Tolerance Induced by (S)-3,5-Dihydroxyphenylglycine Postconditioning is Mediated by the PI3K/Akt/GSK3β Signalling Pathway in an In Vitro Model of Cerebral Ischemia

Gerace, Elisabetta; Scartabelli, Tania; Pellegrini‐Giampietro, Domenico E.; Landucci, Elisa

doi:10.1016/j.neuroscience.2019.12.047

Cited by 7 publications

(8 citation statements)

References 51 publications

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“…Moreover, it has been shown that the mGluR1/5 agonist DHPG can be used as a pre‐ and post‐conditioning stimulus, being able to protect CA1 pyramidal cells in rat hippocampal slices from the deleterious effects of 30 min oxygen and glucose deprivation (OGD); (Blaabjerg, 2003; Gerace, Scartabelli, et al, 2012; Gerace, Scartabelli, Pellegrini‐Giampietro, & Landucci, 2020; Scartabelli, Gerace, Landucci, Moroni, & Pellegrini‐Giampietro, 2008; Werner et al., 2007).…”

Section: Introductionmentioning

confidence: 99%

Differential mechanisms of tolerance induced by NMDA and 3,5‐dihydroxyphenylglycine (DHPG) preconditioning

Gerace

Zianni

Landucci

et al. 2020

Journal of Neurochemistry

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We investigated the molecular events triggered by NMDA and 3,5-dihydroxyphenylglycine (DHPG) preconditioning, that lead to neuroprotection against excitotoxic insults (AMPA or oxygen and glucose deprivation) in rat organotypic hippocampal slices, with particular attention on glutamate receptors and on cannabinoid system. We firstly evaluated the protein expression of NMDA and AMPA receptor subunits after preconditioning using western blot analysis performed in post-synaptic densities. We observed that following NMDA, but not DHPG preconditioning, the expression of GluA1 was significantly reduced and this reduction appeared to be associated with the internalization of AMPA receptors. Whole-cell voltage clamp recordings on CA1 pyramidal neurons of organotypic slices show that 24 hr after exposure to NMDA and DHPG preconditioning, AMPA-induced currents were significantly reduced. To clarify the mechanisms induced by DHPG preconditioning, we then investigated the involvement of the endocannabinoid system. Exposure of slices to the CB1 antagonist AM251 prevented the development of tolerance to AMPA toxicity induced by DHPG but not NMDA. Accordingly, the MAG-lipase inhibitor URB602, that increases arachidonoylglycerol (2-AG) content, but not the FAAH inhibitor URB597, that limits the degradation of anandamide, was also able to induce tolerance versus AMPA and OGD toxicity, suggesting that 2-AG is responsible for the DHPG-induced tolerance. In conclusion, preconditioning with NMDA or DHPG promotes differential neuroprotective mechanisms: NMDA by internalization of GluA1-AMPA receptors, DHPG by producing the endocannabinoid 2-AG.

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Section: Introductionmentioning

confidence: 99%

Differential mechanisms of tolerance induced by NMDA and 3,5‐dihydroxyphenylglycine (DHPG) preconditioning

Gerace

Zianni

Landucci

et al. 2020

Journal of Neurochemistry

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“…We then examined the effects of UCB, pioglitazone and allopurinol on neuronal death and oxidative stress in an in vitro model of ischemic preconditioning in immature slices, in order to mimic what could occur in preterm infants following IH events. Ischemic preconditioning was obtained by exposing the slices to 10 min OGD, as previously reported in Gerace et al (35,45,46). For these experiments, organotypic hippocampal slices were exposed to UCB, UCB plus pioglitazone or UCB plus allopurinol immediately after 10 min OGD preconditioning and maintained for 24 h (Figure 6A).…”

Section: Effects Of Ucb Pioglitazone and Allopurinol On Neuronal Death And Oxidative Stress In An In Vitro Model Of Ischemic Preconditionmentioning

confidence: 95%

“…Cultures were exposed to oxygen and glucose deprivation (OGD) in order to mimic what occur after HI episodes and HIE, as previously reported in detail (35,(44)(45)(46). Briefly, OGD was reproduced by exposing the slices to serum-and glucose-free medium saturated with 95% N 2 and 5% CO 2 for 30 min at 37 • C in an airtight anoxic chamber equipped with an oxygen gas controller (BioSpherix, New York, USA).…”

Section: Ogd Protocol In Rat Organotypic Hippocampal Slicesmentioning

confidence: 99%

“…Ischemic preconditioning was obtained by exposing the slices to 10 min OGD, as previously described in detail (35,45,46). Immature hippocampal slices were exposed to ischemic preconditioning (10 min OGD) or to ischemic preconditioning plus UCB (100 µM) alone or plus pioglitazone (10 µM) or allopurinol (10 µM) for the subsequent 24 h, before exposure to 30 min OGD toxic insult.…”

Section: Ischemic Preconditioning Protocol In Organotypic Hippocampal Slicesmentioning

confidence: 99%

“…In all experiments, oxidative stress and ROS production was assessed in organotypic hippocampal slices using the 2 ′ ,7 ′dichlorodihydrofluorescein diacetate (DCFH2-DA) fluorescent probe, as reported in Gerace et al (45,46). Briefly, at the end of the experiments, hippocampal slices were incubated with 10 mM…”

Section: Reactive Oxygen Species Productionmentioning

confidence: 99%

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Neurotoxicity of Unconjugated Bilirubin in Neonatal Hypoxic-Ischemic Brain Injury in vitro

et al. 2021

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Background: The pathophysiology of bilirubin neurotoxicity in course of hypoxic–ischemic encephalopathy (HIE) in term and preterm infants is still poorly understood. We hypothesized that oxidative stress may be a common mechanism that link hyperbilirubinemia and HIE.Objectives: The objective of the present study was to evaluate whether unconjugated bilirubin (UCB) may enhance the HI brain injury by increasing oxidative stress and to test pioglitazone and allopurinol as new antioxidant therapeutic drugs in vitro.Methods: The effects of UCB were tested on organotypic hippocampal slices subjected to 30 min oxygen-glucose deprivation (OGD), used as in vitro model of HIE. The experiments were performed on mature (14 days in culture) and immature (7 days in culture) slices, to mimic the brains of term and preterm infants, respectively. Mature and immature slices were exposed to UCB, human serum albumin (HSA), pioglitazone, and/or allopurinol for 24 h, immediately after 30 min OGD. Neuronal injury was assessed using propidium iodide (PI) fluorescence. ROS formation was quantified by using the 2′,7′-dichlorodihydrofluorescein diacetate (DCF-DA) method.Results: In mature slices, we found that the neurotoxicity, as well as oxidative stress, induced by OGD were enhanced by UCB. HSA significantly prevented UCB-increased neurotoxicity, but had a slight reduction on ROS production. Allopurinol, but not pioglitazone, significantly reduced UCB-increased neurotoxicity induced by OGD. In immature slices exposed to OGD, no increase of neuronal death was observed, whereas oxidative stress was detected after UCB exposure. HSA, pioglitazone and allopurinol have no protective effects on both OGD-induced neuronal death and on UCB-induced oxidative stress. For this reason, UCB, pioglitazone and allopurinol was also tested on ischemic preconditioning protocol. We found that UCB abolished the neuroprotection induced by preconditioning and increased oxidative stress. These effects were restored by allopurinol but not pioglitazone.Conclusions: UCB characterized a different path of neuronal damage and oxidative stress in mature and immature hippocampal slice model of HIE. Management of hyperbilirubinemia in a complex pathological condition, such as HIE and hyperbilirubinemia, should be very careful. Allopurinol could deserve attention as a novel pharmacological intervention for hyperbilirubinemia and HIE.

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NIR Laser Photobiomodulation Induces Neuroprotection in an In Vitro Model of Cerebral Hypoxia/Ischemia

et al. 2021

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Brain photobiomodulation (PBM) is an innovative treatment for a variety of neurological conditions, including cerebral ischemia. However, the capability of PBM for ischemic stroke needs to be further explored and its mechanisms of action remain currently unclear. The aim of the present research was to identify a treatment protocol capable of inducing neuroprotection and to investigate the molecular mechanisms activated by a dual-wavelength near infrared (NIR) laser source in an organotypic hippocampal slice model of hypoxia/ischemia. Hippocampal slices were exposed to oxygen and glucose deprivation (OGD) for 30 min followed by NIR laser light (fluence 3.71, 7.42, or 14.84 J/cm2; wavelengths 808 nm and 905 nm) delivered immediately or 30 min or 60 min after OGD, in order to establish a therapeutic window. Neuronal injury was assessed by propidium iodide fluorescence 24 h later. Our results show that NIR laser irradiation attenuates OGD neurotoxicity once applied immediately or 30 min after OGD. Western blot analysis of proteins involved in neuroinflammation (iNOS, COX-2, NFkB subunit p65, and Bcl-2) and in glutamatergic-mediated synaptic activity (vGluT1, EAAT2, GluN1, and PSD95) showed that the protein modifications induced by OGD were reverted by NIR laser application. Moreover, CA1 confocal microscopy revealed that the profound morphological changes induced by OGD were reverted by NIR laser radiation. In conclusion, NIR laser radiation attenuates OGD neurotoxicity in organotypic hippocampal slices through attenuation of inflammatory mechanisms. These findings shed light on molecular definition of NIR neuroprotective mechanisms, thus underlining the potential benefit of this technique for the treatment of cerebral ischemia.

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Tolerance Induced by (S)-3,5-Dihydroxyphenylglycine Postconditioning is Mediated by the PI3K/Akt/GSK3β Signalling Pathway in an In Vitro Model of Cerebral Ischemia

Cited by 7 publications

References 51 publications

Differential mechanisms of tolerance induced by NMDA and 3,5‐dihydroxyphenylglycine (DHPG) preconditioning

Differential mechanisms of tolerance induced by NMDA and 3,5‐dihydroxyphenylglycine (DHPG) preconditioning

Neurotoxicity of Unconjugated Bilirubin in Neonatal Hypoxic-Ischemic Brain Injury in vitro

NIR Laser Photobiomodulation Induces Neuroprotection in an In Vitro Model of Cerebral Hypoxia/Ischemia

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