A microglial activation cascade across cortical regions underlies secondary mechanical hypersensitivity to amputation.

Neural mechanisms underlying amputation-related secondary pain are unclear. Using in vivo two-photon imaging, three-dimensional reconstruction, and fiber photometry recording, we show that a microglial activation cascade from the primary somatosensory cortex of forelimb (S1FL) to the primary somatosensory cortex of hindlimb (S1HL) mediates the disinhibition and subsequent hyperexcitation of glutamatergic neurons in the S1HL (S1HLGlu), which then drives secondary mechanical hypersensitivity development in ipsilateral hindpaws of mice with forepaw amputation. Forepaw amputation induces rapid S1FL microglial activation that further activates S1HL microglia via the CCL2-CCR2 signaling pathway. Increased engulfment of GABAergic presynapses by activated microglia stimulates S1HLGlu neuronal activity, ultimately leading to secondary mechanical hypersensitivity of hindpaws. It is widely believed direct neuronal projection drives interactions between distinct brain regions to prime specific behaviors. Our study reveals microglial interactions spanning different subregions of the somatosensory cortex to drive a maladaptive neuronal response underlying secondary mechanical hypersensitivity at non-injured sites.

Microglia govern the extinction of acute stress-induced anxiety-like behaviors in male mice.

Anxiety-associated symptoms following acute stress usually become extinct gradually within a period of time. However, the mechanisms underlying how individuals cope with stress to achieve the extinction of anxiety are not clear. Here we show that acute restraint stress causes an increase in the activity of GABAergic neurons in the CeA (GABACeA) in male mice, resulting in anxiety-like behaviors within 12 hours; meanwhile, elevated GABACeA neuronal CX3CL1 secretion via MST4 (mammalian sterile-20-like kinase 4)-NF-κB-CX3CL1 signaling consequently activates microglia in the CeA. Activated microglia in turn inhibit GABACeA neuronal activity via the engulfment of their dendritic spines, ultimately leading to the extinction of anxiety-like behaviors induced by restraint stress. These findings reveal a dynamic molecular and cellular mechanism in which microglia drive a negative feedback to inhibit GABACeA neuronal activity, thus facilitating maintenance of brain homeostasis in response to acute stress.

Up-regulation of HCN2 channels in a thalamocortical circuit mediates allodynia in mice.

Chronic pain is a significant problem that afflicts individuals and society, and for which the current clinical treatment is inadequate. In addition, the neural circuit and molecular mechanisms subserving chronic pain remain largely uncharacterized. Herein we identified enhanced activity of a glutamatergic neuronal circuit that encompasses projections from the ventral posterolateral nucleus (VPLGlu) to the glutamatergic neurons of the hindlimb primary somatosensory cortex (S1HLGlu), driving allodynia in mouse models of chronic pain. Optogenetic inhibition of this VPLGlu→S1HLGlu circuit reversed allodynia, whereas the enhancement of its activity provoked hyperalgesia in control mice. In addition, we found that the expression and function of the HCN2 (hyperpolarization-activated cyclic nucleotide-gated channel 2) were increased in VPLGlu neurons under conditions of chronic pain. Using in vivo calcium imaging, we demonstrated that downregulation of HCN2 channels in the VPLGlu neurons abrogated the rise in S1HLGlu neuronal activity while alleviating allodynia in mice with chronic pain. With these data, we propose that dysfunction in HCN2 channels in the VPLGlu→S1HLGlu thalamocortical circuit and their upregulation occupy essential roles in the development of chronic pain.

Trpc6 knockout improves behavioral dysfunction and reduces Aß production by inhibiting CN-NFAT1 signaling in T2DM mice.

As the prevalence of diabetes and health awareness increase, type 2 diabetes mellitus -associated cognitive dysfunction is receiving increasing attention. However, the pathogenesis is not entirely understood. Transient receptor potential cation channel 6 (TRPC6) is highly correlated with intracellular Ca2+ concentrations, and neuronal calcium overload is an important cause of cognitive dysfunction. In the present study, we investigated the effect and mechanism of Trpc6 knockout in high-fat diet and streptozotocin-induced T2DM mice. The body weight and fasting blood glucose were recorded during the experiment. Behavioral dysfunction was detected using the open field test (OFT), elevated plus maze (EPM), hole-board test (HBT), Morris water maze (MWM) test and contextual fear conditioning (CFC) test. Nissl and H&E staining were used to examine neuronal damage. Western blot, quantitative real-time polymerase chain reaction (q-PCR), and immunofluorescence were performed to detect amyloid beta protein (Aß) deposition and related indicators of neurological impairments in the cerebral cortex and hippocampus. The results indicated that Trpc6 knockout inhibited body weight loss and fasting blood glucose increase, improved spontaneous activity, learning and memory dysfunction, and alleviated neuroinflammation and neuronal damage in T2DM mice. The further results demonstrated that Trpc6 knockout decreased Aß generation and deposition, and reduced the expressions of inflammasome-related proteins in T2DM mice. In addition, Trpc6 knockout inhibited intracellular calcium overload in diabetic mice and primary cultured hippocampal neurons, which in turn suppressed CN and NFAT1 expression. These data suggest that Trpc6 knockout may inhibit the CN-NFAT1 signaling pathway by decreasing intracellular calcium overload in the brain of T2DM mice, which consequently reduce Aß deposition and neuroinflammation, and ultimately delay the development of T2DM-associated cognitive dysfunction.

ß2-Microglobulin is a Novel and Reliable Biomarker for Predicting Ischemic Stroke Recurrence: A Prospective Cohort Study.

Immune and inflammatory mechanisms play key roles in the development and outcome of acute ischemic stroke (AIS). ß2-Microglobulin (ß2M) is the light chain of major histocompatibility complex-1 (MHC-1), which can directly and quickly reflect the immune and inflammatory state of the body. Previous studies have shown a close relationship between ß2M and AIS, but its relationship with the recurrence of AIS has not been reported. This study attempted to explore the relationship between ß2M and the recurrence of AIS. A single-center AIS cohort involving 135 patients was followed for approximately 26-46 months. Clinical and laboratory data from the patients were collected when hospitalized. The endpoint was the occurrence of recurrent AIS after patients were discharged. Propensity score matching was used to match cohort groups. Cox regression analysis was used to predict risk factors for recurrent AIS, and receiver operating characteristic curve (ROC) analysis was used to calculate the optimal cutoff value for discriminating recurrence in patients with AIS. The rate of recurrence was 29.6% [95% CI, 21.8%-37.3%] in the follow-up group. Patients with higher levels of serum ß2M had a higher risk of AIS recurrence than patients with lower levels of ß2M (adjusted hazard ratio, 3.214 [95% CI, 1.557-6.633]; adjusted hazard ratio after matching, 5.831, [95% CI, 2.052-16.572]). A ß2M value of 2.31 mg/L was calculated by ROC analysis as the optimal cutoff value for AIS recurrence (area under the curve 0.770, [95% CI, 0.687-0.853]). As a quick responder to the body's immune and inflammatory states, ß2M may be a novel and reliable biomarker in predicting AIS recurrence.

Ginsenoside Rg1 attenuates cerebral ischemia-reperfusion injury due to inhibition of NOX2-mediated calcium homeostasis dysregulation in mice.

Background: The incidence of ischemic cerebrovascular disease is increasing in recent years and has been one of the leading causes of neurological dysfunction and death. Ginsenoside Rg1 has been found to protect against neuronal damage in many neurodegenerative diseases. However, the effect and mechanism by which Rg1 protects against cerebral ischemia-reperfusion injury (CIRI) are not fully understood. Here, we report the neuroprotective effects of Rg1 treatment on CIRI and its possible mechanisms in mice. Methods: A bilateral common carotid artery ligation was used to establish a chronic CIRI model in mice. HT22 cells were treated with Rg1 after OGD/R to study its effect on [Ca2+]i. The open-field test and pole-climbing experiment were used to detect behavioral injury. The laser speckle blood flowmeter was used to measure brain blood flow. The Nissl and H&E staining were used to examine the neuronal damage. The Western blotting was used to examine MAP2, PSD95, Tau, p-Tau, NOX2, PLC, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging was used to test the level of [Ca2+]i. Results: Rg1 treatment significantly improved cerebral blood flow, locomotion, and limb coordination, reduced ROS production, increased MAP2 and PSD95 expression, and decreased p-Tau, NOX2, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging results showed that Rg1 could inhibit calcium overload and resist the imbalance of calcium homeostasis after OGD/R in HT22 cells. Conclusion: Rg1 plays a neuroprotective role in attenuating CIRI by inhibiting oxidative stress, calcium overload, and neuroinflammation.

Endovascular treatment for acute basilar artery occlusion: A multicenter randomized controlled trial (ATTENTION).

BACKGROUND AND HYPOTHESIS: Recently, two multicenter randomized controlled trials (RCT) failed to show a significantly beneficial effect of endovascular treatment (EVT) in patients with acute basilar artery occlusion (BAO). However, both trials suffered from equipoise issues which may have hindered the validity of the trial results. Therefore, additional RCT studies are needed to explore the potential benefit of EVT in patients presenting with BAO. STUDY DESIGN: ATTENTION is an investigator-initiated, multicenter, prospective, randomized, controlled clinical trial with open-label treatment and blinded outcome assessment (PROBE) of EVT versus best medical management (BMM). The primary effect parameter is a modified Rankin Score of 0-3 at day 90. DISCUSSION: ATTENTION will provide evidence for the efficacy and safety of EVT in stroke patients within 12 h after BAO. TRIAL REGISTRATION: ClinicalTrials.gov NCT04751708.

Ginkgo biloba extract improves cognitive function and increases neurogenesis by reducing Aß pathology in 5×FAD mice.

Previous studies have indicated that the generation of newborn hippocampal neurons is impaired in the early phase of Alzheimer's disease (AD). A potential therapeutic strategy being pursued for the treatment of AD is increasing the number of newborn neurons in the adult hippocampus. Recent studies have demonstrated that ginkgo biloba extract (EGb 761) plays a neuroprotective role by preventing memory loss in many neurodegenerative diseases. However, the extent of EGb 761's protective role in the AD process is unclear. In this study, different doses of EGb 761 (0, 10, 20, and 30 mg/kg; intraperitoneal injections once every day for four months) were tested on 5×FAD mice. After consecutive 4-month injections, mice were tested in learning memory tasks, Aß, and neurogenesis in the dentate gyrus (DG) of hippocampus and morphological characteristics of neurons in DG of hippocampus. Results indicated that EGb 761 (20 and 30 mg/kg) ameliorated memory deficits. Further analysis indicated that EGb 761 can reduce the number of Aß positive signals in 5×FAD mice, increase the number of newborn neurons, and increase dendritic branching and density of dendritic spines in 5×FAD mice compared to nontreated 5×FAD mice. It was concluded that EGb 761 plays a protective role in the memory deficit of 5×FAD mice.

Neutrophil-to-Lymphocyte Ratios Are Closely Associated With the Severity and Course of Non-mild COVID-19.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is spreading worldwide. Measuring the prevention and control of the disease has become a matter requiring urgent focus. Objective: Based on coronavirus disease 2019 (COVID-19) clinical data from Wuhan, we conducted an in-depth analysis to clarify some of the pathological mechanisms of the disease and identify simple measures to predict its severity early on. Methods: A total of 230 patients with non-mild COVID-19 were recruited, and information on their clinical characteristics, inflammatory cytokines, and T lymphocyte subsets was collected. Risk factors for severity were analyzed by binary logistic regression, and the associations of neutrophil-to-lymphocyte ratios (N/LRs) with illness severity, disease course, CT grading, inflammatory cytokines, and T lymphocyte subsets were evaluated. Results: Our results showed that the N/LRs were closely related to interleukin (IL)-6 and IL-10 (P < 0.001, P = 0.024) and to CD3+ and CD8+ T lymphocytes (P < 0.001, P = 0.046). In particular, the N/LRs were positively correlated with the severity and course of the disease (P = 0.021, P < 0.001). Compared to the values at the first test after admission, IL-6 and IL-10 were significantly decreased and increased, respectively, as of the last test before discharge (P = 0.006, P < 0.001). More importantly, through binary logistic regression, we found that male sex, underlying diseases (such as cardiovascular disease), pulse, and N/LRs were all closely related to the severity of the disease (P = 0.004, P = 0.012, P = 0.013, P = 0.028). Conclusions: As a quick and convenient marker of inflammation, N/LRs may predict the disease course and severity level of non-mild COVID-19; male sex, cardiovascular disease, and pulse are also risk factors for the severity of non-mild COVID-19.

[Analysis of PDHA1 gene variant in a patient with pyruvate dehydrogenase E1alpha deficiency and pyramidal tract involvement].

OBJECTIVE: To explore the genetic basis for a patient with episodic ataxia and pyramidal tract signs. METHODS: The patient was subjected to high-throughput sequencing, Sanger sequencing and analysis of dynamic variant site associated with spinocerebellar ataxias (SCA). RESULTS: The patient was an adolescent male presenting with episodic ataxia, bilateral knee hyper-reflexia and ankle clonus. By genetic testing, he was found to harbor a c.1159-1162dupAAGT variant of PDHA1 gene. The same variant was not found in his parents and elder sister. No abnormalities were found by SCA dynamic variant screening. The patient was diagnosed as pyruvate dehydrogenase E1alpha deficiency due to variant of the PDHA1 gene. CONCLUSION: The de novo c.1159-1162dupAAGT variant of the PDHA1 gene probably underlies the disease in the proband. Patients with pyruvate dehydrogenase E1alpha deficiency have complex phenotypes and very few have pyramidal tract involvement, which may be attributed to abnormal early neuronal development.

A novel dominant-negative mutation of the CSF1R gene causes adult-onset leukoencephalopathy with axonal spheroids and pigmented glia.

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare autosomal dominant disorder that is caused by mutations in the colony-stimulating factor 1 receptor (CSF1R) gene. Functional haplo-insufficiency of the CSF1R gene has been considered for the underlying genetic mechanisms. A novel mutation of CSF1R and its effects on CSF1R expression or clinical characteristics were explored in an ALSP family. Clinical data and imaging data were collected from the family members with ALSP. Peripheral blood samples were collected for DNA and RNA extraction. Whole-exome sequencing and quantitative PCR were used to identify mutations and to determine the expression of CSF1R. The family had a history of a dominant hereditary pattern. Patients in this family presented motor symptoms, emotional abnormality, or memory impairment at onset. MRI findings showed high hyperintensity signals of T2-weighted imaging in the white matter and atrophy of the corpus callosum. NOTCH3 gene sequencing ruled out the diagnosis of CADASIL. Whole-exome sequencing identified a novel splice-site mutation (c.2319+1C>A) in intron 16 of the CSF1R gene. CSF1R mRNA was significantly decreased (~15%) in the peripheral blood samples of affected patients, which was much lower than the expected 50%. Our findings not only supported the pathological implication of this splice-site mutation but also demonstrated for the first time a dominant-negative effect on CSF1R expression. This report extends the genetic spectrum of ALSP with CSF1R mutations and provides evidence for the clinical heterogeneity of ALSP.

Gene polymorphisms and circulating levels of the TNF-alpha are associated with ischemic stroke: A meta-analysis based on 19,873 individuals.

OBJECTIVE: Numerous studies have investigated associations of gene polymorphisms and circulating levels of TNF-α with ischemic stroke (IS), but the results were controversial. The aims of this study were to systematically evaluate these associations. METHODS: Relevant publications were retrieved by searching databases. Odds ratios (ORs) and standard mean differences (SMDs) with 95% confidence intervals (95% CIs) were used to assess the association of the TNF-α gene and cytokine with IS, respectively. The Cochrane Q test and I2 statistic were used to test heterogeneity. Subgroup analysis and publication bias were performed. RESULTS: 25 and 9 articles examined the association of polymorphisms and levels of the TNF-α with IS risk, respectively. Rs1800629 polymorphism was associated with IS susceptibility (OR (95% CI) =0.82 (0.72, 0.95)), especially in Asians (OR (95% CI) =0.75 (0.63, 0.89)); and rs1800610 was associated with IS susceptibility in Asians patients (OR (95% CI) =1.54 (1.31, 1.80)). While rs361525, rs1799964 and rs1799724 polymorphisms were not associated with IS susceptibility. The TNF-α level was elevated in IS patients (SMD (95% CI) =0.65 (0.29, 1.01)) including Asians (SMD (95% CI) =1.26 (0.49, 2.03)) and Caucasians (SMD (95% CI) =0.26 (0.03, 0.49)). In addition, increased level occurred in patients' serum (SMD (95% CI) =0.54 (0.08, 1.01)). CONCLUSIONS: Rs1800629 and rs1800610 polymorphisms were elucidated to be a protective factor for IS (especially in Asians) and a risk factor for Asians patients, respectively. The TNF-α level was elevated in IS, indicating that TNF-α plays an important role in the pathogenesis of IS and is a promising therapeutic target for IS.

Serum beta2-microglobulin levels are highly associated with the risk of acute ischemic stroke.

Inflammation is considered an important mechanism of cell death or survival after ischemic stroke. As an important marker of inflammation, the role of ß2-microglobulin (ß2M) in acute ischemic stroke is unclear. We investigated the relationship between serum ß2M and the risk of acute ischemic stroke (AIS). Patients with AIS (202 cases), intracerebral hemorrhage (ICH, 41 cases), and healthy controls (253 cases) were recruited. Clinical and biochemical characteristics were collected. We used three binary logistic regression models to evaluate the correlation of ß2M with the risk of AIS. Furthermore, we investigated the relationship between serum ß2M and the National Institute of Health Stroke Scale (NIHSS) score, the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) subtypes, and the Essen Stroke Risk Score (ESRS) in patients with AIS. Our results showed that serum ß2M levels in patients with AIS were much higher than those in patients with ICH and in the control subjects. Individuals with higher levels of ß2M had higher odds of AIS. Moreover, serum ß2M levels were significantly and positively correlated with ESRS. In addition, the levels of ß2M were varied with different subgroups of AIS (TOAST classification). Serum ß2M is highly associated with the risk of AIS.

Serum ß2-Microglobulin Is Closely Associated With the Recurrence Risk and 3-Month Outcome of Acute Ischemic Stroke.

Background and Purpose: Inflammation plays a significant role in the pathogenesis of acute ischemic stroke (AIS). The role of ß2-microglobulin (ß2M) as a potential initiator of the inflammatory response in AIS is unclear. The purpose of this study was to analyze the relationship of serum ß2M with the recurrence risk and 3-month outcome of AIS. Methods: A total of 205 patients with AIS were recruited, and their clinical and biochemical characteristics were collected. All patients were followed up for 3 months after stroke onset, and the occurrence of death or major disability at 3 months after onset was the outcome of interest in this study. We evaluated the association of serum ß2M levels with the National Institute of Health Stroke Scale (NIHSS) scores, modified Rankin Scale (mRS) scores, and Essen Stroke Risk Score (ESRS) values in patients with AIS. Then, we used receiver operating curve analysis to calculate the optimal cutoff value for discriminating outcomes in patients with AIS and a binary logistic regression model to evaluate the risk factors for a poor outcome after AIS. Results: Our results showed that serum ß2M levels were significantly and positively correlated with ESRS values (r = 0.176, P < 0.001) and mRS scores (r = 0.402, P < 0.001), but the levels of ß2M were not correlated with NIHSS scores (r = 0.080, P = 0.255) or with infarct volume (r = 0.013, P = 0.859). In a further study, we found that 121 patients (59.02%) had poor outcomes. The optimal ß2M cutoff to predict the 3-month outcome of AIS in this study was 1.865 mg/l, and ß2M was independently associated with a poor outcome at 3 months (OR = 3.325, 95% confidence interval: 1.089~10.148). Conclusions: In conclusion, we inferred that serum ß2M was positively associated with the recurrence risk and 3-month outcome of AIS, but it did not appear to be directly related to the severity of AIS or the size of the infarct at admission.

Neutrophil-To-Lymphocyte Ratio Predicts 3-Month Outcome of Acute Ischemic Stroke.

Increasing evidences have demonstrated that inflammation is involved in the mechanisms of acute ischemic stroke (AIS). As an important and easy-to-measure inflammatory marker, neutrophil-to-lymphocyte ratio (NLR) shows a high association with mortality in patients with stroke in recent studies. In this study, we evaluated the prognostic role of NLR in patients with AIS. One hundred forty-three patients with AIS were enrolled. Clinical data were collected and the NLR was calculated from the admission blood work. The patients were followed up for 3 months after stroke onset. The occurrence of death and the major disability at 3 months after onset were end points in this study. Modified Rankin Scale score ≥3 was considered as poor outcome. In this study, 75 patients (52%) had poor outcome. We used binary logistic regression model to evaluate risk factor for poor outcome of AIS and found that the NLR was independently associated with the poor outcome of 3 months (P < 0.001). The optimal cutoff value for NLR as a predictor for 3-month outcome was 2.995. Therefore, in our study, high NLRs inversely predicted 3-month outcome in patients with AIS.