Integrin Mac1 mediates paraquat and maneb-induced learning and memory impairments in mice through NADPH oxidase-NLRP3 inflammasome axis-dependent microglial activation

Metabolic reprogramming: a new option for the treatment of spinal cord injury

Spinal cord injuries impose a notably economic burden on society, mainly because of the severe after-effects they cause. Despite the ongoing development of various therapies for spinal cord injuries, their effectiveness remains unsatisfactory. However, a deeper understanding of metabolism has opened up a new therapeutic opportunity in the form of metabolic reprogramming. In this review, we explore the metabolic changes that occur during spinal cord injuries, their consequences, and the therapeutic tools available for metabolic reprogramming. Normal spinal cord metabolism is characterized by independent cellular metabolism and intercellular metabolic coupling. However, spinal cord injury results in metabolic disorders that include disturbances in glucose metabolism, lipid metabolism, and mitochondrial dysfunction. These metabolic disturbances lead to corresponding pathological changes, including the failure of axonal regeneration, the accumulation of scarring, and the activation of microglia. To rescue spinal cord injury at the metabolic level, potential metabolic reprogramming approaches have emerged, including replenishing metabolic substrates, reconstituting metabolic couplings, and targeting mitochondrial therapies to alter cell fate. The available evidence suggests that metabolic reprogramming holds great promise as a next-generation approach for the treatment of spinal cord injury. To further advance the metabolic treatment of the spinal cord injury, future efforts should focus on a deeper understanding of neurometabolism, the development of more advanced metabolomics technologies, and the design of highly effective metabolic interventions.

Cycloastragenol reduces microglial NLRP3 inflammasome activation in Parkinson's disease models by promoting autophagy and reducing Scrib-driven ROS

BACKGROUND

In Parkinson's disease (PD), microglial autophagy is crucial for the maintenance of cellular redox homeostasis. Meanwhile, cycloastragenol (CAG), a triterpenoid saponin and the principal active component of Astragalus, reduces the activation of NLRP3 inflammasomes. Nevertheless, the specific molecular mechanisms underlying the CAG-mitigated microglial neuroinflammation remains obscure in PD.

PURPOSE

This study explored the role of CAG in the activation of microglial NLRP3 inflammasome and the mechanisms underlying its therapeutic potential for PD treatment.

STUDY DESIGN

The effect of CAG was assessed in α-Syn-induced primary microglia and PD models.

METHODS

AAV1/2-hsyn-SNCA (A53T) was stereo-injected into the striatum of mice to induce PD models and CAG was orally administered. The mice underwent quantitative 4D proteomics analysis and behavioral assessments. The primary microglia and neuron cultures were analyzed by western blotting, immunofluorescence, transmission electron microscopy, etc. RESULTS: CAG reduced phagocytosis-induced reactive oxygen species (ROS) by suppressing the microglial Scribble (Scrib) and p22phox expression. Concurrently, CAG enhanced autophagy, promoted α-Syn clearance, and reduced mitochondrial damage. These synergistic effects downregulated NLRP3 inflammasome activation, in turn reducing gasdermin D cleavage, caspase-1 activation, and the release of interleukin-1β and interleukin-18. Further investigation revealed that CAG shielded neurons from α-Syn toxicity, thus attenuating behavioral impairments observed in the mouse PD model.

CONCLUSION

CAG mitigates neuroinflammation by inhibiting ROS-induced NLRP3 inflammasome activation in microglia via promoting microglial autophagy and reducing the activity of Scrib-associated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which signifies a promising alternative approach to PD management.

Fucoidan ameliorates rotenone-induced Parkinsonism in mice by regulating the microbiota-gut-brain axis

Microbiota-gut-brain axis, the bidirectional relationship between the gut microbiota and the brain, has been increasingly appreciated in the pathogenesis of Parkinson's disease (PD). Fucoidan, a sulphate-rich polysaccharide, has been shown to be neuroprotective by reducing oxidative stress in PD models. However, the role of microbiota-gut-brain axis in the neuroprotective activity of fucoidan has not been revealed. In this study, the therapeutic effects of fucoidan and involvement of microbiota-gut-brain axis in rotenone (ROT)-induced PD were investigated. The results showed that fucoidan gavage attenuated neuroinflammation, dopamine neuronal damage and motor dysfunction in ROT-induced PD mice. In addition, fucoidan treatment ameliorated gut dysfunction, intestinal inflammation and disruption of the intestinal barrier in PD mice. Fucoidan also affected the composition of gut microbiota in PD mice, indicated particularly by decreased abundance of Akkermansia muciniphila and Lactobacillus johnsonii and increased abundance of Lactobacillus murinus. Mechanistic studies showed that fecal microbiota transplantation (FMT) from the fucoidan-treated mice and probiotic Lactobacillus murinus supplement are as potent as fucoidan treatment in attenuating peripheral and central inflammation and ameliorating dopamine neuronal damage, which might be attributed to the downregulation of LPS/TLR4/NF-κB signaling pathway. Our study suggests that fucoidan might be potential candidates for the treatment of PD.

The Link Between Paraquat and Demyelination: A Review of Current Evidence

Paraquat (1,1'-dimethyl-4,4'-bipyridilium dichloride), a widely used bipyridinium herbicide, is known for inducing oxidative stress, leading to extensive cellular toxicity, particularly in the lungs, liver, kidneys, and central nervous system (CNS), and is implicated in fatal poisonings. Due to its biochemical similarities with the neurotoxin 1-methyl-4-phenylpyridinium (MPP+), paraquat has been used as a Parkinson's disease model, although its broader neurotoxic effects suggest the participation of multiple mechanisms. Demyelinating diseases are conditions characterized by damage to the myelin sheath of neurons. They affect the CNS and peripheral nervous system (PNS), resulting in diverse clinical manifestations. In recent years, growing concerns have emerged about the impact of chronic, low-level exposure to herbicides on human health, particularly due to agricultural runoff contaminating drinking water sources and their presence in food. Studies indicate that paraquat may significantly impact myelinating cells, myelin-related gene expression, myelin structure, and cause neuroinflammation, potentially contributing to demyelination. Therefore, demyelination may represent another mechanism of neurotoxicity associated with paraquat, which requires further investigation. This manuscript reviews the potential association between paraquat and demyelination. Understanding this link is crucial for enhancing strategies to minimize exposure and preserve public health.

CD11b-NOX2 mutual regulation-mediated microglial exosome release contributes to rotenone-induced inflammation and neurotoxicity in BV2 microglia and primary cultures

Epidemiological studies have revealed a potent association between chronic exposure to rotenone, a commonly used pesticide, in individuals and the incidence of Parkinson's disease (PD). We previously identified the contribution of the activation of microglial NADPH oxidase (NOX2) in rotenone-induced neurotoxicity. However, the regulation of NOX2 activation remains unexplored. Integrins are known to be bidirectionally regulated in the plasma membrane through the inside-out and outside-in signaling. CD11b is the α-chain of integrin macrophage antigen complex-1. This study aimed to investigate whether CD11b mediates rotenone-induced NOX2 activation. We observed that rotenone exposure increased NOX2 activation in BV2 microglia, which was associated with elevated CD11b expression. Silencing CD11b significantly reduced rotenone-induced ROS production and p47phox phosphorylation, a key step for NOX2 activation. Furthermore, the Src-FAK-PKB and Syk-Vav1-Rac1 signaling pathways downstream of CD11b were found to be essential for CD11b-mediated NOX2 activation in rotenone-intoxicated microglia. Interestingly, we also found that inhibition of NOX2 decreased rotenone-induced CD11b expression, indicating a crosstalk between CD11b and NOX2. Subsequently, the inhibition of the CD11b-NOX2 axis suppressed rotenone-induced microglial activation and exosome release. Furthermore, inhibiting exosome synthesis in microglia blocked rotenone-induced gene expression of proinflammatory factors and related neurotoxicity. Finally, blocking the CD11b-NOX2 axis and exosome synthesis or endocytosis mitigated microglial activation and dopaminergic neurodegeneration in rotenone-intoxicated midbrain primary cultures. Our findings highlight the crucial involvement of the CD11b-NOX2 axis in rotenone-induced inflammation and neurotoxicity, offering fresh perspectives on the underlying mechanisms of pesticide-induced neuronal damage.

Microglial CR3 promotes neuron ferroptosis via NOX2-mediated iron deposition in rotenone-induced experimental models of Parkinson's disease

The activation of complement receptor 3 (CR3) in microglia contributes to neurodegeneration in neurological disorders, including Parkinson's disease (PD). However, it remains unclear for mechanistic knowledge on how CR3 mediates neuronal damage. In this study, the expression of CR3 and its ligands iC3b and ICAM-1 was found to be up-regulated in the midbrain of rotenone PD mice, which was associated with elevation of iron content and disruption of balance of iron metabolism proteins. Interestingly, genetic deletion of CR3 blunted iron accumulation and recovered the expression of iron metabolism markers in response to rotenone. Furthermore, reduced lipid peroxidation, ferroptosis of dopaminergic neurons and neuroinflammation were detected in rotenone-lesioned CR3-/- mice compared with WT mice. The regulatory effect of CR3 on ferroptotic death of dopaminergic neurons was also mirrored in vitro. Mechanistic study revealed that iron accumulation in neuron but not the physiological contact between microglia and neurons was essential for microglial CR3-regulated neuronal ferroptosis. In a cell-culture system, microglial CR3 silence significantly dampened iron deposition in neuron in response to rotenone, which was accompanied by mitigated lipid peroxidation and neurodegeneration. Furthermore, ROS released from activated microglia via NOX2 was identified to couple microglial CR3-mediated iron accumulation and subsequent neuronal ferroptosis. Finally, supplementation with exogenous iron was found to recover the sensitivity of CR3-/- mice to rotenone-induced neuronal ferroptosis. Altogether, our findings suggested that microglial CR3 regulates neuron ferroptosis through NOX2 -mediated iron accumulation in experimental Parkinsonism, providing novel points of the immunopathogenesis of neurological disorders.

Mitochondrial metabolism regulated macrophage phenotype in myocardial infarction

Cardiovascular disease (CVD) remains the leading cause of death worldwide, with myocardial infarction (MI) being the primary contributor to mortality and disability associated with CVD. Reperfusion therapies are widely recognized as effective strategies for treating MI. However, while intended to restore blood flow, the reperfusion processes paradoxically initiate a series of pathophysiological events that worsen myocardial injury, resulting in ischemia-reperfusion (I/R) injury. Therefore, there is a pressing need for new treatment strategies to reduce the size of MI and enhance cardiac function post-infarction. Macrophages are crucial for maintaining homeostasis and mitigating undesirable remodeling following MI. Extensive research has established a strong link between cellular metabolism and macrophage function. In the context of MI, macrophages undergo adaptive metabolic reprogramming to mount an immune response. Moreover, mitochondrial metabolism in macrophages is evident, leading to significant changes in their metabolism. Therefore, we need to delve deeper into summarizing and understanding the relationship and role between mitochondrial metabolism and macrophage phenotype, and summarize existing treatment methods. In this review, we explore the role of mitochondria in shaping the macrophage phenotype and function. Additionally, we summarize current therapeutic strategies aimed at modulating mitochondrial metabolism of macrophages, which may offer new insights treating of MI.

Parkinson's Disease Treatment: A Bibliometric Analysis

Parkinson's disease (PD) is a progressive neurodegenerative disorder marked by motor symptoms like bradykinesia, tremor, rigidity, and postural instability. Patients also experience non-motor symptoms that greatly affect their quality of life. The global prevalence of PD is increasing, especially among the elderly, necessitating effective treatment strategies. This review provides an overview of the current treatment modalities for PD, including pharmacological and surgical interventions, and employs a bibliometric analysis to evaluate the trends and impact of scientific research in this field. A comprehensive search of the Web of Science Core Collection (WoSCC) database was conducted on July 12, 2024, yielding 3,724 publications related to PD treatment. Bibliometric analysis was performed using Biblioshiny and VOSviewer to assess publication trends, impact, and collaborative networks. Metrics such as the number of publications, citations, h-index, and country/institutional contributions were analyzed to identify key areas of focus and influential research in PD treatment. The analysis revealed a significant increase in PD research output from 2000 onwards, peaking between 2011 and 2016. The United States led in research production, followed by China, Canada, and the United Kingdom. Key researchers included Lang AE, Okun MS, and Lozano AM, with the University of Toronto, University of California System, and Harvard University being the top contributing institutions. The study identified major trends in pharmacological treatments, such as dopamine replacement therapy and deep brain stimulation (DBS) as the most common surgical intervention. Bibliometric analysis highlighted significant international collaborations and identified influential studies shaping the current understanding and treatment of PD. This bibliometric analysis elucidated the trends and impacts of scientific contributions, emphasizing the prolific output from leading countries and institutions in relation to the treatment of Parkinson's disease. Take-home messages for the conclusion of our study are as follows: (1) this study found a substantial increase in Parkinson's disease (PD) research output from 2000 onwards, peaking around 2017-2018, (2) noted a decline in publication output post-2020, (3) the United States had the highest research output, followed by significant contributions from countries like China, Canada, and the United Kingdom, (4) international collaborations played a vital role in advancing PD research, (5) key researchers in the field were Lang AE, Okun MS, and Lozano AM, (6) and established institutions like the University of Toronto, Johns Hopkins University and Harvard University made substantial contributions to the field, emphasizing the role of leading academic centers in driving PD research.

Microglial gp91phox-mediated neuroinflammation and ferroptosis contributes to learning and memory deficits in rotenone-treated mice

Apart from dopaminergic neurotoxicity, exposure to rotenone, a commonly used insecticide in agriculture, also adversely affects hippocampal and cortical neurons, resulting in cognitive impairments in mice. We recently established a role of microglia-mediated neuroinflammation in rotenone-elicited deficits of cognition, yet the mechanisms remain elusive. Here, we investigated the involvement of NADPH oxidase 2 (NOX2) catalytic subunit gp91phox in rotenone-induced cognitive deficits and the associated mechanisms. Our study demonstrated that rotenone exposure elevated expression of gp91phox and phosphorylation of the NOX2 cytosolic subunit p47phox, along with NADPH depletion in the hippocampus and cortex of mice, indicating NOX2 activation. Specific knockdown of gp91phox in microglia via adeno-associated virus delivery resulted in reduced microglial activation, proinflammatory gene expression and improved learning and memory capacity in rotenone-intoxicated mice. Genetic deletion of gp91phox also reversed rotenone-elicited cognitive dysfunction in mice. Furthermore, microglial gp91phox knockdown attenuated neuronal damage and synaptic loss in mice. This intervention also suppressed iron accumulation, disruption of iron-metabolism proteins and iron-dependent lipid peroxidation and restored the balance of ferroptosis-related parameters, including GPX4, SLC711, PTGS2, and ACSL4 in rotenone-lesioned mice. Intriguingly, pharmacological inhibition of ferroptosis with liproxstatin-1 conferred protection against rotenone-induced neurodegeneration and cognitive dysfunction in mice. In summary, our findings underscored the contribution of microglial gp91phox-dependent neuroinflammation and ferroptosis to learning and memory dysfunction in rotenone-lesioned mice. These results provided valuable insights into the pathogenesis of cognitive deficits associated with pesticide-induced Parkinsonism, suggesting potential therapeutic avenues for intervention.

Microglial exosomes in paraquat-induced Parkinson's disease: Neuroprotection and biomarker clues

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.

Inflammasomes in neurological disorders - mechanisms and therapeutic potential

Inflammasomes are molecular scaffolds that are activated by damage-associated and pathogen-associated molecular patterns and form a key element of innate immune responses. Consequently, the involvement of inflammasomes in several diseases that are characterized by inflammatory processes, such as multiple sclerosis, is widely appreciated. However, many other neurological conditions, including Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, stroke, epilepsy, traumatic brain injury, sepsis-associated encephalopathy and neurological sequelae of COVID-19, all involve persistent inflammation in the brain, and increasing evidence suggests that inflammasome activation contributes to disease progression in these conditions. Understanding the biology and mechanisms of inflammasome activation is, therefore, crucial for the development of inflammasome-targeted therapies for neurological conditions. In this Review, we present the current evidence for and understanding of inflammasome activation in neurological diseases and discuss current and potential interventional strategies that target inflammasome activation to mitigate its pathological consequences.

Pick fecal microbiota transplantation to enhance therapy for major depressive disorder

In recent years, fecal microbiota transplantation (FMT) has emerged as a promising therapy for major depressive disorder (MDD). The goal of the operation is to restore a healthy gut microbiota by introducing feces from a healthy donor into the recipient's digestive system. The brain-gut axis is thought to have a significant role in regulating mood, behavior, and cognition, which supports the use of FMT in the treatment of MDD. Numerous studies have shown a correlation between abnormalities of the gut microbiota and MDD, whereas FMT has demonstrated the potential to restore microbial equilibrium. While FMT has shown encouraging results, it is crucial to highlight the potential hazards and limits inherent to this therapeutic approach. Stool donor-to-recipient disease transfer is a concern of FMT. Furthermore, it still needs to be determined what effect FMT has on the gut microbiota and the brain in the long run. This literature review provides an overview of the possible efficacy of FMT as a therapeutic modality for MDD. There is hope for patients who have not reacted well to typical antidepressant therapy since FMT may become an invaluable tool in the treatment of MDD as researchers continue to examine the relationship between gut microbiota and MDD.

Multi-omics reveals aspirin eugenol ester alleviates neurological disease

BACKGROUND

Exosomes play an essential role in maintaining normal brain function due to their ability to cross the blood-brain barrier. Aspirin eugenol ester (AEE) is a new medicinal compound synthesized by the esterification of aspirin with eugenol using the prodrug principle. Aspirin has been reported to have neuroprotective effects and may be effective against neurodegenerative diseases.

PURPOSE

This study wanted to investigate how AEE affected neurological diseases in vivo and in vitro.

EXPERIMENTAL APPROACH

A multi-omics approach was used to explore the effects of AEE on the nervous system. Gene and protein expression changes of BDNF and NEFM in SY5Y cells after AEE treatment were detected using RT-qPCR and Western Blot.

KEY RESULTS

The multi-omics results showed that AEE could regulate neuronal synapses, neuronal axons, neuronal migration, and neuropeptide signaling by affecting transport, inflammatory response, and regulating apoptosis. Exosomes secreted by AEE-treated Caco-2 cells could promote the growth of neurofilaments in SY5Y cells and increased the expression of BDNF and NEFM proteins in SY5Y cells. miRNAs in the exosomes of AEE-treated Caco-2 cells may play an important role in the activation of SY5Y neuronal cells.

CONCLUSIONS

In conclusion, AEE could play positive effects on neurological-related diseases.