Reduction of the neuroprotective transcription factor Npas4 results in increased neuronal necrosis, inflammation and brain lesion size following ischaemia

Stroke is the second leading cause of death and the most frequent cause of adult disability. Neuronal Per-Arnt-Sim domain protein 4 (Npas4) is an activity-dependent transcription factor whose expression is induced in various brain insults, including cerebral ischaemia. Although previous studies have demonstrated that Npas4 plays a critical role in protecting neurons against neurodegenerative insults, the neuroprotective effect of Npas4 in response to ischaemic brain injury remains unknown. In this study, we used a loss-of-function approach to examine the neuroprotective potential of Npas4 in the context of ischaemic damage. Using oxygen and glucose deprivation, we demonstrated that the knockdown of Npas4 in mouse cortical neurons resulted in increased susceptibility to cell death. The protective effect of Npas4 was further investigated in vivo using a photochemically-induced stroke model in mice. We found a significantly larger lesion size and increased neurodegeneration in Npas4 knockout mice as compared to wild-type mice. Moreover, we also showed that ablation of Npas4 caused an increase in activated astrocytes and microglia, pro-inflammatory cytokines interleukin-6 and tumour necrosis factor alpha levels and a switch from apoptotic to necrotic cell death. Taken together, these data suggest that Npas4 plays a neuroprotective role in ischaemic stroke by limiting progressive neurodegeneration and neuroinflammation.

Download Full-text

Protective Effect of Osmundacetone against Neurological Cell Death Caused by Oxidative Glutamate Toxicity

Biomolecules ◽

10.3390/biom11020328 ◽

2021 ◽

Vol 11 (2) ◽

pp. 328

Author(s):

Tuy An Trinh ◽

Young Hye Seo ◽

Sungyoul Choi ◽

Jun Lee ◽

Ki Sung Kang

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Defense Mechanism ◽

Neuroprotective Effect ◽

Glutamate Release ◽

Chromatin Condensation ◽

Critical Role ◽

Glutamate Toxicity ◽

Heme Oxygenase 1 ◽

Brain Functions

Oxidative stress is one of the main causes of brain cell death in neurological disorders. The use of natural antioxidants to maintain redox homeostasis contributes to alleviating neurodegeneration. Glutamate is an excitatory neurotransmitter that plays a critical role in many brain functions. However, excessive glutamate release induces excitotoxicity and oxidative stress, leading to programmed cell death. Our study aimed to evaluate the effect of osmundacetone (OAC), isolated from Elsholtzia ciliata (Thunb.) Hylander, against glutamate-induced oxidative toxicity in HT22 hippocampal cells. The effect of OAC treatment on excess reactive oxygen species (ROS), intracellular calcium levels, chromatin condensation, apoptosis, and the expression level of oxidative stress-related proteins was evaluated. OAC showed a neuroprotective effect against glutamate toxicity at a concentration of 2 μM. By diminishing the accumulation of ROS, as well as stimulating the expression of heat shock protein 70 (HSP70) and heme oxygenase-1 (HO-1), OAC triggered the self-defense mechanism in neuronal cells. The anti-apoptotic effect of OAC was demonstrated through its inhibition of chromatin condensation, calcium accumulation, and reduction of apoptotic cells. OAC significantly suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs), including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 kinases. Thus, OAC could be a potential agent for supportive treatment of neurodegenerative diseases.

Download Full-text

Loss of function of the mitochondrial peptidase PITRM1 induces proteotoxic stress and Alzheimer’s disease-like pathology in human cerebral organoids

10.1101/2020.01.27.919522 ◽

2020 ◽

Cited By ~ 1

Author(s):

Dina Ivanyuk ◽

María José Pérez ◽

Vasiliki Panagiotakopoulou ◽

Gabriele Di Napoli ◽

Dario Brunetti ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cell Death ◽

Cortical Neurons ◽

Amyloid Β ◽

Neuronal Cell ◽

Protein Aggregates ◽

Neuronal Cultures ◽

Loss Of Function ◽

Proteotoxic Stress

AbstractMutations in pitrilysin metallopeptidase 1 (PITRM1), a mitochondrial protease involved in mitochondrial precursor processing and degradation, result in a slow-progressive syndrome, characterized by cerebellar ataxia, psychotic episodes and obsessive behavior as well as cognitive decline. To investigate the pathogenetic mechanisms of mitochondrial presequence processing, we employed cortical neurons and cerebral organoids generated from PITRM1 knockout human induced pluripotent stem cells (iPSCs). PITRM1 deficiency strongly induced mitochondrial unfolded protein response (UPRmt) and enhanced mitochondrial clearance in iPSC-derived neurons. Furthermore, we observed increased levels of amyloid precursor protein and amyloid β in PITRM1 knockout neurons. However, neither cell death nor protein aggregates were observed in 2D iPSC-derived cortical neuronal cultures. On the contrary, cerebral organoids generated from PITRM1 knockout iPSCs spontaneously developed over time pathological features of Alzheimer’s disease (AD), including accumulation of protein aggregates, tau pathology, and neuronal cell death. Importantly, we provide evidence for a protective role of UPRmt and mitochondrial clearance against impaired mitochondrial presequence processing and proteotoxic stress. In summary, we propose a novel concept of PITRM1-linked neurological syndrome whereby defects of mitochondrial presequence processing induce an early activation of UPRmt that, in turn, modulates cytosolic quality control pathways. Thus our work supports a mechanistic link between mitochondrial function and common neurodegenerative proteinopathies.

Download Full-text

iPSC-induced neurons with the V337M MAPT mutation are selectively vulnerable to caspase-mediated cleavage of tau and apoptotic cell death

10.21203/rs.3.rs-300172/v2 ◽

2021 ◽

Author(s):

Panos Theofilas ◽

Chao Wang ◽

David Butler ◽

Dulce O. Morales ◽

Cathrine Petersen ◽

...

Keyword(s):

Cell Death ◽

Cortical Neurons ◽

Apoptotic Cell ◽

Neuroprotective Effect ◽

Neuronal Loss ◽

Age Related ◽

Postmortem Brains ◽

Caspase 6 ◽

Induced Neurons ◽

Tau Cleavage

Abstract Background: Tau post-translational modifications (PTMs) are associated with progressive tau accumulation and neuronal loss in tauopathies, including forms of frontotemporal lobar degeneration (FTLD) and Alzheimer’s disease (AD). Tau proteolysis by caspases, including caspase-6, represents an understudied PTM that may increase neurotoxicity and tau self-aggregation. Methods: To elucidate the presence and temporal course of caspase activation, tau cleavage, and neuronal death, we generated two novel epitope (neoepitope) monoclonal antibodies (mAbs) against caspase-6 tau proteolytic sites. We evaluated tau cleavage and response to apoptotic stress in cortical neurons derived from induced pluripotent stem cells (iPSCs) with frontotemporal dementia (FTD)-causing V337M MAPT mutation. We tested the neuroprotective effect of caspase inhibitors in the induced neurons. We also demonstrated the presence of the tau neoepitopes in postmortem brains from an individual with FTD (V337M MAPT) and an individual with AD, compared to a healthy control.Results: FTLD V337M MAPT and AD postmortem brains showed positivity for both cleaved tau mAbs and active caspase-6. Relative to isogenic wild-type MAPT controls, V337M MAPT neurons cultured for 3 months showed a time-dependent increase in pathogenic tau in the form of caspase-cleaved tau and phosphorylated (p)-tau, and higher levels of tau oligomers. Accumulation of toxic tau species in V337M MAPT neurons was correlated with increased vulnerability to pro-apoptotic stress. Notably, this mutation-associated cell death was pharmacologically rescued by inhibition of effector caspases.Conclusions: Culturing iPSC-derived neurons for three months exposes age-related tau pathologies, including caspase-mediated cleavage, that are also observed in human postmortem brains with abnormal tau deposition. Neoepitope antibodies to caspase-cleaved tau may serve as biomarkers of tau pathology. Furthermore, caspases could be viable therapeutic targets for tau pathogenesis in FTLD and other tauopathies.

Download Full-text

Inhibition of Lithium Sensitive Orai1/ STIM1 Expression and Store Operated Ca2+ Entry in Chorea-Acanthocytosis Neurons by NF-κB Inhibitor Wogonin

Cellular Physiology and Biochemistry ◽

10.1159/000495229 ◽

2018 ◽

Vol 51 (1) ◽

pp. 278-289 ◽

Cited By ~ 5

Author(s):

Basma Sukkar ◽

Stefan Hauser ◽

Lisann Pelzl ◽

Zohreh Hosseinzadeh ◽

Itishri Sahu ◽

...

Keyword(s):

Cell Death ◽

Cortical Neurons ◽

Lithium Treatment ◽

Cell Types ◽

Protein Abundance ◽

Loss Of Function ◽

Atpase Inhibitor ◽

Patch Clamp Recording ◽

Transcript Levels ◽

Induced Pluripotent

Background/Aims: The neurodegenerative disease Chorea-Acanthocytosis (ChAc) is caused by loss-of-function-mutations of the chorein-encoding gene VPS13A. In ChAc neurons transcript levels and protein abundance of Ca2+ release activated channel moiety (CRAC) Orai1 as well as its regulator STIM1/2 are decreased, resulting in blunted store operated Ca2+-entry (SOCE) and enhanced suicidal cell death. SOCE is up-regulated and cell death decreased by lithium. The effects of lithium are paralleled by upregulation of serum & glucocorticoid inducible kinase SGK1 and abrogated by pharmacological SGK1 inhibition. In other cell types SGK1 has been shown to be partially effective by upregulation of NFκB, a transcription factor stimulating the expression of Orai1 and STIM. The present study explored whether pharmacological inhibition of NFκB interferes with Orai1/STIM1/2 expression and SOCE and their upregulation by lithium in ChAc neurons. Methods: Cortical neurons were differentiated from induced pluripotent stem cells generated from fibroblasts of ChAc patients and healthy volunteers. Orai1 and STIM1 transcript levels and protein abundance were estimated from qRT-PCR and Western blotting, respectively, cytosolic Ca2+-activity ([Ca2+]i) from Fura-2-fluorescence, SOCE from increase of [Ca2+]i following Ca2+ re-addition after Ca2+-store depletion with sarco-endoplasmatic Ca2+-ATPase inhibitor thapsigargin (1µM), as well as CRAC current utilizing whole cell patch clamp recording. Results: Orai1 and STIM1 transcript levels and protein abundance as well as SOCE and CRAC current were significantly enhanced by lithium treatment (2 mM, 24 hours). These effects were reversed by NFκB inhibitor wogonin (50 µM). Conclusion: The stimulation of expression and function of Orai1/STIM1/2 by lithium in ChAc neurons are disrupted by pharmacological NFκB inhibition.

Download Full-text

p38 Map Kinase Mediates Bax Translocation in Nitric Oxide–Induced Apoptosis in Neurons

The Journal of Cell Biology ◽

10.1083/jcb.150.2.335 ◽

2000 ◽

Vol 150 (2) ◽

pp. 335-348 ◽

Cited By ~ 284

Author(s):

Saadi Ghatan ◽

Stephen Larner ◽

Yoshito Kinoshita ◽

Michal Hetman ◽

Leena Patel ◽

...

Keyword(s):

Nitric Oxide ◽

Cell Death ◽

Map Kinase ◽

Cortical Neurons ◽

Kinase Activity ◽

Critical Role ◽

Primary Cultures ◽

P38 Map Kinase ◽

Concomitant Treatment ◽

Cell Death Pathway

Nitric oxide is a chemical messenger implicated in neuronal damage associated with ischemia, neurodegenerative disease, and excitotoxicity. Excitotoxic injury leads to increased NO formation, as well as stimulation of the p38 mitogen-activated protein (MAP) kinase in neurons. In the present study, we determined if NO-induced cell death in neurons was dependent on p38 MAP kinase activity. Sodium nitroprusside (SNP), an NO donor, elevated caspase activity and induced death in human SH-SY5Y neuroblastoma cells and primary cultures of cortical neurons. Concomitant treatment with SB203580, a p38 MAP kinase inhibitor, diminished caspase induction and protected SH-SY5Y cells and primary cultures of cortical neurons from NO-induced cell death, whereas the caspase inhibitor zVAD-fmk did not provide significant protection. A role for p38 MAP kinase was further substantiated by the observation that SB203580 blocked translocation of the cell death activator, Bax, from the cytosol to the mitochondria after treatment with SNP. Moreover, expressing a constitutively active form of MKK3, a direct activator of p38 MAP kinase promoted Bax translocation and cell death in the absence of SNP. Bax-deficient cortical neurons were resistant to SNP, further demonstrating the necessity of Bax in this mode of cell death. These results demonstrate that p38 MAP kinase activity plays a critical role in NO-mediated cell death in neurons by stimulating Bax translocation to the mitochondria, thereby activating the cell death pathway.

Download Full-text

The Snail transcription factor CES-1 regulates glutamatergic behavior in C. elegans

PLoS ONE ◽

10.1371/journal.pone.0245587 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0245587

Author(s):

Lidia Park ◽

Eric S. Luth ◽

Kelsey Jones ◽

Julia Hofer ◽

Irene Nguyen ◽

...

Keyword(s):

Cell Death ◽

Transcription Factor ◽

Transcription Factors ◽

Synaptic Plasticity ◽

Ampa Receptor ◽

Active Form ◽

Cell Lineage ◽

Receptor Expression ◽

Loss Of Function ◽

Major Mechanism

Regulation of AMPA-type glutamate receptor (AMPAR) expression and function alters synaptic strength and is a major mechanism underlying synaptic plasticity. Although transcription is required for some forms of synaptic plasticity, the transcription factors that regulate AMPA receptor expression and signaling are incompletely understood. Here, we identify the Snail family transcription factor ces-1 in an RNAi screen for conserved transcription factors that regulate glutamatergic behavior in C. elegans. ces-1 was originally discovered as a selective cell death regulator of neuro-secretory motor neuron (NSM) and I2 interneuron sister cells in C. elegans, and has almost exclusively been studied in the NSM cell lineage. We found that ces-1 loss-of-function mutants have defects in two glutamatergic behaviors dependent on the C. elegans AMPA receptor GLR-1, the mechanosensory nose-touch response and spontaneous locomotion reversals. In contrast, ces-1 gain-of-function mutants exhibit increased spontaneous reversals, and these are dependent on glr-1 consistent with these genes acting in the same pathway. ces-1 mutants have wild type cholinergic neuromuscular junction function, suggesting that they do not have a general defect in synaptic transmission or muscle function. The effect of ces-1 mutation on glutamatergic behaviors is not due to ectopic cell death of ASH sensory neurons or GLR-1-expressing neurons that mediate one or both of these behaviors, nor due to an indirect effect on NSM sister cell deaths. Rescue experiments suggest that ces-1 may act, in part, in GLR-1-expressing neurons to regulate glutamatergic behaviors. Interestingly, ces-1 mutants suppress the increased reversal frequencies stimulated by a constitutively-active form of GLR-1. However, expression of glr-1 mRNA or GFP-tagged GLR-1 was not decreased in ces-1 mutants suggesting that ces-1 likely promotes GLR-1 function. This study identifies a novel role for ces-1 in regulating glutamatergic behavior that appears to be independent of its canonical role in regulating cell death in the NSM cell lineage.

Download Full-text

Loss of function of transcription factor EB remodels lipid metabolism and cell death pathways in the cardiomyocyte

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease ◽

10.1016/j.bbadis.2020.165832 ◽

2020 ◽

Vol 1866 (10) ◽

pp. 165832

Author(s):

Purvi C. Trivedi ◽

Jordan J. Bartlett ◽

Angella Mercer ◽

Logan Slade ◽

Marc Surette ◽

...

Keyword(s):

Cell Death ◽

Transcription Factor ◽

Lipid Metabolism ◽

Loss Of Function ◽

Cell Death Pathways ◽

Transcription Factor Eb

Download Full-text

iPSC-Induced Neurons with the V337M MAPT Mutation are Selectively Vulnerable to Caspase-Mediated Cleavage of Tau and Apoptotic Cell Death

10.21203/rs.3.rs-300172/v1 ◽

2021 ◽

Author(s):

Panos Theofilas ◽

Chao Wang ◽

David Butler ◽

Dulce O. Morales ◽

Cathrine Petersen ◽

...

Keyword(s):

Cell Death ◽

Cortical Neurons ◽

Apoptotic Cell ◽

Neuroprotective Effect ◽

Neuronal Loss ◽

Age Related ◽

Postmortem Brains ◽

Caspase 6 ◽

Induced Neurons ◽

Tau Cleavage

Abstract Background: Tau post-translational modifications (PTMs) are associated with progressive tau accumulation and neuronal loss in tauopathies, including forms of frontotemporal lobar degeneration (FTLD) and Alzheimer’s disease (AD). Tau proteolysis by caspases, including caspase-6, represents an understudied PTM that may increase neurotoxicity and tau self-aggregation. Methods: To elucidate the presence and temporal course of caspase activation, tau cleavage, and neuronal death, we generated two novel epitope (neoepitope) monoclonal antibodies (mAbs) against caspase-6 tau proteolytic sites. We evaluated tau cleavage and response to apoptotic stress in cortical neurons derived from induced pluripotent stem cells (iPSCs) with frontotemporal dementia (FTD)-causing V337M MAPT mutation. We tested the neuroprotective effect of caspase inhibitors in the induced neurons. We also demonstrated the presence of the tau neoepitopes in postmortem brains from an individual with FTD (V337M MAPT) and an individual with AD, compared to a healthy control. Results: FTLD V337M MAPT and AD postmortem brains showed positivity for both cleaved tau mAbs and active caspase-6. Relative to isogenic wild-type MAPT controls, V337M MAPT neurons cultured for 3 months showed a time-dependent increase in pathogenic tau in the form of caspase-cleaved tau and phosphorylated (p)-tau, and higher levels of tau oligomers. Accumulation of toxic tau species in V337M MAPT neurons was correlated with increased vulnerability to pro-apoptotic stress. Notably, this mutation-associated cell death was pharmacologically rescued by inhibition of effector caspases.Conclusions: Culturing iPSC-derived neurons for three months exposes age-related tau pathologies, including caspase-mediated cleavage, that are also observed in human postmortem brains with abnormal tau deposition. Neoepitope antibodies to caspase-cleaved tau may serve as biomarkers of tau pathology. Furthermore, caspases could be viable therapeutic targets for tau pathogenesis in FTLD and other tauopathies.

Download Full-text

Signalling pathways mediating inflammatory responses in brain ischaemia

Biochemical Society Transactions ◽

10.1042/bst0341267 ◽

2006 ◽

Vol 34 (6) ◽

pp. 1267-1270 ◽

Cited By ~ 81

Author(s):

A.M. Planas ◽

R. Gorina ◽

Á. Chamorro

Keyword(s):

Cell Death ◽

Inflammatory Cytokines ◽

Cell Activation ◽

Inflammatory Responses ◽

Interleukin 10 ◽

Janus Kinase ◽

Signalling Pathways ◽

Neuronal Necrosis ◽

Ischaemic Brain ◽

Anti Inflammatory

Stroke causes neuronal necrosis and generates inflammation. Pro-inflammatory molecules intervene in this process by triggering glial cell activation and leucocyte infiltration to the injured tissue. Cytokines are major mediators of the inflammatory response. Pro-inflammatory and anti-inflammatory cytokines are released in the ischaemic brain. Anti-inflammatory cytokines, such as interleukin-10, promote cell survival, whereas pro-inflammatory cytokines, such as TNFα (tumour necrosis factor α), can induce cell death. However, deleterious effects of certain cytokines can turn to beneficial actions, depending on particular features such as the concentration, time point and the very intricate network of intracellular signals that become activated and interact. A key player in the intracellular response to cytokines is the JAK (Janus kinase)/STAT (signal transducer and activator of transcription) pathway that induces alterations in the pattern of gene transcription. These changes are associated either with cell death or survival depending, among other things, on the specific proteins involved. STAT1 activation is related to cell death, whereas STAT3 activation is often associated with survival. Yet, it is clear that STAT activation must be tightly controlled, and for this reason the function of JAK/STAT modulators, such as SOCS (suppressors of cytokine signalling) and PIAS (protein inhibitor of activated STAT), and phosphatases is most relevant. Besides local effects in the ischaemic brain, cytokines are released to the circulation and affect the immune system. Unbalanced pro-inflammatory and anti-inflammatory plasma cytokine concentrations favouring an ‘anti-inflammatory’ state can decrease the immune response. Robust evidence now supports that stroke can induce an immunodepression syndrome, increasing the risk of infection. The contribution of individual cytokines and their intracellular signalling pathways to this response needs to be further investigated.

Download Full-text

Lycopus lucidus Turcz exerts neuroprotective effect against H2O2‑induced neuroinflammation by inhibiting NLRP3 inflammasome activation in cortical neurons

10.21203/rs.3.rs-149006/v1 ◽

2021 ◽

Author(s):

Hyunseong Kim ◽

Jin Young Hong ◽

Wan-Jin Jeon ◽

Junseon Lee ◽

Seung Ho Baek ◽

...

Keyword(s):

Cell Death ◽

Nlrp3 Inflammasome ◽

Cortical Neurons ◽

Neuronal Damage ◽

Neuroprotective Effect ◽

Synaptic Connectivity ◽

Inflammasome Activation ◽

Caspase 1 ◽

Nlrp3 Inflammasome Activation ◽

Rat Cortical Neurons

Abstract Background Central nervous system (CNS) injuries are a leading cause of permanent functional impairment in humans. Nerve damage can be aggravated by neuroinflammation mediated by protein complexes known as inflammasomes, such as the NLRP3 inflammasome which is a key mediator of caspase-1 and interleukin-1β (IL-1β) /interleukin-18 (IL-18) activation. Lycopus lucidus Turcz (LLT) is a traditional medicinal herb that exerts therapeutic effects against oxidative stress, inflammation, and angiogenesis; however, it remains unclear whether LLT can directly protect neurons against damage, and the underlying molecular mechanisms are poorly understood. Methods We investigated the neuroprotective effect of LLT against hydrogen peroxide (H2O2)-induced neuronal damage in cultured primary rat cortical neurons, as well as the potential underlying mechanisms. Neuronal viability and cell death assays were used to determine the effects of LLT on neuroprotection, while the mode of cell death was confirmed using flow cytometry. Changes in the expression of inflammatory factors involved in activation of the NLRP3 inflammasome were measured using immunocytochemistry (ICC) and confirmed by real-time PCR. And, we analyzed that the effect of LLT on neurotrophic factors secretion and synaptic connectivity using ICC in H2O2-induced neuron at 7 days in vitro. Results LLT effectively protected cultured rat cortical neurons from H2O2-induced injury by significantly inhibiting NLRP3 inflammasome activation. In addition, LLT significantly reduced caspase1 activation, which is known to be induced by inflammasome formation, and consequently regulated the secretion of IL-1β/IL-18. We demonstrated that LLT enhances axonal elongation and synaptic connectivity against H2O2-induced injury of rat primary cortical neuron. Conclusions Together, these results demonstrate that LLT can directly protect cultured cortical neurons from H2O2-induced neuronal damage by inhibiting NLRP3 inflammasome activation and the secretion of caspase-1 and IL-1β/IL-18. Thus, our study provides new insights into the therapeutic mechanisms of LLT and suggests that the NLRP3 inflammasome could be a promising target for treating neurological diseases.

Download Full-text