100 nM and 1 μM). α,β-methylene-ATP and β,γ-methylene-ATP applied for 30 min to 4 h increased the expression of NR4A1; NF449 blocked or attenuated this effect. Small interfering RNA directed against NR4A1 diminished the antiproliferative effects of α,β-methylene-ATP and β,γ-methylene-ATP. α,β-methylene-ATP (0.1 to 30 μM) decreased migration of cultured human coronary smooth muscle cells in a chamber measuring changes in impedance; NF449 blocked the effect. In conclusion, our results demonstrate for the first time that adenine nucleotides acting at P2X 1 receptors inhibit the proliferation of human coronary smooth muscle cells via the induction of the early gene NR4A1.

NR4A1 Promotes PDGF-BB-Induced Cell Colony Formation in Soft Agar

“…Consistent with studies in smooth muscle cells [53] [54] , we found that NR4A1 reduces proliferation. However, in other studies, e.g.…”

Regulation of Coronary Blood Flow

“…Thus, it appears that T-type channels are more characteristic of the coronary myocytes from small animal models than of larger animals and humans. Third, while a number of voltage-independent Ca 2+ channels are expressed in coronary vascular smooth muscle, their roles are not entirely clear and may have more to do with, for example, cell proliferation than coronary vascular reactivity (476). In contrast, when it comes to regulating coronary vascular tone, L-type Ca 2+ channels clearly have the most dominant role, as: (i) diltiazem [a benzothiazepine-type Ca 2+ channel antagonist) blocks ~90% of myogenic tone in human coronary arterioles (674); (ii) nifedipine (a dihydropyrdine-type Ca 2+ channel antagonist) blocks 100% of agonist-induced tone in porcine coronary arterioles (50); and (iii) diltiazem completely eliminates coronary autoregulation, a mechanism that requires active coronary vasoconstriction (94) Figure 31].…”

In mice and humans, the brain’s blood vessels mature postnatally to acquire barrier and contractile properties

“…The vast majority of VSMC-preferentially expressed or -specific transcripts identified in our study were related to muscle differentiation and contractility. Apart from well-known VSMCs transcripts (such as Acta2, Myh11, desmin and Tgln ), our analysis highlighted the expression of markers like NR4a1 (coding for nuclear receptor subfamily 4, group A, member 1, involved in SMC proliferation) (Hinze et al, 2013; Yu et al, 2015), Pdlim3 (coding for actinin-associated LIM protein, involved in myocyte stability (Zheng et al, 2010), Mustn1 (regulating myoblast differentiation) (Hadjiargyrou, 2018; Liu et al, 2010), and Pln (coding for phospholamban, which regulates the sarcoplasmic reticulum Ca 2+ ATPase (SERCA) activity and muscle contractility) (Kranias and Hajjar, 2012). Surprisingly, about half of the genes were strongly upregulated on P15; this indicates that VSMC contractility continued to differentiate between P5 and P15.…”