Microglial M1/M2 polarization and metabolic states

Glioblastoma Drives Protease-Independent Extracellular Matrix Invasion of Microglia

Glioblastoma (GBM) is the most common and lethal form of primary brain cancer. Microglia infiltration into the tumor microenvironment is associated with immunosuppression and poor prognosis. Improved physicochemical understanding of microglia activation and invasion may provide novel GBM therapeutic strategies essential for improving long-term treatment efficacy. Here, we combine microfluidic systems with 3-D collagen hydrogels to systematically investigate microglia activation, invasion, contractility and cytokine secretion in response of GBM-microglia crosstalk. GBM inflammatory biomolecules significantly promote activation and 3D invasion of microglia. Interestingly, microglia invasion is not significantly affected by inhibitors of MMP activity or cellular glycolysis. In contrast, ROCK-pathway inhibition significantly impedes microglia invasion. Infrared microscopy analyses show that GBM co-culture does not significantly alter microglia lipid content. Further, GBM conditioned media resulted in significantly increased collagen hydrogel contraction, suggesting the importance of microglia contractility to physically remodel the local extracellular matrix (ECM). We also identify a panel of soluble proteins that may contribute to microglia chemotaxis, such as TIMP-1 and CXCL12. Taken together, this study suggests that the presence of GBM cells can enhance microglia invasion via increased cellular contractility, independent of MMP activity and cellular glycolysis.

Unraveling Macrophage Polarization: Functions, Mechanisms, and "Double-Edged Sword" Roles in Host Antiviral Immune Responses

Numerous viruses that propagate through the respiratory tract may be initially engulfed by macrophages (Mφs) within the alveoli, where they complete their first replication cycle and subsequently infect the adjacent epithelial cells. This process can lead to significant pathological damage to tissues and organs, leading to various diseases. As essential components in host antiviral immune systems, Mφs can be polarized into pro-inflammatory M1 Mφs or anti-inflammatory M2 Mφs, a process involving multiple signaling pathways and molecular mechanisms that yield diverse phenotypic and functional features in response to various stimuli. In general, when infected by a virus, M1 macrophages secrete pro-inflammatory cytokines to play an antiviral role, while M2 macrophages play an anti-inflammatory role to promote the replication of the virus. However, recent studies have shown that some viruses may exhibit the opposite trend. Viruses have evolved various strategies to disrupt Mφ polarization for efficient replication and transmission. Notably, various factors, such as mechanical softness, the altered pH value of the endolysosomal system, and the homeostasis between M1/M2 Mφs populations, contribute to crucial events in the viral replication cycle. Here, we summarize the regulation of Mφ polarization, virus-induced alterations in Mφ polarization, and the antiviral mechanisms associated with these changes. Collectively, this review provides insights into recent advances regarding Mφ polarization in host antiviral immune responses, which will contribute to the development of precise prevention strategies as well as management approaches to disease incidence and transmission.

CD200-CD200R Pathway: A Regulator of Microglial Polarization in Postoperative Cognitive Dysfunction

Microglial polarization refers to the ability of microglia to exhibit different functional states under various conditions. As the resident immune cells of the brain, changes in the functional state of microglia play a crucial role in the progression of postoperative cognitive dysfunction. Recent studies have indicated that CD200-CD200R signaling is associated with microglial polarization. This review focuses on the latest advancements regarding whether CD200-CD200R signaling can regulate microglial polarization and thereby influence postoperative cognitive dysfunction.

The anti-inflammatory and immunomodulatory effects of olfactory ensheathing cells transplantation in spinal cord injury and concomitant pathological pain

Spinal cord injury (SCI) is a serious and disabling injury that is often accompanied by neuropathic pain (NeP), which severely affects patients' motor and sensory functions and reduces their quality of life. Currently, there is no specific treatment for treating SCI and relieving the accompanying pain, and we can only rely on medication and physical rehabilitation, both of which are ineffective. Researchers have recently identified a novel class of glial cells, olfactory ensheathing cells (OECs), which originate from the olfactory system. Transplantation of OECs into damaged spinal cords has demonstrated their capacity to repair damaged nerves, improve the microenvironment at the point of injury, and They can also restore neural connectivity and alleviate the patient's NeP to a certain extent. Although the effectiveness of OECs transplantation has been confirmed in experiments, the specific mechanisms by which it repairs the spinal cord and relieves pain have not been articulated. Through a review of the literature, it has been established that the ability of OECs to repair and relieve pain is inextricably linked to its anti-inflammatory and immunomodulatory effects. In this regard, it is imperative to gain a deeper understanding of how OECs exert their anti-inflammatory and immunomodulatory effects. The objective of this paper is to provide a comprehensive overview of the mechanisms by which OECs exert anti-inflammatory and immunomodulatory effects. We aim to manipulate the immune microenvironment at the transplantation site through the intervention of cytokines and immune cells, with the goal of enhancing OECs' function or creating a conducive microenvironment for OECs' survival. This approach is expected to improve the therapeutic efficacy of OECs in clinical settings. However, numerous fundamental and clinical challenges remain to be addressed if OEC transplantation therapy is to become a standardized treatment in clinical practice.

A Peptide-Drug Conjugate-Based Nanoplatform for Immunometabolic Activation and In Situ Nerve Regeneration in Advanced-Stage Alzheimer's Disease

The formidable protection of physiological barriers and unclear pathogenic mechanisms impede drug development for Alzheimer's disease (AD). As defenders of the central nervous system, immune-metabolism function, and stemness of glial cells remain dormant during degeneration, representing a significant challenge for simultaneously targeting and modulating. Here, a modular nanoplatform is presented composed of peptide-drug conjugates and an inflammation-responsive core. The nanoplatform is transported through the blood-brain barrier via transcytosis and disassembles in the oxidative stress microenvironment upon intravenous administration. The released drug-conjugated modules can specifically target and deliver hydroxychloroquine (HCQ) and all-trans retinoic acid (ATRA) to microglia and astrocytes, respectively. The immune function of chronic tolerant microglia is activated by metabolic modulation, and reactive astrocytes trans-differentiate into functional neurons. In a transgenic mouse model, nanoplatform reduces levels of toxic proteins and inflammation while increasing neuronal density. This results in the amelioration of learning and memory decline. The modular nanoplatform provides design principles for multi-cellular targeting and combination nano-therapy for inflammation-related diseases.

A high-fat diet influences neural stem and progenitor cell environment in the medulla of adult mice

It has been widely established that neural stem cells (NSCs) exist in the adult mammalian brain. The area postrema (AP) and the ependymal cell layer of the central canal (CC) in the medulla were recently identified as NSC niches. There are two types of NSCs: astrocyte-like cells in the AP and tanycyte-like cells in the CC. However, limited information is currently available on the characteristics and functional significance of these NSCs and their progeny in the AP and CC. The AP is a part of the dorsal vagal complex (DVC), together with the nucleus of the solitary tract (Sol) and the dorsal motor nucleus of the vagus (10 N). DVC is the primary site for the integration of visceral neuronal and hormonal cues that act to inhibit food intake. Therefore, we examined the effects of high-fat diet (HFD) on NSCs and progenitor cells in the AP and CC. Eight-week-old male mice were fed HFD for short (1 week) and long periods (4 weeks). To detect proliferating cells, mice consecutively received intraperitoneal injections of BrdU for 7 days. Brain sections were processed with immunohistochemistry using various cell markers and BrdU antibodies. Our data demonstrated that adult NSCs and neural progenitor cells (NPCs) in the medulla responded more strongly to short-term HFD than to long-term HFD. HFD increased astrocyte density in the Sol and 10 N, and increased microglial/macrophage density in the AP and Sol. Furthermore, long-term HFD induced mild inflammation in the medulla, suggesting that it affected the proliferation of NSCs and NPCs.

Ruscogenin Exerts Anxiolytic-Like Effect via Microglial NF-κB/MAPKs/NLRP3 Signaling Pathways in Mouse Model of Chronic Inflammatory Pain

Long-term inflammation can cause chronic pain and trigger patients' anxiety by sensitizing the central nervous system. However, effective drugs with few side effects for treating chronic pain-induced anxiety are still lacking. The anxiolytic and anti-inflammatory effects of ruscogenin (RUS), an important active compound in Ophiopogon japonicus, were evaluated in a mouse model of chronic inflammatory pain and N9 cells. RUS (5, 10, or 20 mg/kg/day, i.g.) was administered once daily for 7 days after CFA injection; pain- and anxiety-like behaviors were assessed in mice. Anti-inflammatory effect of RUS (0.1, 1, 10 μM) on N9 microglia after LPS treatment was evaluated. Inflammatory markers (TNF-α, IL-1β, IL-6, CD86, IL-4, ARG-1, and CD206) were measured using qPCR. The levels of IBA1, ROS, NF-κB, TLR4, P-IKK, P-IκBα, and P65, MAPKs (ERK, JNK, and P38), NLRP3 (caspase-1, ASC, and NLRP3) were detected by Western blotting or immunofluorescence staining. The potential target of RUS was validated by molecular docking and adeno-associated virus injection. Mice in CFA group exhibited allodynia and anxiety-like behaviors. LPS induced neuroinflammation in N9 cells. Both CFA and LPS increased the levels of IBA1, ROS, and inflammatory markers. RUS (10 mg/kg in vivo and 1 μM in vitro) alleviated these alterations through NF-κB/MAPKs/NLRP3 signaling pathways but had no effect on pain hypersensitivity. TLR4 strongly interacted with RUS, and TLR4 overexpression abolished the effects of RUS on anxiety and neuroinflammation. RUS exerts anti-inflammatory and anxiolytic effects via TLR4-mediated NF-κB/MAPKs/NLRP3 signaling pathways, which provides a basis for the treatment of chronic pain-induced anxiety.

The role of microglia in neurological diseases with involvement of extracellular vesicles

As a subset of mononuclear phagocytes in the central nervous system, microglia play a crucial role in immune defense and homeostasis maintenance. Microglia can regulate their states in response to specific signals of health and pathology. Microglia-mediated neuroinflammation is a pathological hallmark of neurodegenerative diseases, neurological damage and neurological tumors, underscoring its key immunoregulatory role in these conditions. Intriguingly, a substantial body of research has indicated that extracellular vesicles can mediate intercellular communication by transporting cargoes from parental cells, a property that is also reflected in microenvironmental signaling networks involving microglia. Based on the microglial characteristics, we briefly outline the biological features of extracellular vesicles and focus on summarizing the integrative role played by microglia in the maintenance of nervous system homeostasis and progression of different neurological diseases. Extracellular vesicles may engage in the homeostasis maintenance and pathological process as a medium of intercellular communication. Here, we aim to provide new insights for further exploration of neurological disease pathogenesis, which may provide theoretical foundations for cell-free therapies.

Paeoniflorin regulates microglia-astrocyte crosstalk, inhibits inflammatory response, and alleviates neuropathic pain through HSP90AA1/HMGB1 signaling pathway

Given the unclear, complex pathogenesis of neuropathic pain and the potential of paeoniflorin in relieving neuropathic pain, this study aimed to further clarify the therapeutic effect of paeoniflorin on neuropathic pain and to preliminarily explore the possible protective mechanisms of paeoniflorin. Chronic constrictive injury-induced Sprague Dawley rats and lipopolysaccharide-induced BV-2 cells were used for in vivo and in vitro experiments, respectively. The exosome uptake assay of mouse astrocytes (PKH-67 fluorescent labeling) and the mechanical nociceptive assay (the von Frey fibrous filaments) were performed. The effects of paeoniflorin and its downstream mechanisms on microglial and astrocyte activation, inflammation-associated proteins and exosome marker were determined. Paeoniflorin alleviated mechanical abnormal pain, decreased levels of ionized calcium binding adapter molecule-1 (Iba-1), glial fibrillary acidic protein, Heat Shock Protein 90 Alpha Family Class A Member 1 (HSP90AA1, inflammatory factor) and High Mobility Group Box 1 (HMGB1, inflammation-related protein), and inhibited neuronal apoptosis in chronic constrictive injury rats or lipopolysaccharide-induced BV-2 cells. However, these effects were offset by HSP90AA1 overexpression in lipopolysaccharide-induced BV-2 cells. Exosomes of BV-2 cells could be absorbed by mouse astrocytes. In addition, HSP90AA1 overexpression reversed the effects of paeoniflorin on HMGB1 expression and inflammatory factors and proteins in mouse astrocytes co-cultured with exosome. Collectively, paeoniflorin alleviates neuropathic pain and inhibits inflammatory responses in chronic constrictive injury by modulating microglia-astrocyte crosstalk through HSP90AA1/HMGB1 pathways, which further evidences the potential of paeoniflorin in the treatment of neuropathic pain.

Vagus nerve stimulation with a small total charge transfer improves motor behavior and reduces neuroinflammation in a mouse model of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN). Conventional treatments are ineffective in reversing disease progression. Recently, the therapeutic and rehabilitation potential of vagus nerve stimulation (VNS) in PD has been explored. However, the underlying mechanisms remain largely unknown. In this study, we investigated the neuroprotective effects of VNS in a lateral lesioned mice model of PD. Excluding controls, experimental mice received cuff electrode implantation on the left vagus nerve and 6-hydroxydopamine administration into the bilateral striatum. After ten days, electrical stimulation was delivered for 11 consecutive days onto PD animals. Behavioral tests were performed after stimulation. The expression of TH, Iba-1, GFAP, adrenergic receptors and cytokines in the SN and striatum was detected by immunofluorescence or western blotting. The activity of noradrenergic neurons in the locus coeruleus (LC) was also measured. Our results suggest that VNS improved behavioral performance in rod rotation, open field tests and pole-climbing tests in PD mice, accompanied by a decrease in the loss of dopaminergic neurons in the SN and increased TH expression in the striatum. Neuroinflammation-related factors, such as GFAP, Iba-1, TNF-α and IL-1β were also suppressed in PD mice after VNS compared to those without treatment. Furthermore, the proportion of c-Fos-positive noradrenergic neurons in the LC increased when animals received VNS. Additionally, the expression of the adrenergic receptor of α1BR was also upregulated after VNS compared to PD mice. In conclusion, VNS has potential as a novel PD therapy for neuroprotective effects, and indicate that activation of norepinephric neurons in LC may plays an important role in VNS treatment for PD.

Crosstalk between peripheral inflammation and brain: Focus on the responses of microglia and astrocytes to peripheral challenge

A growing body of evidence supports the link between peripheral inflammation and impairment of neurologic functions, including mood and cognitive abilities. The pathogenic event connecting peripheral inflammation and brain dysfunction is represented by neuroinflammation, a pathogenic phenomenon that provides an important contribution to neurodegeneration and cognitive decline also in Alzheimer's, Parkinson's, Huntington's diseases, as well as in Multiple Sclerosis. It is driven by resident brain immune cells, microglia and astrocytes, that acquire an activated phenotype in response to proinflammatory molecules moving from the periphery to the brain parenchyma. Although a huge progress has been made in clarifying cellular and molecular mechanisms bridging peripheral and central inflammation, a clear picture has not been achieved so far. Therefore, experimental models are of crucial relevance to clarify knowledge gaps in this regard. Many findings demonstrate that systemic inflammation induced by pathogen-associated molecular patterns, such as lipopolysaccharide (LPS), is able to trigger neuroinflammation. Therefore, LPS-administration is widely considered a useful tool to study this phenomenon. On this basis, the present review will focus on in vivo studies based on acute and subacute effects of systemic administration of LPS, with special attention on the state of art of microglia and astrocyte response to peripheral challenge.

The evolving pathophysiology of TBI and the advantages of temporally-guided combination therapies

Several clinical and experimental studies have demonstrated that traumatic brain injury (TBI) activates cascades of biochemical, molecular, structural, and pathological changes in the brain. These changes combine to contribute to the various outcomes observed after TBI. Given the breadth and complexity of changes, combination treatments may be an effective approach for targeting multiple detrimental pathways to yield meaningful improvements. In order to identify targets for therapy development, the temporally evolving pathophysiology of TBI needs to be elucidated in detail at both the cellular and molecular levels, as it has been shown that the mechanisms contributing to cognitive dysfunction change over time. Thus, a combination of individual mechanism-based therapies is likely to be effective when maintained based on the time courses of the cellular and molecular changes being targeted. In this review, we will discuss the temporal changes of some of the key clinical pathologies of human TBI, the underlying cellular and molecular mechanisms, and the results from preclinical and clinical studies aimed at mitigating their consequences. As most of the pathological events that occur after TBI are likely to have subsided in the chronic stage of the disease, combination treatments aimed at attenuating chronic conditions such as cognitive dysfunction may not require the initiation of individual treatments at a specific time. We propose that a combination of acute, subacute, and chronic interventions may be necessary to maximally improve health-related quality of life (HRQoL) for persons who have sustained a TBI.

Cytokine-induced reprogramming of human macrophages toward Alzheimer's disease-relevant molecular and cellular phenotypes in vitro

Myeloid cells including brain-resident (microglia) and peripheral macrophages play a crucial role in various pathological conditions, including neurodegenerative disorders like Alzheimer's disease (AD). They respond to disruption of tissue homeostasis associated with disease conditions by acquiring various transcriptional and functional states. Experimental investigation of these states is hampered by the lack of tools that enable accessible and robust reprogramming of human macrophages toward Alzheimer's disease-relevant molecular and cellular phenotypes in vitro. In this study, we investigated the ability of a cytokine mix, including interleukin-4 (IL4), colony stimulating factor 1 (CSF1/MCSF), interleukin 34 (IL34) and transforming growth factor beta (TGFβ), to induce reprogramming of cultured human THP-1 macrophages. Our results indicate this treatment led to significant transcriptomic changes, driving THP-1 macrophages towards a transcriptional state reminiscent of disease-associated microglia (DAM) and lipid-associated macrophages (LAM) collectively referred to as DLAM. Transcriptome profiling revealed gene expression changes related to oxidative phosphorylation, lysosome function, and lipid metabolism. Single-cell RNA sequencing revealed an increased proportion of DLAM clusters in cytokine mix-treated THP-1 macrophages. Functional assays demonstrated alterations in cell motility, phagocytosis, lysosomal activity, and metabolic and energetic profiles. Our findings provide insights into the cytokine-mediated reprogramming of macrophages towards disease-relevant states, highlighting their role in neurodegenerative diseases and potential for therapeutic development.

In Vitro Assessment of the Neuroprotective Effects of Pomegranate (Punica granatum L.) Polyphenols Against Tau Phosphorylation, Neuroinflammation, and Oxidative Stress

BACKGROUND

Oxidative stress and chronic inflammation, at both the systemic and the central level, are critical early events in atherosclerosis and Alzheimer's disease (AD).

PURPOSE

To investigate the oxidative stress-, inflammation-, and Tau-phosphorylation-lowering effects of pomegranate polyphenols (PPs) (punicalagin, ellagic acid, peel, and aril extracts).

METHODS

We used flow cytometry to quantify the protein expression of proinflammatory cytokines (IL-1β) and anti-inflammatory mediators (IL-10) in THP-1 macrophages, as well as M1/M2 cell-specific marker (CD86 and CD163) expression in human microglia HMC3 cells. The IL-10 protein expression was also quantified in U373-MG human astrocytes. The effect of PPs on human amyloid beta 1-42 (Aβ1-42)-induced oxidative stress was assessed in the microglia by measuring ROS generation and lipid peroxidation, using 2',7'-dichlorofluorescein diacetate (DCFH-DA) and thiobarbituric acid reactive substance (TBARS) tests, respectively. Neuronal viability and cell apoptotic response to Aβ1-42 toxicity were assayed using the MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay and the annexin-V-FITC apoptosis detection kit, respectively. Finally, flow cytometry analysis was also performed to evaluate the ability of PPs to modulate Aβ1-42-induced Tau-181 phosphorylation (pTau-181).

RESULTS

Our data indicate that PPs are significantly (p < 0.05) effective in countering Aβ1-42-induced inflammation through increasing the anti-inflammatory cytokines (IL-10) in U373-MG astrocytes and THP1 macrophages and decreasing proinflammatory marker (IL-1β) expression in THP1 macrophages. The PPs were also significantly (p < 0.05) effective in inducing the phenotypic transition of THP-1 macrophages and microglial cells from M1 to M2 by decreasing CD86 and increasing CD163 surface receptor expression. Moreover, our treatments have a significant (p < 0.05) beneficial impact on oxidative stress, illustrated in the reduction in TBARS and ROS generation. Our treatments have significant (p < 0.05) cell viability improvement capacities and anti-apoptotic effects on human H4 neurons. Furthermore, our results suggest that Aβ1-42 significantly (p < 0.05) increases pTau-181. This effect is significantly (p < 0.05) attenuated by arils, peels, and punicalagin and drastically reduced by the ellagic acid treatment.

CONCLUSION

Overall, our results attribute to PPs anti-inflammatory, antioxidant, anti-apoptotic, and anti-Tau-pathology potential. Future studies should aim to extend our knowledge of the potential role of PPs in Aβ1-42-induced neurodegeneration, particularly concerning its association with the tauopathy involved in AD.

Erjingpill bionic cerebrospinal fluid alleviates LPS-induced inflammatory response in BV2 cells by inhibiting glycolysis via mTOR

ETHNOPHARMACOLOGICAL RELEVANCE

Erjingpill, a well-known prescription documented in the classic Chinese medical text "Shengji Zonglu," has been proven to have effective alleviating effects on neuroinflammation in Alzheimer's disease (AD). Although the alterations in microglial cell glycolysis are known to play a crucial role in the development of neuroinflammation, it remains unclear whether the anti-neuroinflammatory effects of Erjingpill are associated with its impact on microglial cell glycolysis.

AIM OF THE STUDY

This study aims to determine whether Erjingpill exerts anti-neuroinflammatory effects by influencing microglial cell glycolysis.

MATERIALS AND METHODS

Firstly, Erjingpill decoction was prepared into an Erjingpill bionic cerebrospinal fluid (EBCF) through a process of in vitro intestinal absorption, hepatocyte incubation, and blood-brain barrier (BBB) transcytosis. Subsequently, UPLC/Q-TOF-MS/MS technology was used to analyze the compounds in Erjingpill and EBCF. Next, an in vitro neuroinflammation model was established by LPS-induced BV2 cells. The impact of EBCF on BV2 cell proliferation activity was evaluated using the CCK-8 assay, while the NO release was assessed using the Griess assay. Additionally, mRNA levels of pro-inflammatory factors (IL-1β, IL-6, TNF-α, and COX-2), anti-inflammatory factors (IL-10, IL-4, Arg-1, and TGF-β), M1 microglial markers (iNOS, CD86), M2 microglial markers (CD36, CD206), and glycolytic enzymes (HK2, GLUT1, PKM, and LDHA) were measured using qPCR. Furthermore, protein expression of microglial activation marker Iba-1, M1 marker iNOS, and M2 marker CD206 were identified through immunofluorescence, while concentrations of pro-inflammatory cytokines IL-1β and TNF-α were measured using ELISA. Enzymatic activity of glycolytic enzymes (HK, PK, and LDH) was assessed using assay kits, and the protein levels of pro-inflammatory factors (IL-1β, iNOS, and COX-2), anti-inflammatory factors (IL-10 and Arg-1), and key glycolytic proteins GLUT1 and PI3K/AKT/mTOR were detected by Western blot.

RESULTS

Through the analysis of Erjingpill and EBCF, 144 compounds were identified in Erjingpill and 40 compounds were identified in EBCF. The results demonstrated that EBCF effectively inhibited the elevation of inflammatory factors and glycolysis levels in LPS-induced BV2 cells, promoted polarization of M1 microglial cells towards the M2 phenotype, and suppressed the PI3K/AKT/mTOR inflammatory pathway. Moreover, EBCF alleviated LPS-induced BV2 cell inflammatory response by modulating mTOR to inhibit glycolysis.

CONCLUSIONS

EBCF exhibits significant anti-neuroinflammatory effects, likely attributed to its modulation of mTOR to inhibit microglial cell glycolysis. This study furnishes experimental evidence supporting the clinical utilization of Erjingpill for preventing and treating AD.

Brain inflammaging in the pathogenesis of late-life depression

Late-life depression (LLD) is a prevalent mental disorder among older adults. Previous studies revealed that many pathologic factors are associated with the onset and development of LLD. However, the precise mechanisms that cause LLD remain elusive. Aging induces chronic inflammatory changes mediated by alterations of immune responses. The chronic systemic inflammation termed "inflammaging" is linked to the etiology of aging-related disorders. Aged microglia induce senescence-associated secretory phenotype (SASP) and transition to M1-phenotype, cause neuroinflammation, and diminish neuroprotective effects. In addition, there is an age-dependent loss of blood-brain barrier (BBB) integrity. As the BBB breakdown can lead to invasion of immune cells into brain parenchyma, peripheral immunosenescence may cause microglial activation and neuroinflammation. Therefore, it is suggested that these mechanisms related to brain inflammaging may be involved in the pathogenesis of LLD. In this review, we described the role of brain inflammaging in LLD. Pharmacologic approaches to prevent brain inflammaging appears to be a promising strategy for treating LLD.

Intestinal dysbiosis causes spatial memory impairment in alcohol-exposed male mice by inducing neuroinflammation

Alcohol abuse damages the brain and triggers cognitive impairment. Intestinal dysbiosis has recently been shown to be involved in psychiatric disorders, which suggests the possibility of intestine-to-brain interactions in the development of alcohol abuse. In this study, chronic intermittent alcohol exposure (CIAE) model was established in C57BL/6 male mice and the spatial memory were detected by Barnes maze (n = 16/group). The fecal microbiota and its metabolites were detected by 16S rDNA sequencing and non-target liquid chromatograph mass spectrometer (LC-MS) (n = 8/group). Effects of alcohol on intestinal barrier and blood-brain barrier (BBB) permeability were detected by Evens blue leakage assay (n = 4/group), and the activation state of microglia and TLR4 expression were conducted by immunofluorescence co-localization (n = 4/group). The morphological changes of microglia were analyzed with Image J Analyze Skeleton software, and the protein levels of TLR4 and inflammatory factors were detected by Western Blot (n = 8/group). Results indicated that alcohol alters the components of fecal microbiota and metabolites, and damages the intestinal barrier and BBB, leading to spatial memory impairment in mice. By giving mice specific prebiotics (n = 16/group), we pointed out that increased endotoxin coming from Gram negative bacteria such as lipopolysaccharides (LPS) cross the BBB to activate microglia and inflammatory pathways in the prefrontal cortical (PFC) and hippocampus (HIP), releasing inflammatory factors and resulting in neuroinflammation. Thus, the fecal microbiota seems to be a potential target in the management of alcoholic brain disease.

Immune Checkpoint VISTA Negatively Regulates Microglia Glycolysis and Activation via TRIM28-Mediated Ubiquitination of HK2 in Sepsis-Associated Encephalopathy

V-domain immunoglobulin suppressor of T cell activation (VISTA) has emerged as a crucial player in the pathogenesis of neurological disorders. However, the specific mechanism by which VISTA regulates microglial activation remains unclear. Septic mice were intracerebroventricularly injected with an agonistic anti-VISTA antibody or isotype control. To investigate the differential gene expression profiles, RNA sequencing was conducted on brain tissues from these mice. In vitro, VISTA was silenced in BV2 microglial cells using shRNA. Co-immunoprecipitation assays were performed to identify protein-protein interactions involving hexokinase 2 (HK2), and ubiquitination assays were used to examine the ubiquitination status of HK2. Additionally, BV2 cells were transfected with either tripartite motif-containing 28 overexpression plasmids (TRIM28-PcDNA3.1( +)) or TRIM28-specific siRNA to assess the impact of TRIM28 on VISTA-mediated microglial activation. The cellular glycolytic activity was measured using extracellular acidification rate assays, and proinflammatory cytokine and chemokines were quantified. Treatment with VISTA antibodies significantly alleviated microglial activation and prevented cognitive impairment in septic mice. In contrast, VISTA silencing in BV2 microglia led to the overexpression of proinflammatory cytokines and enhanced glycolysis in an HK2-dependent manner. Mechanistically, HK2 expression was regulated by the E3 ubiquitin ligase TRIM28 through K63-linked ubiquitination, which targeted HK2 for proteasomal degradation. Furthermore, knockdown of TRIM28 reduced the elevated glycolysis and proinflammatory response observed in VISTA-silenced microglia. VISTA modulates microglial activation in sepsis-associated encephalopathy by regulating HK2 expression through TRIM28-mediated K63-linked ubiquitination. These findings highlight VISTA as a potential therapeutic target for modulating microglial activation in sepsis.

Ouabain Ameliorates Alzheimer's Disease-Associated Neuropathology and Cognitive Impairment in FAD4T Mice

Background: Alzheimer's disease (AD) is a common clinical neurodegenerative disorder, primarily characterized by progressive cognitive decline and behavioral abnormalities. The hallmark pathological changes of AD include widespread neuronal degeneration, plaques formed by the deposition of amyloid β-protein (Aβ), and neurofibrillary tangles (NFTs). With the acceleration of global aging, the incidence of AD is rising year by year, making it a major global public health concern. Due to the complex pathology of AD, finding effective interventions has become a key focus of research. Ouabain (OUA), a cardiac glycoside, is well-known for its efficacy in treating heart disease. Recent studies have also indicated its potential in AD therapy, although its exact mechanism of action remains unclear. Methods: This study integrates bioinformatics, multi-omics technologies, and in vivo and in vitro experiments to investigate the effects of OUA on the pathophysiological changes of AD and its underlying molecular mechanisms. Results: This study analyzed the expression of the triggering receptor expressed on myeloid cells 2 (TREM2) across different stages of AD using bioinformatics. Serum samples from patients were used to validate soluble TREM2 (sTREM2) levels. Using an Aβ1-42-induced microglial cell model, we confirmed that OUA enhances the PI3K/AKT signaling pathway activation by upregulating TREM2, which reduces neuroinflammation and promotes the transition of microglia from an M1 proinflammatory state to an M2 anti-inflammatory state. To evaluate the in vivo effects of OUA, we assessed the learning and memory capacity of FAD4T transgenic mice using the Morris water maze and contextual fear conditioning tests. We used real-time quantitative PCR, immunohistochemistry, and Western blotting to measure the expression of inflammation-associated cytokines and to assess microglia polarization. OUA enhances cognitive function in FAD4T mice and has been confirmed to modulate microglial M1/M2 phenotypes both in vitro and in vivo. Furthermore, through bioinformatics analysis, molecular docking, and experimental validation, TREM2 was identified as a potential target for OUA. It regulates PI3K/Akt signaling pathway activation, playing a crucial role in OUA-mediated M2 microglial polarization and its anti-inflammatory effects in models involving Aβ1-42-stimulated BV-2 cells and FAD4T mice. Conclusions: These findings indicate that OUA exerts anti-neuroinflammatory effects by regulating microglial polarization, reducing the production of inflammatory mediators, and activating the PI3K/Akt signaling pathway. Given its natural origin and dual effects on microglial polarization and neuroinflammation, OUA emerges as a promising therapeutic candidate for neuroinflammatory diseases such as AD.

A Novel Mitochondrial-Related Gene Signature for the Prediction of Prognosis and Therapeutic Efficacy in Lower-Grade Glioma

Lower-grade glioma (LGG) is a common primary brain tumor with a highly heterogeneous clinical presentation, and its prognosis cannot be accurately predicted by current histopathology. It has been found that mitochondria play an important role in hypoxia, angiogenesis, and energy metabolism in glioma, and mitochondrial function may have an important impact on LGG prognosis. The goal of this study was to develop a novel prognostic model based on Mitochondrial-related genes (MRGs). We first analyzed the somatic alterations profiles of MRGs in patients with LGG and found that somatic alterations were common in LGG and correlated with prognosis. Using RNA-seq data from TCGA and CGGA, 12 prognosis-related MRGs were identified to construct a mitochondrial activation score (MiAS) model by combining univariate regression and LASSO regression analysis. The model and nomogram were evaluated using the area under the ROC curve with AUC = 0.910. The model was closely correlated with the clinical characteristics of LGG patients and performed well in predicting the prognosis of LGG patients with significantly shorter overall survival (OS) time in the high-MiAS group. GSVA and GSEA results showed that oxidative stress, pro-cancer, and immune-related pathways were significantly enriched in the high-MiAS group. CIBERSORT results showed that MiAS was significantly associated with immune cell infiltration in LGG. Macrophage M1 and follicular helper T cells had increased infiltration in the high-MiAS group. TIDE predicted a better immunotherapy outcome in patients in the low-MiAS group. Finally, using data from the CTRPv2 and GDSC2 datasets to assess chemotherapy response in LGG, it was predicted that the chemotherapeutic agents AZD6482, MG-132, and PLX-4720 might be potential agents for patients in the high-MiAS group of LGG. In addition, we performed in vitro experiments and found that knockdown of OCIAD2 expression reduced the abilities of glioma cells to proliferate, migrate, and invade. In contrast, overexpression of OCIAD2 enhanced these abilities of glioma cells. This study found that MRGs were correlated with LGG patient prognosis, which is expected to provide new treatment strategies for LGG patients with different MiAS.

Rhein inhibits M1 polarization of BV2 microglia through MAPK/IκB signalling pathway and reduces neurotoxicity caused by neuroinflammation

BACKGROUND

Rhein is an anthraquinone compound with anti-inflammatory pharmacological activity. It has been found to play a neuroprotective role in neurological diseases, but the neuroprotective mechanism of rhein remains unclear.

METHODS

SH-SY5Y cells serving as neuron-like cells and BV2 microglia were used. The toxicity of rhein on BV2 microglia and the viability of SH-SY5Y cells were measured by CCK-8 assay. The mRNA expression and secretion of pro-inflammatory cytokines were detected by qPCR and ELISA. Iba1, CD86 and pathway signalling protein in BV2 microglia were assessed by Western blot and immunofluorescence. Apoptosis of SH-SY5Y cells exposed to neuroinflammation was analysed through flow cytometry.

RESULTS

Rhein inhibited MAPK/IκB signalling pathways. Further studies revealed that rhein inhibited the production of pro-inflammatory cytokines TNF-α, IL-6, IL-1β and iNOS in BV2 cells and also inhibited the expression of M1 polarization markers Iba1 and CD86 in BV2 cells. Furthermore, rhein reduced the apoptotic rate and restored cell viability of SH-SY5Y cells exposed to neuroinflammation.

CONCLUSIONS

Our study demonstrated that rhein inhibited microglia M1 polarization via MAPK/IκB signalling pathway and protected nerve cells through suppressing neuroinflammation.

The impact of neuroinflammation on neuronal integrity

Neuroinflammation, characterized by a complex interplay among innate and adaptive immune responses within the central nervous system (CNS), is crucial in responding to infections, injuries, and disease pathologies. However, the dysregulation of the neuroinflammatory response could significantly affect neurons in terms of function and structure, leading to profound health implications. Although tremendous progress has been made in understanding the relationship between neuroinflammatory processes and alterations in neuronal integrity, the specific implications concerning both structure and function have not been extensively covered, with the exception of perspectives on glial activation and neurodegeneration. Thus, this review aims to provide a comprehensive overview of the multifaceted interactions among neurons and key inflammatory players, exploring mechanisms through which inflammation influences neuronal functionality and structural integrity in the CNS. Further, it will discuss how these inflammatory mechanisms lead to impairment in neuronal functions and architecture and highlight the consequences caused by dysregulated neuronal functions, such as cognitive dysfunction and mood disorders. By integrating insights from recent research findings, this review will enhance our understanding of the neuroinflammatory landscape and set the stage for future interventions that could transform current approaches to preserve neuronal integrity and function in CNS-related inflammatory conditions.

Naringin and Naringenin: Potential Multi-Target Agents for Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common forms of neurodegenerative dementia. The etiology of AD is multifactorial, and its complex pathophysiology involves tau and amyloid-β deposition, increased oxidative stress, neuroinflammation, metabolic disorders, and massive neuronal loss. Due to its complex pathology, no effective cure for AD has been found to date. Therefore, there is an unmet clinical need for the development of new drugs against AD. Natural products are known to be good sources of compounds with pharmacological activity and have potential for the development of new therapeutic agents. Naringin, a naturally occurring flavanone glycoside, is predominantly found in citrus fruits and Chinese medicinal herbs. Mounting evidence shows that naringin and its aglycone, naringenin, have direct neuroprotective effects on AD, such as anti-amyloidogenic, antioxidant, anti-acetylcholinesterase, and anti-neuroinflammatory effects, as well as metal chelation. Furthermore, they are known to improve disordered glucose/lipid metabolism, which is a high risk factor for AD. In this review, we summarize the latest data on the impact of naringin and naringenin on the molecular mechanisms involved in AD pathophysiology. Additionally, we provide an overview of the current clinical applications of naringin and naringenin. The novel delivery systems for naringin and naringenin, which can address their widespread pharmacokinetic limitations, are also discussed. The literature indicates that naringin and naringenin could be multilevel, multitargeted, and multifaceted for preventing and treating AD.

M2 Microglia-Derived Exosomes Protect Against Glutamate-Induced HT22 Cell Injury via Exosomal miR-124-3p

As one of the most serious complications of sepsis, sepsis-associated encephalopathy has not been effectively treated or prevented. Exosomes, as a new therapeutic method, play a protective role in neurodegenerative diseases, stroke and traumatic brain injury in recent years. The purpose of this study was to investigate the role of exosomes in glutamate (Glu)-induced neuronal injury, and to explore its mechanism, providing new ideas for the treatment of sepsis-associated encephalopathy. The neuron damage model induced by Glu was established, and its metabolomics was analyzed and identified. BV2 cells were induced to differentiate into M1 and M2 subtypes. After the exosomes from both M1-BV2 cells and M2-BV2 cells were collected, exosome morphological identification was performed by transmission electron microscopy and exosome-specific markers were also detected. These exosomes were then cocultured with HT22 cells. CCK-8 method and LDH kit were used to detect cell viability and toxicity. Cell apoptosis, mitochondrial membrane potential and ROS content were respectively detected by flow cytometry, JC-1 assay and DCFH-DA assay. MiR-124-3p expression level was detected by qRT-PCR and Western blot. Bioinformatics analysis and luciferase reporter assay predicted and verified the relationship between miR-124-3p and ROCK1 or ROCK2. Through metabolomics, 81 different metabolites were found, including fructose, GABA, 2, 4-diaminobutyric acid, etc. The enrichment analysis of differential metabolites showed that they were mainly enriched in glutathione metabolism, glycine and serine metabolism, and urea cycle. M2 microglia-derived exosomes could reduce the apoptosis, decrease the accumulation of ROS, restore the mitochondrial membrane potential and the anti-oxidative stress ability in HT22 cells induced by Glu. It was also found that the protective effect of miR-124-3p mimic on neurons was comparable to that of M2-EXOs. Additionally, M2-EXOs might carry miR-124-3p to target ROCK1 and ROCK2 in neurons, affecting ROCK/PTEN/AKT/mTOR signaling pathway, and then reducing Glu-induced neuronal apoptosis. M2 microglia-derived exosomes may protect HT22 cells against Glu-induced injury by transferring miR-124-3p into HT22 cells, with ROCK being a target gene for miR-124-3p.

Unravelling the Road to Recovery: Mechanisms of Wnt Signalling in Spinal Cord Injury

Spinal cord injury (SCI) is a complex neurodegenerative pathology that consistently harbours a poor prognostic outcome. At present, there are few therapeutic strategies that can halt neuronal cell death and facilitate functional motor recovery. However, recent studies have highlighted the Wnt pathway as a key promoter of axon regeneration following central nervous system (CNS) injuries. Emerging evidence also suggests that the temporal dysregulation of Wnt may drive cell death post-SCI. A major challenge in SCI treatment resides in developing therapeutics that can effectively target inflammation and facilitate glial scar repair. Before Wnt signalling is exploited for SCI therapy, further research is needed to clarify the implications of Wnt on neuroinflammation during chronic stages of injury. In this review, an attempt is made to dissect the impact of canonical and non-canonical Wnt pathways in relation to individual aspects of glial and fibrotic scar formation. Furthermore, it is also highlighted how modulating Wnt activity at chronic time points may aid in limiting lesion expansion and promoting axonal repair.

An insight into the concept of neuroinflammation and neurodegeneration in Alzheimer's disease: targeting molecular approach Nrf2, NF-κB, and CREB

Alzheimer's disease (AD) is a most prevalent neurologic disorder characterized by cognitive dysfunction, amyloid-β (Aβ) protein accumulation, and excessive neuroinflammation. It affects various life tasks and reduces thinking, memory, capability, reasoning and orientation ability, decision, and language. The major parts responsible for these abnormalities are the cerebral cortex, amygdala, and hippocampus. Excessive inflammatory markers release, and microglial activation affect post-synaptic neurotransmission. Various mechanisms of AD pathogenesis have been explored, but still, there is a need to debate the role of NF-κB, Nrf2, inflammatory markers, CREB signaling, etc. In this review, we have briefly discussed the signaling mechanisms and function of the NF-ĸB signaling pathway, inflammatory mediators, microglia activation, and alteration of autophagy. NF-κB inhibition is a current strategy to counter neuroinflammation and neurodegeneration in the brain of individuals with AD. In clinical trials, numbers of NF-κB modulators are being examined. Recent reports revealed that molecular and cellular pathways initiate complex pathological competencies that cause AD. Moreover, this review will provide extensive knowledge of the cAMP response element binding protein (CREB) and how these nuclear proteins affect neuronal plasticity.

Microglial forkhead box O3a deficiency attenuates LPS-induced neuro-inflammation and depressive-like behaviour through regulating the expression of peroxisome proliferator-activated receptor-γ

BACKGROUND AND PURPOSE

Depression is closely linked with microglial activation and neuro-inflammation. Peroxisome proliferator-activated receptor-γ (PPAR-γ) plays an important role in M2 activation of microglia. Forkhead box (FOX) O3a has been implicated in the regulation of mood-relevant behaviour. However, little is known about the inflammatory mechanisms of in the microglia of the brain. Here, we have investigated the role of microglial FOXO3a/PPAR-γ in the development of depression.

EXPERIMENTAL APPROACH

The effect of FOXO3a on microglia inflammation was analysed in vitro and in lipopolysaccharide (LPS)-induced depression-like behaviours in vivo. ChIP-seq and Dual-luciferase reporter assays were used to confirm the interaction between FOXO3a and PPAR-γ. Behavioural changes were measured, while inflammatory cytokines, microglial phenotype and morphological properties were determined by ELISA, qRT-PCR, western blotting and immunostaining.

KEY RESULTS

Overexpression of FOXO3a significantly attenuated expression of PPAR-γ and enhanced the microglial polarization towards the M1 phenotype, while knockdown of FOXO3a had the opposite effect. FOXO3a binds to the promoters of PPAR-γ and decreases its transcription activity. Importantly, deacetylation and activation of FOXO3a regulate LPS-induced neuro-inflammation by inhibiting the expression of PPAR-γ in microglia cells, supporting the antidepressant potential of histone deacetylase inhibitors. Microglial FOXO3a deficiency in mice alleviated LPS-induced neuro-inflammation and depression-like behaviours but failed to reduce anxiety behaviour, whereas pharmacological inhibition of PPAR-γ by GW9662 restored LPS-induced microglial activation and depressive-like behaviours in microglial FOXO3a-deficient mice.

CONCLUSION AND IMPLICATIONS

FOXO3a/PPAR-γ axis plays an important role in microglial activation and depression, identifying a new therapeutic avenue for the treatment of major depression.

Z-ligustilide provides a neuroprotective effect by regulating the phenotypic polarization of microglia via activating Nrf2-TrxR axis in the Parkinson's disease mouse model

The polarization phenotype of microglia is critical in the progression of Parkinson's disease (PD). Molecules that can polarize microglia toward the M2 phenotype represent a promising class of compounds for anti-PD medications. Z-ligustilide (ZLG) is a naturally occurring enol ester with diverse pharmacological properties, especially in neuroprotection. For the first time, we investigated the effect of ZLG on anti-PD and elucidated its underlying mechanism. The results primarily showed that ZLG attenuated motor deficits in mice and prevented the loss of dopaminergic neurons in the substantia nigra. Mechanistically, ZLG alleviates oxidative stress-induced apoptosis of microglia by triggering the endogenous antioxidant system. Besides, ZLG modulated phenotypic polarization of the microglia through the activation of the Nrf2-TrxR axis, leading to microglia polarization towards the M2 phenotype. Taken together, our research showed that ZLG is a prospective therapy candidate for PD by altering microglia polarization and restoring redox equilibrium through the Nrf2-TrxR axis.

Mesenchymal Stem Cells Regulate Microglial Polarization via Inhibition of the HMGB1/TLR4 Signaling Pathway in Diabetic Retinopathy

Diabetic retinopathy (DR) is recognized as the most prevalent retinal degenerative disorder. Inflammatory response usually precedes microvascular alteration and is the primary factor of diabetic retinopathy. Activated microglia express many pro-inflammatory cytokines that exacerbate retina inflammation and disruption. In the present study, we found that MSCs alleviated blood-retina barrier (BRB) breakdown in diabetic rats, as evidenced by reduced retinal edema, decreased vascular leakage, and increased occludin expression. The MSC-treated retinal microglia exhibited reduced expression of M1-phenotype markers in the diabetic rats, including inducible nitric oxide synthase (iNOS), CD16, and pro-inflammatory cytokines. On the other hand, MSCs increased the expression of M2-phenotype markers, such as arginase-1 (Arg-1), CD206, and anti-inflammatory cytokines. HMGB1/TLR4 signaling pathway is activated in DR and inhibited after MSC treatment. Consistent with in vivo evidence, MSCs drove BV2 microglia toward M2 phenotype in vitro. Overexpression of HMGB1 in microglia reversed the effects of MSC treatment, suggesting HMGB1/TLR4 pathway is necessary for MSCs' regulatory effects on microglia polarization. Collectively, MSCs exert beneficial effects on DR by polarizing microglia from M1 toward M2 phenotype via inhibiting the HMGB1/TLR4 signaling pathway.

cGAS Deficiency Regulates the Phenotypic Polarization and Glycolysis of Microglia Through Lactylation in Hypoxic-Ischemic Encephalopathy Cell Model

Promoting the M2 phenotype polarization of microglia is of great significance in alleviating hypoxic-ischemic encephalopathy (HIE). The umbilical artery blood sample was collected to evaluate the expression of cGAS, and the aberrant expressed cGAS was verified in the oxygen glucose deprivation (OGD) microglia which was established to mimic HIE in vitro. Then the regulating role of cGAS on the transformation of microglia M2 phenotype polarization and glycolysis was investigated. Moreover, the lactylation of cGAS in OGD treated microglia was evaluated by western blot. cGAS was found to be highly expressed in umbilical artery blood of HIE group, and OGD treated microglia. OGD interference activated microglia into M1 phenotype by enhancing CD86 and suppressing CD206 levels; meanwhile, the microglia in OGD group highly expressed IL-1β, iNOS and TNF-α, and lowly expressed IL-4, IL-10, and Arg-1. Inhibition of cGAS promotes the transformation of microglia from M1 to M2 phenotype. Meanwhile, OGD increased ECAR and decreased OCR to regulate glycolysis, cGAS deficiency inhibits glycolysis in OGD treated microglia. Moreover, the pan lysine lactylation (Pan-Kla) levels and lactated cGAS levels in microglia were upregulated in the OGD group. Lactate reversed the effects of cGAS knockdown on microglia polarization and glycolysis. The present study reveals that the cGAS-mediated neuron injury is associated with high level of cGAS lactylation. Inhibition of cGAS promotes the M2 phenotype polarization of microglia and suppress glycolysis. Thereby, targeting cGAS provides a new strategy for the development of therapeutic agents against HIE.

Microglia signaling in health and disease - Implications in sex-specific brain development and plasticity

Microglia, the intrinsic neuroimmune cells residing in the central nervous system (CNS), exert a pivotal influence on brain development, homeostasis, and functionality, encompassing critical roles during both aging and pathological states. Recent advancements in comprehending brain plasticity and functions have spotlighted conspicuous variances between male and female brains, notably in neurogenesis, neuronal myelination, axon fasciculation, and synaptogenesis. Nevertheless, the precise impact of microglia on sex-specific brain cell plasticity, sculpting diverse neural network architectures and circuits, remains largely unexplored. This article seeks to unravel the present understanding of microglial involvement in brain development, plasticity, and function, with a specific emphasis on microglial signaling in brain sex polymorphism. Commencing with an overview of microglia in the CNS and their associated signaling cascades, we subsequently probe recent revelations regarding molecular signaling by microglia in sex-dependent brain developmental plasticity, functions, and diseases. Notably, C-X3-C motif chemokine receptor 1 (CX3CR1), triggering receptors expressed on myeloid cells 2 (TREM2), calcium (Ca2+), and apolipoprotein E (APOE) emerge as molecular candidates significantly contributing to sex-dependent brain development and plasticity. In conclusion, we address burgeoning inquiries surrounding microglia's pivotal role in the functional diversity of developing and aging brains, contemplating their potential implications for gender-tailored therapeutic strategies in neurodegenerative diseases.

Microglial activation and polarization in type 2 diabetes-related cognitive impairment: A focused review of pathogenesis

Microglia, as immune cells in the central nervous system, are closely related to cognitive impairment associated with type 2 diabetes (T2D). Preliminary explorations have investigated the relationship between T2D-related cognitive impairment and the activation and polarization of microglia. This review summarizes the potential mechanisms of microglial activation and polarization in the context of T2D. It discusses central inflammatory responses, neuronal apoptosis, amyloid-β deposition, and abnormal phosphorylation of Tau protein mediated by microglial activation and polarization, exploring the connections between microglial activation and polarization and T2D-related cognitive impairment from multiple perspectives. Additionally, this review provides references for future treatment targeting microglia in T2D-related cognitive impairment and for clinical translation.

Caveolin-1 protects retinal ganglion cells in glaucoma by reducing TLR4 and activating the Akt/PTEN signaling pathway

Glaucoma is a degenerative disease characterized by retinal ganglion cell (RGC) death and visual impairment caused by elevated intraocular pressure (IOP). Elevated IOP can activate microglia, which participate in ganglion cell injury. Based on the study of caveolin-1 (Cav-1) in glaucoma, we aimed to explore the effect and mechanism of Cav-1 on RGC apoptosis in mice with acute ocular hypertension (AOH). AOH mice were established, and Cav-1 was intravitreally injected. Retinal microglia and RGCs were isolated from neonatal mice. TUNEL staining, hematoxylin-eosin staining, immunohistochemistry, flow cytometry, PCR and western blotting were used to observe the effect of Cav-1 on RGCs and mouse retinas. The thickness of the whole retina and the inner retinal sublayer decreased significantly, retinal cell apoptosis increased after AOH injury, and Cav-1 treatment reversed the effect of AOH injury. In addition, Cav-1 treatment promoted the conversion of proinflammatory M1 microglia to anti-inflammatory M2 microglia. Microglia and RGCs were isolated from neonatal mice. Cav-1 protects RGCs from OGD/R-induced injury by changing the polarization status of retinal microglia in vitro. Further studies revealed that Cav-1 activated the Akt/PTEN signaling pathway and inhibited TLR4. Our study provides evidence that Cav-1 may be a promising therapeutic target for glaucoma.

Ginsenoside Rg1 ameliorates cerebral ischemia-reperfusion injury by regulating Pink1/ Parkin-mediated mitochondrial autophagy and inhibiting microglia NLRP3 activation

OBJECTIVE

This study aimed to further elucidate the mechanism of ginsenoside Rg1 in the treatment of cerebral ischemia-reperfusion.

METHODS

In this study, we observed the apoptosis of RM cells (microglia) after oxygen-glucose deprivation/reoxygenation (OGD/R) modeling before and after Rg1 administration, changes in mitochondrial membrane potential, changes in the content of Reactive oxygen species (ROS) and inflammatory vesicles NLR Family Pyrin Domain Containing 3 (NLRP3), and the expression levels of autophagy-related proteins, inflammatory factors, and apoptosis proteins. We further examined the pathomorphological changes in brain tissue, neuronal damage, changes in mitochondrial morphology and mitochondrial structure, and the autophagy-related proteins, inflammatory factors, and apoptosis proteins expression levels in CI/RI rats before and after administration of Rg1 in vivo experiments.

RESULTS

In vitro experiments showed that Rg1 induced mitochondrial autophagy, decreased mitochondrial membrane potential, and reduced ROS content thereby inhibiting NLRP3 activation, decreasing secretion of inflammatory factors and RM cell apoptosis by regulating the PTEN induced putative kinase 1(Pink1) /Parkin signaling pathway. In vivo experiments showed that Rg1 induced mitochondrial autophagy, inhibited NLRP3 activation, improved inflammatory response, and reduced apoptosis by regulating the Pink1/Parkin signaling pathway, and Rg1 significantly reduced the area of cerebral infarcts, improved the pathological state of brain tissue, and attenuated the neuronal damage, thus improving cerebral ischemia/reperfusion injury in rats.

CONCLUSION

Our results suggest that ginsenoside Rg1 can ameliorate cerebral ischemia-reperfusion injury by modulating Pink1/ Parkin-mediated mitochondrial autophagy in microglia and inhibiting microglial NLRP3 activation.

Changes in Type 1 Diabetes-Associated Gut Microbiota Aggravate Brain Ischemia Injury by Affecting Microglial Polarization Via the Butyrate-MyD88 Pathway in Mice

People with type 1 diabetes (T1D) have a significantly elevated risk of stroke, but the mechanism through which T1D worsens ischemic stroke remains unclear. This study was aimed at investigating the roles of T1D-associated changes in the gut microbiota in aggravating ischemic stroke and the underlying mechanism. Fecal 16SrRNA sequencing indicated that T1D mice and mice with transplantation of T1D mouse gut microbiota had lower relative abundance of butyric acid producers, f_Erysipelotrichaceae and g_Allobaculum, and lower content of butyric acid in feces. After middle cerebral artery occlusion (MCAO), these mice had poorer neurological outcomes and more severe inflammation, but higher expression of myeloid differentiation factor 88 (MyD88) in the ischemic penumbra; moreover, the microglia were inclined to polarize toward the pro-inflammatory type. Administration of butyrate to T1D mice in the drinking water alleviated the neurological damage after MCAO. Butyrate influenced the response and polarization of BV2 and decreased the production of inflammatory cytokines via MyD88 after oxygen-glucose deprivation/reoxygenation. Knocking down MyD88 in the brain alleviated neurological outcomes and decreased the concentrations of inflammatory cytokines in the brain after stroke in mice with transplantation of T1D mouse gut microbiota. Poor neurological outcomes and aggravated inflammatory responses of T1D mice after ischemic stroke may be partly due to differences in microglial polarization mediated by the gut microbiota-butyrate-MyD88 pathway. These findings provide new ideas and potential intervention targets for alleviating neurological damage after ischemic stroke in T1D.

Fish microglia: Beyond the resident macrophages of the central nervous system - A review of their morphofunctional characteristics

From classical to modern literature on microglia, the importance of the potential and variability of these immune cells in vertebrates has been pointed out. Recent aspects such as relationships and interactions between microglia and neurons in both normal and injured neural tissues, as well as their nexus with other organs and with the microbiota, or how these cells are modulated during development and adulthood are current topics of major interest. State-of-the-art research methodologies, including microscopy and potent in vivo imaging techniques, genomic and proteomic methods, current culture conditions together with the easy maintenance and manipulation of some fish embryos and adult specimens such as zebrafish (Danio rerio), have emerged and adapted to the phylogenetic position of some fish species. Furthermore, these advancements have facilitated the development of successful protocols aimed at addressing significant hypotheses and unresolved questions regarding vertebrate glia. The present review aims to analyse the available information on fish microglia, mainly the most recent one concerning teleosts, to establish an overview of their structural and immune functional features as a basis for their potentialities, heterogeneity, diversification, involvement, and relationships with neurons under normal and pathological conditions.

MicroRNA-195-5p Inhibits Intracerebral Hemorrhage-Induced Inflammatory Response and Neuron Cell Apoptosis

Intracerebral hemorrhage (ICH) is a severe condition characterized by bleeding within brain tissue. Primary brain injury in ICH results from a mechanical insult caused by blood accumulation, whereas secondary injury involves inflammation, oxidative stress, and disruption of brain physiology. miR-195-5p may participate in ICH pathology by regulating cell proliferation, oxidative stress, and inflammation. Therefore, we assessed the performance of miR-195-5p in alleviating ICH-induced secondary brain injury. ICH was established in male Sprague-Dawley rats (7 weeks old, 200-250 g) via the stereotaxic intrastriatal injection of type IV bacterial collagenase, after which miR-195-5p was administered intravenously. Neurological function was assessed using corner turn and forelimb grip strength tests. Protein expression was assessed by western blotting and ELISA. The miR-195-5p treatment significantly improved neurological function; modulated macrophage polarization by promoting anti-inflammatory marker (CD206 and Arg1) production and inhibiting pro-inflammatory marker (CD68 and iNOS) production; enhanced Akt signalling, reduced oxidative stress by increasing Sirt1 and Nrf2 levels, and attenuated inflammation by decreasing NF-κB activation; inhibited apoptosis via increased Bcl-2 and decreased cleaved caspase-3 levels; and regulated synaptic plasticity by modulating NMDAR2A, NMDAR2B, BDNF, and TrkB expression and ERK and CREB phosphorylation. In conclusion, miR-195-5p exerts neuroprotective effects in ICH by reducing inflammation and oxidative stress, inhibiting apoptosis, and restoring synaptic plasticity, ultimately restoring behavioral recovery, and represents a promising therapeutic agent that warrants clinical studies.

Repeated LPS induces training and tolerance of microglial responses across brain regions

BACKGROUND

Neuroinflammation is involved in the pathogenesis of almost every central nervous system disorder. As the brain's innate immune cells, microglia fine tune their activity to a dynamic brain environment. Previous studies have shown that repeated bouts of peripheral inflammation can trigger long-term changes in microglial gene expression and function, a form of innate immune memory.

METHODS AND RESULTS

In this study, we used multiple low-dose lipopolysaccharide (LPS) injections in adult mice to study the acute cytokine, transcriptomic, and microglia morphological changes that contribute to the formation of immune memory in the frontal cortex, hippocampus, and striatum, as well as the long-term effects of these changes on behavior. Training and tolerance of gene expression was shared across regions, and we identified 3 unique clusters of DEGs (2xLPS-sensitive, 4xLPS-sensitive, LPS-decreased) enriched for different biological functions. 2xLPS-sensitive DEG promoters were enriched for binding sites for IRF and NFkB family transcription factors, two key regulators of innate immune memory. We quantified shifts in microglia morphological populations and found that while the proportion of ramified and rod-like microglia mostly remained consistent within brain regions and sexes with LPS treatment, there was a shift from ameboid towards hypertrophic morphological states across immune memory states and a dynamic emergence and resolution of events of microglia aligning end-to-end with repeated LPS.

CONCLUSIONS

Together, findings support the dynamic regulation of microglia during the formation of immune memories in the brain and support future work to exploit this model in brain disease contexts.

Stress-induced NLRP3 inflammasome activation and myelin alterations in the hippocampus of PTSD rats

Inflammatory and myelin changes may contribute to the pathophysiology of post-traumatic stress disorder (PTSD). The NOD-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3), a brain inflammasome, is activated in the hippocampus of mice with PTSD. In other psychiatric disorders, NLRP3 expression has been associated with axonal myelination and demyelination. However, the association between NLRP3 and myelin in rats with PTSD remains unclear. Therefore, this study aims to investigate the relationship between the NLRP3 inflammasome and myelin in the hippocampus of rats with PTSD. A rat model of post-traumatic stress disorder was established using the single-prolonged stress (SPS) approach. Hippocampal tissues were collected for the detection of NLRP3 inflammasome-associated proteins and myelin basic protein at 3, 7, and 14 days after SPS. To further explore the relationship between NLRP3 and myelin, the NLRP3-specific inhibitor MCC950 was administered intraperitoneally to rats starting 72 h before SPS, and then alterations in NLRP3 inflammasome-associated proteins and myelin were observed in the PTSD and control groups. We found that NLRP3 and downstream related proteins were activated in the hippocampus of rats 3 days after SPS, and the myelin content in the hippocampus increased after SPS stress. MCC950 reduced the expression of NLRP3-related pathway proteins, improved anxiety behaviour and spatial learning memory impairment, and inhibited the increase in myelin content in the hippocampal region of rats after SPS. In conclusion the study indicates that NLRP3 has a significant role in the hippocampal region of rats with PTSD. Inhibition of the NLRP3 inflammasome could be a potential target for treating PTSD.

BV2 Microglial Cell Activation/Polarization Is Influenced by Extracellular Vesicles Released from Mutated SOD1 NSC-34 Motoneuron-like Cells

Microglia-mediated neuroinflammation is a key player in the pathogenesis of amyotrophic lateral sclerosis (ALS) as it can contribute to the progressive degeneration of motor neurons (MNs). Here, we investigated the role of mSOD1 NSC-34 MN-like cell-derived extracellular vesicles (EVs) in inducing the activation of BV2 microglial cells. NSC-34-released EVs were isolated by culture medium differential ultracentrifugation to obtain two fractions, one containing small EVs (diameter < 200 nm) and the other containing large EVs (diameter > 200 nm). BV2 cells were incubated with the two EV fractions for 12, 24, and 48 h to evaluate 1) the state of microglial inflammation through RT-PCR of IL-1β, IL-6, IL-4, and IL-10 and 2) the expression of proteins involved in inflammasome activation (IL-β and caspase 1), cell death (caspase 3), and glial cell recruitment (CXCR1), and presence of the TGFβ cytokine receptor (TGFβ-R2). The obtained results suggest a mSOD1 type-dependent polarization of BV2 cells towards an early neurotoxic phenotype and a late neuroprotective status, with an appearance of mixed M1 and M2 microglia subpopulations. A significant role in driving microglial cell activation is played by the TGFβ/CX3CR1 axis. Therefore, targeting the dysregulated microglial response and modulating neuroinflammation could hold promise as a therapeutic strategy for ALS.

Nanozymes in Alzheimer's disease diagnostics and therapy

Alzheimer's disease (AD) is a progressive neurodegenerative condition that has become an important public health problem of global concern, and the early diagnosis and etiological treatment of AD are currently the focus of research. In the course of clinical treatment, approved clinical drugs mainly serve to slow down the disease process by relieving patients' clinical symptoms. However, these drugs do not target the cause of the disease, and the lack of specificity of these drugs has led to undesirable side effects in treatment. Meanwhile, AD is mainly diagnosed by clinical symptoms and imaging, which does not have the advantage of early diagnosis. Nanozymes have been extensively investigated for the diagnosis and treatment of AD with high stability and specificity. Therefore, this review summarizes the recent advances in various nanozymes for AD diagnosis and therapy, including with peroxidase-like-activity gold nanozymes, iron nanozymes, superoxide dismutase-like- and catalase-like-activity selenium dioxide nanozymes, platinum nanozymes, and peroxidase-like palladium nanozymes, among others. A comprehensive analysis was conducted on the diagnostic and therapeutic characteristics of nanozyme therapy for AD, as well as the prospects and challenges of its clinical application. Our goal is to advance this emerging topic by building on our own work and the new insights we have learned from others. This review will assist researchers to quickly understand relevant nanozymes' therapeutic and diagnostic information and further advance the field of nanozymes in AD.

Observations on the efficacy of edaravone dexborneol in preventing post-stroke depression and its inflammatory mechanism: a prospective, randomized, control trial

Objective

This study aimed to observe the effect of edaravone dexborneol (EDB) on the incidence of early post-stroke depression (PSD) and explore its inflammatory mechanisms.

Methods

A prospective, randomized controlled study was conducted from January 2022 to June 2023, involving patients with acute ischemic stroke (AIS) at the Neurology Department of the Third Affiliated Hospital of Beijing University of Traditional Chinese Medicine. The control group received routine treatment, while the experimental group received routine combined EDB treatment. The main outcome measures included PSD incidence, Patient Health Questionnaire (PHQ-9) and Hamilton Depression Scale (HAMD) scores on days 14 and 30, and inflammatory factor levels on day 14.

Results

A total of 93 patients were included in the study, 51 in the experimental group and 42 in the control group. On day 14, the PSD incidence was 13.7% in the experimental group, lower than 31.0% in the control group (95%CI 0.127-0.996; p = 0.044). Compared to the control group, the experimental group showed significantly lower concentrations of pro-inflammatory cytokines IL-1β (95%CI 3.353-5.184), IL-6 (95%CI 2.694-3.426), TNF-α (95%CI 4.985-12.196), IFN-γ (95%CI 0.163-0.451), MCP-1 (95%CI 0.335-0.787), IL-17A (95%CI 0.543-1.024), and IL-23p19 (95%CI 1.677-1.959) (all p < 0.001), and higher levels of anti-inflammatory cytokines IL-4 (95%CI -1.087 to -0.941), IL-10 (95%CI -6.125 to -1.662), and IL-13 (95%CI -6.078 to -2.953) (all p ≤ 0.001). On day 30, the PSD incidence in the experimental group was 15.7%, lower than 40.5% in the control group (95%CI 0.103-0.725; p = 0.007). Compared with the control group, the experimental group had lower PHQ-9 scores on day 14 (95%CI 0.034-1.577; p = 0.041) and day 30 (95%CI 0.018-1.573; p = 0.045), and also had lower HAMD scores on day 14 (95% CI 0.281-2.856; p = 0.018) and day 30 (95% CI 0.647-3.482; p = 0.005).

Conclusion

EDB could reduce the incidence of early PSD, reduce pro-inflammatory cytokine levels, and elevate anti-inflammatory cytokine levels, which was possibly related to the anti-inflammatory mechanism of EDB.

Clinical trial registration

http://www.chictr.org.cn/, identifier [ChiCTR2300067750].

Microglia in physiological conditions and the importance of understanding their homeostatic functions in the arcuate nucleus

Microglia are highly dynamic cells that have been mainly studied under pathological conditions. The present review discusses the possible implication of microglia as modulators of neuronal electrical responses in physiological conditions and hypothesizes how these cells might modulate hypothalamic circuits in health and during obesity. Microglial cells studied under physiological conditions are highly diverse, depending on the developmental stage and brain region. The evidence also suggests that neuronal electrical activity modulates microglial motility to control neuronal excitability. Additionally, we show that the expression of genes associated with neuron-microglia interaction is down-regulated in obese mice compared to control-fed mice, suggesting an alteration in the contact-dependent mechanisms that sustain hypothalamic arcuate-median eminence neuronal function. We also discuss the possible implication of microglial-derived signals for the excitability of hypothalamic neurons during homeostasis and obesity. This review emphasizes the importance of studying the physiological interplay between microglia and neurons to maintain proper neuronal circuit function. It aims to elucidate how disruptions in the normal activities of microglia can adversely affect neuronal health.

Unraveling the Protective Role of Oleocanthal and Its Oxidation Product, Oleocanthalic Acid, against Neuroinflammation

Neuroinflammation is a critical aspect of various neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. This study investigates the anti-neuroinflammatory properties of oleocanthal and its oxidation product, oleocanthalic acid, using the BV-2 cell line activated with lipopolysaccharide. Our findings revealed that oleocanthal significantly inhibited the production of pro-inflammatory cytokines and reduced the expression of inflammatory genes, counteracted oxidative stress induced by lipopolysaccharide, and increased cell phagocytic activity. Conversely, oleocanthalic acid was not able to counteract lipopolysaccharide-induced activation. The docking analysis revealed a plausible interaction of oleocanthal, with both CD14 and MD-2 leading to a potential interference with TLR4 signaling. Since our data show that oleocanthal only partially reduces the lipopolysaccharide-induced activation of NF-kB, its action as a TLR4 antagonist alone cannot explain its remarkable effect against neuroinflammation. Proteomic analysis revealed that oleocanthal counteracts the LPS modulation of 31 proteins, including significant targets such as gelsolin, clathrin, ACOD1, and four different isoforms of 14-3-3 protein, indicating new potential molecular targets of the compound. In conclusion, oleocanthal, but not oleocanthalic acid, mitigates neuroinflammation through multiple mechanisms, highlighting a pleiotropic action that is particularly important in the context of neurodegeneration.

Low-Dose LPS Modulates Microglia/Macrophages Phenotypic Transformation to Amplify Rehabilitation Effects in Chronic Spinal Cord Injured (CSCI) Mice

Spinal cord injury (SCI) results in stalled motor function recovery under the chronic phase. One of the reasons due to the presence of ongoing inflammation. Therefore, regulating the status of immune cells may help reopen the window for neural repair, which represents a potential therapeutic target. In this study, we aimed to investigate whether this could be achieved in mice with cervical 5 crush CSCI (4 W) by utilizing a concentration of 0.5 mg/kg of lipopolysaccharide (LPS) to stimulate microglia/macrophages. Additionally, the mice underwent rehabilitation training for another 6 weeks. Our results showed that systemic injection of LPS enhanced the effects of forelimb rehabilitation training, as evaluated through single pellet grasping (SPG). Electrophysiological studies revealed the restoration of cortical drive to the injured side's forelimb muscles in the training combined with LPS group. Tract tracing studies demonstrated the reconstruction of cortical innervation to the cervical spinal cord. Furthermore, the levels of pro-inflammatory phenotype markers, such as inducible nitric oxide synthase (INOS) and CD68, decreased, while the expression of anti-inflammatory phenotype markers, including arginase 1 (ARG-1) and CD206, increased. Importantly, this phenotypic switch in microglia/macrophages was accompanied by an increase in phagocytic activity markers as indicated by BODIPY + IBA1 + staining. Collectively, our data suggests that low-dose LPS improves the effects of rehabilitation training by regulating the phenotypic transformation of microglia/macrophages in CSCI. This study provides a fresh perspective and intervention direction for the clinical treatment of chronic spinal cord injuries.

M1 polarization induction by lead and amyloid peptides in microglial cells: Implications for neurodegeneration process

Neurodegeneration in conditions like Alzheimer's and Parkinson's disease is influenced by genetic and environmental factors. This study explores the potential neurodegenerative effects of lead (Pb) toxicity and amyloid beta peptides (Aβp 1-40 and Aβp 25-35) by promoting M1 polarization in microglial cells. To this end, we investigated and observed that IC50 concentrations of Pb (22.8 μM) and Aβp 25-35(29.6 μM). Our results demonstrated significant Pb uptake (31.13% at 25 μM Pb) and increased intracellular ROS levels (77.1%) upon treatment with Pb in combination of both Aβp 1-40 and Aβp 25-35. Protein carbonylation significantly increased (73.12 nmol/mL) upon treatment with Pb in combination of both Aβp 1-40 and Aβp 25-35, indicating oxidative damage and compromised cellular defenses against oxidative stress along with elevated DNA oxidative damage (164.9 pg/mL of 8-OH-dG) upon treatment with Pb in combination with both Aβp 1-40 and Aβp 25-35. Microglial polarization showed elevated M1 markers (inducible nitric oxide synthase and cyclooxygenase 2) and reduced M2 markers (arginase-1 and cluster of differentiation 206), suggesting Pb's role in inducing neurodegenerative microglial polarization. These findings provide insights into the complex molecular events contributing to Pb-induced neurotoxicity and neurodegenerative diseases.

Multifaceted interactions between cancer cells and glial cells in brain metastasis

Cancer brain metastasis has a poor prognosis, is commonly observed in clinical practice, and the number of cases is increasing as overall cancer survival improves. However, experiments in mouse models have shown that brain metastasis itself is an inefficient process. One reason for this inefficiency is the brain microenvironment, which differs significantly from that of other organs, making it difficult for cancer cells to adapt. The brain microenvironment consists of unique resident cell types such as neurons, oligodendrocytes, astrocytes, and microglia. Accumulating evidence over the past decades suggests that the interactions between cancer cells and glial cells can positively or negatively influence the development of brain metastasis. Nevertheless, elucidating the complex interactions between cancer cells and glial cells remains challenging, in part due to the limitations of existing experimental models for glial cell culture. In this review, we first provide an overview of glial cell culture methods and then examine recent discoveries regarding the interactions between brain metastatic cancer cells and the surrounding glial cells, with a special focus on astrocytes and microglia. Finally, we discuss future perspectives for understanding the multifaceted interactions between cancer cells and glial cells for the treatment of metastatic brain tumors.

Cannabinoid receptor 2 agonist AM1241 alleviates epileptic seizures and epilepsy-associated depression via inhibiting neuroinflammation in a pilocarpine-induced chronic epilepsy mouse model

Increasing evidence suggests that cannabinoid receptor 2 (CB2R) serves as a promising anti-inflammatory target. While inflammation is known to play crucial roles in the pathogenesis of epilepsy, the involvement of CB2R in epilepsy remains unclear. This study aimed to investigate the effects of a CB2R agonist, AM1241, on epileptic seizures and depressive-like behaviors in a mouse model of chronic epilepsy induced by pilocarpine. A chronic epilepsy mouse model was established by intraperitoneal administration of pilocarpine. The endogenous cannabinoid system (eCBs) in the hippocampus was examined after status epilepticus (SE). Animals were then treated with AM1241 and compared with a vehicle-treated control group. Additionally, the role of the AMPK/NLRP3 signaling pathway was explored using the selective AMPK inhibitor dorsomorphin. Following SE, CB2R expression increased significantly in hippocampal microglia. Administration of AM1241 significantly reduced seizure frequency, immobility time in the tail suspension test, and neuronal loss in the hippocampus. In addition, AM1241 treatment attenuated microglial activation, inhibited pro-inflammatory polarization of microglia, and suppressed NLRP3 inflammasome activation in the hippocampus after SE. Further, the therapeutic effects of AM1241 were abolished by the AMPK inhibitor dorsomorphin. Our findings suggest that CB2R agonist AM1241 may alleviate epileptic seizures and its associated depression by inhibiting neuroinflammation through the AMPK/NLRP3 signaling pathway. These results provide insight into a novel therapeutic approach for epilepsy.

Progress in the Pathogenesis of Diabetic Encephalopathy: The Key Role of Neuroinflammation

Diabetic encephalopathy (DE) is a severe complication that occurs in the central nervous system (CNS) and leads to cognitive impairment. DE involves various pathophysiological processes, and its pathogenesis is still unclear. This review summarised current research on the pathogenesis of diabetic encephalopathy, which involves neuroinflammation, oxidative stress, iron homoeostasis, blood-brain barrier disruption, altered gut microbiota, insulin resistance, etc. Among these pathological mechanisms, neuroinflammation has been focused on. This paper summarises some of the molecular mechanisms involved in neuroinflammation, including the Mammalian Target of Rapamycin (mTOR), Lipocalin-2 (LCN-2), Pyroptosis, Advanced Glycosylation End Products (AGEs), and some common pro-inflammatory factors. In addition, we discuss recent advances in the study of potential therapeutic targets for the treatment of DE against neuroinflammation. The current research on the pathogenesis of DE is progressing slowly, and more research is needed in the future. Further study of neuroinflammation as a mechanism is conducive to the discovery of more effective treatments for DE in the future.