Role of intracellular Ca²⁺ and calmodulin/MAP kinase kinase/extracellular signal‐regulated protein kinase signalling pathway in the mitogenic and antimitogenic effect of nitric oxide in glia‐ and neurone‐derived cell lines

Abstract

To elucidate the mechanism of cell growth regulation by nitric oxide (NO) and the role played in it by Ca2+, we studied the relationship among intracellular Ca2+ concentration ([Ca2+]i), mitogen-activated protein kinases [extracellular signal-regulated protein kinase (ERK)] and proliferation in cell lines exposed to different levels of NO. Data showed that NO released by low [(z)-1-[2-aminiethyl]-N-[2-ammonioethyl]amino]diazen-1-ium-1,2diolate (DETA/NO) concentrations (10 microm) determined a gradual, moderate elevation in [Ca2+]i (46.8 +/- 7.2% over controls) which paralleled activation of ERK and potentiation of cell division. Functionally blocking Ca2+ or inhibiting calmodulin or MAP kinase kinase activities prevented ERK activation and antagonized the mitogenic effect of NO. Experimental conditions favouring Ca2+ entry into cells led to increased [Ca2+]i (189.5 +/- 4.8%), ERK activation and cell division. NO potentiated the Ca2+ elevation (358 +/- 16.8%) and ERK activation leading to expression of p21Cip1 and inhibition of cell proliferation. Furthermore, functionally blocking Ca2+ down-regulated ERK activation and reversed the antiproliferative effect of NO. Both the mitogenic and antimitogenic responses induced by NO were mimicked by a cGMP analogue whereas they were completely antagonized by selective cGMP inhibitors. These results demonstrate for the first time that regulation of cell proliferation by low NO levels is cGMP dependent and occurs via the Ca2+/calmodulin/MAP kinase kinase/ERK pathway. In this effect the amplitude of Ca2+ signalling determines the specificity of the proliferative response to NO possibly by modulating the strength of ERK activation. In contrast to the low level, the high levels (50-300 microm) of DETA/NO negatively regulated cell proliferation via a Ca2+-independent mechanism.

The Effects of Hypoxia/Reoxygenation on the Physiological Behaviour of U373-Mg Astrocytes

“…It has been demonstrated that the NO-calmodulin-calcium signal is responsible for phosphorylation of ERK proteins and activation of hypoxia-inducible factor 1 [13,14]. We did not observe significant increases of ERK 1/2 proteins after hypoxia, in accordance with the slight decrease of proliferation.…”

“…We did not observe significant increases of ERK 1/2 proteins after hypoxia, in accordance with the slight decrease of proliferation. Moreover, low ERK activation has been shown to induce cell growth in different cell types [14] and is in accordance with the restored proliferation indexes observed after the 24 h reoxygenation period.…”

Non-Thermal Atmospheric Pressure Plasma Efficiently Promotes the Proliferation of Adipose Tissue-Derived Stem Cells by Activating NO-Response Pathways

“…NO is known to be produced by activated nitric oxide synthase (NOS) via the PI-3K/Akt signaling pathway5960 and to induce the mitogen-activated protein kinase (MAPK)/ERK pathway that leads to cell proliferation6162. Also, it has been well reported that both PI-3K/Akt and MAPK/ERK signaling pathways activate the phosphorylation of NF-κB and allow it to enter the nucleus, thereby promoting cell proliferation by NF-κB-dependent transcription6364.…”

Involvement of the extracellular signal-regulated kinase 1/2 signaling pathway in amylin's eating inhibitory effect

“…Furthermore, reduction of meal size by local administration of the membrane permeable analog 8-Br-cGMP into the AP suggests a functional role of cGMP signaling in amylin's eating inhibitory effect (35). Interestingly, cGMP accumulation is able to activate the ERK cascade in neurons in vitro (14,19,32) but the potential link between cGMP accumulation in the AP and ERK cascade activation, and the necessity for such a link for amylin's eating inhibitory effect, remains to be elucidated.…”