Silencing TRPM7 mimics the effects of magnesium deficiency in human microvascular endothelial cells

Abstract

Evidence has accumulated to suggest that magnesium might play a role in controlling angiogenesis. Since microvascular endothelial cells are protagonists in this process, we investigated the behavior of these cells cultured in low extracellular magnesium or silenced for its transporter Transient Receptor Potential Melastatin (TRPM)7, essential for cellular magnesium homeostasis. In particular, we focused on some crucial steps of the angiogenic process, i.e. proliferation, migration, protease production and organization in tridimensional structures. Silencing TRPM7 mimics the effects of low extracellular magnesium on human microvascular endothelial cells (HMEC). Indeed, while no effects were observed on the production of metalloproteases and on tridimensional organization on matrigel, both magnesium deficiency and silencing of TRPM7 impair cell migration and inhibit growth by arresting the cells in the G0/G1 and G2/M phases of the cell cycle. Since low extracellular magnesium markedly decreases TRPM7 in HMEC, we suggest that TRPM7 downregulation might mediate low magnesium-induced inhibition of cell growth and migration. Human endothelial cells from the umbilical vein are growth inhibited by low magnesium and growth stimulated after TRPM7 silencing. An impairment of ERK phosphorylation in HMEC silencing TRPM7 is responsible, in part, for the different proliferative behavior of these two cell types. We broadened our studies also to endothelial colony-forming cells and found that they are sensitive to fluctuations of the concentrations of extracellular magnesium, while their proliferation rate is not modulated by TRPM7 silencing. Our results point to magnesium and TRPM7 as a modulators of the angiogenic phenotype of microvascular endothelial cells.

Update on vascular endothelial Ca2+signalling: A tale of ion channels, pumps and transporters

“…TRPM7 might, therefore, act as "Mg 2+ -sensor" [323,326] . Consistently, silencing TRPM7 mimics the effect of lowering extracellular Mg 2+ in human microvascular ECs by impairing cell migration and arresting the cells in G0/G1 and G2/M phases [327] . Similarly, TRPM7 may inhibit EC proliferation via an extracellular signalregulated kinase (ERK)-dependent reduction in eNOS levels [328] .…”

“…Human umbilical vein ECs [325,327,328] +(RT-PCR, WB) -(RT-PCR) +(RT-PCR, WB) Mouse aortic ECs [329] +(RT-PCR, WB) +(RT-PCR) Human dermal microvascular ECs [327] +(RT-PCR, [8] +(RT-PCR, WB)…”

Transient Receptor Potential Melastatin 7 (TRPM7) Contributes to H2O2-Induced Cardiac Fibrosis via Mediating Ca2+ Influx and Extracellular Signal–Regulated Kinase 1/2 (ERK1/2) Activation in Cardiac Fibroblasts

“…Channel function for sustained phosphorylation of ERK1/2 is required for TRPM7-regulating cell behaviors (24,25). Meanwhile, extensive evidence has shown that ERK1/2 is significantly activated after various types of stimulation and subsequent cardiac fibrosis (26).…”

TRPM7 regulates vascular endothelial cell adhesion and tube formation

“…TRPM7 has been shown to be expressed in the human vascular system and to play a role in vascular functions (3,4,6,25,31,52,68,69,74,76). For example, in vascular smooth muscle cells, TRPM7 modulates Mg 2ϩ homeostasis (6,25).…”