scholarly journals Amyloid-Beta1-42 -Induced Increase in GABAergic Tonic Conductance in Mouse Hippocampal CA1 Pyramidal Cells

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 693 ◽  
Author(s):  
Beatriz Calvo-Flores Guzmán ◽  
SooHyun Kim ◽  
Bhavya Chawdhary ◽  
Katie Peppercorn ◽  
Warren P Tate ◽  
...  
Keyword(s):  
Cognitive Decline ◽  
Cognitive Deficits ◽  
Gaba Receptors ◽  
Neurodegenerative Disorder ◽  
Pyramidal Cells ◽  
Gamma Aminobutyric Acid ◽  
Ca1 Region ◽  
Underlying Mechanisms ◽  
And Function

Alzheimer’s disease (AD) is a complex and chronic neurodegenerative disorder that involves a progressive and severe decline in cognition and memory. During the last few decades a considerable amount of research has been done in order to better understand tau-pathology, inflammatory activity and neuronal synapse loss in AD, all of them contributing to cognitive decline. Early hippocampal network dysfunction is one of the main factors associated with cognitive decline in AD. Much has been published about amyloid-beta1-42 (Aβ1-42)-mediated excitotoxicity in AD. However, increasing evidence demonstrates that the remodeling of the inhibitory gamma-aminobutyric acid (GABAergic) system contributes to the excitatory/inhibitory (E/I) disruption in the AD hippocampus, but the underlying mechanisms are not well understood. In the present study, we show that hippocampal injection of Aβ1-42 is sufficient to induce cognitive deficits 7 days post-injection. We demonstrate using in vitro whole-cell patch-clamping an increased inhibitory GABAergic tonic conductance mediated by extrasynaptic type A GABA receptors (GABAARs), recorded in the CA1 region of the mouse hippocampus following Aβ1-42 micro injection. Such alterations in GABA neurotransmission and/or inhibitory GABAARs could have a significant impact on both hippocampal structure and function, causing E/I balance disruption and potentially contributing to cognitive deficits in AD.

scholarly journals Cohen I, Navarro V, Clemenceau S, Baulac M, Miles R:On the origin of interictal activity in human temporal lobe epilepsy in vitro. Science 298:1418–1421, 2002

2003 ◽  
Vol 14 (2) ◽  
pp. 1
Author(s):  
William T. Couldwell
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Pyramidal Cells ◽  
Rhythmic Activity ◽  
Gamma Aminobutyric Acid ◽  
Ca1 Region ◽  
Interictal Discharges ◽  
Human Temporal Lobe ◽  
Spontaneous Rhythmic Activity

The origin and mechanisms of human interictal epileptic discharges remain unclear. Here, we describe a spontaneous, rhythmic activity initiated in the subiculum of slices from patients with temporal lobe epilepsy. Synchronous events were similar to interictal discharges of patient electroencephalograms. They were suppressed by antagonists of either glutamatergic or gamma-aminobutyric acid (GABA)-ergic signaling. The network of neurons discharging during population events comprises both subicular interneurons and a subgroup of pyramidal cells. In these pyramidal cells, GABAergic synaptic events reversed at depolarized potentials. Depolarizing GABAergic responses in neurons downstream to the sclerotic CA1 region contribute to human interictal activity.

scholarly journals Activation of group 2 innate lymphoid cells alleviates aging-associated cognitive decline

2020 ◽  
Vol 217 (4) ◽  
Author(s):  
Ivan Ting Hin Fung ◽  
Poornima Sankar ◽  
Yuanyue Zhang ◽  
Lisa S. Robison ◽  
Xiuli Zhao ◽  
...  
Keyword(s):  
Cognitive Decline ◽  
Innate Lymphoid Cells ◽  
Lymphoid Cells ◽  
Brain Physiology ◽  
Aged Brain ◽  
Group 2 ◽  
Resident Group ◽  
And Function

Increasing evidence has challenged the traditional view about the immune privilege of the brain, but the precise roles of immune cells in regulating brain physiology and function remain poorly understood. Here, we report that tissue-resident group 2 innate lymphoid cells (ILC2) accumulate in the choroid plexus of aged brains. ILC2 in the aged brain are long-lived, are relatively resistant to cellular senescence and exhaustion, and are capable of switching between cell cycle dormancy and proliferation. They are functionally quiescent at homeostasis but can be activated by IL-33 to produce large amounts of type 2 cytokines and other effector molecules in vitro and in vivo. Intracerebroventricular transfer of activated ILC2 revitalized the aged brain and enhanced the cognitive function of aged mice. Administration of IL-5, a major ILC2 product, was sufficient to repress aging-associated neuroinflammation and alleviate aging-associated cognitive decline. Targeting ILC2 in the aged brain may provide new avenues to combat aging-associated neurodegenerative disorders.

scholarly journals Neuronal over-expression of Oxr1 is protective against ALS-associated mutant TDP-43 mislocalisation in motor neurons and neuromuscular defects in vivo

2019 ◽  
Vol 28 (21) ◽  
pp. 3584-3599 ◽  
Author(s):  
Matthew G Williamson ◽  
Mattéa J Finelli ◽  
James N Sleigh ◽  
Amy Reddington ◽  
David Gordon ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Gene Encoding ◽  
Over Expression ◽  
Neuromuscular Abnormalities ◽  
And Function ◽  
Lateral Sclerosis

Abstract A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and the related neurodegenerative disorder frontotemporal dementia, is the cellular mislocalization of transactive response DNA-binding protein 43 kDa (TDP-43). Additionally, multiple mutations in the TARDBP gene (encoding TDP-43) are associated with familial forms of ALS. While the exact role for TDP-43 in the onset and progression of ALS remains unclear, the identification of factors that can prevent aberrant TDP-43 localization and function could be clinically beneficial. Previously, we discovered that the oxidation resistance 1 (Oxr1) protein could alleviate cellular mislocalization phenotypes associated with TDP-43 mutations, and that over-expression of Oxr1 was able to delay neuromuscular abnormalities in the hSOD1G93A ALS mouse model. Here, to determine whether Oxr1 can protect against TDP-43-associated phenotypes in vitro and in vivo, we used the same genetic approach in a newly described transgenic mouse expressing the human TDP-43 locus harbouring an ALS disease mutation (TDP-43M337V). We show in primary motor neurons from TDP-43M337V mice that genetically-driven Oxr1 over-expression significantly alleviates cytoplasmic mislocalization of mutant TDP-43. We also further quantified newly-identified, late-onset neuromuscular phenotypes of this mutant line, and demonstrate that neuronal Oxr1 over-expression causes a significant reduction in muscle denervation and neuromuscular junction degeneration in homozygous mutants in parallel with improved motor function and a reduction in neuroinflammation. Together these data support the application of Oxr1 as a viable and safe modifier of TDP-43-associated ALS phenotypes.

scholarly journals Plants-Derived Neuroprotective Agents: Cutting the Cycle of Cell Death through Multiple Mechanisms

2017 ◽  
Vol 2017 ◽  
pp. 1-27 ◽  
Author(s):  
Taiwo Olayemi Elufioye ◽  
Tomayo Ireti Berida ◽  
Solomon Habtemariam
Keyword(s):  
Mechanisms Of Action ◽  
Neuroprotective Agents ◽  
Structural Class ◽  
Molecular Features ◽  
Amyotropic Lateral Sclerosis ◽  
Underlying Mechanisms ◽  
And Function ◽  
Lateral Sclerosis

Neuroprotection is the preservation of the structure and function of neurons from insults arising from cellular injuries induced by a variety of agents or neurodegenerative diseases (NDs). The various NDs including Alzheimer’s, Parkinson’s, and Huntington’s diseases as well as amyotropic lateral sclerosis affect millions of people around the world with the main risk factor being advancing age. Each of these diseases affects specific neurons and/or regions in the brain and involves characteristic pathological and molecular features. Hence, several in vitro and in vivo study models specific to each disease have been employed to study NDs with the aim of understanding their underlying mechanisms and identifying new therapeutic strategies. Of the most prevalent drug development efforts employed in the past few decades, mechanisms implicated in the accumulation of protein-based deposits, oxidative stress, neuroinflammation, and certain neurotransmitter deficits such as acetylcholine and dopamine have been scrutinized in great detail. In this review, we presented classical examples of plant-derived neuroprotective agents by highlighting their structural class and specific mechanisms of action. Many of these natural products that have shown therapeutic efficacies appear to be working through the above-mentioned key multiple mechanisms of action.

Role of norepinephrine in seizurelike activity of hippocampal pyramidal cells maintained in vitro: alteration by 6-hydroxydopamine lesions of norepinephrine-containing systems

1983 ◽  
Vol 61 (8) ◽  
pp. 841-846 ◽  
Author(s):  
I. Mody ◽  
P. Leung ◽  
J. J. Miller
Keyword(s):  
Epileptiform Activity ◽  
Pyramidal Cells ◽  
Population Spike ◽  
Stratum Radiatum ◽  
Excitatory Postsynaptic Potential ◽  
Ca1 Pyramidal Cells ◽  
Ca1 Region ◽  
Population Spike Amplitude ◽  
6 Hydroxydopamine

Perfusion of 50 μM norepinephrine (NE) produced a marked, reversible decrease (range 20–28%) of the extracellular population spike and excitatory postsynaptic potential (EPSP) responses of the CA1 region evoked by stratum radiatum stimulation in the rat hippocampal slice preparation. The effects of NE were dramatically altered in slices obtained from animals which were previously treated with intracerebral or intraventricular injections of 6-hydroxydopamine (6-OHDA) to destroy forebrain catecholamine systems. In the latter preparations NE produced a reduction in the inhibition of the EPSP (50%), enhancement of the population spike amplitude, and multiple spike discharges characteristic of ongoing epileptiform activity. The reversal of NE-induced inhibition and the generation of seizurelike activity in 6-OHDA-treated animals suggests that NE may, in part, act upon interneurons to produce a disinhibition of CA1 pyramidal cells.

scholarly journals Thyroid Stimulating Hormone Triggers Hepatic Mitochondrial Stress through Cyclophilin D Acetylation

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaolei Wang ◽  
Jinbao Mao ◽  
Xinli Zhou ◽  
Qiu Li ◽  
Ling Gao ◽  
...  
Keyword(s):  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Cyclophilin D ◽  
Mitochondrial Stress ◽  
Knockout Mouse Model ◽  
Cellular Reactive Oxygen Species ◽  
Underlying Mechanisms ◽  
And Function ◽  
Stimulating Hormone

Background & Aims. Oxidative stress-related liver diseases were shown to be associated with elevated serum thyroid stimulating hormone (TSH) levels. Mitochondria are the main source of cellular reactive oxygen species. However, the relationship between TSH and hepatic mitochondrial stress/dysfunction and the underlying mechanisms are largely unknown. Here, we focused on exploring the effects and mechanism of TSH on hepatic mitochondrial stress. Methods. As the function of TSH is mediated through the TSH receptor (TSHR), Tshr-/- mice and liver-specific Tshr knockout (LKO) mice were used in our study. The thyroid-specific Tshr knockout mouse model injected with TSH (TKO+TSH) was used as a mimic for subclinical hypothyroidism (SCH) patients. Hepatic mitochondrial stress and function were analyzed in these mouse models, and the expression of key genes involved in mitochondrial stress was measured. Results. A relatively lower degree of mitochondrial stress was observed in the livers of Tshr-/- mice and LKO mice than those of their littermate counterparts. TSH caused concentration- and time-dependent effects on mitochondrial stress and cyclophilin D (CypD) acetylation in hepatocytes in vitro. Microarray and RT-PCR analyses showed that Tshr-/- mice had much higher lncRNA-AK044604 expression than their littermate counterparts. The use of the AK044604 overexpression plasmid and SIRT1 agonist proved that TSH aggravates CypD acetylation and mitochondrial stress via lncRNA-AK044604 and SIRT1. An inhibitor of CypD acetylation, cyclosporine A, suppressed TSH-induced hepatic mitochondrial stress and dysfunction. Conclusions. TSH stimulates hepatic CypD acetylation through the lncRNA-AK044604/SIRT1/SIRT3 signaling pathway, indicating an essential role for TSH in mitochondrial stress in the liver.

SNHG5 inhibits the progression of EMT through the ubiquitin-degradation of MTA2 in oesophageal cancer

2020 ◽  
Author(s):  
Sisi Wei ◽  
Shiping Sun ◽  
Xinliang Zhou ◽  
Cong Zhang ◽  
Xiaoya Li ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Progression ◽  
Epithelial Mesenchymal Transition ◽  
Survival Rates ◽  
Migration And Invasion ◽  
Mesenchymal Transition ◽  
Underlying Mechanisms ◽  
And Function

Abstract A substantial fraction of transcripts are known as long noncoding RNAs (lncRNAs), and these transcripts play pivotal roles in the development of cancer. However, little information has been published regarding the functions of lncRNAs in oesophageal squamous cell carcinoma (ESCC) and the underlying mechanisms. In our previous studies, we demonstrated that small nucleolar RNA host gene 5 (SNHG5), a known lncRNA, is dysregulated in gastric cancer (GC). In this study, we explored the expression and function of SNHG5 in development of ESCC. SNHG5 was found to be downregulated in human ESCC tissues and cell lines, and this downregulation was associated with cancer progression, clinical outcomes and survival rates of ESCC patients. Furthermore, we also found that overexpression of SNHG5 significantly inhibited the proliferation, migration and invasion of ESCC cells in vivo and in vitro. Notably, we found that metastasis-associated protein 2 (MTA2) was pulled down by SNHG5 in ESCC cells using RNA pulldown assay. We also found that SNHG5 reversed the epithelial–mesenchymal transition by interacting with MTA2. In addition, overexpression of SNHG5 downregulated the transcription of MTA2 and caused its ubiquitin-mediated degradation. Thus, overexpression of MTA2 partially abrogated the effect of SNHG5 in ESCC cell lines. Furthermore, we found that MTA2 mRNA expression was significantly elevated in ESCC specimens, and a negative correlation between SNHG5 and MTA2 expression was detected. Overall, this study demonstrated, for the first time, that SNHG5-regulated MTA2 functions as an important player in the progression of ESCC and provide a new potential therapeutic strategy for ESCC.

scholarly journals Glutamatergic Propagation of GABAergic Seizure-Like Afterdischarge in the Hippocampus In Vitro

2003 ◽  
Vol 90 (4) ◽  
pp. 2746-2751 ◽  
Author(s):  
Yoshikazu Isomura ◽  
Yoko Fujiwara-Tsukamoto ◽  
Masahiko Takada
Keyword(s):  
Epileptiform Activity ◽  
Hippocampal Slices ◽  
In Vitro Study ◽  
Pyramidal Cells ◽  
Inhibitory Effect ◽  
Experimental Models ◽  
Fluoride Ions ◽  
Ca1 Region ◽  
Cortical Regions

Previous investigations have suggested that GABA may act actively as an excitatory mediator in the generation of seizure-like (ictal) or interictal epileptiform activity in several experimental models of temporal lobe epilepsy. However, it remains to be known whether or not such GABAergic excitation may participate in seizure propagation into neighboring cortical regions. In our in vitro study using mature rat hippocampal slices, we examined the cellular mechanism underlying synchronous propagation of seizure-like afterdischarge in the CA1 region, which is driven by depolarizing GABAergic transmission, into the adjacent subiculum region. Tetanically induced seizure-like afterdischarge was always preceded by a GABAergic, slow posttetanic depolarization in the pyramidal cells of the original seizure-generating region. In contrast, the slow posttetanic depolarization was no longer observed in the subicular pyramidal cells when the afterdischarge was induced in the CA1 region. Surgical cutting of axonal pathways through the stratum oriens and the alveus between the CA1 and the subiculum region abolished the CA1-generated afterdischarge in the subicular pyramidal cells. Intracellular loading of fluoride ions, a GABAA receptor blocker, into single subicular pyramidal cells had no inhibitory effect on the CA1-generated afterdischarge in the pyramidal cells. Furthermore, the CA1-generated afterdischarge in the subicular pyramidal cells was largely depressed by local application of glutamate receptor antagonists to the subiculum region during afterdischarge generation. The present results indicate that the excitatory GABAergic generation of seizure-like activity seems to be restricted to epileptogenic foci of origin in the seizure-like epilepsy model in vitro.

Abstract 15671: Adipocyte-derived Exosomal Lncrna Nbr2 Promotes Diabetic Myocardial Fibrosis Through Regulating the Ikba/nf-kb Pathway

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yue Guo ◽  
Xingfeng Xu ◽  
Lingling Wu ◽  
Xiaodong Zhuang ◽  
Xinxue Liao
Keyword(s):  
Myocardial Fibrosis ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Epigenetic Mechanism ◽  
Ang Ii ◽  
Intramyocardial Injection ◽  
Underlying Mechanisms ◽  
Human Cardiac Fibroblasts ◽  
And Function

Introduction: The activation of NF-κB is the dominant process that correlates with the pathogenesis of diabetic cardiomyopathy (DCM). Recently, accumulating evidence shows that long noncoding RNAs (lncRNAs) play crucial roles in sustaining the NF-κB pathway. However, the underlying mechanisms remain unclear. In this study, we identified the upregulated expressed lncRNA NBR2 in adipocyte-derived exosomes (AdEXO) and investigated its regulatory role in diabetic myocardial fibrosis. Hypothesis: We hypothesized that AdEXO-NBR2 promotes diabetic myocardial fibrosis through regulating the IκBα/NF-κB pathway. Methods: We examined the effect of exosomes from diabetic (db/db) mice-derived adipocytes on ANG-II-induced cardiac fibrosis and function in non-diabetic (C57BL/6J mice). In the invitro study, HG (33mmol/L)-stimulated AdEXO were cultured with adult human cardiac fibroblasts (aHCFs). Differentially expressed lncRNAs in AdEXO were screened using lncRNA sequencing. Results: Intramyocardial injection of diabetic AdEXO in the non-diabetic heart significantly exacerbated myocardial fibrosis, as evidenced by poorer cardiac function and enhancer collagen deposition. Whereas administration of a exosomes biogenesis inhibitor mitigated cardiac fibrosis in diabetic mice. We found lncRNA-NBR2 is a common molecule significantly increased in diabetic AdEXO and HG-stimulated non-diabetic AdEXO. After four weeks of ANG II infusion, EXO-db/dbWT-injected mice displayed fibrosis in the heart. However, interestingly, mice receiving NBR2-deficient db/db-EXO showed a decrease in cardiac fibrosis. Similarly, AdEXO-NBR2 promoted aHCFs proliferation and transformation capabilities in vitro. Mechanistically, NBR2 was loaded to AdEXO by directly interacting with heterogeneous nuclear ribonucleoprotein K (hnRNPK). Subsequently, AdEXO-NBR2 was internalized by aHCFs and epigenetically downregulated IκBα expression by recruitment of hnRNPK/SETDB1 and increasing the H3K9 trimethylation level in the IκBα promoter, ultimately activating the NF-κB pathway. Conclusions: Our findings highlight a novel epigenetic mechanism of AdEXO lncRNA-mediated diabetic cardiac fibrosis and identify NBR2 as a therapeutic target of DCM.

Clemastine Attenuates AD-like Pathology in an AD Model Mouse via Enhancing mTOR-Mediated Autophagy

2020 ◽  
Author(s):  
Zhen-Yu Li ◽  
Li-Hua Chen ◽  
Xiu-Yun Zhao ◽  
Hong Chen ◽  
Mei-Hong Lu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Cognitive Deficits ◽  
First Generation ◽  
Neurodegenerative Disorder ◽  
Amyloid Β ◽  
Beneficial Effects ◽  
Model Mouse ◽  
Aβ Generation ◽  
Ad Therapy

Abstract Background: Alzheimer’s disease (AD) is a neurodegenerative disorder with limited available drugs for treatment. Enhancing autophagy attenuates AD pathology in various AD model mice. Thus, development of potential drugs enhancing autophagy may bring beneficial effects in AD therapy. Methods: In the present study, we showed clemastine, a first-generation histamine H1R antagonist and being originally marketed for the treatment of allergic rhinitis, ameliorates AD pathogenesis in APP/PS1 transgenic mice. Chronic treatment with clemastine orally reduced amyloid-β (Aβ) load, neuroinflammation and cognitive deficits of APP/PS1 transgenic mice as shown by immunohistochemistry and behavioral analysis. We further analyzed the mechanisms underlying the beneficial effects of clemastine with using the combination of both in vivo and in vitro experiments. We observed that clemastine decreased Aβ generation via reducing the levels of BACE1, CTFs of APP. Clemastine enhanced autophagy concomitant with a suppression of mTOR signaling. Conclusion: Therefore, we propose that clemastine attenuates AD pathology via enhancing mTOR-mediated autophagy.

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