Manipulations of Glutathione Metabolism Modulate IP3-Mediated Store-Operated Ca2+ Entry on Astroglioma Cell Line

Nawfel Mokrane; Yassin Snabi; Thierry Cens; Janique Guiramand; Pierre Charnet; Anaïs Bertaud; Claudine Menard; Matthieu Rousset; Marie-Céleste de Jesus Ferreira; Jean-Baptiste Thibaud; Catherine Cohen-Solal; Michel Vignes; Julien Roussel

doi:10.3389/fnagi.2021.785727

Manipulations of Glutathione Metabolism Modulate IP₃-Mediated Store-Operated Ca²⁺ Entry on Astroglioma Cell Line

Front Aging Neurosci. 2021 Dec 17:13:785727. doi: 10.3389/fnagi.2021.785727. eCollection 2021.

Authors

Nawfel Mokrane^{1

2}, Yassin Snabi^{1

2}, Thierry Cens¹, Janique Guiramand¹, Pierre Charnet¹, Anaïs Bertaud^{1

2}, Claudine Menard^{1

2}, Matthieu Rousset¹, Marie-Céleste de Jesus Ferreira^{1

2}, Jean-Baptiste Thibaud¹, Catherine Cohen-Solal^{1

2}, Michel Vignes^{1

2}, Julien Roussel^{1

2}

Affiliations

¹ UMR 5247 Institut des Biomolécules Max Mousseron (IBMM), Montpellier, France.
² Department of Biological Sciences, Université de Montpellier, Montpellier, France.

Abstract

The regulation of the redox status involves the activation of intracellular pathways as Nrf2 which provides hormetic adaptations against oxidative stress in response to environmental stimuli. In the brain, Nrf2 activation upregulates the formation of glutathione (GSH) which is the primary antioxidant system mainly produced by astrocytes. Astrocytes have also been shown to be themselves the target of oxidative stress. However, how changes in the redox status itself could impact the intracellular Ca²⁺ homeostasis in astrocytes is not known, although this could be of great help to understand the neuronal damage caused by oxidative stress. Indeed, intracellular Ca²⁺ changes in astrocytes are crucial for their regulatory actions on neuronal networks. We have manipulated GSH concentration in astroglioma cells with selective inhibitors and activators of the enzymes involved in the GSH cycle and analyzed how this could modify Ca²⁺ homeostasis. IP₃-mediated store-operated calcium entry (SOCE), obtained after store depletion elicited by G_q-linked purinergic P₂Y receptors activation, are either sensitized or desensitized, following GSH depletion or increase, respectively. The desensitization may involve decreased expression of the proteins STIM2, Orai1, and Orai3 which support SOCE mechanism. The sensitization process revealed by exposing cells to oxidative stress likely involves the increase in the activity of Calcium Release-Activated Channels (CRAC) and/or in their membrane expression. In addition, we observe that GSH depletion drastically impacts P₂Y receptor-mediated changes in membrane currents, as evidenced by large increases in Ca²⁺-dependent K⁺ currents. We conclude that changes in the redox status of astrocytes could dramatically modify Ca²⁺ responses to Gq-linked GPCR activation in both directions, by impacting store-dependent Ca²⁺-channels, and thus modify cellular excitability under purinergic stimulation.

Keywords: BSO (l-buthionine-sulfoximine); CRAC channel; GSH (glutathione); GSK 7975A; STIM and Orai; store-operated calcium entry; sulforaphane.