RESUMO
The utilization of Cobalt (Co) has surged due to it is critical role in renewable energy technologies and other high-tech applications. Concurrently, the potential health risks associated with Co exposure have raised concerns. Previous studies, including our own, have shown that Co can impair learn and memory functions as an epigenetic hazard, even at low concentrations. In this study, we explore the mechanisms of Co-induced ferroptosis in neurodegenerative damage both in vivo and in vitro, focusing on the epigenetic regulation by N6-methyladenosine (m6A) demethylase alkB homolog 5 (ALKBH5). We identify heme oxygenase-1 (HO-1) as a direct target gene of ALKBH5, playing a crucial role in mitigating Co-induced ferroptosis. ALKBH5 deficiency affects the post-transcriptional regulation of HO-1 through m6A modification, which in turn influences mRNA's stability, intracellular distribution, and alternative splicing, thereby enhancing susceptibility to Co-induced ferroptosis. Additionally, we discuss the potential involvement of heterogeneous nuclear ribonucleoprotein M (hnRNPM) in regulating alternative splicing of HO-1 mRNA, potentially mediated by m6A modifications. This study provides new epigenetic insights into the post-transcriptional regulatory mechanisms involved in Co-induced ferroptosis and highlights the broader implications of environmental hazards in neurodegenerative damage.
RESUMO
BACKGROUND: Vascular dementia (VaD) resulting from chronic cerebral hypoperfusion (CCH) induces cognitive impairment and white matter injury (WMI). We previously found that CCH induces dysfunction of the autophagy-lysosomal pathway (ALP) in white matter (WM) of rats. Enhancing oligodendrocyte autophagy to counteract ALP deficiency is beneficial for cognitive recovery. Pseudogenoside-F11 (PF11), a saponin extracted from Panax quinquefolium l., provides neuroprotective benefits in many animal models of cerebral ischemia and dementia. PURPOSE: To investigate how PF11 affects cognitive deterioration in rats with VaD induced by two vessel occlusion (2VO), and to determine if PF11 regulates ALP dysfunction in WM. METHODS: CCH-related VaD was induced in rats using the 2VO method. PF11 (6, 12, 24 mg/kg, intragastric administration) was given continuously for 4 weeks postoperatively. Behavioral tests related to cognitive function were performed on the 28th day following 2VO. Transmission electron microscopy, immunofluorescence, western blotting and Luxol fast blue staining were used to assess the WMI and the mechanism of action of PF11 in 2VO-induced VaD. RESULTS: PF11 (12 mg/kg) ameliorated 2VO-induced cognitive impairment. PF11 also alleviated WMI on the 28th day following 2VO, as characterized by reduction of neuronal axonal demyelination and axonal loss. Furthermore, PF11 prevented mature oligodendrocytes death by attenuating ALP deficiency in WM on the 14th day following 2VO, as manifested by enhancement of mechanistic target of rapamycin-mediated autophagy and lysosomal function, thereby reducing the aberrant accumulation of autophagy substrates and increasing the level of autophagosomes in WM. In addition, PF11 also prevented microglia and astrocytes from activating in WM on the 28th day following 2VO. CONCLUSION: PF11 significantly ameliorates cognitive impairment and WMI, and the mechanism is at least partly related to lessening ALP dysfunction in WM by enhancing autophagy and reducing lysosomal defects in oligodendrocytes.
RESUMO
Parkinson's disease (PD) is a prevalent neurodegenerative disease and approximately one third of patients with PD are estimated to experience depression. Paraquat (PQ) is the most widely used herbicide worldwide and PQ exposure is reported to induce PD with depression. However, the specific brain region and neural networks underlying the etiology of depression in PD, especially in the PQ-induced model, have not yet been elucidated. Here, we report that the VGluT2-positive glutamatergic neurons in the paraventricular thalamic nucleus (PVT) promote depression in the PQ-induced PD mouse model. Our results show that PVTVGluT2 neurons are activated by PQ and their activation increases the susceptibility to depression in PD mice. Conversely, inhibition of PVTVGluT2 neurons reversed the depressive-behavioral changes induced by PQ. Similar to the effects of intervention the soma of PVTVGluT2 neurons, stimulation of their projections into the central amygdaloid nucleus (CeA) also strongly influenced depression in PD mice. PQ induced malfunctioning of the glutamate system and changes in the dendritic and synaptic morphology in the CeA through its role on PVTVGluT2 neuronal activation. In summary, our results demonstrate that PVTVGluT2 neurons are key neuronal subtypes for depression in PQ-induced PD and promote depression processes through the PVTVGluT2-CeA pathway.
Assuntos
Núcleos da Linha Média do Tálamo , Neurônios , Paraquat , Proteína Vesicular 2 de Transporte de Glutamato , Animais , Paraquat/toxicidade , Masculino , Proteína Vesicular 2 de Transporte de Glutamato/metabolismo , Neurônios/efeitos dos fármacos , Núcleos da Linha Média do Tálamo/efeitos dos fármacos , Núcleos da Linha Média do Tálamo/metabolismo , Depressão/induzido quimicamente , Depressão/metabolismo , Camundongos Endogâmicos C57BL , Herbicidas/toxicidade , Camundongos , Doença de Parkinson/metabolismoRESUMO
Bilirubin-induced brain damage is a serious clinical consequence of hyperbilirubinemia, yet the underlying molecular mechanisms remain largely unknown. Ferroptosis, an iron-dependent cell death, is characterized by iron overload and lipid peroxidation. Here, we report a novel regulatory mechanism of demethylase AlkB homolog 5 (ALKBH5) in acyl-coenzyme A synthetase long-chain family member 4 (ACSL4)-mediated ferroptosis in hyperbilirubinemia. Hyperdifferential PC12 cells and newborn Sprague-Dawley rats were used to establish in vitro and in vivo hyperbilirubinemia models, respectively. Proteomics, coupled with bioinformatics analysis, first suggested the important role of ferroptosis in hyperbilirubinemia-induced brain damage. In vitro experiments showed that ferroptosis is activated in hyperbilirubinemia, and ferroptosis inhibitors (desferrioxamine and ferrostatin-1) treatment effectively alleviates hyperbilirubinemia-induced oxidative damage. Notably, we observed that the ferroptosis in hyperbilirubinemia was regulated by m6A modification through the downregulation of ALKBH5 expression. MeRIP-seq and RIP-seq showed that ALKBH5 may trigger hyperbilirubinemia ferroptosis by stabilizing ACSL4 mRNA via m6A modification. Further, hyperbilirubinemia-induced oxidative damage was alleviated through ACSL4 genetic knockdown or rosiglitazone-mediated chemical repression but was exacerbated by ACSL4 overexpression. Mechanistically, ALKBH5 promotes ACSL4 mRNA stability and ferroptosis by combining the 669 and 2015 m6A modified sites within 3' UTR of ACSL4 mRNA. Our findings unveil a novel molecular mechanism of ferroptosis and suggest that m6A-dependent ferroptosis could be an underlying clinical target for the therapy of hyperbilirubinemia.
Assuntos
Homólogo AlkB 5 da RNA Desmetilase , Coenzima A Ligases , Ferroptose , Estabilidade de RNA , Ratos Sprague-Dawley , Animais , Ferroptose/genética , Ratos , Coenzima A Ligases/genética , Coenzima A Ligases/metabolismo , Homólogo AlkB 5 da RNA Desmetilase/metabolismo , Homólogo AlkB 5 da RNA Desmetilase/genética , Células PC12 , Cicloexilaminas/farmacologia , Humanos , Desferroxamina/farmacologia , Estresse Oxidativo , Lesões Encefálicas/metabolismo , Lesões Encefálicas/genética , Lesões Encefálicas/patologia , Lesões Encefálicas/etiologia , Fenilenodiaminas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Masculino , Modelos Animais de Doenças , Peroxidação de LipídeosRESUMO
The exact mechanisms underlying the initiation and exacerbation of Parkinson's disease (PD) by paraquat remain unclear. We have revealed that exosomes mediate neurotoxicity induced by low dose paraquat exposure by transmitting intercellular signaling. Exposure to 40 µM paraquat promoted exosome release from mouse microglia cells (BV2) in vitro. Paraquat exposure at 100 µM caused degeneration of mouse dopaminergic MN9D cells and inhibited microglia exosome uptake by fluorescently labeling exosomes. We established an incubation model for exosomes and dopaminergic neuron cells under PQ treatment. The results indicated that microglial exosomes alleviated degeneration, increasing proliferation and PD-related protein expression of dopaminergic neurons; however, paraquat reversed this effect. Then, through exosome high-throughput sequencing and qRT-PCR experiments, miR-92a-3p and miR-24-3p were observed to transfer from exosomes to dopaminergic neurons, inhibited by paraquat. The specificity of miR-92a-3p and miR-24-3p was verified in PD patients exosomes, indicating the potential diagnostic value of the exosomal miRNAs in paraquat-induced PD. These results suggest glia-neuron communication in paraquat-induced neurodegeneration and may identify stable paraquat-mediated PD biomarkers, offering clues for early recognition and prevention of pesticide-induced degenerative diseases.
Assuntos
Biomarcadores , Neurônios Dopaminérgicos , Exossomos , MicroRNAs , Microglia , Paraquat , Doença de Parkinson , Paraquat/toxicidade , Exossomos/metabolismo , Animais , Microglia/efeitos dos fármacos , Microglia/metabolismo , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Biomarcadores/metabolismo , Neuroproteção/efeitos dos fármacos , Humanos , Linhagem CelularRESUMO
With the evidence emerging that abnormal expression of long noncoding RNAs (lncRNAs) are involved in onset of Parkinson's disease (PD), the role of NR_030777 contributing to this disease is of great interest. We recently found that a novel lncRNA "NR_030777" demonstrates protective effects on PQ-induced neurodegeneration. However, the underlying molecular mechanisms of NR_030777 in the regulation of mitochondrial fission and mitophagy involved in PQ-induced neuronal damage remain to be explored. NR_030777 brain conditional overexpressing mice as well as in vitro primary neuronal cells from cerebral cortex and Neuro2a cells were adopted. Immunofluorescence, Immunohistochemistry, qRT-PCR and Western blotting were used to evaluate the expression levels of RNA and proteins. RNA immunoprecipitation and RNA pulldown experiment were used to evaluate the interaction of NR_030777 with its target proteins. NR_030777 and mitophagy were increased, and tyrosine hydroxylase (TH) levels recovered after NR_030777 overexpression upon PQ treatment. The overexpression and knockdown of NR_030777 unveiled that NR_030777 positively regulated mitophagy such as the upregulation of LC3B-II:I, ATG12-ATG5, p62 and NBR1. Moreover, the application of mdivi-1, a DRP-1 inhibitor, in combination with NR_030777 genetic modified cells unveiled that NR_030777 promoted DRP1-mediated mitochondrial fission and mitophagy. Furthermore, NR_030777 were directly bound to CDK1 to increase p-DRP1 levels at the Ser616 site, leading to mitochondrial fission and mitophagy. On the other hand, NR_030777 acted directly on ATG12 within the ATG12-ATG5 complex in the 800-1400 nt region to modulate the membrane formation. Accordingly, NR_030777 deficiency in neuron cells compromised cell mitophagy. Finally, the above findings were confirmed using NR_030777-overexpressing mice. NR_030777 exerted a protective effect on PQ-exposed mice by enhancing mitophagy. Our data provide the first scientific evidence for the precise invention of PQ-induced PD. Our findings further propose a breakthrough for understanding the regulatory relationship between NR_030777, CDK1, ATG12 and mitophagy in PQ-induced PD.
Assuntos
Proteína Quinase CDC2 , Dinâmica Mitocondrial , Mitofagia , Doença de Parkinson , RNA Longo não Codificante , Animais , Camundongos , Proteína Quinase CDC2/metabolismo , Proteína Quinase CDC2/genética , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Dinâmica Mitocondrial/efeitos dos fármacos , Mitofagia/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Paraquat/toxicidade , Doença de Parkinson/metabolismo , Doença de Parkinson/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
Parkinson's disease (PD) is among the most prevalent neurodegenerative diseases, and approximately one third of patients with PD are estimated to have depression. Paraquat (PQ) exposure is an important environmental risk factor for PD. In this study, we established a mouse model of PQ-induced PD with depression to comprehensively investigate cellular heterogeneity and the mechanisms underlying the progression of depression in the context of PD. We utilized single-cell RNA-seq (scRNA-seq) to acquire the transcriptomic atlas of individual cells from model mice and characterize the gene expression profiles in each differentially expressed cell type. We identified a specific glutamatergic neuron cluster responsible for the development of heterogeneous depression-associated changes and established a comprehensive gene expression atlas. Furthermore, functional enrichment and cell trajectory analyses revealed that the mechanisms underlying the progression of PD with depression were associated with specific glutamatergic neurons. Together, our findings provide a valuable resource for deciphering the cellular heterogeneity of PD with depression. The suggested connection between intrinsic transcriptional states of neurons and the progression of depression can provide insight into potential biomarkers and specific targets for anti-depression treatment in patients with PD. SYNOPSIS: Our results obtained using model mice confirm the core effects of PQ exposure on glutamatergic neurons and their potential role in the development of PD with depression.
Assuntos
Paraquat , Doença de Parkinson , Humanos , Animais , Camundongos , Paraquat/toxicidade , Doença de Parkinson/genética , Depressão/induzido quimicamente , Depressão/genética , Perfilação da Expressão Gênica , RNARESUMO
BACKGROUND: As the demand and application of engineered nanomaterials have increased, their potential toxicity to the central nervous system has drawn increasing attention. Tunneling nanotubes (TNTs) are novel cell-cell communication that plays a crucial role in pathology and physiology. However, the relationship between TNTs and nanomaterials neurotoxicity remains unclear. Here, three types of commonly used engineered nanomaterials, namely cobalt nanoparticles (CoNPs), titanium dioxide nanoparticles (TiO2NPs), and multi-walled carbon nanotubes (MWCNTs), were selected to address this limitation. RESULTS: After the complete characterization of the nanomaterials, the induction of TNTs formation with all of the nanomaterials was observed using high-content screening system and confocal microscopy in both primary astrocytes and U251 cells. It was further revealed that TNT formation protected against nanomaterial-induced neurotoxicity due to cell apoptosis and disrupted ATP production. We then determined the mechanism underlying the protective role of TNTs. Since oxidative stress is a common mechanism in nanotoxicity, we first observed a significant increase in total and mitochondrial reactive oxygen species (namely ROS, mtROS), causing mitochondrial damage. Moreover, pretreatment of U251 cells with either the ROS scavenger N-acetylcysteine or the mtROS scavenger mitoquinone attenuated nanomaterial-induced neurotoxicity and TNTs generation, suggesting a central role of ROS in nanomaterials-induced TNTs formation. Furthermore, a vigorous downstream pathway of ROS, the PI3K/AKT/mTOR pathway, was found to be actively involved in nanomaterials-promoted TNTs development, which was abolished by LY294002, Perifosine and Rapamycin, inhibitors of PI3K, AKT, and mTOR, respectively. Finally, western blot analysis demonstrated that ROS and mtROS scavengers suppressed the PI3K/AKT/mTOR pathway, which abrogated TNTs formation. CONCLUSION: Despite their biophysical properties, various types of nanomaterials promote TNTs formation and mitochondrial transfer, preventing cell apoptosis and disrupting ATP production induced by nanomaterials. ROS/mtROS and the activation of the downstream PI3K/AKT/mTOR pathway are common mechanisms to regulate TNTs formation and mitochondrial transfer. Our study reveals that engineered nanomaterials share the same molecular mechanism of TNTs formation and intercellular mitochondrial transfer, and the proposed adverse outcome pathway contributes to a better understanding of the intercellular protection mechanism against nanomaterials-induced neurotoxicity.
Assuntos
Estruturas da Membrana Celular , Nanotubos de Carbono , Nanotubos , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Nanotubos de Carbono/toxicidade , Serina-Treonina Quinases TOR/metabolismo , Neuroglia/metabolismo , Trifosfato de Adenosina , ApoptoseRESUMO
BACKGROUND/AIM: Chronic obstructive pulmonary disease (COPD) has become a prominent healthcare issue in recent years. Cigarette smoking (CS) and fine particulate matter (PM2.5) are important causative factors for COPD. This study assessed the aberrant lncRNA profiles in the tissue of rats with COPD caused by CS or PM2.5 Materials and Methods: A COPD rat model was developed using CS (CSM) or PM2.5 (PMM), and lung tissue RNA was extracted. The Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) were used to investigate the correlations between the distinct lncRNAs and mRNA pathways. A coding-non-coding gene co-expression network (CNC) was constructed by establishing connections between differentially expressed long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) associated with mitochondrial dysfunction and the inflammatory response. RESULTS: A quantitative real-time reverse transcription PCR (qRT-PCR) experiment was performed to verify the expression of the particular lncRNAs. Microarray analysis of lung tissue from the COPD model revealed that 123 and 444 lncRNAs were substantially raised and reduced in PMM vs. the control group (Ctrl), respectively, as were 621 and 1,178 mRNAs. Meanwhile, 81 and 340 lncRNAs were consistently raised and lowered in CSM vs. Ctrl, respectively, as were 408 and 931 mRNAs. GO enrichment and KEGG pathway analysis indicated that the COPD model was connected to inflammatory responses, mitochondrial dysfunction, and others. CONCLUSION: XR_340674, ENSRNOT00000089642, XR_597045, and XR_340651 were decreased, and XR_592469 was elevated. These lncRNAs were shown to be related to mitochondrial dysfunction in the lung tissue of animals exposed to CS or PM2.5.
Assuntos
Doença Pulmonar Obstrutiva Crônica , RNA Longo não Codificante , Ratos , Animais , RNA Longo não Codificante/genética , Ratos Wistar , Doença Pulmonar Obstrutiva Crônica/genética , Material Particulado , Mitocôndrias/genética , Mitocôndrias/metabolismo , Perfilação da Expressão GênicaRESUMO
Paraquat (PQ) is an environmental poison that causes clinical symptoms similar to those of Parkinson's disease (PD) in vitro and in rodents. It can lead to the activation of microglia and apoptosis of dopaminergic neurons. However, the exact role and mechanism of microglial activation in PQ-induced neuronal degeneration remain unknown. Here, we isolated the microglia-derived exosomes exposed with 0 and 40 µM PQ, which were subsequently co-incubated with PQ-exposed neuronal cells to simulate intercellular communication. First, we found that exosomes released from microglia caused a change in neuronal cell vitality and reversed PQ-induced neuronal apoptosis. RNA sequencing data showed that these activated microglia-derived exosomes carried large amounts of circZNRF1. Moreover, a bioinformatics method was used to study the underlying mechanism of circZNRF1 in regulating PD, and miR-17-5p was predicted to be its target. Second, an increased Bcl2/Bax ratio could play an anti-apoptotic role. Bcl2 was predicted to be a downstream target of miR-17-5p. Our results showed that circZNRF1 plays an anti-apoptotic role by absorbing miR-17-5p and regulating the binding of Bcl2 after exosomes are internalized by dopaminergic neurons. In conclusion, we demonstrated a new intercellular communication mechanism between microglia and neurons, in which circZNRF1 plays a key role in protecting against PQ-induced neuronal apoptosis through miR-17-5p to regulate the biological process of PD. These findings may offer a novel approach to preventing and treating PD.
Assuntos
MicroRNAs , Microglia , Paraquat/toxicidade , Neurônios Dopaminérgicos , Proteínas Proto-Oncogênicas c-bcl-2 , MicroRNAs/genéticaRESUMO
The widespread use of nanomaterials in daily life has led to increased concern about their potential neurotoxicity. Therefore, it is particularly important to establish a simple and reproducible assessment system. Representative nanomaterials, including cobalt nanoparticles (CoNPs), titanium dioxide nanoparticles (TiO2-NPs), and multiwall carbon nanotubes (MWCNTs), were compared in terms of their neurotoxicity and underlying mechanisms. In 0, 25, 50, and 75 µg/ml of these nanomaterials, the survival, locomotion behaviors, acetylcholinesterase (AchE) activity, reactive oxygen species production, and glutathione-S transferase 4 (Gst-4) activation in wildtype and transgenic Caenorhabditis elegans (C. elegans) were evaluated. All nanomaterials induced an imbalance in oxidative stress, decreased the ratio of survival, impaired locomotion behaviors, as well as reduced the activity of AchE in C. elegans. Interestingly, CoNPs and MWCNTs activated Gst-4, but not TiO2-NPs. The reactive oxygen species scavenger, N-acetyl-l-cysteine, alleviated oxidative stress and Gst-4 upregulation upon exposure to CoNPs and MWCNTs, and rescued the locomotion behaviors. MWCNTs caused the most severe damage, followed by CoNPs and TiO2-NPs. Furthermore, oxidative stress and subsequent activation of Gst-4 were involved in nanomaterials-induced neurotoxicity. Our study provides a comprehensive comparison of the neurotoxicity and mechanisms of typical nanomaterials, which could serve as a model for hazard assessment of environmental pollutants using C. elegans as an experimental model system.
Assuntos
Nanopartículas , Nanotubos de Carbono , Animais , Espécies Reativas de Oxigênio , Caenorhabditis elegans , Nanotubos de Carbono/toxicidade , Cobalto/toxicidade , Acetilcolinesterase , Estresse Oxidativo , Nanopartículas/toxicidadeRESUMO
Cognitive impairment caused by chronic cerebral hypoperfusion (CCH) is associated with white matter injury (WMI), possibly through the alteration of autophagy. Here, the autophagy-lysosomal pathway (ALP) dysfunction in white matter (WM) and its relationship with cognitive impairment were investigated in rats subjected to two vessel occlusion (2VO). The results showed that cognitive impairment occurred by the 28th day after 2VO. Injury and autophagy activation of mature oligodendrocytes and neuronal axons sequentially occurred in WM by the 3rd day. By the 14th day, abnormal accumulation of autophagy substrate, lysosomal dysfunction, and the activation of mechanistic target of rapamycin (MTOR) pathway were observed in WM, paralleled with mature oligodendrocyte death. This indicates autophagy activation was followed by ALP dysfunction caused by autophagy inhibition or lysosomal dysfunction. To target the ALP dysfunction, enhanced autophagy by systemic rapamycin treatment or overexpression of Beclin1 (BECN1) in oligodendrocytes reduced mature oligodendrocyte death, and subsequently alleviated the WMI and cognitive impairment after CCH. These results reveal that early autophagy activation was followed by ALP dysfunction in WM after 2VO, which was associated with the aggravation of WMI and cognitive impairment. This study highlights that alleviating ALP dysfunction by enhancing oligodendrocyte autophagy has benefits for cognitive recovery after CCH.
RESUMO
Cobalt exposure, even at low concentrations, induces neurodegenerative damage, such as Alzheimer's disease (AD). The specific underlying mechanisms remain unclear. Our previous study demonstrated that m6A methylation alteration is involved in cobalt-induced neurodegenerative damage, such as in AD. However, the role of m6A RNA methylation and its underlying mechanisms are poorly understood. In this study, both epidemiological and laboratory studies showed that cobalt exposure could downregulate the expression of the m6A demethylase ALKBH5, suggesting a key role for ALKBH5. Moreover, Methylated RNA immunoprecipitation and sequencing (MeRIP-seq) analysis revealed that ALKBH5 deficiency is associated with neurodegenerative diseases. KEGG pathway and Gene ontology analyses further revealed that the differentially m6A-modified genes resulting from ALKBH5 downregulation and cobalt exposure were aggregated in the pathways of proliferation, apoptosis, and autophagy. Subsequently, ALKBH5 deficiency was shown to exacerbate cell viability decline, motivate cell apoptosis and attenuate cell autophagy induced by cobalt with experimental techniques of gene overexpression/inhibition. In addition, morphological changes in neurons and the expression of AD-related proteins, such as APP, P-Tau, and Tau, in the cerebral hippocampus of wild-type and ALKBH5 knockout mice after chronic cobalt exposure were also investigated. Both in vitro and in vivo results showed that lower expression of ALKBH5 aggravated cobalt-induced neurodegenerative damage. These results suggest that ALKBH5, as an epigenetic regulator, could be a potential target for alleviating cobalt-induced neurodegenerative damage. In addition, we propose a novel strategy for the prevention and treatment of environmental toxicant-related neurodegeneration from an epigenetic perspective.
Assuntos
Cobalto , RNA , Camundongos , Animais , Cobalto/toxicidade , MetilaçãoRESUMO
Cobalt is the most widely used heavy metal pollutant in medicine and industry. Excessive cobalt exposure can adversely affect human health. Neurodegenerative symptoms have been observed in cobalt-exposed populations; however, the underlying mechanisms remain largely unknown. In this study, we demonstrate that the N6-methyladenosine (m6A) demethylase fat mass and obesity-associated gene (FTO) mediates cobalt-induced neurodegeneration by impairing autophagic flux. Cobalt-induced neurodegeneration was exacerbated through FTO genetic knockdown or repression of demethylase activity, but was alleviated by FTO overexpression. Mechanistically, we showed that FTO regulates TSC1/2-mTOR signaling pathway by targeting TSC1 mRNA stability in an m6A-YTHDF2 manner, which resulted in autophagosome accumulation. Furthermore, FTO decreases lysosome-associated membrane protein-2 (LAMP2) to inhibit the integration of autophagosomes and lysosomes, leading to autophagic flux damage. In vivo experiments further identified that central nervous system (CNS)-Fto-specific knockout resulted in serious neurobehavioral and pathological damage as well as TSC1-related autophagy impairment in cobalt-exposed mice. Interestingly, FTO-regulated autophagy impairment has been confirmed in patients with hip replacement. Collectively, our results provide novel insights into m6A-modulated autophagy through FTO-YTHDF2 targeted TSC1 mRNA stability, revealing cobalt is a novel epigenetic hazard that induces neurodegeneration. These findings suggest the potential therapeutic targets for hip replacement in patients with neurodegenerative damage.
Assuntos
Autofagia , Cobalto , Animais , Humanos , Camundongos , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Cobalto/toxicidade , Obesidade , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismoRESUMO
Paraquat (PQ) has been widely acknowledged as an environmental risk factor for Parkinson's disease (PD). However, the interaction between splicing factor and long non-coding RNA (lncRNA) in the process of PQ-induced PD has rarely been studied. Based on previous research, this study focused on splicing factor 3 subunit 3 (SF3B3) and lncRNA NR_030777. After changing the target gene expression level by lentiviral transfection technology, the related gene expression was detected by western blot and qRT-PCR. The expression of SF3B3 protein was reduced in Neuro-2a cells after PQ exposure, and the reactive oxygen species (ROS) scavenger N-acetylcysteine prevented this decline. Knockdown of SF3B3 reduced the PQ-triggered NR_030777 expression increase, and overexpression of NR_030777 reduced the transcriptional and translational level of Sf3b3. Then, knockdown of SF3B3 exacerbated the PQ-induced decrease in cell viability and aggravated the reduction of tyrosine hydroxylase (TH) protein expression. Overexpressing SF3B3 reversed the reduction of TH expression caused by PQ. Moreover, after intervention with the autophagy inhibitor Bafilomycin A1, LC3B-II protein expression was further increased in Neuro-2a cells with the knockdown of SF3B3, indicating that autophagy was enhanced. In conclusion, PQ modulated the interplay between NR_030777 and SF3B3 through ROS production, thereby impairing autophagic flux and causing neuronal damage.
Assuntos
Paraquat , RNA Longo não Codificante , Acetilcisteína/farmacologia , Neurônios/metabolismo , Paraquat/toxicidade , Espécies Reativas de Oxigênio/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Fatores de Processamento de RNA/metabolismoRESUMO
Exposure to cobalt nanoparticles (CoNPs) has been associated with neurodegenerative disorders, while the mitochondrial-associated mechanisms that mediate their neurotoxicity have yet to be fully characterized. In this study, we reported that CoNPs exposure reduced the survival and lifespan in the nematodes, Caenorhabditis elegans (C. elegans). Moreover, exposure to CoNPs aggravated the induction of paralysis and the aggregation of ß-amyloid (Aß). These effects were accompanied by reactive oxygen species (ROS) overproduction, ATP reduction as well as mitochondrial fragmentation. Dynamin-related protein 1 (drp-1) activation and ensuing mitochondrial fragmentation have been shown to be associated with CoNPs-reduced survival. In order to address the role of mitochondrial damage and ROS production in CoNPs-induced Aß toxicity, the mitochondrial reactive oxygen species scavenger mitoquinone (Mito Q) was used. Our results showed that Mito Q pretreatment alleviated CoNPs-induced ROS generation, rescuing mitochondrial dysfunction, thereby lessening the CoNPs-induced Aß toxicity. Taken together, we show for the first time, that increasing of ROS and the upregulation of drp-1 lead to CoNPs-induced Aß toxicity. Our novel findings provide in vivo evidence for the mechanisms of environmental toxicant-induced Aß toxicity, and can afford new modalities for the prevention and treatment of CoNPs-induced neurodegeneration.
Assuntos
Peptídeos beta-Amiloides , Nanopartículas , Animais , Espécies Reativas de Oxigênio/metabolismo , Peptídeos beta-Amiloides/toxicidade , Cobalto/toxicidade , Caenorhabditis elegans/metabolismo , Nanopartículas/toxicidadeRESUMO
Cobalt is an environmental toxicant, and excessive bodily exposure can damage the nervous system. Particularly, our previous study reported that low-dose cobalt (significantly less than the safety threshold) is still able to induce neurodegenerative changes. However, the underlying molecular mechanism is still insufficient revealed. Herein, we further investigate the molecular mechanism between cobalt-induced neurodegeneration and autophagy, as well as explore the interplay between hypoxia-inducible factor-1α (HIF-1α), reactive oxygen species (ROS), and autophagy in cobalt-exposed mice and human neuroglioma cells. We first reveal cobalt as an environmental toxicant to severely induce ß amyloid (Aß) deposition, tau hyperphosphorylation, and dysregulated autophagy in the hippocampus and cortex of mice. In particular, we further identify that cobalt-induced neurotoxicity is triggered by the impairment of autophagic flux in vitro experiments. Moreover, the mechanistic study reveals that cobalt exposure extremely activates HIF-1α expression to facilitate the overproduction of ROS. Then, elevated ROS can target the amino-threonine kinase (AKT)-mammalian target of rapamycin (mTOR)-Unc-51 like autophagy activating kinase 1 (ULK1) signaling pathway to participate in cobalt-induced impairment of autophagic flux. Subsequently, defected autophagy further exacerbates cobalt-induced neurotoxicity for its unable to eliminate the deposition of pathological protein. Therefore, our data provide scientific evidence for cobalt safety evaluation and risk assessment and propose a breakthrough for understanding the regulatory relationship between HIF-1α, ROS, and autophagy in cobalt-induced neurodegeneration.
Assuntos
Cobalto , Subunidade alfa do Fator 1 Induzível por Hipóxia , Espécies Reativas de Oxigênio , Animais , Humanos , Camundongos , Autofagia/fisiologia , Cobalto/toxicidade , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de SinaisRESUMO
Background: This study sought to explore the underlying mechanism of long non-coding ribonucleic acid nuclear enriched abundant transcript 1 (NEAT1) and PTEN-induced kinase 1 (PINK1)-mediated mitophagy in chronic obstructive pulmonary disease (COPD) induced by cigarette smoke (CS) or fine particular matter (PM2.5). Methods: In total, 30 male Wistar Rats were divided into the following 3 groups: (I) the COPD group exposed to CS (CSM); (II) the COPD group exposed to PM2.5 (PMM); and (III) the control (Ctrl) group. Pulmonary function, the enzyme-linked immunoassay analysis results, the histopathology results, and the ultrastructures of the lung tissues were examined in the 3 groups, and NEAT1 expression levels and the mitophagy-related protein PINK1, Parkin, LC3B, and p62 levels were assessed by quantitative reverse transcription PCR (RT-qPCR) and Western blotting. The A549 cells were transfected with small interfering ribonucleic acid (siRNA) targeting NEAT1, and subsequently stimulated with CS extract (CSE) and PM2.5 suspension (PMS). Mitochondrial dysfunction and enhanced mitophagy were observed, and the expression of the NEAT1/PINK1 pathway was assessed by RT-qPCR and Western blotting. Results: Both the CSM and PMM groups had a lower tidal volume (VT), minute ventilation (MV), and a higher respiratory rate (f) than the Ctrl group. The interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha levels in the serum and bronchoalveolar lavage fluid of the CSM and PMM groups were significantly increased. The histological examination results revealed airway remodeling, the formation of pulmonary bullae, and emphysema in the CSM and PMM groups. Subsequently, the ultrastructures of the lung tissues in the CSM and PMM groups showed mitochondrial swelling and autophagosomes. Additionally, NEAT1 expression, the level of the mitophagy-related protein PINK1, Parkin, and the ratio of LC3-II/I increased synchronously. Further, NEAT1 siRNA blocked PINK1 expression, inhibited mitochondrial dysfunctions, and mitophagy activation in the A549 cells exposed to CSE or PMS. Conclusions: Our results suggest that CS and PM2.5 exposure induce mitochondrial dysfunction, and the NEAT1/PINK1 pathway plays a critical role in the occurrence and development of COPD by regulating mitophagy.
RESUMO
Paraquat (PQ) is a ubiquitously applied herbicide. Long-term PQ exposure with low dose has been reported to induce abnormal expression of long non-coding RNAs (lncRNAs) in brain nerve cells, which could further lead to Parkinson's disease (PD). N6-methyladenosine (m6A) modification has recently been identified as having an important role in regulating the function of lncRNAs. However, how m6A modification regulates lncRNAs following PQ exposure remains largely unknown. Herein, this study reported m6A modification of lncRNAs in mouse neuroblastoma cells (Neuro-2a) following PQ induced reactive oxide species (ROS). M6A sequencing was performed to explore the m6A modificated pattern of lncRNAs in Neuro-2a cells which were treated with 200 µM PQ for 3 h. It was found that PQ hypermethylated total RNA and changed the expression of m6A methyltransferase and demethylase proteins, which leading to the alteration of m6A modification of lncRNAs. Furthermore, the functional analysis further revealed that N-acetyl-L-cysteine (NAC)ï¼a ROS scavengers, partly reversed PQ-induced distinct m6A modificated pattern of lncRNAs. In addition, tow specific m6A modified lncRNAs were identified: cell division cycle 5-like (lncRNA CDC5L) and signal transducer and activator of transcription 3 (lncRNA STAT3), which could influence downstream autophagy related biological function. In summary, this work could potentially contribute to the new insight of lncRNAs m6A modification mechanism in the field of environmental toxicology.
Assuntos
Paraquat , RNA Longo não Codificante , Adenosina/análogos & derivados , Adenosina/metabolismo , Animais , Camundongos , Estresse Oxidativo/genética , Paraquat/toxicidade , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
The coal gasification fine slag (FS) is industrial waste consisting of residual carbon (RC) and slag particles (SP). High-performance hierarchical porous composite (HPC) was synthesized by chemical activation followed by hydrothermal treatment from FS. It has been realized that SP could play the positive role in developing pore structure of HPC which makes CO2 uptake have a sharp increase. Through taking the advantage of SP, HPC has an obvious increase in surface area and pore volume from 914 to 1932 m2/g and 0.617 to 1.332 cm3/g, respectively. The changes of pore structure were mainly attributed to the two factors in a synergetic way. First, hydrothermal treatment could decrease the content of SP which acted as a ballast to reduce the surface area of activated carbon. Second, the formed silicate/aluminosilicate deposits on the carbon surface and forms silicate/aluminosilicate film on internal surface of carbon particles. This makes the meso-macropores change to micro- mesopores leading to the increase of the surface area and pore volume. The porous composites also showed high CO2 adsorption performance. The 4-FSAC-HPC sample exhibits the highest CO2 uptake of 3.25 mol/kg and 1.41 mol/kg at 25 and 50 °C, respectively, which is an increase of around 52% and 83% comparing with that of FSAC sample. Besides, CO2 adsorption up to saturation can be achieved in less than 3 min. CO2 uptake of the 4-FSAC-HPC sample was well regeneration efficiencies above 98% after 10 cycles adsorption/desorption. This work provides a new approach to prepare high-performance porous compositions using the material which contains not only carbon component but mineral matters. Furthermore, it realizes solving two industrial waste issues (fine slag and CO2) simultaneous.