Microglia TREM1-mediated neuroinflammation contributes to central sensitization via the NF-κB pathway in a chronic migraine model.

BACKGROUND: Neuroinflammation, mediated by the activation of microglia, contributes to central sensitization, which is associated with the development of chronic migraine (CM). TREM1 receptors amplify the inflammatory response. However, their relationship to CM is unclear. Thus, this study endeavoured to elucidate the exact role of TREM1 in CM. METHODS: Nitroglycerin (NTG) was repeatedly administered intraperitoneally to establish the CM model. Mechanical and thermal sensitivities were assessed using von Frey filaments and hot plate assays. Using Western blotting, TREM1, NF-κB pathway, NLRP3 inflammasome components, and proinflammatory cytokines were all detected. Immunofluorescence was used to examine the cellular distribution of TREM1 and NLRP3, the number of microglia, immunoreactivity, and morphological changes. We examined the effects of TREM1 antagonists (LR12) and NF-κB inhibitors (PDTC) on pain behaviour, as well as the production of c-fos and CGRP. Additionally, we investigated whether LR12 and PDTC affect the activation of microglia and the NLRP3 inflammasome. We synthesized siRNA and TREM1-overexpressing plasmids to transfect BV2 cells treated with LPS and normal BV2 cells and treated TREM1-overexpressing BV2 cells with PDTC. The NF-κB pathway, NLRP3 inflammasome components, and proinflammatory cytokines were quantified using Western blotting. RESULTS: Following NTG administration, the expression of TREM1 was significantly upregulated and exclusively localized in microglia in the TNC, and was well co-localized with NLRP3. Furthermore, activation of the classical NF-κB pathway was observed. Pre-treatment with LR12 and PDTC effectively attenuated mechanical hypersensitivity, suppressed the expression of c-fos and CGRP, and inhibited NF-κB activity in CM mice. Additionally, inhibition of TREM1 and NF-κB activity mitigated NTG-induced microglia and NLRP3 activation, as well as proinflammatory cytokines production. In vitro, knockdown of TREM1 resulted in attenuated activation of the NF-κB pathway following lipopolysaccharide (LPS) treatment and reduced expression of NLRP3 inflammasome components as well as proinflammatory cytokines. After TREM1 overexpression, the NF-κB pathway was activated, NLRP3 inflammasome components and proinflammatory cytokines were upregulated, and PDTC reversed this phenomenon. CONCLUSIONS: Our findings suggest that TREM1 regulates microglia and NLRP3 activation via the NF-κB pathway, thereby contributing to central sensitization and implicating its involvement in chronic migraine pathogenesis.

TLR2 Mediates Microglial Activation and Contributes to Central Sensitization in a Recurrent Nitroglycerin-induced Chronic Migraine Model.

Central sensitization is an important pathophysiological mechanism underlying chronic migraine (CM). Previous studies have shown that microglial activation and subsequent inflammation in the trigeminal nucleus caudalis (TNC) contribute to central sensitization. Toll-like receptor 2 (TLR2) is a receptor expressed on the membrane of microglia and participates in central sensitization in inflammatory and chronic pain; however, its role in CM is unclear. Therefore, this study investigated TLR2 involvement in CM in detail. Mice treated with recurrent nitroglycerin (NTG) were used as a CM model. Hyperalgesia was assessed using a 50% paw mechanical threshold and a 50% periorbital threshold on a Von Frey filament pain meter. Western blotting and immunofluorescence analyses were used to detect the expression of TLR2, microglia, c-fos and CGRP in TNC. The expression of inflammatory factors (IL-6, IL-1ß、 IL-10、TNF-α and IFN-ß1) was detected using quantitative real-time polymerase chain reaction (qRT-PCR). A selective TLR2 antagonist (C29) was systematically administered to observe its effect on hyperalgesia, microglia activation and the expression of c-fos, CGRP and inflammatory factors. Recurrent administration of NTG resulted in acute and chronic hypersensitivity, accompanied by upregulation of TLR2 expression and microglial activation in TNC. C29 partially inhibited pain hypersensitivity. C29 suppressed microglial activation induced by NTG administration. Inhibition of TLR2 reduced the expression of c-fos and CGRP in TNC after NTG treatment. C29 inhibited the expression of inflammatory mediators in TNC. These data showed that microglial TLR2 plays a critical role in the pathogenesis of CM by regulating microglial activation in TNC.

Corrigendum: Serum cold-inducible RNA-binding protein (CIRP) levels as a prognostic indicator in patients with acute ischemic stroke.

[This corrects the article DOI: 10.3389/fneur.2023.1211108.].

A Nomogram for Predicting the Recurrence of Acute Non-Cardioembolic Ischemic Stroke: A Retrospective Hospital-Based Cohort Analysis.

Non-cardioembolic ischemic stroke (IS) is the predominant subtype of IS. This study aimed to construct a nomogram for recurrence risks in patients with non-cardioembolic IS in order to maximize clinical benefits. From April 2015 to December 2019, data from consecutive patients who were diagnosed with non-cardioembolic IS were collected from Lanzhou University Second Hospital. The least absolute shrinkage and selection operator (LASSO) regression analysis was used to optimize variable selection. Multivariable Cox regression analyses were used to identify the independent risk factors. A nomogram model was constructed using the "rms" package in R software via multifactor Cox regression. The accuracy of the model was evaluated using the receiver operating characteristic (ROC), calibration curve, and decision curve analyses (DCA). A total of 729 non-cardioembolic IS patients were enrolled, including 498 (68.3%) male patients and 231 (31.7%) female patients. Among them, there were 137 patients (18.8%) with recurrence. The patients were randomly divided into training and testing sets. The Kaplan-Meier survival analysis of the training and testing sets consistently revealed that the recurrence rates in the high-risk group were significantly higher than those in the low-risk group (p < 0.01). Moreover, the receiver operating characteristic curve analysis of the risk score demonstrated that the area under the curve was 0.778 and 0.760 in the training and testing sets, respectively. The nomogram comprised independent risk factors, including age, diabetes, platelet-lymphocyte ratio, leukoencephalopathy, neutrophil, monocytes, total protein, platelet, albumin, indirect bilirubin, and high-density lipoprotein. The C-index of the nomogram was 0.752 (95% CI: 0.705~0.799) in the training set and 0.749 (95% CI: 0.663~0.835) in the testing set. The nomogram model can be used as an effective tool for carrying out individualized recurrence predictions for non-cardioembolic IS.

Serum cold-inducible RNA-binding protein (CIRP) levels as a prognostic indicator in patients with acute ischemic stroke.

Background: Acute ischemic stroke (AIS) is the leading cause of morbidity and mortality among cerebrovascular diseases. While animal studies have suggested a correlation between cold-inducible RNA-binding protein (CIRP) serum levels and the severity and prognosis of cerebral infarction, there has been a lack of research exploring this association in humans with cerebral infarction. Materials and methods: A total of 148 patients diagnosed with AIS within 7 days from symptom onset were included in this study. Comprehensive information regarding the patients' basic demographics, medical history, clinical parameters, the severity of cerebral infarction, and serum CIRP levels was collected. Follow-up data were obtained through telephonic interviews or by reviewing clinical notes for 3 months after the patients were discharged to assess the functional outcomes of treatment. Results: The findings of this study demonstrated a significant increase in serum CIRP levels during the early stages of AIS, followed by a gradual decline after 3 days. Significant differences were observed in the serum CIRP levels between the 1-day group and the 4-7 day group (P < 0.0047), as well as between the 2-3 day group and the 4-7 day group (P < 0.0006). Moreover, a significant positive correlation was observed between the serum CIRP levels and the severity of cerebral infarction. Higher serum CIRP levels were associated with more severe National Institutes of Health Stroke Scale scores (P < 0.05) and larger cerebral infarction volumes (P < 0.05). Furthermore, patients with higher serum CIRP levels exhibited poorer modified Rankin scale scores (P < 0.05). These findings indicate that serum CIRP serves as an essential pro-inflammatory mediator and a valuable biomarker for assessing brain injury in patients with AIS. Conclusion: The findings of this study suggest an elevation in serum CIRP levels among patients with AIS. These levels are positively correlated with the severity of AIS and serve as indicators of a poor prognosis. Therefore, CIRP could serve as a target for early clinical intervention while managing AIS, and further research should explore serum CIRP levels as prognostic indicators in AIS.

[Research progress of extracorporeal cardiopulmonary resuscitation combined with therapeutic hypothermia on brain protection].

Compared with conventional cardiopulmonary resuscitation (CCPR), extracorporeal cardiopulmonary resuscitation (ECPR) can improve the survival rate of patients with cardiac arrest, and reduce the risk of reperfusion injury. However, it is still difficult to avoid the risk of secondary brain damage. Low temperature management has good neuroprotective potential for ECPR patients, which minimizes brain damage. However, unlike CCPR, ECPR has no clear prognostic indicator. The relationship between ECPR combined with hypothermia management-related treatment measure and neurological prognosis is not clear. This article reviews the effect of ECPR combined with different therapeutic hypothermia on brain protection and provides a reference for the prevention and treatment of neurological injury in patients with ECPR.

Tree-Based Risk Factor Identification and Stroke Level Prediction in Stroke Cohort Study.

Objective. This study focuses on the identification of risk factors, classification of stroke level, and evaluation of the importance and interactions of various patient characteristics using cohort data from the Second Hospital of Lanzhou University. Methodology. Risk factors are identified by evaluation of the relationships between factors and response, as well as by ranking the importance of characteristics. Then, after discarding negligible factors, some well-known multicategorical classification algorithms are used to predict the level of stroke. In addition, using the Shapley additive explanation method (SHAP), factors with positive and negative effects are identified, and some important interactions for classifying the level of stroke are proposed. A waterfall plot for a specific patient is presented and used to determine the risk degree of that patient. Results and Conclusion. The results show that (1) the most important risk factors for stroke are hypertension, history of transient ischemia, and history of stroke; age and gender have a negligible impact. (2) The XGBoost model shows the best performance in predicting stroke risk; it also gives a ranking of risk factors based on their impact. (3) A combination of SHAP and XGBoost can be used to identify positive and negative factors and their interactions in stroke prediction, thereby providing helpful guidance for diagnosis.

Post-ischemic inflammatory response in the brain: Targeting immune cell in ischemic stroke therapy.

An ischemic stroke occurs when the blood supply is obstructed to the vascular basin, causing the death of nerve cells and forming the ischemic core. Subsequently, the brain enters the stage of reconstruction and repair. The whole process includes cellular brain damage, inflammatory reaction, blood-brain barrier destruction, and nerve repair. During this process, the proportion and function of neurons, immune cells, glial cells, endothelial cells, and other cells change. Identifying potential differences in gene expression between cell types or heterogeneity between cells of the same type helps to understand the cellular changes that occur in the brain and the context of disease. The recent emergence of single-cell sequencing technology has promoted the exploration of single-cell diversity and the elucidation of the molecular mechanism of ischemic stroke, thus providing new ideas and directions for the diagnosis and clinical treatment of ischemic stroke.

Toll-like receptors and their role in neuropathic pain and migraine.

Migraine is a complex neurological disease of unknown etiology involving both genetic and environmental factors. It has previously been reported that persistent pain may be mediated by the immune and inflammatory systems. Toll-like receptors (TLRs) play a significant role in immune and inflammatory responses and are expressed by microglia and astrocytes. One of the fundamental mechanisms of the innate immune system in coordinating inflammatory signal transduction is through TLRs, which protect the host organism by initiating inflammatory signaling cascades in response to tissue damage or stress. TLRs reside at the neuroimmune interface, and accumulating evidence has suggested that the inflammatory consequences of TLR activation on glia (mainly microglia and astrocytes), sensory neurons, and other cell types can influence nociceptive processing and lead to pain. Several studies have shown that TLRs may play a key role in neuropathic pain and migraine etiology by activating the microglia. The pathogenesis of migraine may involve a TLR-mediated crosstalk between neurons and immune cells. Innate responses in the central nervous system (CNS) occur during neuroinflammatory phenomena, including migraine. Antigens found in the environment play a crucial role in the inflammatory response, causing a broad range of diseases, including migraines. These can be recognized by several innate immune cells, including macrophages, microglia, and dendritic cells, and can be activated through TLR signaling. Given the prevalence of migraine and the insufficient efficacy and safety of current treatment options, a deeper understanding of TLRs is expected to provide novel therapies for managing chronic migraine. This review aimed to justify the view that TLRs may be involved in migraine.

Paraneoplastic neurological syndrome with positive anti-Hu and anti-Yo antibodies: A case report.

BACKGROUND: Paraneoplastic neurological syndrome (PNS) is a rare complication in patients with cancer. PNS can affect the central, peripheral, autonomic nervous system, neuromuscular junction, or muscles and cause various neurological symptoms. Anti-Yo antibody-positive neurological paraneoplasms and anti-Hu antibody-positive neurological paraneoplasms are common, but coexistence of both types has not been described in the literature. CASE SUMMARY: Here we present a rare case of paraneoplastic neuropathy occurring in both breast and lung cancers. A 55-year-old woman was admitted to our hospital with unsteadiness while walking. The patient had a history of breast cancer two years previously. Chest computed tomography revealed a 4.6 cm × 3.6 cm mass in the right lung, which was diagnosed as small-cell lung cancer (SCLC). Blood test was positive for anti-Yo antibodies, and the cerebrospinal fluid was positive for both anti-Yo and anti-Hu antibodies, and the neurological symptoms were considered to be related to the paraneoplasm. The patient was treated with a course of intravenous immunoglobulin, without noticeable improvement. After being discharged from hospital, the patient underwent regular chemotherapy for SCLC and periodic reviews. The patient's neurological symptoms continued to deteriorate at the follow-up visit in April 2021. CONCLUSION: This case suggests the possibility of two types of tumors appearing simultaneously with two paraneoplastic antibodies. The clinical appearance of two or more paraneoplastic tumors requires additional attention.

Analysis on the Clinical Effect of High-Dose Glucocorticoids Combined with Immunosuppressants on Patients with Myasthenia Gravis Undergoing Video-Assisted Thoracoscopic Surgery.

OBJECTIVE: The purpose of the study was to investigate the clinical effect of high-dose glucocorticoids (GCS) combined with immunosuppressants on the treatment of myasthenia gravis (MG) with video-assisted thoracoscopic surgery (VATS). METHODS: A total of 106 MG patients admitted to the neurology department of our hospital from February 2016 to February 2020 were selected as the study subjects and divided into experimental group (n = 53) and control group (n = 53). The patients in the control group underwent VATS, while the patients in the experimental group were treated with high-dose GCS combined with immunosuppressants on the basis of VATS treatment. The clinical efficacy of different MG treatment methods was analyzed. RESULTS: No significant differences were observed in visual analogue score (VAS) at T1 between the two groups (P > 0.05), while VAS scores at T2, T3, and T4 in the experimental group were significantly lower than those in the control group (P < 0.001). In the experimental group, the overall response rate was significantly higher than the control group (P < 0.05). Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) level in regulatory T (Treg) cells in experimental groups after treatment was significantly higher, compared to that in before treatment and the control group (P < 0.05). Similar results of each quantitative MG score were displayed in both groups after treatment, compared to before treatment and the control group (P < 0.05). Clinical performance of patients with lower incidence of adverse reactions in the experimental groups after treatment was significantly higher than those in the control group (P < 0.001). CONCLUSION: GCS combined with immunosuppressants can effectively relieve patients' clinical symptoms and improve their quality of life, with significant clinical efficacy and high safety, which is worthy of application and promotion.

Correlation between serum renin-angiotensin system (RAS) level and depression and anxiety symptoms in patients with Parkinson's disease.

To investigate the correlation between serum renin-angiotensin system (RAS) level and Symptoms of anxiety and depression in Parkinson disease patients (PD). A number of 90 PD patients (47 males and 43 females) were collected on an empty stomach 12 h after stopping taking anti-PD medicines. ELISA has been found in Serum RAS ((Ang) I, Ang II, Ang (1-7), Angiotensin converting enzyme (ACE), ACE2). Depression scale (HAMD) and Anxiety scale (HAMA) in Hamilton are used for the assessment of signs of depression and anxiety. The 90 patients were diagnosed with moderate depression (HAMD score 8 ~ 19); in 32 of those (35.56 percent), and 12 (13.33%) were diagnosed as moderate and severe depression (HAMD score ≥ 20). 20 cases (22.22%) were diagnosed as possible anxiety disorder (HAMA score 7 ~ 13) and 16 cases (17.78%) as definite anxiety disorder (HAMA score ≥ 14). The association of serum Ang I, Ang II and Ang (1-7) with HAMD (r= - 0.820, P < 0.001; r = -0.846, P < 0.001) showed negative linkage with HAMD (r = -0.887, P < 0.003; P < 0.001; Negative correlation of the settings with HAMA (r = -0.850, P < 0.001; r = -0.887, P < 0.001; r = 0.003; r = 0.001, P < 0.001, Fig. 2, Fig. 3); The HAMD score and the HAMA score (all P > 0.05) were not associated to the serum ACE and ACE2. The serum Ang I, Ang II, and Ang (1-7) were found to be adversely associated with HAMD score (r = 0.826, P < 0,001; r = -0.818, p> >0,001; r = -0.876, P < 0,001; P = 0,001) P < 0,001; And have been negatively correlated (r = 0.870, Fig. 1, Fig. 2, Fig. 3) with AMA-scores (r = -0.876, P < 0.001, Table 1, Fig. 3), R = -0.862, P > 0.001; The HAMD score and the HAMA score (all P > 0.05) were not correlated to the serum ACE and ACE2. Finally, in PD patients, non-engine signs, including depression and anxiety, are normal. Thus, Serum levels Ang I, Ang II and Ang (1-7) were substantially decreased in female and male patients and associated with symptoms of depression and anxiety, ACE and ACE2 levels have not been attributed to signs of depression and anxiety. Serum Ang I, Ang II, and Ang (1-7) are important markers of depression and anxiety prevention and diagnosis in patients with DP.

M2-Like Microglia Polarization Attenuates Neuropathic Pain Associated with Alzheimer's Disease.

Many Alzheimer's disease (AD) patients suffer from persistent neuropathic pain (NP), which is mediated, at least partially, but microglia. Nevertheless, the exact underlying mechanism is unknown. Moreover, a clinically translatable approach through modulating microglia for treating AD-associated NP is not available. Here, in a doxycycline-induced mouse model (rTg4510) for AD, we showed development of NP. We found that the total number of microglia in the CA3 region was not increased, but polarized to pro-inflammatory M1-like phenotype, with concomitant increases in production and secretion of pro-inflammatory cytokines. To examine whether this microglia polarization plays an essential role in the AD-associated NP, we generated an adeno-associated virus (AAV) serotype PHP.B (capable of crossing the blood-brain barrier) carrying shRNA for DNA methyltransferase 1 (DNMT1) under a microglia-specific TMEM119 promoter (AAV-pTMEM119-shDNMT1), which specifically targeted microglia and induced a M2-like polarization in vitro and in vivo in doxycycline-treated rTg4510 mice. Intravenous infusion of AAV-pTMEM119-shDNMT1 induced M2-polarization of microglia and attenuated both AD-associated behavior impairment but also NP in the doxycycline-treated rTg4510 mice. Thus, our data suggest that AD-associated NP may be treated through M2-polarization of microglia.

Diabetes-Induced H3K9 Hyperacetylation Promotes Development of Alzheimer's Disease Through CDK5.

The connection between diabetes and Alzheimer's disease (AD) is not fully determined. Hyperphosphorylation of tau protein is mediated by binding and stabilization of truncated p25 with cyclin-dependent kinase-5 (CDK5) in AD. We recently showed that diabetes-associated hyperglycemia increased the CDK5 levels to promote development of AD. Here, we examined the underlying mechanisms. Hyperglycemia and glucose intolerance were induced in rats that had received a low dose of streptozotocin (STZ) and a high fat diet (HFD). Compared to the control rats that received no STZ and normal diet-fed, the STZ + HFD rats exhibited poorer performance in the behavioral test and showed hyperacetylation of H3K9 histone on CDK5 promoter, likely resulting from upregulation of a histone acetyltransferase, GCN5. Inhibition of acetylation of H3K9 histone by a specific GCN5 inhibitor, MB3, attenuated activation of CDK5, resulting in decreased tau phosphorylation in rat brain and improved performance of the rats in the behavior test. Thus, these data suggest that diabetes may promote future development of AD through hyperacetylation of H3K9 histone on CDK5 promoter.

miR-15a regulates oxygen glucose deprivation/reperfusion (OGD/R)-induced neuronal injury by targeting BDNF.

Multiple microRNAs (miRs) have also been implicated in ischemic brain injury. This research intended to probe the regulatory function and the mechanism of miR-15a on the ischemic brain injury induced by oxygen-glucose deprivation/reoxygenation (OGD/R) in neurons of rats. The OGD/R model was established with the cortical neurons separated from rats. After transfection with miR-15a mimic negative control (NC), miR-15a mimic, miR-15a inhibitor NC and miR-15a inhibitor, the OGD/R-induced apoptosis were detected. Using bioinformatic softwares including TargetScan, miRanda, and miRWalk to predict the underlying targets of miR-15a, and the binding of miR-15a with brain-derived neurotrophic factor (BDNF) were validated with double-fluorescein reporter assay system. The expression levels of BDNF mRNA and protein were detected with qRT-PCR and western blot. The effect of miR-15a on PI3K/AKT pathway in neurons submitted to OGD/R was also investigated. The findings showed that miR-15a may mediate the apoptosis of neurons submitted to OGD/R, and lower expression of Bcl-2 and higher expression of Bax and cleaved caspase-3 were observed. BDNF was screened as the candidate target, and the direct binding of miR-15a with 3'-UTR of BDNF were verified. Further research showed that miR-15a downregulated the expression of BDNF mRNA and protein, thus exerted negative regulatory effect on the OGD/R injury. PI3K/AKT pathway may be related to the regulatory effect of miR-15a. Our findings contribute to uncovering novel pathogenesis for ischemic brain injury.

Elevated serum macrophage migration inhibitory factor levels correlate with benign paroxysmal positional vertigo and recurrence events.

Objective: We aimed to assess the possible relations between serum levels of macrophage migration inhibitory factor (MIF), a central cytokine of the innate immunity and inflammatory response, and benign paroxysmal positional vertigo (BPPV) risk and BPPV recurrence events.Methods: In the present study, 154 patients with BPPV, and 100 age-and sex-matched control subjects were enrolled in the study. All the patients and controls underwent a complete audio-vestibular test battery including the Dix-Hallpike maneuver and supine roll test. In the BPPV group, measurements of MIF levels were repeated 1 month after the vertigo attack. The patients were also divided into the recurrence group and the nonrecurrence group in the 1-year follow-up.Results: The serum levels of MIF in patients with BPPV were higher than in those controls (13.9[interquartile range {IQR}, 8.9-18.4] ng/ml vs. 9.8[7.8-11.8]; P<0.001). As a continuous variable, MIF was associated with increased risk of BPPV (odds ratio [OR] 1.21, 95% confidence interval [CI]: 1.11-1.39; P=0.004) in multiple regression analyses. Recurrent attacks of BPPV were reported in 35 patients, and those patients had higher levels of MIF than those patients were not recurrence (18.0[IQR, 13.6-22.2] ng/ml vs. 12.6[9.3-16.8] ng/ml). In multivariate models comparing the second (Q2), third (Q3) and fourth(Q4) quartiles against the first (Q1) quartile of MIF, levels of MIF in Q4 were associated with recurrent BPPV, and the odds were increased by approximately 305% (OR = 4.05; 95%CI: 1.65-15.44; P=0.009).Conclusions: Elevated MIF is positively correlated with BPPV risk and BPPV recurrence events, requiring further efforts to clarify the exact mechanism.

Epigenetic Control of CDK5 Promoter Regulates Diabetes-Associated Development of Alzheimer's Disease.

Cyclin-dependent kinase-5 (CDK5) is activated by p35 and then binds to both p35 and its truncated form p25 to promote hyperphosphorylation of tau protein, thereby facilitating the pathological progression of Alzheimer's disease (AD). However, it is unknown whether a patient's diabetic status promotes the later onset of AD in a CDK5-dependent manner. Here, we induced pro-diabetic insulin resistance and glucose intolerance in rats using a combined high fat and high glucose diet. Compared to normal diet-fed rats, these pro-diabetic rats exhibited poorer behavioral performance in the Morris water maze test and the novel object recognition test. Increased phosphorylation of tau protein was detected in the hippocampal CA1 region of the rat brain, suggesting neurodegeneration. Moreover, CDK5 transcriptional activity was significantly increased in the HFGD-rat brain, likely resulting from an increase in acetylation and a decrease in methylation of the CDK5 promoter. Together, these data suggest that epigenetic control of the CDK5 promoter by acetylation and methylation may regulate the diabetes-associated development of AD.