Microglial Phenotype Research Articles

Taming Microglia in Alzheimer's Disease: Exploring Potential Implications of Choline Alphoscerate via α7 nAChR Modulation.

Alzheimer's disease (AD), marked by cognitive impairment, predominantly affects the brain regions regulated by cholinergic innervation, such as the cerebral cortex and hippocampus. Cholinergic dysfunction, a key contributor to age-related cognitive decline, has spurred investigations into potential therapeutic interventions. We have previously shown that choline alphoscerate (α-GPC), a cholinergic neurotransmission-enhancing agent, protects from Aβ-mediated neurotoxicity. Herein, we investigated the effects of α-GPC on the microglial phenotype in response to Aβ via modulation of the nicotinic alpha-7 acetylcholine receptor (α7 nAChR). BV2 microglial cells were pre-treated for 1 h with α-GPC and were treated for 24, 48, and 72 h with Aβ1-42 and/or α-BTX, a selective α7nAchR antagonist. Fluorescent immunocytochemistry and Western blot analysis showed that α-GPC was able to antagonize Aβ-induced inflammatory effects. Of note, α-GPC exerted its anti-inflammatory effect by directly activating the α7nAChR receptor, as suggested by the induction of an increase in [Ca2+]i and Ach-like currents. Considering that cholinergic transmission appears crucial in regulating the inflammatory profiles of glial cells, its modulation emerges as a potential pharmaco-therapeutic target to improve outcomes in inflammatory neurodegenerative disorders, such as AD.

Rutin promotes M2 phenotype microglia polarization by suppressing the JAK/STAT3 signaling to protect against retinal ischemia-reperfusion injury.

We aimed to investigate the neuroprotective effect of rutin on retinal ganglion cells (RGCs) under ischemia-reperfusion (I/R) conditions and the underlying mechanisms involving microglia polarization and JAK/STAT3 signaling. RGCs isolated from C57/Bl6 mice were co-cultured with BV2 microglial cells under normal or in vitro oxygen-glucose deprivation and reoxygenation (OGD/R) conditions. Rutin's effects were evaluated by assessing cell viability, apoptosis rates, cytokine levels, microglial polarization markers and JAK/STAT3 phosphorylation levels. The specific target is confirmed through the inhibitory effect of rutin on the respectively activated signaling factors. Furthermore, molecular docking analyses elucidated rutin-JAK1 interactions. OGD/R conditions significantly reduced RGC viability, exacerbated by BV2 co-culture. However, both 1 μM and 5 μM rutin treatment dose-dependently enhanced RGC viability, reduced apoptosis, and suppressed pro-inflammatory cytokine levels. Western blot analysis indicated that rutin promoted the M2 microglial phenotype and suppressed JAK/STAT3 signaling. Notably, rutin selectively inhibited JAK1 phosphorylation without affecting STAT3. Molecular docking highlighted potential interaction sites between rutin and specific JAK1 pseudokinase domain. Rutin exerts neuroprotective effects against retinal I/R injury by promoting M2 microglial polarization, potentially through the selective inhibition of JAK1 phosphorylation within the JAK/STAT3 signaling pathway. These findings provide a foundation for the therapeutic potential of rutin in retinal I/R injuries.

Tumor necrosis factor α-induced protein 8-like-2 controls microglia phenotype via metabolic reprogramming in BV2 microglial cells and responses to neuropathic pain

Microglial are major players in neuroinflammation that have recently emerged as potential therapeutic targets for neuropathic pain. Glucose metabolic programming has been linked to differential activation state and function in microglia. Tumor necrosis factor α-induced protein 8-like-2 (TNFAIP8L2) is an important component in regulating the anti-inflammatory response. However, the role of TNFAIP8L2 in microglia differential state during neuropathic pain and its interplay with glucose metabolic reprogramming in microglia has not yet been determined. Thus, we aimed to investigate the role of TNFAIP8L2 in the status of microglia in vitro and in vivo. BV2 microglial cells were treated with lipopolysaccharides plus interferon-gamma (LPS/IFNγ) or interleukin-4 (IL-4) to induce the two different phenotypes of microglia in vitro. In vivo experiments were conducted by chronic constriction injury of the sciatic nerve (CCI). We investigated whether TNFAIP8L2 regulates glucose metabolic programming in BV2 microglial cells. The data in vitro showed that TNFAIP8L2 lowers glycolysis and increases mitochondrial oxidative phosphorylation (OXPHOS) in inflammatory microglia. Blockade of glycolytic pathway abolished TNFAIP8L2-mediated differential activation of microglia. TNFAIP8L2 suppresses inflammatory microglial activation and promotes restorative microglial activation in BV2 microglial cells and in spinal cord microglia after neuropathic pain. Furthermore, TNFAIP8L2 controls differential activation of microglia and glucose metabolic reprogramming through the MAPK/mTOR/HIF-1α signaling axis. This study reveals that TNFAIP8L2 plays a critical role in neuropathic pain, providing important insights into glucose metabolic reprogramming and microglial phenotypic transition, which indicates that TNFAIP8L2 may be used as a potential drug target for the prevention of neuropathic pain.

Abstract 146: Trained Immunity Induced by Dietary Salt Impedes Long-Term Brain Recovery in Experimental Intracerebral Hemorrhage

Introduction: Excessive sodium intake is the top dietary risk factor for mortality and non-communicable diseases such as stroke. However, whether and how a high salt diet (HSD) impacts long-term stroke outcomes - even after salt reduction/withdrawal prior to a stroke is unknown. Methods: Intracerebral hemorrhage (ICH) was modeled by blood or collagenase injections in mice. Bone marrow (BM) progenitor and immune cell compositions as well as monocyte-derived macrophage (MDM) and microglial phenotypes were profiled using flow cytometry. BM chimeras were created to test innate immune memory. Glycolysis and OXPHOS were measured by Seahorse assays. Macrophage phagocytosis was evaluated using in vivo and in vitro erythrophagocytosis assays. RNA-seq was used to analyze the progenitor transcriptome. Hematoma, neuron loss, and astrogliosis were assessed with immunofluorescence. LysM Cre/+ : NR4a1 fl/fl ; Nr4a2 fl/fl ; NR4a3 -/- mice, LysM Cre/+ : NR4a1 fl/fl mice, and celastrol treatment were used to elucidate the mechanism underlying HSD-induced trained immunity. Results: HSD impaired long-term ICH recovery despite prior salt withdrawal. HSD triggered innate immune training in BM progenitor cells by downregulating the NR4a family and OXPHOS. This training selectively compromised MDM reparative polarization without altering their initial inflammatory response in the ICH brain. Healthy mice transplanted with BM from HSD-fed mice retained training signatures, confirming a persistent form of trained immunity that originates in the BM. Lack of NR4a1 in MDMs recapitulated HSD-induced negative impacts on ICH outcomes. Notably, transplantation of healthy BM and gain of NR4a1 function enabled stroke recovery in the HSD animals. Conclusions: These findings provide the first evidence that links HSD-induced trained immunity to the acquisition of persistent dysregulated inflammatory responses and unveil NR4a1 as a potential therapeutic target.

Abstract TP28: The Effects of Social Isolation on Cerebral Amyloid Angiopathy

Introduction: Cerebral amyloid angiopathy (CAA) is characterized by amyloid β (Aβ) deposition in the cortical and leptomeningeal vessels, and it is a largely untreatable cause of intracerebral hemorrhage and dementia. Studies estimate a 10-50% prevalence of CAA in the general elderly population, positioning it as one of the strongest vascular contributors to age-related cognitive impairment. With aging, the prevalence of social isolation (SI) also increases. Isolated individuals have an increased risk of Aβ-related cognitive decline and heightened inflammatory response to stress. Yet, whether and how SI exacerbates CAA-induced cognitive decline is unknown. Methods: TgSwDI mice harboring Swedish, Dutch, and Iowa mutations of human amyloid precursor protein were used as a mouse model of CAA. Male and female C57BL6 wildtype (WT) and CAA mice were randomly assigned to paired housing (PH) or SI at 3 months. Neurobehaviors were measured at baseline and every 3 months using the novel object recognition test (NORT), tail suspension test (TST), and fear conditioning (FC). At 12 months, microglia phenotype, vascular structure, and Aβ burden were assessed using flow cytometry and immunostaining. Results: Both WT and CAA isolated animals displayed significantly greater immobility in TST at 9 months post-SI, suggesting a depression-like behavior (n=10-15/grp, p<0.0001). Isolated CAA mice displayed exacerbated cognitive deficits in NORT and FC while WT mice showed intact cognition (n=10-15/grp, p<0.05). Specifically, SI-induced cognitive deficits were more prominent in the female CAA mice compared to males (n=5-8/grp, p<0.01). Sex differences were also observed in CAA mice in frequencies of Aβ-containing endothelial cells (CD31 + ) and vessel-associated microglia (VAM, CD45 int CD11b + CD31 + ) as well as in microglial phagocytosis of Aβ (n=3/grp, p<0.05). SI increased the frequency of Aβ-containing microglia in isolated CAA mice compared to their PH littermates. Conclusion: SI induced behavioral deficits in both WT and CAA mice but exacerbated cognitive decline only in the CAA SI mice. SI also influences microglial phagocytosis of Aβ. Further research is needed to determine the cellular and molecular mechanism underlying SI-induced changes in CAA.

Abstract TP298: Cellular Senescence and Microglial Dysfunction are Linked to Progressive Cognitive Deficits in the Chronic Phase of Ischemic Stroke

Improvements in acute stroke treatment, including endovascular thrombectomy and critical care management, have increased survival rates after stroke. However, many survivors have significant neurological deficits, as stroke remains one of the leading causes of long-term disability. Despite this, the chronic progression and long-term sequelae of ischemic stroke pathology remains woefully understudied. This study examined long-term progressive deficits in young adult male C57Bl/6 mice at 3 and 6 months after a 60-minute transient middle cerebral artery occlusion (MCAO) or sham surgery to identify secondary injury processes, and neuropathology of chronic stroke human brains. Depressive-like behavior persisted for 6 months post-stroke (PS) (p= <0.0001). Cognitive function progressively worsened from 3 to 6 months as seen by a continual reduction in the discrimination index in the novel object recognition task (p=.0063). Deficits in memory retention in mice 6-months PS were observed using the fear-conditioning test (p=.0084). Brain atrophy was evident by MicroCT imaging. Histopathological assessment revealed increased microglial activation in the hippocampus and frontal cortex in both mouse and human brains chronically after stroke. Interestingly, we also observed microglia activation proximal to apoptotic neurons in the brains of stroke mice, as shown by TUNEL assay. TUNEL co-labeling with a neuronal marker showed the same neuronal apoptosis in human samples from patients with chronic stroke, in both the hippocampus and thalamus. Disease-associated microglial (DAM) phenotypes were marked by both increased proliferative status and senescent-like phenotypes, including elevated production of cytokines and other proinflammatory molecules. Our findings demonstrate that experimental stroke accelerates inflammaging in the brain, which induces premature senescence within the chronic infarct microenvironment. Cellular senescence and chronic neurodegenerative signatures likely contribute to progressive cognitive impairment following stroke. The chronic and evolving neurological consequences of stroke may offer viable targets for delayed treatment strategies to reduce risk of vascular dementia and neurodegenerative disease.

METTL3 Mediates Microglial Activation and Blood-Brain Barrier Permeability in Cerebral Ischemic Stroke by Regulating NLRP3 Inflammasomes Through m6A Methylation Modification.

Cerebral ischemic stroke (CIS) is the main cause of disability. METTL3 is implicated in CIS, and we explored its specific mechanism. Middle cerebral artery occlusion (MCAO) rat model and oxygen-glucose deprivation/reperfusion (OGD/R) HAPI cell model were established and treated with LV-METTL3 or DAA, oe-METTL3, miR-335-3p mimics, or DAA, to assess their effects on MCAO rat neurological and motor function, cerebral infarction area, brain water content, microglial activation, blood-brain barrier (BBB) permeability, and NLRP3 inflammasome activation. METTL3, pri-miR-335-3p, mature miR-335-3p, and miR-335-3p mRNA levels were assessed by RT-qPCR; M1/M2 microglial phenotype proportion and M1/M2 microglia ratio, inflammatory factor levels, and m6A modification were assessed. MCAO rats manifested cerebral ischemia injury. METTL3 was under-expressed in CIS. METTL3 overexpression inhibited microglial activation and M1 polarization and BBB permeability in MCAO rats and inhibited OGD/R-induced microglial activation and reduced M1 polarization. METTL3 regulated miR-335-3p expression and inhibited NLRP3 inflammasome activation. m6A methylation inhibition averted METTL3's effects on NLRP3 activation, thus promoting microglial activation in OGD/R-induced cells and METTL3's effects on BBB permeability in MCAO rats. Briefly, METTL3 regulated miR-335-3p expression through RNA m6A methylation and inhibited NLRP3 inflammasome activation, thus repressing microglial activation, BBB permeability, and protecting against CIS.

Differential roles of M1 and M2 microglia in Parkinson’s disease: a critical narrative review

Parkinson's disease (PD) is marked by the selective loss of dopaminergic neurons, leading to debilitating motor and non-motor symptoms. Central to PD pathogenesis is the intricate involvement of microglia, the resident immune cells of the brain. This narrative review delves into the distinct functions of M1 and M2 microglia in the context of PD. M1 microglia exhibit pro-inflammatory characteristics, releasing cytotoxic factors that exacerbate neuronal damage. In contrast, M2 microglia contribute to neuroprotection by secreting anti-inflammatory cytokines and participating in the clearance of cellular debris. The dynamic interplay between these microglial phenotypes is explored, providing insights into their roles in disease progression. Emerging therapeutic strategies aimed at modulating microglial polarization are discussed, emphasizing their potential in PD intervention. By unraveling the nuanced contributions of M1 and M2 microglia in PD, this review not only advances our understanding of neuroinflammatory mechanisms but also underscores the importance of targeted interventions to alleviate disease-associated pathology and preserve neuronal integrity in Parkinson's disease.

Astrocyte-Derived Exosomal miR-148a-3p Suppresses Neuroinflammation and Restores Neurological Function in Traumatic Brain Injury by Regulating the Microglial Phenotype.

Interactions between astrocytes and microglia play an important role in the regeneration and repair of traumatic brain injury (TBI), and exosomes are involved in cell-cell interactions. A TBI model was constructed in rats. Brain extract (Ext) was isolated 1 d after TBI. Astrocyte-derived exosomes were obtained by coculturing Ext with primary astrocytes, and the morphology of exosomes was observed by electron microscopy. The isolated exosomes were cocultured with microglia to observe phenotypic changes in M1 and M2 markers. Aberrant RNA expression was detected in necrotic brain tissue and edematous brain tissue. The role of miR-148a-3p in regulating microglial phenotype was explored by knocking down or overexpressing miR-148a-3p. Finally, the effect of miR-148a-3p on TBI was studied in a rat TBI model. Astrocyte-derived exosomes stimulated by Ext promoted the transition of microglia from the M1 phenotype to the M2 phenotype. MiR-148a-3p was highly expressed in TBI. Transfecting miR-148a-3p promoted the transition of microglia from the M1 phenotype to the M2 phenotype and inhibited the lipopolysaccharide-induced inflammatory response in pre-microglia. In a rat TBI model, miR-148a-3p significantly improved the modified neurological severity score and attenuated brain injury, which promoted the transition of microglia from the M1 phenotype to the M2 phenotype. MiR-148a-3p alleviated TBI by inhibiting the nuclear factor κB pathway. Astrocyte-derived exosomal miR-148a-3p regulates the microglial phenotype, inhibits neuroinflammation, and restores neurological function in TBI. These results provide new potential targets for the treatment of TBI.

The neuroprotective effect of near infrared light therapy in aged mice with postoperative neurocognitive disorder by upregulating IRF7

BackgroundPostoperative neurocognitive disorder (PND) is a common central nervous system complication after undergoing surgery and anesthesia especially in elderly patients, while the therapeutic options are very limited. This study was carried out to investigate the beneficial effects of transcranial near infrared light (NIRL) which was employed to the treatment of PND and propose the involved mechanisms. MethodsThe PND mice were established through left carotid artery exposure under isoflurane anesthesia and received transcranial NIRL treatment. Behavioral testing was performed to evaluate the cognitive function of PND mice after transcranial NIRL therapy. Changes in the transcriptomic profiles of prefrontal cortex (PFC) and hippocampus (HP) were identified by next generation sequencing (NGS), and the molecular mechanisms involved were examined by both in vivo mouse model and in vitro cell culture studies. ResultsWe found that transcranial NIRL therapy effectively ameliorated learning and memory deficit induced by anesthesia and surgery in aged mice. Specifically, we identified down-regulation of interferon regulatory factor 7 (IRF7) in the brains of PND mice that was mechanistically associated with increased pro-inflammatory M1 phenotype of microglia and elevated neuroinflammatory. NIRL treatment produced protective effects through the upregulation of IRF7 expression and reversing microglial phenotypes from pro-inflammatory to neuroprotective, resulting in reduced brain damage and improved cognitive function in PND mice. ConclusionOur results indicate that transcranial NIRL is an effective and safe therapy for PND via alleviating neuroinflammation, and IRF7 plays a key transcription factor in regulating the M1-to-M2 switch of microglia.

The Effect of Pregabalin on Microglia Differentiation in Rat with Neuropathic pain: A Preliminary Study.

This study investigated the effects of pregabalin on microglial differentiation in rats with neuropathic pain (NP) induced by sciatic nerve ligation and transection. After confirming NP, the rats were randomly allocated to either a pregabalin or control group. The pregabalin group received intraperitoneal injections of 10 mg/kg pregabalin, while the control group received an equivalent volume of normal saline following surgery. On postoperative day 28, neuronal damage, microglial activity, and microglial differentiation were assessed. The pregabalin group exhibited significantly less neuronal damage compared to the control group, along with a significant decrease in activated microglial expression in both the brain and spinal cord. Pregabalin treatment also significantly altered the microglial phenotype expression, with a decrease in the M1 phenotype percentage and an increase in the M2 phenotype percentage in both the brain (M1 phenotype: 43.52 ± 12.16% and 18.00 ± 8.57% in the control and pregabalin groups, respectively; difference: 27.26 [15.18-42.10], p = 0.002; M2 phenotype: 16.88 ± 6.47% and 39.63 ± 5.82% in the control and pregabalin groups, respectively; difference 22.04 [17.17-32.70], p < 0.001) and the spinal cord ipsilateral to nerve injury (M1 phenotype: 44.35 ± 12.12% and 13.78 ± 5.39% in the control and pregabalin groups, respectively; difference 30.46 [21.73-44.45], p < 0.001; M2 phenotype: 7.64 ± 3.91% and 33.66 ± 7.95% in the control and pregabalin groups, respectively; difference 27.41 [21.21-36.30], p < 0.001). Overall, pregabalin treatment significantly decreased the microglial M1 phenotype while increasing the microglial M2 phenotype in NP rats.

Anti-inflammatory Effects of Umbilical Cord Mesenchymal Stem Cell and Autologous Conditioned Serum on Oligodendrocyte, Astrocyte, and Microglial Specific Gene in Cuprizone Animal Model.

Inflammation, myelin loss, astrocytosis, and microgliosis are pathological signs of the autoimmune and demyelinating disease known as multiple sclerosis (MS). Axonal and neuronal degenerations have basic molecular pathways. The remyelination process can be influenced by the secretome of mesenchymal stem cells due to their capacity for immunomodulation, differentiation, and neuroprotection. Microglial cells are divided into two subgroups: M1 and M2 phenotypes. A crucial component of the microglial function is the colony stimulating factor 1 receptor (CSF1R). We aimed to evaluate the immunomodulating effects of secretome and conditioned serum on the microglial phenotypes and improvement of demyelination in a cuprizone model of MS. The study used 48 male C57BL/6 mice, which were randomly distributed into 6 subgroups (n = 8), i.e., control, cuprizone, MSC (confluency 40% and 80%) secretome group, and blood derived conditioned serum (autologous and humanized). The animals were fed with 0.2% cuprizone diet for 12 weeks. Supplements were injected into the lateral tail vein using a 27-gauge needle every 3 days 500 μl per injection. At 14 days after transplantation, animals from each group were sacrificed and analyzed by Real time PCR. The results showed that the administration of MSC secretome can efficiently reduce expression of pro-inflammatory cytokines (IL-1, IL6 and TNF-α) in the corpus callosum; also, conditioned serum downregulated IL-1. Moreover, the oligodendrocyte-specific gene was upregulated by secretome and conditioned serum treatment. Also, the expression of microglial- specific gene was reduced after treatment. These findings demonstrated that the secretome isolated from MSCs used as a therapy decreased and increased the M1 and M2 levels, respectively, to control neuroinflammation in CPZ mice. In conclusion, the current study showed the viability of devising a method to prepare suitable MSCs and secreted factor to cure neurodegenerative diseases, as well as the capability of regulating MSC secretome patterns by manipulating the cell density.

Anti‐cytokine antibodies attenuated neuroglial degeneration under hypoxic stress

Aims/Purpose: Hypoxia is a vital cause of neurodegenerative diseases such as glaucoma and retinal ischemia. We investigated the potential neuroprotective effects of anti‐cytokine antibodies against hypoxic damage.Methods: An in vitro hypoxia model was established using cobalt chloride (CoCl2) stimulation in microglial cells (BV‐2). Immunofluorescence staining was performed to detect the expression markers of different microglial phenotypes in BV‐2. Different concentrations of CoCl2 (0–150 μM) were tested to generate dose–response curves. Following exposure to CoCl2 at an approximate IC50 of 0.1 mM, BV‐2 were treated with anti‐tumour necrosis factor‐alpha (anti‐TNF‐α) or anti‐ interleukin‐1 beta (anti‐IL‐1β) antibodies for 24 h. Cell viability was determined by MTS assay. Proteome changes in BV‐2 were analysed with the mass spectrometry‐based proteomics approach.Results: Immunocytochemistry revealed the expression of M1 marker consisting CD68 and M2 marker CD206 in the BV‐2 cells. Hypoxia induced by mimetic CoCl2 led to a concentration‐dependent viability impairment in BV‐2 and cells treated with 0.1 mM CoCl2 for 24 h showed decreased viability of ~46%‐ 50%. Interestingly, the application of anti‐TNF‐α (2ug/ml) and anti‐IL‐1β (4ug/ml) antibodies significantly improved the BV‐2 cell viability to 80% (p &lt; 0.0001) and 76% (p &lt; 0.0001), respectively. Proteomics and bioinformatics analyses of the differentially expressed proteins revealed that CoCl2 induced proteome alterations involved in mitochondrial dysfunction signalling pathway (p = 1.10 × 10−3), which were eliminated by the treatment with both anti‐TNF‐α and anti‐IL‐1β. Besides, CoCl2‐induced activation of endoplasmic reticulum (ER) stress response (p = 3.33 × 10−9) was alleviated by anti‐IL‐1β and anti‐TNF‐α treatment (p = 1.7 × 10−7 and p = 8.82 × 10−7, respectively). Particularly, anti‐TNF‐α antibody significantly downregulated proteins involved in apoptosis (p = 1.58 × 10−10). Anti‐IL‐1β induced Nrf2‐mediated antioxidant response and exerts protection against oxidative stress (p = 1.00 × 10−6).Conclusions: Antibodies targeting cytokines provide neuroprotective effects on microglial cells from hypoxic stress. These findings demonstrated the potential use of anti‐cytokines in the treatment of neurodegenerative diseases.

A high-fat diet induced depression-like phenotype via hypocretin-HCRTR1 mediated inflammation activation.

Background: A high-fat diet (HFD) is generally associated with an increased risk of mental disorders that constitute a sizeable worldwide health. A HFD results in the gut microbiota-brain axis being altered and linked to mental disorders. Hypocretin-1, which can promote appetite, has been previously confirmed to be associated with depression. However, no exact relationship has been found for hypocretin between depression and HFDs. Methods: Adult male SD rats were randomly assigned to either a HFD or a normal diet for eight weeks, followed by behavioral tests and plasma biochemical analyses. Then, we investigated the protein and mRNA levels of inflammation-related factors in the hippocampus. We also observed morphological changes in brain microglia and lipid accumulation. Additionally, metagenomic and metabolomic analyses of gut microbiomes were performed. 3T3-L1 cells were utilized in vitro to investigate the impact of hypocretin receptor 1 antagonists (SB334867) on lipid accumulation. To consider the connection between the brain and adipose tissue, we used a conditioned medium (CM) treated with 3T3-L1 cells to observe the activation and phagocytosis of BV2 cells. Following a 12-week period of feeding a HFD to C57BL/6 mice, a three-week intervention period was initiated during which the administration of SB334867 was observed. This was followed by a series of assessments, including monitoring of body weight changes and emotional problems, as well as attention to plasma biochemical levels and microglial cell phenotypes in the brain. Results: The HFD rats displayed anxiety and depressive-like behaviors. HFD rats exhibited increased plasma HDL, LDL, and TC levels. A HFD also causes an increase in hypocretin-1 and hypocretin-2 in the hypothalamus. Metagenomics and metabolomics revealed that the HFD caused an increase in the relative abundance of associated inflammatory bacteria and decreased the abundance of anti-inflammatory and bile acid metabolites. Compared with the CTR group, hippocampal microglia in the HFD group were significantly activated and accompanied by lipid deposition. At the same time, protein and mRNA expression levels of inflammation-related factors were increased. We found that SB334867 could significantly reduce lipid accumulation in 3T3-L1 cells after differentiation. The expression of inflammatory factors decreased in the SB334867 group. The administration of SB334867 was found to reverse the adverse effects of the HFD on body weight, depressive-like behaviour and anxiety-like mood. Furthermore, this treatment was associated with improvements in plasma biochemical levels and a reduction in the number of microglia in the brain. Conclusions: In summary, our results demonstrated that a HFD induced anxiety and depressive-like behaviors, which may be linked to the increased hypocretin-1 level and lipid accumulation. Supplementation with SB334867 improved the above. These observations highlight the possibility of hypocretin-1 inducing the risk of HFD-associated emotional dysfunctions.

Emerging Models to Study Human Microglia In vitro.

New in vitro models provide an exciting opportunity to study live human microglia. Previously, a major limitation in understanding human microglia in health and disease has been their limited availability. Here, we provide an overview of methods to obtain human stem cell or blood monocyte-derived microglia-like cells that provide a nearly unlimited source of live human microglia for research. We address how understanding microglial ontogeny can help modeling microglial identity and function in a dish with increased accuracy. Moreover, we categorize stem cell-derived differentiation methods into embryoid body based, growth factor driven, and coculture-driven approaches, and review novel viral approaches to reprogram stem cells directly into microglia-like cells. Furthermore, we review typical readouts used in the field to verify microglial identity and characterize functional microglial phenotypes. We provide an overview of methods used to study microglia in environments more closely resembling the (developing) human CNS, such as cocultures and brain organoid systems with incorporated or innately developing microglia. We highlight how microglia-like cells can be utilized to reveal molecular and functional mechanisms in human disease context, focusing on Alzheimer's disease and other neurodegenerative diseases as well as neurodevelopmental diseases. Finally, we provide a critical overview of challenges and future opportunities to more accurately model human microglia in a dish and conclude that novel in vitro microglia-like cells provide an exciting potential to bring preclinical research of microglia to a new era.

Correction Notice: Flow Cytometry Analysis of Microglial Phenotypes in the Murine Brain During Aging and Disease

Correction Notice: Flow Cytometry Analysis of Microglial Phenotypes in the Murine Brain During Aging and Disease

Biomimetic engineering of a neuroinflammation-targeted MOF nanozyme scaffolded with photo-trigger released CO for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is one of the most fatal and irreversible neurodegenerative diseases, which causes a huge emotional and financial burden on families and society. Despite the progress made with recent clinical use of inhibitors of acetylcholinesterase and amyloid-β (Aβ) antibodies, the curative effects of AD treatment remain unsatisfactory, which is probably due to the complexity of pathogenesis and the multiplicity of therapeutic targets. Thus, modulating complex pathological networks could be an alternative approach to treat AD. Here, a neutrophil membrane-coated MOF nanozyme (denoted as Neu-MOF/Fla) is biomimetically engineered to disturb the malignant Aβ deposition-inflammation cycle and ameliorate the pathological network for effective AD treatment. Neu-MOF/Fla could recognize the pathological inflammatory signals of AD, and deliver the photo-triggered anti-inflammatory CO and MOF based hydrolytic nanozymes to the lesion area of the brain in a spontaneous manner. Based on the in vitro and in vivo studies, Neu-MOF/Fla significantly suppresses neuroinflammation, mitigates the Aβ burden, beneficially modulates the pro-inflammatory microglial phenotypes and improves the cognitive defects of AD mice models. Our work presents a good example for developing biomimetic multifunctional nanotherapeutics against AD by means of amelioration of multiple symptoms and improvement of cognitive defects.

CANNABINOIDS AS A TREATMENT APPROACH FOR ASD: A LITERATURE REVIEW

Given the increasing incidence and high economic and social costs associated with ASD, along with the need for effective pharmacotherapies for its core symptoms, alternative treatment options have become widely researched. The present study is a literature review that explored the DeCS/MeSH descriptors 'cannabinoid,' 'treatment,' and 'autism.' It is estimated that up to 80% of children with ASD experience sleep disturbances, such as prolonged latency for sleep onset, along with nocturnal and early morning awakenings, which are widely associated with alterations in the sleep-wake circadian cycle. In this context, it is known that the endocannabinoid system (eCB) is one of the main regulators of the sleep-wake cycle. However, the effect of phytocannabinoids on the sleep quality of children with ASD still lacks further clarification. Furthermore, these cannabinoids exhibit anti-inflammatory properties, reducing levels of pro-inflammatory cytokines and contributing to a neuroprotective microglial phenotype. In ASD, cannabinoid derivatives have demonstrated efficacy in controlling behavior and irritability. However, as of now, there is no FDA-approved product for regular use.

Coffee's protective mechanisms against neurodegeneration.

A widely consumed beverage, coffee has emerged as a potential protective natural agent against neurodegenerative diseases. This chapter explores the intricate mechanisms by which coffee and its bioactive compounds exert neuroprotective effects. The antioxidant properties of coffee polyphenols, such as chlorogenic acid and caffeic acid, mitigate oxidative stress and neuroinflammation. Coffee modulates neurotransmitter systems, including dopaminergic, cholinergic, and glutamatergic pathways implicated in neurodegeneration. Additionally, coffee activates neuroprotective signaling cascades, such as the Nrf2 pathway, and inhibits pro-inflammatory pathways like NF-κB. Coffee components also influence mitochondrial function, biogenesis, and energy metabolism, thereby promoting neuronal survival. Furthermore, coffee suppresses microglial activation and modulates microglial phenotypes, reducing neuroinflammatory responses. Epidemiological studies and clinical trials provide insights into the potential benefits of coffee consumption on cognitive function and neurodegenerative disease risk. However, future research should focus on identifying specific coffee bioactive compounds and their mechanism of action. This chapter highlights the multifaceted neuroprotective mechanisms of coffee, paving the way for future research and potential therapeutic interventions.

Effects of Mycobacterium vaccae NCTC 11659 and Lipopolysaccharide Challenge on Polarization of Murine BV-2 Microglial Cells.

Previous studies have shown that the in vivo administration of soil-derived bacteria with anti-inflammatory and immunoregulatory properties, such as Mycobacterium vaccae NCTC 11659, can prevent a stress-induced shift toward an inflammatory M1 microglial immunophenotype and microglial priming in the central nervous system (CNS). It remains unclear whether M. vaccae NCTC 11659 can act directly on microglia to mediate these effects. This study was designed to determine the effects of M. vaccae NCTC 11659 on the polarization of naïve BV-2 cells, a murine microglial cell line, and BV-2 cells subsequently challenged with lipopolysaccharide (LPS). Briefly, murine BV-2 cells were exposed to 100 µg/mL whole-cell, heat-killed M. vaccae NCTC 11659 or sterile borate-buffered saline (BBS) vehicle, followed, 24 h later, by exposure to 0.250 µg/mL LPS (Escherichia coli 0111: B4; n = 3) in cell culture media vehicle (CMV) or a CMV control condition. Twenty-four hours after the LPS or CMV challenge, cells were harvested to isolate total RNA. An analysis using the NanoString platform revealed that, by itself, M. vaccae NCTC 11659 had an "adjuvant-like" effect, while exposure to LPS increased the expression of mRNAs encoding proinflammatory cytokines, chemokine ligands, the C3 component of complement, and components of inflammasome signaling such as Nlrp3. Among LPS-challenged cells, M. vaccae NCTC 11659 had limited effects on differential gene expression using a threshold of 1.5-fold change. A subset of genes was assessed using real-time reverse transcription polymerase chain reaction (real-time RT-PCR), including Arg1, Ccl2, Il1b, Il6, Nlrp3, and Tnf. Based on the analysis using real-time RT-PCR, M. vaccae NCTC 11659 by itself again induced "adjuvant-like" effects, increasing the expression of Il1b, Il6, and Tnf while decreasing the expression of Arg1. LPS by itself increased the expression of Ccl2, Il1b, Il6, Nlrp3, and Tnf while decreasing the expression of Arg1. Among LPS-challenged cells, M. vaccae NCTC 11659 enhanced LPS-induced increases in the expression of Nlrp3 and Tnf, consistent with microglial priming. In contrast, among LPS-challenged cells, although M. vaccae NCTC 11659 did not fully prevent the effects of LPS relative to vehicle-treated control conditions, it increased Arg1 mRNA expression, suggesting that M. vaccae NCTC 11659 induces an atypical microglial phenotype. Thus, M. vaccae NCTC 11659 acutely (within 48 h) induced immune-activating and microglial-priming effects when applied directly to murine BV-2 microglial cells, in contrast to its long-term anti-inflammatory and immunoregulatory effects observed on the CNS when whole-cell, heat-killed preparations of M. vaccae NCTC 11659 were given peripherally in vivo.