Edward Beamer1,2, James Morgan1,3, Mariana Alves1, Aida Menéndez Méndez1, Gareth Morris1,4, Béla Zimmer5, Giorgia Conte1, Laura de Diego-Garcia1, Cristina Alarcón-Vila6, Nico Ka Yiu Ng1, Stephen Madden7, Francesco Calzaferri8, Cristóbal de Los Ríos8,9, Antonio G García8,9, Michael Hamacher10, Klaus Dinkel11, Pablo Pelegrín6,12, David C Henshall1,4, Annette Nicke5, Tobias Engel1,4. 1. Department of Physiology and Medical Physics, RCSI University of Medicine and Health Sciences, Dublin, Ireland. 2. School of Science and Technology, Nottingham Trent University, Nottingham, UK. 3. Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK. 4. FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, Ireland. 5. Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany. 6. Instituto Murciano de Investigación Biosanitaria (IMIB-Arrixaca), Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain. 7. Data Science Centre, RCSI University of Medicine and Health Sciences, Dublin, Ireland. 8. Instituto-Fundación Teofilo Hernando and Departamento de Farmacologia, Facultad de Medicina, Universidad Autonoma de Madrid, Madrid, Spain. 9. Instituto de Investigacion Sanitaria, Hospital Universitario de La Princesa, Madrid, Spain. 10. Affectis Pharmaceuticals AG, Dortmund, Germany. 11. Lead Discovery Center GmbH, Dortmund, Germany. 12. Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Murcia, Spain.
Abstract
BACKGROUND AND PURPOSE: Refractory status epilepticus is a clinical emergency associated with high mortality and morbidity. Increasing evidence suggests neuroinflammation contributes to the development of drug-refractoriness during status epilepticus. Here, we have determined the contribution of the ATP-gated P2X7 receptor, previously linked to inflammation and increased hyperexcitability, to drug-refractory status epilepticus and its therapeutic potential. EXPERIMENTAL APPROACH: Status epilepticus was induced via a unilateral microinjection of kainic acid into the amygdala in adult mice. Severity of status epilepticus was compared in animals with overexpressing or knock-out of the P2X7 receptor, after inflammatory priming by pre-injection of bacterial lipopolysaccharide (LPS) and in mice treated with P2X7 receptor-targeting and anti-inflammatory drugs. KEY RESULTS: Mice overexpressing P2X7 receptors were unresponsive to several anticonvulsants (lorazepam, midazolam, phenytoin and carbamazepine) during status epilepticus. P2X7 receptor expression increased in microglia during status epilepticus, at times when responses to anticonvulsants were reduced. Overexpression of P2X7 receptors induced a pro-inflammatory phenotype in microglia during status epilepticus and the anti-inflammatory drug minocycline restored normal responses to anticonvulsants in mice overexpressing P2X7 receptors. Pretreatment of wild-type mice with LPS increased P2X7 receptor levels in the brain and reduced responsiveness to anticonvulsants during status epilepticus, which was overcome by either genetic deletion of P2X7 receptors or treatment with the P2X7 receptor antagonists, AFC-5128 or ITH15004. CONCLUSION AND IMPLICATIONS: Our results demonstrate that P2X7 receptor-induced pro-inflammatory effects contribute to resistance to pharmacotherapy during status epilepticus. Therapies targeting P2X7 receptors could be novel adjunctive treatments for drug-refractory status epilepticus.
BACKGROUND AND PURPOSE: Refractory status epilepticus is a clinical emergency associated with high mortality and morbidity. Increasing evidence suggests neuroinflammation contributes to the development of drug-refractoriness during status epilepticus. Here, we have determined the contribution of the ATP-gated P2X7 receptor, previously linked to inflammation and increased hyperexcitability, to drug-refractory status epilepticus and its therapeutic potential. EXPERIMENTAL APPROACH: Status epilepticus was induced via a unilateral microinjection of kainic acid into the amygdala in adult mice. Severity of status epilepticus was compared in animals with overexpressing or knock-out of the P2X7 receptor, after inflammatory priming by pre-injection of bacterial lipopolysaccharide (LPS) and in mice treated with P2X7 receptor-targeting and anti-inflammatory drugs. KEY RESULTS: Mice overexpressing P2X7 receptors were unresponsive to several anticonvulsants (lorazepam, midazolam, phenytoin and carbamazepine) during status epilepticus. P2X7 receptor expression increased in microglia during status epilepticus, at times when responses to anticonvulsants were reduced. Overexpression of P2X7 receptors induced a pro-inflammatory phenotype in microglia during status epilepticus and the anti-inflammatory drug minocycline restored normal responses to anticonvulsants in mice overexpressing P2X7 receptors. Pretreatment of wild-type mice with LPS increased P2X7 receptor levels in the brain and reduced responsiveness to anticonvulsants during status epilepticus, which was overcome by either genetic deletion of P2X7 receptors or treatment with the P2X7 receptor antagonists, AFC-5128 or ITH15004. CONCLUSION AND IMPLICATIONS: Our results demonstrate that P2X7 receptor-induced pro-inflammatory effects contribute to resistance to pharmacotherapy during status epilepticus. Therapies targeting P2X7 receptors could be novel adjunctive treatments for drug-refractory status epilepticus.
Authors: Bárbara Guerra Leal; Aurora Barros-Barbosa; Fátima Ferreirinha; João Chaves; Rui Rangel; Agostinho Santos; Cláudia Carvalho; Ricardo Martins-Ferreira; Raquel Samões; Joel Freitas; João Lopes; João Ramalheira; Maria Graça Lobo; António Martins da Silva; Paulo P Costa; Paulo Correia-de-Sá Journal: Front Cell Neurosci Date: 2022-07-07 Impact factor: 6.147