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Journal of Applied Biomedicine Jun 2024Resveratrol (RSV) is a polyphenol antioxidant that has been shown to have neuroprotective effects. We sought molecular mechanisms that emphasize the anti-inflammatory...
Resveratrol (RSV) is a polyphenol antioxidant that has been shown to have neuroprotective effects. We sought molecular mechanisms that emphasize the anti-inflammatory activity of RSV in traumatic brain injury (TBI) in mice associated with endoplasmic reticulum stress (ERS). After establishing three experimental groups (sham, TBI, and TBI+RSV), we explored the results of RSV after TBI on ERS and caspase-12 apoptotic pathways. The expression levels of C/EBP homologous protein (CHOP), glucose regulated protein 78kD (GRP78), caspase-3, and caspase-12 in cortical brain tissues were assessed by western blotting. The qPCR analysis was also performed on mRNA expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in cortical brain tissue. In addition, the expression of GRP78 in microglia (ionized calcium binding adaptor molecule 1; Iba-1) and neurons (neuronal nuclei; NeuN) was identified by immunofluorescence staining. The neurological function of mice was assessed by modified neurological severity scores (mNSS). After drug treatment, the expression of CHOP, GRP78, caspase-3 and caspase-12 decreased, and qPCR results showed that TNF-α and IL-1β were down-regulated. Immunofluorescence staining showed down-regulation of Iba-1+/GRP78+ and NeuN+/GRP78+ cells after RSV treatment. The mNSS analysis confirmed improvement after RSV treatment. RSV improved apoptosis by downregulating the ERS signaling pathway and improved neurological prognosis in mice with TBI.
Topics: Animals; Brain Injuries, Traumatic; Resveratrol; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Mice; Male; Apoptosis; Prognosis; Neuroprotective Agents; Neurons; Interleukin-1beta; Caspase 12; Heat-Shock Proteins; Tumor Necrosis Factor-alpha; Mice, Inbred C57BL; Cell Death; Microglia; Transcription Factor CHOP
PubMed: 38912865
DOI: 10.32725/jab.2024.008 -
Frontiers in Neuroscience 2024There is a well-established link between physical activity and brain health. As such, the effectiveness of physical exercise as a therapeutic strategy has been explored... (Review)
Review
There is a well-established link between physical activity and brain health. As such, the effectiveness of physical exercise as a therapeutic strategy has been explored in a variety of neurological contexts. To determine the extent to which physical exercise could be most beneficial under different circumstances, studies are needed to uncover the underlying mechanisms behind the benefits of physical activity. Interest has grown in understanding how physical activity can regulate microglia, the resident immune cells of the central nervous system. Microglia are key mediators of neuroinflammatory processes and play a role in maintaining brain homeostasis in healthy and pathological settings. Here, we explore the evidence suggesting that physical activity has the potential to regulate microglia activity in various animal models. We emphasize key areas where future research could contribute to uncovering the therapeutic benefits of engaging in physical exercise.
PubMed: 38911597
DOI: 10.3389/fnins.2024.1420322 -
International Journal of Nanomedicine 2024Ginsenoside Rg3 (Rg3) and Panax notoginseng saponins (PNS) can be used for ischemic stroke treatment, however, the lack of targeting to the ischemic region limits the...
PURPOSE
Ginsenoside Rg3 (Rg3) and Panax notoginseng saponins (PNS) can be used for ischemic stroke treatment, however, the lack of targeting to the ischemic region limits the therapeutic effect. To address this, we leveraged the affinity of macrophage membrane proteins for inflamed brain microvascular endothelial cells to develop a macrophage membrane-cloaked liposome loaded with Rg3 and PNS (MM-Lip-Rg3/PNS), which can precisely target brain lesion region through intranasal administration.
METHODS
MM-Lip-Rg3/PNS was prepared by co-extrusion method and was performed by characterization, stability, surface protein, and morphology. The cellular uptake, immune escape ability, and blood-brain barrier crossing ability of MM-Lip-Rg3/PNS were studied in vitro. The in vivo brain targeting, biodistribution and anti-ischemic efficacy of MM-Lip-Rg3/PNS were evaluated in MACO rats, and we determined the diversity of the nasal brain pathway through the olfactory nerve blockade model in rats. Finally, the pharmacokinetics and brain targeting index of MM-Lip-Rg3/PNS were investigated.
RESULTS
Our results indicated that MM-Lip-Rg3/PNS was spherical with a shell-core structure. MM-Lip-Rg3/PNS can avoid mononuclear phagocytosis, actively bind to inflammatory endothelial cells, and have the ability to cross the blood-brain barrier. Moreover, MM-Lip-Rg3/PNS could specifically target ischemic sites, even microglia, increase the cumulative number of drugs in the brain, improve the inflammatory environment of the brain, and reduce the infarct size. By comparing olfactory nerve-blocking rats with normal rats, it was found that there are direct and indirect pathways for nasal entry into the brain. Pharmacokinetics demonstrated that MM-Lip-Rg3/PNS exhibited stronger brain targeting and prolonged drug half-life.
CONCLUSION
MM-Lip-Rg3/PNS might contribute to the accumulation of Rg3 and PNS in the ischemic brain area to improve treatment efficacy. This biomimetic nano-drug delivery system provides a new and promising strategy for the treatment of ischemic stroke.
Topics: Animals; Liposomes; Administration, Intranasal; Ischemic Stroke; Rats; Male; Ginsenosides; Blood-Brain Barrier; Macrophages; Drug Delivery Systems; Rats, Sprague-Dawley; Tissue Distribution; Brain; Biomimetic Materials; Saponins; Mice
PubMed: 38911498
DOI: 10.2147/IJN.S458656 -
Dementia and Geriatric Cognitive... 2024Microglia exert a crucial role in homeostasis of white matter integrity, and several studies highlight the role of microglial dysfunctions in neurodegeneration. Primary...
INTRODUCTION
Microglia exert a crucial role in homeostasis of white matter integrity, and several studies highlight the role of microglial dysfunctions in neurodegeneration. Primary microgliopathy is a disorder where the pathogenic abnormality of the microglia causes white matter disorder and leads to a neuropsychiatric disease. Triggering receptor expressed on myeloid cells (), TYRO protein tyrosine kinase binding protein () and colony-stimulating factor 1 receptor () are genes implicated in primary microgliopathy. The clinical manifestations of primary microgliopathy are myriad ranging from neuropsychiatric syndrome, motor disability, gait dysfunction, ataxia, pure dementia, frontotemporal dementia (FTD), Alzheimer's dementia (AD), and so on. It becomes imperative to establish the diagnosis of microgliopathy masquerading as degenerative dementia, especially with promising therapies on horizon for the same. We aimed to describe a case series of subjects with dementia harbouring novel genes of primary microgliopathy, along with their clinical, neuropsychological, cognitive profile and radiological patterns.
METHODS
The prospective study was conducted in a university referral hospital in South India, as a part of an ongoing clinico-genetic research on dementia subjects, and was approved by the Institutional Ethics Committee. All patients underwent detailed assessment including sociodemographic profile, clinical and cognitive assessment, pedigree analysis and comprehensive neurological examination. Subjects consenting for blood sampling underwent genetic testing by whole-exome sequencing (WES).
RESULTS
A total of 100 patients with dementia underwent genetic analysis using WES and three pathogenic variants, one each of , , and and two variants of uncertain significance in were identified as cause of primary microgliopathy. and presented as frontotemporal syndrome whereas CSF1R presented as frontotemporal syndrome and as AD.
CONCLUSION
WES has widened the spectrum of underlying neuropathology of degenerative dementias, and diagnosing primary microglial dysfunction with emerging therapeutic options is of paramount importance. The cases of primary microgliopathy due to novel mutations in , , and with the phenotype of degenerative dementia are being first time reported from Indian cohort. Our study enriches the spectrum of genetic variants implicated in degenerative dementia and provides the basis for exploring complex molecular mechanisms like microglial dysfunction, as underlying cause for neurodegeneration.
PubMed: 38910897
DOI: 10.1159/000538145 -
Lipids in Health and Disease Jun 2024Lipid droplet (LD)-laden microglia is a key pathological hallmark of multiple sclerosis. The recent discovery of this novel microglial subtype,...
BACKGROUND
Lipid droplet (LD)-laden microglia is a key pathological hallmark of multiple sclerosis. The recent discovery of this novel microglial subtype, lipid-droplet-accumulating microglia (LDAM), is notable for increased inflammatory factor secretion and diminished phagocytic capability. Lipophagy, the autophagy-mediated selective degradation of LDs, plays a critical role in this context. This study investigated the involvement of microRNAs (miRNAs) in lipophagy during demyelinating diseases, assessed their capacity to modulate LDAM subtypes, and elucidated the potential underlying mechanisms involved.
METHODS
C57BL/6 mice were used for in vivo experiments. Two weeks post demyelination induction at cervical level 4 (C4), histological assessments and confocal imaging were performed to examine LD accumulation in microglia within the lesion site. Autophagic changes were observed using transmission electron microscopy. miRNA and mRNA multi-omics analyses identified differentially expressed miRNAs and mRNAs under demyelinating conditions and the related autophagy target genes. The role of miR-223 in lipophagy under these conditions was specifically explored. In vitro studies, including miR-223 upregulation in BV2 cells via lentiviral infection, validated the bioinformatics findings. Immunofluorescence staining was used to measure LD accumulation, autophagy levels, target gene expression, and inflammatory mediator levels to elucidate the mechanisms of action of miR-223 in LDAM.
RESULTS
Oil Red O staining and confocal imaging revealed substantial LD accumulation in the demyelinated spinal cord. Transmission electron microscopy revealed increased numbers of autophagic vacuoles at the injury site. Multi-omics analysis revealed miR-223 as a crucial regulatory gene in lipophagy during demyelination. It was identified that cathepsin B (CTSB) targets miR-223 in autophagy to integrate miRNA, mRNA, and autophagy gene databases. In vitro, miR-223 upregulation suppressed CTSB expression in BV2 cells, augmented autophagy, alleviated LD accumulation, and decreased the expression of the inflammatory mediator IL-1β.
CONCLUSION
These findings indicate that miR-223 plays a pivotal role in lipophagy under demyelinating conditions. By inhibiting CTSB, miR-223 promotes selective LD degradation, thereby reducing the lipid burden and inflammatory phenotype in LDAM. This study broadens the understanding of the molecular mechanisms of lipophagy and proposes lipophagy induction as a potential therapeutic approach to mitigate inflammatory responses in demyelinating diseases.
Topics: Animals; MicroRNAs; Microglia; Mice; Autophagy; Lipid Droplets; Mice, Inbred C57BL; Demyelinating Diseases; Cathepsin B; Lysophosphatidylcholines; Disease Models, Animal; Male; Gene Expression Regulation; Cell Line
PubMed: 38909243
DOI: 10.1186/s12944-024-02185-y -
Scientific Reports Jun 2024Microglia, brain-resident macrophages, can acquire distinct functional phenotypes, which are supported by differential reprogramming of cell metabolism. These...
Microglia, brain-resident macrophages, can acquire distinct functional phenotypes, which are supported by differential reprogramming of cell metabolism. These adaptations include remodeling in glycolytic and mitochondrial metabolic fluxes, potentially altering energy substrate availability at the tissue level. This phenomenon may be highly relevant in the brain, where metabolism must be precisely regulated to maintain appropriate neuronal excitability and synaptic transmission. Direct evidence that microglia can impact on neuronal energy metabolism has been widely lacking, however. Combining molecular profiling, electrophysiology, oxygen microsensor recordings and mathematical modeling, we investigated microglia-mediated disturbances in brain energetics during neuroinflammation. Our results suggest that proinflammatory microglia showing enhanced nitric oxide release and decreased CX3CR1 expression transiently increase the tissue lactate/glucose ratio that depends on transcriptional reprogramming in microglia, not in neurons. In this condition, neuronal network activity such as gamma oscillations (30-70 Hz) can be fueled by increased ATP production in mitochondria, which is reflected by elevated oxygen consumption. During dysregulated inflammation, high energy demand and low glucose availability can be boundary conditions for neuronal metabolic fitness as revealed by kinetic modeling of single neuron energetics. Collectively, these findings indicate that metabolic flexibility protects neuronal network function against alterations in local substrate availability during moderate neuroinflammation.
Topics: Animals; Neurons; Energy Metabolism; Microglia; Mice; Neuroinflammatory Diseases; Glucose; Mitochondria; Nitric Oxide; Lactic Acid; Nerve Net; Brain; Oxygen Consumption; Adenosine Triphosphate; Inflammation; Male; Mice, Inbred C57BL
PubMed: 38909138
DOI: 10.1038/s41598-024-64872-1 -
Biomedicine & Pharmacotherapy =... Jun 2024Neuropathic pain is a pathological state induced by the aberrant generation of pain signals within the nervous system. Ginkgolide B(GB), an active component found of...
Neuropathic pain is a pathological state induced by the aberrant generation of pain signals within the nervous system. Ginkgolide B(GB), an active component found of Ginkgo. biloba leaves, has neuroprotective properties. This study aimed to explore the effects of GB on neuropathic pain and its underlying mechanisms. In the in vivo study, we adopted the rat chronic constriction injury model, and the results showed that GB(4 mg/kg) treatment effectively reduced pain sensation in rats and decreased the expressions of Iba-1 (a microglia marker), NLRP3 inflammasome, and inflammatory factors, such as interleukin (IL)-1β, in the spinal cord 7 days post-surgery. In the in vitro study, we induced microglial inflammation using lipopolysaccharide (500 ng/mL) / adenosine triphosphate (5 mM) and treated it with GB (10, 20, and 40 μM). GB upregulated the expression of mitophagy proteins, such as PINK1, Parkin, LC3 II/I, Tom20, and Beclin1, and decreased the cellular production of reactive oxygen species. Moreover, it lowered the expression of inflammation-related proteins, such as Caspase-1, IL-1β, and NLRP3 in microglia. However, this effect was reversed by Parkin shRNA/siRNA or the autophagy inhibitor 3-methyladenine (5 mM). These findings reveal that GB alleviates neuropathic pain by mitigating neuroinflammation through the activation of PINK1-Parkin-mediated mitophagy.
PubMed: 38908197
DOI: 10.1016/j.biopha.2024.117006 -
Nature Communications Jun 2024While TGF-β signaling is essential for microglial function, the cellular source of TGF-β1 ligand and its spatial regulation remains unclear in the adult CNS. Our data...
While TGF-β signaling is essential for microglial function, the cellular source of TGF-β1 ligand and its spatial regulation remains unclear in the adult CNS. Our data supports that microglia but not astrocytes or neurons are the primary producers of TGF-β1 ligands needed for microglial homeostasis. Microglia-Tgfb1 KO leads to the activation of microglia featuring a dyshomeostatic transcriptome that resembles disease-associated, injury-associated, and aged microglia, suggesting microglial self-produced TGF-β1 ligands are important in the adult CNS. Astrocytes in MG-Tgfb1 inducible (i)KO mice show a transcriptome profile that is closely aligned with an LPS-associated astrocyte profile. Additionally, using sparse mosaic single-cell microglia KO of TGF-β1 ligand we established an autocrine mechanism for signaling. Here we show that MG-Tgfb1 iKO mice present cognitive deficits, supporting that precise spatial regulation of TGF-β1 ligand derived from microglia is required for the maintenance of brain homeostasis and normal cognitive function in the adult brain.
Topics: Animals; Microglia; Transforming Growth Factor beta1; Homeostasis; Mice, Knockout; Mice; Autocrine Communication; Cognition; Astrocytes; Signal Transduction; Brain; Male; Transcriptome; Mice, Inbred C57BL; Neurons
PubMed: 38906887
DOI: 10.1038/s41467-024-49596-0 -
NPJ Parkinson's Disease Jun 2024Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by mitochondrial dysfunction and accumulation of alpha-synuclein (α-Syn)-containing...
Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by mitochondrial dysfunction and accumulation of alpha-synuclein (α-Syn)-containing protein aggregates known as Lewy bodies (LB). Here, we investigated the entry of α-Syn into mitochondria to cause mitochondrial dysfunction and loss of cellular fitness in vivo. We show that α-Syn expressed in yeast and human cells is constitutively imported into mitochondria. In a transgenic mouse model, the level of endogenous α-Syn accumulation in mitochondria of dopaminergic neurons and microglia increases with age. The imported α-Syn is degraded by conserved mitochondrial proteases, most notably NLN and PITRM1 (Prd1 and Cym1 in yeast, respectively). α-Syn in the mitochondrial matrix that is not degraded interacts with respiratory chain complexes, leading to loss of mitochondrial DNA (mtDNA), mitochondrial membrane potential and cellular fitness decline. Importantly, enhancing mitochondrial proteolysis by increasing levels of specific proteases alleviated these defects in yeast, human cells, and a PD model of mouse primary neurons. Together, our results provide a direct link between α-synuclein-mediated cellular toxicity and its import into mitochondria and reveal potential therapeutic targets for the treatment of α-synucleinopathies.
PubMed: 38906862
DOI: 10.1038/s41531-024-00733-y -
The Primary Care Companion For CNS... Jun 2024To review the literature on the neurobiological mechanisms of obsessive-compulsive symptoms (OCS) in people with dementia. MEDLINE/PubMed, CENTRAL, and PsycNet... (Review)
Review
To review the literature on the neurobiological mechanisms of obsessive-compulsive symptoms (OCS) in people with dementia. MEDLINE/PubMed, CENTRAL, and PsycNet databases were searched from inception to March 2023. Original studies of any methodology with newly published data on the neurobiological underpinnings of OCS in patients with dementia, regardless of patient age or comorbidity and publication year, were included. The following search terms were used: (Obses* OR compul* OR OCD) AND (cognitive de* OR cognitive dysfunction OR cognitive disfunction OR dementia). Individual study data were extracted onto a piloted extractions sheet. Patients with dementia and OCS were reported to have atrophy and hypoperfusion of frontal, temporal, striatal, and limbic structures. Serotonergic agents may be efficacious in reducing OCS. One randomized controlled trial of paroxetine in behavioral symptoms of dementia did not show efficacy. Evidence of dopaminergic dysfunction is too sparse to draw conclusions. Microglia dysfunction mediates obsessive-compulsive-like symptoms. Mutations of microtubule-associated protein τ may increase the risk of OCS. Cognitive self-consciousness and obsessive-compulsive-related cognitions may mediate OCS in old age. Dysfunction of the processing of one class of stimuli may increase the salience of other classes of stimuli, leading to OCS. Frontal lobe hypometabolism and temporal lobe atrophy and hypometabolism are unexpected given previous research in obsessive compulsive disorder. Serotonergic agents have encouraging efficacy in case reports but require more specific research. .
Topics: Humans; Obsessive-Compulsive Disorder; Dementia
PubMed: 38905511
DOI: 10.4088/PCC.23r03689