Postictal apnea is thought to be a major cause of sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying postictal apnea are unknown. To understand causes of postictal apnea, we used a multimodal approach to study brain mechanisms of breathing control in 20 patients (ranging from pediatric to adult) undergoing intracranial electroencephalography (iEEG) for intractable epilepsy. Our results indicate that amygdala seizures can cause postictal apnea. Moreover, we identified a distinct region within the amygdala where electrical stimulation was sufficient to reproduce prolonged breathing loss persisting well beyond the end of stimulation. The persistent apnea was resistant to rising CO2 levels, and air hunger failed to occur, suggesting impaired CO2 chemosensitivity. Using es-fMRI, a novel approach combining electrical stimulation with functional MRI, we found amygdala stimulation altered BOLD activity in the pons/medulla and ventral insula. Together, these findings suggest that seizure activity in a focal subregion of the amygdala is sufficient to suppress breathing and air hunger for prolonged periods of time in the postictal period, likely via brainstem and insula sites involved in chemosensation and interoception. They further provide new insights into SUDEP, may help identify those at greatest risk, and may lead to treatments to prevent SUDEP.
Gail I.S. Harmata, Ariane E. Rhone, Christopher K. Kovach, Sukhbinder Kumar, Md Rakibul Mowla, Rup K. Sainju, Yasunori Nagahama, Hiroyuki Oya, Brian K. Gehlbach, Michael A. Ciliberto, Rashmi N. Mueller, Hiroto Kawasaki, Kyle T.S. Pattinson, Kristina Simonyan, Paul W. Davenport, Matthew A. Howard III, Mitchell Steinschneider, Aubrey C. Chan, George B. Richerson, John A. Wemmie, Brian J. Dlouhy
Germline de novo missense variants of the CACNA1D gene, encoding the pore-forming α1-subunit of Cav1.3 L-type Ca2+ channels (LTCCs), have been found in patients with neurodevelopmental and endocrine dysfunction, but their disease-causing potential is unproven. These variants alter channel gating enabling enhanced Cav1.3 activity, suggesting Cav1.3 inhibition as a potential therapeutic option. Here we provide direct proof of the disease-causing nature of such gating-modifying CACNA1D variants using mice (Cav1.3AG) containing the A749G variant reported de novo in a patient with autism and intellectual impairment. In heterozygous mutants native LTCC currents in adrenal chromaffin cells exhibited gating changes as predicted from heterologous expression. The A749G mutation induced aberrant excitability of dorsomedial striatum-projecting substantia nigra dopamine neurons and medium spiny neurons in the dorsal striatum. The phenotype observed in heterozygous mutants reproduced many of the abnormalities described within the human disease spectrum, including developmental delay, social deficit and pronounced hyperactivity without major changes in gross neuroanatomy. Despite an ~7-fold higher sensitivity of A749G-containing channels to the LTCC inhibitor isradipine, oral pretreatment over two days did not rescue the hyperlocomotion. Cav1.3AG mice confirm the pathogenicity of the A749G variant and point towards a pathogenetic role of altered signaling in the dopamine midbrain system.
Nadine J. Ortner, Anupam Sah, Enrica Paradiso, Josef Shin, Strahinja Stojanovic, Niklas Hammer, Maria Haritonova, Nadja T. Hofer, Andrea Marcantoni, Laura Guarina, Petronel Tuluc, Tamara Theiner, Florian Pitterl, Karl Ebner, Herbert Oberacher, Emilio Carbone, Nadia Stefanova, Francesco Ferraguti, Nicolas Singewald, Jochen Roeper, Joerg Striessnig
Somatic gain-of-function mutations in the L-type calcium channel CaV1.3 (CACNA1D gene) cause adrenal aldosterone-producing adenomas and micronodules. De novo germline mutations are found in a syndrome of primary aldosteronism, seizures and neurologic abnormalities (PASNA) as well as in autism spectrum disease. Using CRISPR/Cas9, we here generated mice with a Cacna1d gain-of-function mutation found in both adenomas and PASNA syndrome (Cacna1dIle772Met/+). These mice show reduced body weight and increased mortality from weaning to approximately 100 days of age. Male mice do not breed, likely due to neuromotor impairment, and the offspring of female mice die perinatally, likely due to lack of maternal care. Mice generated by in vitro fertilization show elevated intracellular calcium in the aldosterone-producing zona glomerulosa, an elevated aldosterone:renin ratio and persistently elevated serum aldosterone on a high-salt diet as signs of primary aldosteronism. Anesthesia with ketamine and xylazine induces tonic-clonic seizures. Neurologic abnormalities include hyperlocomotion, impaired performance in the rotarod test, impaired nest building and slight changes in social behavior. Intracellular calcium in the zona glomerulosa, aldosterone levels and rotarod performance respond to treatment with the calcium channel blocker isradipine, with implications for the therapy of patients with aldosterone-producing lesions and with PASNA syndrome.
Gabriel Stölting, Hoang An Dinh, Marina Volkert, Nicole Hellmig, Julia Schewe, Luise Hennicke, Eric Seidel, Herbert Oberacher, Junhui Zhang, Richard P. Lifton, Iris Urban, Melissa Long, Marion Rivalan, Timothy Nottoli, Ute I. Scholl
BACKGROUND. The locus coeruleus (LC) is the primary source of norepinephrine in the brain and regulates arousal and sleep. Animal research shows that it plays important roles in the transition between sleep and wakefulness, and between slow wave sleep and rapid eye movement sleep (REMS). It is unclear, however, whether the activity of the LC predicts sleep variability in humans. METHODS. We used 7 Tesla functional Magnetic Resonance Imaging, sleep electroencephalography (EEG) and a sleep questionnaire to test whether the LC activity during wakefulness was associated with sleep quality in 33 healthy younger (~22y; 28 women) and 19 older (~61y; 14 women) individuals. RESULTS. We found that, in older, but not in younger participants, higher LC activity, as probed during an auditory attentional task, was associated with worse subjective sleep quality and with lower power over the EEG theta band during REMS. The results remained robust even when accounting for the age-related changes in the integrity of the LC. CONCLUSION. These findings suggest that LC activity correlates with the perception of the sleep quality and an essential oscillatory mode of REMS, and that the LC may be an important target in the treatment of sleep and age-related diseases. FUNDING. This work was supported by Fonds National de la Recherche Scientifique (FRS-FNRS, T.0242.19 & J. 0222.20). Action de Recherche Concertée – Fédération Wallonie-Bruxelles (ARC SLEEPDEM 17/27-09), Fondation Recherche Alzheimer (SAO-FRA 2019/0025), University of Liège, European Regional Development Fund (Radiomed & Biomed-Hub).
Ekaterina Koshmanova, Alexandre Berger, Elise Beckers, Islay Campbell, Nasrin Mortazavi, Roya Sharifpour, Ilenia Paparella, Fermin Balda, Christian Berthomier, Christian Degueldre, Eric Salmon, Laurent Lamalle, Christine Bastin, Maxime Van Egroo, Christophe Phillips, Pierre Maquet, Fabienne Collette, Vincenzo Muto, Daphne Chylinski, Heidi I.L. Jacobs, Puneet Talwar, Siya Sherif, Gilles Vandewalle
Autophagy is a promising target for promoting neural regeneration, which is essential for sensorimotor recovery following traumatic brain injury (TBI). Whether neuronal heat shock protein B2 (HSPB2), a small molecular heat shock protein, reduces injury and promotes recovery following TBI remains unclear. In this study, we demonstrated that HSPB2 was significantly increased in the neurons of a TBI mouse model, patients, and primary neuron cultures subjected to oxygen/glucose deprivation and reperfusion treatment. Upon creating a tamoxifen-induced neuron-specific HSPB2 overexpression transgenic mouse model, we found that elevated HSPB2 levels promoted long-term sensorimotor recovery and alleviated tissue loss after TBI. We also demonstrated that HSPB2 enhanced white matter structural and functional integrity, promoted central nervous system (CNS) plasticity, and accelerated long-term neural remodeling. Moreover, we found that autophagy occurred around injured brain tissues in patients, and the pro-regenerative effects of HSPB2 relied on its autophagy-promoting function. Mechanistically, HSPB2 may regulate autophagy possibly by forming the HSPB2/BCL2-associated athanogene 3/sequestosome-1 complex to facilitate the clearance of erroneously accumulated proteins in the axons. Treatment with the autophagy inhibitor chloroquine during the acute stage or delayed induction of HSPB2 remarkably impeded HSPB2’s long-term reparative function, indicating the importance of acute-stage autophagy in long-term neuro-regeneration. Our findings highlight the beneficial role of HSPB2 in neuro-regeneration and functional recovery following acute CNS injury, thereby emphasizing the therapeutic potential of autophagy regulation for enhancing neuro-regeneration.
Yichen Huang, Shan Meng, Biwu Wu, Hong Shi, Yana Wang, Jiakun Xiang, Jiaying Li, Ziyu Shi, Gang Wu, Yanchen Lyu, Xu Jia, Jin Hu, Zhi-Xiang Xu, Yanqin Gao
Attention-deficit hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder that affects approximately 5.3% of children and approximately 2.5% of adults. There is an intimate relationship between ADHD and sleep disturbance. Specifically, individuals carry a mutation in the core circadian gene CRY1 (c. 1657 + 3A > C), which results in the deletion of exon 11 expression in the CRY1 protein (CRY1Δ11), causing them to exhibit typical ADHD symptoms. However, the underlying mechanism is still elusive. In this study, we demonstrate that Cry1Δ11 (c. 1717 + 3A > C) mice showed ADHD-like symptoms, including hyperactivity, impulsivity, and deficits in learning and memory. A hyperactive cAMP signaling pathway was found in the nucleus accumbens (NAc) of Cry1Δ11 mice. We further demonstrated that upregulated c-Fos was mainly localized in dopamine D1 receptor-expressing medium spiny neurons (DRD1-MSNs) in the NAc. Neuronal excitability of DRD1-MSNs in the NAc of Cry1Δ11 mice was significantly higher than that of WT controls. Mechanistically, the CRY1Δ11 protein, in contrast to the WT CRY1 protein, failed to interact with the Gαs protein and inhibit DRD1 signaling. Finally, the DRD1 antagonist SCH23390 normalized most ADHD-like symptoms in Cry1Δ11 mice. Thus, our results reveal hyperactive DRD1 signaling as an underlying mechanism and therapeutic target for ADHD induced by the highly prevalent CRY1Δ11 mutation.
Dengfeng Liu, Zhengyu Xie, Panyang Gu, Xiangyu Li, Yichun Zhang, Xinying Wang, Zhiheng Chen, Suixin Deng, Yousheng Shu, Jia-Da Li
Spreading depolarization (SD) is a massive wave of cellular depolarization that slowly migrates across the brain gray matter. Cortical SD is frequently generated following brain injury, while less is understood about its potential contribution to genetic disorders of hyperexcitability, such as SCN1A-deficient epilepsy, in which febrile seizure often contributes to disease initiation. Here we report that spontaneous SD waves are predominant EEG abnormalities in the Scn1a-deficient mouse (Scn1a+/R1407X) and undergo sustained intensification following a single hyperthermic seizure. Chronic DC-band EEG recording detected spontaneous SDs, seizures, and seizure-SD complexes in Scn1a+/R1407X mice but not WT littermates. The SD events were infrequent, while a single hyperthermia-induced seizure robustly increased SD frequency over 4-fold during the initial postictal week. This prolonged neurological aftermath could be suppressed by memantine administration. Video, electromyogram, and EEG spectral analysis revealed distinct neurobehavioral patterns; individual seizures were associated with increased motor activities, while SDs were generally associated with immobility. We also identified a stereotypic SD prodrome, detectable over a minute before the onset of the DC potential shift, characterized by increased motor activity and bilateral EEG frequency changes. Our study suggests that cortical SD is a pathological manifestation in SCN1A-deficient epileptic encephalopathy.
Isamu Aiba, Yao Ning, Jeffrey L. Noebels
Nitric oxide (NO) is a critical signaling molecule that has been implicated in the pathogenesis of neurocognitive diseases. Both excessive and insufficient NO production have been linked to pathology. Previously, we have shown that argininosuccinate lyase deficiency (ASLD) is a novel model system to investigate cell-autonomous, nitric oxide synthase (NOS)-dependent NO deficiency. Humans with ASLD are at increased risk for developing hyperammonemia due to a block in ureagenesis. However, natural history studies have shown that individuals with ASLD have multi-systemic disease including neurocognitive deficits that can be independent of ammonia. Here, using ASLD as a model of NO deficiency, we investigated the effects of NO on brain endothelial cells in vitro and the blood-brain barrier (BBB) in vivo. Knockdown of ASL in human brain microvascular endothelial cells (HBMECs) led to decreased transendothelial electrical resistance (TEER), indicative of increased cell permeability. Mechanistically, treatment with an NO donor or inhibition of Claudin-1 improved barrier integrity in ASL-deficient HBMECs. Furthermore, in vivo assessment of a hypomorphic mouse model of ASLD showed increased BBB leakage, which was partially rescued by NO supplementation. Our results suggest that ASL-mediated NO synthesis is required for proper maintenance of brain microvascular endothelial cell functions as well as BBB integrity.
Jordan Kho, Urszula Polak, Ming-Ming Jiang, John D. Odom, Jill V. Hunter, Saima M. Ali, Lindsay C. Burrage, Sandesh C.S. Nagamani, Robia G. Pautler, Hannah P. Thompson, Akihiko Urayama, Zixue Jin, Brendan Lee
BACKGROUND Weight-loss diets often target dietary fat or carbohydrates, macronutrients that are sensed via distinct gut-brain pathways and differentially affect peripheral hormones and metabolism. However, the effects of such diet changes on the human brain are unclear. METHODS We investigated whether selective isocaloric reductions in dietary fat or carbohydrates altered dopamine D2/3 receptor binding potential (D2BP) and neural activity in brain-reward regions in response to visual food cues in 17 inpatient adults with obesity as compared with a eucaloric baseline diet using a randomized crossover design. RESULTS On the fifth day of dietary fat restriction, but not carbohydrate restriction, both D2BP and neural activity to food cues were decreased in brain-reward regions. After the reduced-fat diet, ad libitum intake shifted toward foods high in both fat and carbohydrates. CONCLUSION These results suggest that dietary fat restriction increases tonic dopamine in brain-reward regions and affects food choice in ways that may hamper diet adherence. TRIAL REGISTRATION ClinicalTrials.gov NCT00846040 FUNDING. NIDDK 1ZIADK013037.
Valerie L. Darcey, Juen Guo, Amber B. Courville, Isabelle Gallagher, Jason A. Avery, W. Kyle Simmons, John E. Ingeholm, Peter Herscovitch, Alex Martin, Kevin D. Hall
Changes in neuronal activity modulate the vulnerability of motoneurons (MNs) in neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). So far, the molecular basis of neuronal activity’s impact in ALS is poorly understood. Herein we investigated the impact of deleting the neuronal activity stimulated transcription factor (TF) serum response factor (SRF) in MNs of SOD1G93A mice. SRF was present in vulnerable MMP9 positive MNs. Ablation of SRF in MNs induced an earlier disease onset starting around 7-8 weeks after birth revealed by enhanced weight loss and decreased motor ability. This earlier disease onset in SRF depleted MNs was accompanied by mild elevation of neuroinflammation and neuromuscular synapse degeneration whereas overall MN numbers and mortality were unaffected. In SRF deficient mice, MNs showed impaired induction of autophagy encoding genes suggesting a new SRF function in transcriptional regulation of autophagy. Complementary, constitutive-active SRF-VP16 enhanced autophagy encoding gene transcription and autophagy progression in cells. Furthermore, SRF-VP16 decreased ALS-associated aggregate induction. Chemogenetic modulation of neuronal activity uncovered SRF as important TF mediating activity-dependent effects which might be beneficial to reduce ALS disease burden. Thus, our data identify with SRF a new gene regulator connecting neuronal activity with the cellular autophagy program initiated in degenerating MNs.
Jialei Song, Natalie Yashoda Dikwella, Daniela Sinske, Francesco Roselli, Bernd Knöll
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