Selective protection of murine cerebral Gi/o-proteins from inactivation by parenterally injected pertussis toxin

Vega, Salvador Castaneda; Leiss, Veronika; Piekorz, Roland P.; Calaminus, Carsten; Pexa, Katja; Vuozzo, Marta; Schmid, Andreas M.; Devanathan, Vasudharani; Kesenheimer, Christian; Pichler, Bernd J.; Beer‐Hammer, Sandra; Nürnberg, Bernd

doi:10.1007/s00109-019-01854-1

Cited by 6 publications

(11 citation statements)

References 45 publications

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“…Workflows of all experiments are sketched in the corresponding figures. We induced non-cerebral G i PCR KO using a single dose of PTX (150 μg/kg body weight) (Merck, Darmstadt, Germany) 48 h before intervention (sham or surgery), as previously shown [19,23,24]. Details are provided in the "Supplementary Information.…”

Section: Animal Experimentsmentioning

confidence: 99%

“…In arteries and microvessels, PTX inhibits endothelium-dependent relaxation to certain agonists such as β-adrenergic ligands, angiotensin, serotonin, or relaxins and is therefore useful for the study of vasculopathies [2,7,8,[12][13][14][15][16][17][18]. We have previously demonstrated that PTX, administered in a single peritoneal injection, does not cross the blood-brain barrier (BBB) and does not modify G i PCR signaling in neurons [19]. PTX administration, however, still irreversibly interrupts G i PCR signaling for up to 96 h in cells outside of the CNS, including brain vasculature.…”

Section: Introductionmentioning

confidence: 99%

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Cerebrovascular Gi Proteins Protect Against Brain Hypoperfusion and Collateral Failure in Cerebral Ischemia

et al. 2022

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Cerebral hypoperfusion and vascular dysfunction are closely related to common risk factors for ischemic stroke such as hypertension, dyslipidemia, diabetes, and smoking. The role of inhibitory G protein-dependent receptor (GiPCR) signaling in regulating cerebrovascular functions remains largely elusive. We examined the importance of GiPCR signaling in cerebral blood flow (CBF) and its stability after sudden interruption using various in vivo high-resolution magnetic resonance imaging techniques. To this end, we induced a functional knockout of GiPCR signaling in the brain vasculature by injection of pertussis toxin (PTX). Our results show that PTX induced global brain hypoperfusion and microvascular collapse. When PTX-pretreated animals underwent transient unilateral occlusion of one common carotid artery, CBF was disrupted in the ipsilateral hemisphere resulting in the collapse of the cortically penetrating microvessels. In addition, pronounced stroke features in the affected brain regions appeared in both MRI and histological examination. Our findings suggest an impact of cerebrovascular GiPCR signaling in the maintenance of CBF, which may be useful for novel pharmacotherapeutic approaches to prevent and treat cerebrovascular dysfunction and stroke.

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Section: Animal Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cerebrovascular Gi Proteins Protect Against Brain Hypoperfusion and Collateral Failure in Cerebral Ischemia

et al. 2022

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Section: In Vivo Modelsmentioning

confidence: 99%

“…Experiments using islets isolated from rats [ 81 ] and mice [ 82 ] were performed to investigate the mechanisms underlying the effect of PTx on insulin secretion. Islets isolated from PTx treated mice were associated with lower blood glucose levels and enhanced insulin levels [ 82 ]. Similarly, islets from PTx-treated rats released higher levels of insulin than control islets and negated the inhibitory effect of epinephrine [ 72 ].…”

Section: In Vivo Modelsmentioning

confidence: 99%

“…Similarly, islets from PTx-treated rats released higher levels of insulin than control islets and negated the inhibitory effect of epinephrine [ 72 ]. PTx has a similar effect on islets from untreated rats [ 73 ] and mice [ 82 ], that upon exposure to PTx release insulin in a PTx concentration-dependent manner (0.001–1000 ng/mL)[ 73 ]. PTx was not found to affect any properties of ACs including their affinity for substrates, sensitivity to guanine nucleotide or fluoride activation, thereby suggesting that neither ACs nor the Gα s is the target site of PTx in islets [ 74 ].…”

Section: In Vivo Modelsmentioning

confidence: 99%

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In Vivo Models and In Vitro Assays for the Assessment of Pertussis Toxin Activity

Hoonakker

2021

Toxins

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One of the main virulence factors produced by Bordetella pertussis is pertussis toxin (PTx) which, in its inactivated form, is the major component of all marketed acellular pertussis vaccines. PTx ADP ribosylates Gαi proteins, thereby affecting the inhibition of adenylate cyclases and resulting in the accumulation of cAMP. Apart from this classical model, PTx also activates some receptors and can affect various ADP ribosylation- and adenylate cyclase-independent signalling pathways. Due to its potent ADP-ribosylation properties, PTx has been used in many research areas. Initially the research primarily focussed on the in vivo effects of the toxin, including histamine sensitization, insulin secretion and leukocytosis. Nowadays, PTx is also used in toxicology research, cell signalling, research involving the blood–brain barrier, and testing of neutralizing antibodies. However, the most important area of use is testing of acellular pertussis vaccines for the presence of residual PTx. In vivo models and in vitro assays for PTx often reflect one of the toxin’s properties or details of its mechanism. Here, the established and novel in vivo and in vitro methods used to evaluate PTx are reviewed, their mechanisms, characteristics and limitations are described, and their application for regulatory and research purposes are considered.

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Protective effects of Gαi3 deficiency in a murine heart-failure model of β1-adrenoceptor overexpression

Schröper,

Mehrkens,

Leiss

et al. 2023

Naunyn-Schmiedeberg's Arch Pharmacol

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We have shown that in murine cardiomyopathy caused by overexpression of the β1-adrenoceptor, Gαi2-deficiency is detrimental. Given the growing evidence for isoform-specific Gαi-functions, we now examined the consequences of Gαi3 deficiency in the same heart-failure model. Mice overexpressing cardiac β1-adrenoceptors with (β1-tg) or without Gαi3-expression (β1-tg/Gαi3−/−) were compared to C57BL/6 wildtypes and global Gαi3-knockouts (Gαi3−/−). The life span of β1-tg mice was significantly shortened but improved when Gαi3 was lacking (95% CI: 592–655 vs. 644–747 days). At 300 days of age, left-ventricular function and survival rate were similar in all groups. At 550 days of age, β1-tg but not β1-tg/Gαi3−/− mice displayed impaired ejection fraction (35 ± 18% vs. 52 ± 16%) compared to wildtype (59 ± 4%) and Gαi3−/− mice (60 ± 5%). Diastolic dysfunction of β1-tg mice was prevented by Gαi3 deficiency, too. The increase of ANP mRNA levels and ventricular fibrosis observed in β1-tg hearts was significantly attenuated in β1-tg/Gαi3−/− mice. Transcript levels of phospholamban, ryanodine receptor 2, and cardiac troponin I were similar in all groups. However, Western blots and phospho-proteomic analyses showed that in β1-tg, but not β1-tg/Gαi3−/− ventricles, phospholamban protein was reduced while its phosphorylation increased. Here, we show that in mice overexpressing the cardiac β1-adrenoceptor, Gαi3 deficiency slows or even prevents cardiomyopathy and increases shortened life span. Previously, we found Gαi2 deficiency to aggravate cardiac dysfunction and mortality in the same heart-failure model. Our findings indicate isoform-specific interventions into Gi-dependent signaling to be promising cardio-protective strategies.

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Selective protection of murine cerebral Gi/o-proteins from inactivation by parenterally injected pertussis toxin

Cited by 6 publications

References 45 publications

Cerebrovascular Gi Proteins Protect Against Brain Hypoperfusion and Collateral Failure in Cerebral Ischemia

Cerebrovascular Gi Proteins Protect Against Brain Hypoperfusion and Collateral Failure in Cerebral Ischemia

In Vivo Models and In Vitro Assays for the Assessment of Pertussis Toxin Activity

Protective effects of Gαi3 deficiency in a murine heart-failure model of β1-adrenoceptor overexpression

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