scholarly journals Naked mole-rat brain neurons are resistant to acid-induced cell death

2018 ◽  
Author(s):  
Zoé Husson ◽  
Ewan St John Smith

AbstractRegulation of brain pH is a critical homeostatic process and changes in brain pH modulate various ion channels and receptors and thus neuronal excitability. Tissue acidosis, resulting from hypoxia or hypercapnia, can activate various proteins and ion channels, among which acid-sensing ion channels (ASICs) a family of primarily Na+permeable ion channels, which alongside classical excitotoxicity causes neuronal death. Naked mole-rats (NMRs,Heterocephalus glaber) are long-lived, fossorial, eusocial rodents that display remarkable behavioral/cellular hypoxia and hypercapnia resistance. In the central nervous system, ASIC subunit expression is similar between mouse and NMR with the exception of much lower expression of ASIC4 throughout the NMR brain. However, ASIC function and neuronal sensitivity to sustained acidosis has not been examined in the NMR brain. Here, we show with whole-cell patch-clamp electrophysiology of cultured NMR and mouse cortical and hippocampal neurons that NMR neurons have smaller voltage-gated Na+channel currents and more hyperpolarized resting membrane potentials. We further demonstrate that acid-mediated currents in NMR neurons are of smaller magnitude than in mouse, and that all currents in both species are fully blocked by the ASIC antagonist benzamil. We further demonstrate that NMR neurons show greater resistance to acid-induced cell death than mouse neurons. In summary, NMR neurons show significant cellular resistance to acidotoxicity compared to mouse neurons, contributing factors likely to be smaller ASIC-mediated currents and reduced NaV activity.AbbreviationsASIC, acid-sensing ion channel; CNS, central nervous system; DRG, dorsal root ganglion; NaV, voltage-gated Na+channel; NMR, naked mole-rat; TTX, tetrodotoxin

2020 ◽  
Vol 18 (10) ◽  
pp. 936-965
Author(s):  
Xuechao Hao ◽  
Mengchan Ou ◽  
Donghang Zhang ◽  
Wenling Zhao ◽  
Yaoxin Yang ◽  
...  

General anesthetics are a class of drugs that target the central nervous system and are widely used for various medical procedures. General anesthetics produce many behavioral changes required for clinical intervention, including amnesia, hypnosis, analgesia, and immobility; while they may also induce side effects like respiration and cardiovascular depressions. Understanding the mechanism of general anesthesia is essential for the development of selective general anesthetics which can preserve wanted pharmacological actions and exclude the side effects and underlying neural toxicities. However, the exact mechanism of how general anesthetics work is still elusive. Various molecular targets have been identified as specific targets for general anesthetics. Among these molecular targets, ion channels are the most principal category, including ligand-gated ionotropic receptors like γ-aminobutyric acid, glutamate and acetylcholine receptors, voltage-gated ion channels like voltage-gated sodium channel, calcium channel and potassium channels, and some second massager coupled channels. For neural functions of the central nervous system, synaptic transmission is the main procedure for which information is transmitted between neurons through brain regions, and intact synaptic function is fundamentally important for almost all the nervous functions, including consciousness, memory, and cognition. Therefore, it is important to understand the effects of general anesthetics on synaptic transmission via modulations of specific ion channels and relevant molecular targets, which can lead to the development of safer general anesthetics with selective actions. The present review will summarize the effects of various general anesthetics on synaptic transmissions and plasticity.


2021 ◽  
Author(s):  
William E. Barclay ◽  
M. Elizabeth Deerhake ◽  
Makoto Inoue ◽  
Toshiaki Nonaka ◽  
Kengo Nozaki ◽  
...  

ABSTRACTInflammasomes are a class of innate immune signaling platforms that activate in response to an array of cellular damage and pathogens. Inflammasomes promote inflammation under many circumstances to enhance immunity against pathogens and inflammatory responses through their effector cytokines, IL-1β and IL-18. Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are such autoimmune conditions influenced by inflammasomes. Despite work investigating inflammasomes during EAE, little remains known concerning the role of inflammasomes in the central nervous system (CNS) during the disease. Here we use multiple genetically modified mouse models to monitor activated inflammasomes in situ based on ASC oligomerization in the spinal cord. Using inflammasome reporter mice, we found heightened inflammasome activation in astrocytes after the disease peak. In contrast, microglia and CNS-infiltrated myeloid cells had few activated inflammasomes in the CNS during EAE. Astrocyte inflammasome activation was dependent on AIM2, but low IL-1β expression and no significant signs of cell death were found in astrocytes during EAE. Thus, the AIM2 inflammasome activation in astrocytes may have a distinct role from traditional inflammasome-mediated inflammation.SIGNIFICANCE STATEMENTInflammasome activation in the peripheral immune system is pathogenic in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). However, inflammasome activity in the central nervous system (CNS) is largely unexplored. Here, we used genetically modified mice to determine inflammasome activation in the CNS during EAE. Our data indicated heightened AIM2 inflammasome activation in astrocytes after the disease peak. Unexpectedly, neither CNS-infiltrated myeloid cells nor microglia were the primary cells with activated inflammasomes in SC during EAE. Despite AIM2 inflammasome activation, astrocytes did not undergo apparent cell death and produced little of the proinflammatory cytokine, IL-1β, during EAE. This study showed that CNS inflammasome activation occurs during EAE without associating with IL-1β-mediated inflammation.


2004 ◽  
Vol 77 (1) ◽  
pp. 35-53 ◽  
Author(s):  
Milena Penkowa ◽  
Albert Quintana ◽  
Javier Carrasco ◽  
Mercedes Giralt ◽  
Amalia Molinero ◽  
...  

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Hiroshi Kataoka ◽  
Daisuke Shimada ◽  
Hitoki Nanaura ◽  
Kazuma Sugie

ABSTRACT This case is the first document to describe a patient receiving anti-programmed cell death 1 (PD-1) antibodies which showed cranial dura matter involvement. According to the increasing use of anti-PD-1 monoclonal antibodies, adverse effects can occur in several organs since its ligand PD-L1 and PD-L2 are expressed in a wide variety of tissues. The estimated rate of neurological complications is 1–4.2% of patients, and neuromuscular disorders are the most common. Adverse effects on the central nervous system including encephalitis are less frequent. Here, a patient receiving anti-PD-1 antibodies showed cranial dura matter involvement, and the dura enhancement on MRI was resolved by withdrawal of the treatment with anti-PD-1 antibodies only.


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