Conditional deletion of LRRC8A in the brain reduces stroke damage independently of swelling-activated glutamate release

Balkaya, Mustafa; Dohare, Preeti; Chen, Sophie; Schober, Alexandra L.; Fidaleo, Antonio M.; Nalwalk, Julia W.; Sah, Rajan; Mongin, Alexander A.

doi:10.1016/j.isci.2023.106669

Cited by 8 publications

(14 citation statements)

References 84 publications

(141 reference statements)

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“…Previous studies have shown LRRC8A subunits was most important for macrophage/microgliamediated injury as a transport for glutamatergic input, ATP and cGAMP [35,36]. However, a recent study showed that LRRC8A contributed to ischemic brain injury via the mechanism other than VRAC-mediated glutamate release, considering that LRRC8A played a regulatory role in signaling pathway [15]. S1PR1, a G-protein coupled receptor which was activated by S1P, widely expressed in nervous system and plays an immunomodulatory role through downstream signaling pathways [28,37].…”

Section: Discussionmentioning

confidence: 99%

“…The widely accepted idea that LRRC8A subunits are most important for the VRAC to increase glutamatergic input after brain injury and non-speci c VRAC blockers or conditional knockout of LRRC8A may play a neuroprotective role in rodent models of stroke [13,14]. However, a recent study showed that LRRC8A contributed to ischemic brain injury via the mechanism other than swelling-activated VRACmediated glutamate release by the brain-wide LRRC8A deletion and astrocytic LRRC8A knockout, considering that LRRC8A played a role in signaling pathway as a regulatory protein [15]. Meanwhile, our previous research also found that LRRC8A, as a regulatory protein played a role in the cardiovascular system by its LRRD [16,17].…”

Section: Introductionmentioning

confidence: 99%

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LRRC8A contributes to neuroinflammation after acute ischemic stroke by interacting with S1PR1 regulating MAPK signal pathway

Cao,

Guo,

Yang

et al. 2023

Preprint

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Objective and design: Neuroinflammation exerts important roles in the progression of acute ischemic stroke (AIS). LRRC8A, an essential component of volume-regulated anion channel (VRAC) is expressed predominantly in central nervous system. The aim of this study is to investigate the role of LRRC8A in microglia-mediated neuroinflammation after AIS and the underlying mechanism. Materials and methods TTC assay, HE and Nissl staining, RT-PCR, ELISA assay, flow cytometry, Western blot (WB) and immunofluorescence were used to detect the effect of DCPIB on brain injury, neuroinflammation after AIS. Concomitantly, immunofluorescence, FLIM-FRET, and co-immunoprecipitation were used to examine the interplays between LRRC8A and S1P receptor-1(S1PR1). Results In mice tMCAO/R model, the administration of LRRC8A-dependent VRAC blocker DCPIB remarkably increased the survival rate and effectively reduced neuronal injury. In addition, DCPIB markedly reversed microglia polarization toward the M1 phenotype and enhanced M2 phenotype. More importantly, LRRC8A physically interacted with S1PR1 via C-terminal leucine-rich repeat domain (LRRD) and DCPIB weakened their interaction. Meanwhile, DCPIB also eliminated the activation MAPK pathway mediated by S1PR1. Conclusions The present study revealed a novel regulatory role of LRRC8A in regulating microglia-mediated neuroinflammation through interacting with S1PR1 by LRRD and elucidated a molecular mechanism for the effects of DCPIB on microglia polarization.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LRRC8A contributes to neuroinflammation after acute ischemic stroke by interacting with S1PR1 regulating MAPK signal pathway

Cao,

Guo,

Yang

et al. 2023

Preprint

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“…It is also important to note that recent studies have challenged the primary narrative of VRAC-mediated glutamatergic excitotoxicity. One group found that the total deletion of LRRC8A in nestin + cells resulted in complete loss of VRAC-mediated glutamate release, whereas heterozygous knockout animals exhibited full swell-activated glutamate release ( Balkaya et al, 2023 ). Despite this difference, both full and heterozygous knockout animals displayed identical protection against ischemia in an experimental stroke model, suggesting VRAC ablation may exert its neuroprotective function through nonglutamatergic mechanisms ( Balkaya et al, 2023 ).…”

Section: Discussionmentioning

confidence: 99%

Regulation of the Volume-Regulated Anion Channel Pore-Forming Subunit LRRC8A in the Intrahippocampal Kainic Acid Model of Mesial Temporal Lobe Epilepsy

et al. 2023

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Volume-regulated anion channels (VRACs) are a group of ubiquitously expressed outwardly-rectifying anion channels that sense increases in cell volume and act to return cells to baseline volume through an efflux of anions and organic osmolytes, including glutamate. Because cell swelling, increased extracellular glutamate levels, and reduction of the brain extracellular space (ECS) all occur during seizure generation, we set out to determine whether VRACs are dysregulated throughout mesial temporal lobe epilepsy (MTLE), the most common form of adult epilepsy. To accomplish this, we employed the IHKA experimental model of MTLE, and probed for the expression of LRRC8A, the essential pore-forming VRAC subunit, at acute, early-, mid-, and late-epileptogenic time points (1-, 7-, 14-, and 30-days post-IHKA, respectively). Western blot analysis revealed the upregulation of total dorsal hippocampal LRRC8A 14-days post-IHKA in both the ipsilateral and contralateral hippocampus. Immunohistochemical analyses showed an increased LRRC8A signal 7-days post-IHKA in both the ipsilateral and contralateral hippocampus, along with layer-specific changes 1-, 7-, and 30-days post-IHKA bilaterally. LRRC8A upregulation 1 day post-IHKA was observed primarily in astrocytes; however, some upregulation was also observed in neurons. Glutamate-GABA/glutamine cycle enzymes glutamic acid decarboxylase, glutaminase, and glutamine synthetase were also dysregulated at the 7-day timepoint post status epilepticus. The timepoint-dependent upregulation of total hippocampal LRRC8A and the possible subsequent increased efflux of glutamate in the epileptic hippocampus suggest that the dysregulation of astrocytic VRAC may play an important role in the development of epilepsy.

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“…Given that VRAC inhibitors and LRRC8A gene disruption reduce ischemic neuronal injury (Balkaya et al, 2023;Feng et al, 2004;Kimelberg et al, 2000;Kimelberg et al, 2003;Yang et al, 2019;Zhang et al, 2008;Zhou et al, 2020), we also investigated whether selective neuronal LRRC8A gene disruption blocks neuronal oxidative stress during cortical ischemia-reperfusion.…”

Section: Requisite Role For Neuronal Vracs In Nmda-and Ischemia-induc...mentioning

confidence: 99%

“…VRAC inhibitors have long been recognized as neuroprotective in rodent stoke models (Balkaya et al, 2023;Feng et al, 2004;Kimelberg et al, 2000;Zhang et al, 2008). This effect was initially ascribed to inhibition of excitotoxic glutamate release from astrocyte VRACs (Phillis et al, 1998;Seki et al, 1999;Zhang et al, 2008); however, VRACs are a relatively minor route of glutamate efflux during ischemia (Rossi et al, 2000;Swanson et al, 2004), and more recent work shows a poor correlation between VRAC-mediated glutamate release and ischemic neuronal injury (Balkaya et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Superoxide enters neurons via LRRC8A – containing volume-regulated anion channels

Harris,

Uruk,

Won

et al. 2024

Preprint

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SummarySuperoxide (O2-) is both an intercellular signaling molecule and a cause of neuronal oxidative stress. Superoxide entry into neurons is thought to be indirect, requiring its dismutation to nonpolar hydrogen peroxide. Here we show instead that superoxide enters neurons directly, via LRRC8A-containing volume-sensitive organic anion channels. In primary cultures, neuronal oxidative stress induced either by NMDA receptor stimulation or exposure to authentic superoxide was blocked by the anion channel blockers DIDS and DCPIB and by LRRC8A gene disruption. In mouse cortex, neuronal oxidative stress induced by either NMDA injection or transient ischemia was likewise blocked by both DCPIB and LRRC8A gene disruption. These findings identify a role for LRRC8A-containing volume-sensitive organic anion channels in neuronal oxidative signaling, stress, and glutamate excitotoxicity.

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Conditional deletion of LRRC8A in the brain reduces stroke damage independently of swelling-activated glutamate release

Cited by 8 publications

References 84 publications

LRRC8A contributes to neuroinflammation after acute ischemic stroke by interacting with S1PR1 regulating MAPK signal pathway

LRRC8A contributes to neuroinflammation after acute ischemic stroke by interacting with S1PR1 regulating MAPK signal pathway

Regulation of the Volume-Regulated Anion Channel Pore-Forming Subunit LRRC8A in the Intrahippocampal Kainic Acid Model of Mesial Temporal Lobe Epilepsy

Superoxide enters neurons via LRRC8A – containing volume-regulated anion channels

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