Increased Cerebrospinal Fluid Levels of Soluble Triggering Receptor Expressed on Myeloid Cells 2 and Chitinase-3-Like Protein 1 in Idiopathic Normal-Pressure Hydrocephalus.

BACKGROUND: Neurodegenerative disease pathology is associated with neuroinflammation, but evidence on idiopathic normal pressure hydrocephalus (iNPH) remains limited and cerebrospinal fluid (CSF) biomarker profiles need to be elucidated. OBJECTIVE: To investigate whether iNPH pathological mechanisms are associated with greater CSF markers of core Alzheimer's disease pathology (amyloid-ß42 (Aß42), phosphorylated tau (P-tau)), neurodegeneration (total tau (T-tau)), and neuroinflammation (soluble triggering receptor expressed on myeloid cells 2 (sTREM2), chitinase-3-like protein 1 (YKL-40)). METHODS: The study analyzed lumbar CSF samples from 63 patients with iNPH and 20 age-matched orthopedic surgery patients who had no preoperative gait or cognitive impairment (control group). Aß42, T-tau, P-tau, sTREM2, and YKL-40 in different subgroups were investigated. RESULTS: CSF sTREM2 levels were significantly higher in the iNPH group than in the control group, but no significant between-group difference was noted in YKL-40. Moreover, YKL-40 levels were significantly higher in the tap test non-responders than in the tap test responders (p = 0.021). At the 1-year follow-up after shunt surgery, the CSF P-tau levels were significantly lower (p = 0.020) in those with gait improvement and the CSF sTREM2 levels were significantly lower (p = 0.041) in those with cognitive improvement. In subgroup analysis, CSF sTREM2 levels were strongly correlated with CSF YKL-40 in the iNPH group (r = 0.443, p < 0.001), especially in the tap test non-responders (r = 0.653, p = 0.002). CONCLUSION: YKL-40 and sTREM2 are disease-specific markers of neuroinflammation, showing higher CSF levels in iNPH. In addition, sTREM2 is positively associated with YKL-40, indicating that interactions of glial cells play an important role in iNPH pathogenesis.

White matter hyperintensity mediating gait disorders in iNPH patients via neurofilament light chain.

Purpose: This study aimed to analyze the differences in regional white matter hyperintensities (WMH) volume and cerebrospinal fluid biomarker levels between idiopathic normal pressure hydrocephalus (iNPH) patients with or without gait disorder. Methods: Forty-eight iNPH patients undergoing bypass surgery and 20 normal senile individuals were included. The LST toolkit was used to segment all MRI fluid attenuation inversion images and quantify the WMH volume in each brain region. Cerebrospinal fluid was collected from all individuals and measured for concentrations of Aß, t-tau, p-tau, and neurofilament light chain (NfL). Patients with iNPH were followed up for 1 year and divided categorized into a gait disorder improvement group and no improvement group according to the 3 m round-trip test time parameter improvement by more than 10%. Results: We found that WMH in all areas of iNPH patients was higher than that in the control group. CSF levels of Aß, t-tau, and p-tau were lower than those in the control group, while NfL levels were higher than those in the control group. The gait (+) group NfL level was higher than that in gait (-), and there were no statistical differences in Aß, t-tau, and p-tau levels. The gait (+) group of frontal and parietal lobe WMH volume PVH above the gait (-) group. The mediating effect model analysis showed that PVH might affect the gait disorder of iNPH patients through NfL. A 1-year follow-up of the patients after the bypass surgery found that 24 of the 35 patients in the gait (+) group had improvements, while 11 had no significant improvements. The comparison of CSF marker levels between the two groups showed that the CSF NfL level in the improved group was lower than that in the non-improved group. The WMH volume and PVH in the frontal-parietal lobe of the improved group were lower than those of the non-improved group. Conclusion: iNPH patients have more serious frontoparietal and periventricular white matter lesions, and WMH volume in the frontoparietal may mediate the occurrence of gait disorder in iNPH patients through the increase of NfL level.

White matter hyperintensities-related cortical changes and correlation with mild behavioral impairment.

PURPOSE: The aim of this study was to analyze cortical thickness and gray matter volume (GMV) changes in white matter hyperintensities (WMH) which were associated brain regions and their association with mild behavioral impairment (MBI) by means of voxel- and surface-based morphology (VBM and SBM). METHODS: A total of 60 patients underwent 3T MRI scan and MBI checklist (MBI-C) assessment and were divided into two groups: lower WMH (LWMH) and higher WMH (HWMH). After adjusting for confounding factors i.e. age, gender, education, and total intracranial volume, we found a GMV decrease in the left anterior insula (AIns), right middle frontal gyrus, right central operculum, right fusiform gyrus, left cerebellum exterior, and thalamus proper in the HWMH group based VBM, while in the HWMH group based SBM we found cortical thickness decrease in the left lingual, right posterior cingulate cortex (rPCC), right precentral, left superior frontal, right medial orbitofrontal gyrus, and left pars opercularis. RESULTS: The HWMH group had higher MBI-C scores. The GMV in the left AIns and thalamus proper and the thickness of rPCC negatively correlated with the MBI-C scores. The mediation analysis suggested that WMH may partially mediate MBI-C scores by reducing the GMV and cortical thickness of the mentioned brain regions. CONCLUSIONS: In WMH patients, the occurrence of MBI is associated with atrophy of gray matter and cortex. The occurrence of MBI may be partially mediated by WMH through gray matter and cortical atrophy. It provides a new insight into the relationship between WMH and dementia.

Association of Pre-stroke Frailty With Prognosis of Elderly Patients With Acute Cerebral Infarction: A Cohort Study.

Background: Frailty is a state of cumulative degradation of physiological functions that leads to adverse outcomes such as disability or mortality. Currently, there is still little understanding of the prognosis of pre-stroke frailty status with acute cerebral infarction in the elderly. Objective: We investigated the association between pre-stroke frailty status, 28-day and 1-year survival outcomes, and functional recovery after acute cerebral infarction. Methods: Clinical data were collected from 314 patients with acute cerebral infarction aged 65-99 years. A total of 261 patients completed follow-up in the survival cohort analysis and 215 patients in the functional recovery cohort analysis. Pre-stroke frailty status was assessed using the FRAIL score, the prognosis was assessed using the modified Rankin Scale (mRS), and disease severity using the National Institutes of Health Stroke Scale (NIHSS). Results: Frailty was independently associated with 28-day mortality in the survival analysis cohort [hazard ratio (HR) = 4.30, 95% CI 1.35-13.67, p = 0.014]. However, frailty had no independent effect on 1-year mortality (HR = 1.47, 95% CI 0.78-2.79, p = 0.237), but it was independently associated with advanced age, the severity of cerebral infarction, and combined infection during hospitalization. Logistic regression analysis after adjusting for potential confounders in the functional recovery cohort revealed frailty, and the NIHSS score was significantly associated with post-stroke severe disability (mRS > 2) at 28 days [pre-frailty adjusted odds ratio (aOR): 8.86, 95% CI 3.07-25.58, p < 0.001; frailty aOR: 7.68, 95% CI 2.03-29.12, p = 0.002] or 1 year (pre-frailty aOR: 8.86, 95% CI 3.07-25.58, p < 0.001; frailty aOR: 7.68, 95% CI 2.03-29.12, p = 0.003). Conclusions: Pre-stroke frailty is an independent risk factor for 28-day mortality and 28-day or 1-year severe disability. Age, the NIHSS score, and co-infection are likewise independent risk factors for 1-year mortality.

Exosomes Derived From M2 Microglia Cells Attenuates Neuronal Impairment and Mitochondrial Dysfunction in Alzheimer's Disease Through the PINK1/Parkin Pathway.

The accumulation of abnormal aggregation of amyloid-ß plaques is one of the most distinguishing pathologies of Alzheimer's disease (AD) and is highly toxic to neurons. Exosomes have demonstrated great potential for AD therapy. However, the impact and underlying mechanism of M2 microglia-derived exosomes (M2-EXOs) in AD progression and outcome are seldom explored. Therefore, we employed an Aß1-42 oligomer (Aß)-induced AD model in neuronal HT-22 cells and 7-month-old APP/PS1 mice to investigate the effects of M2-EXOs on AD. We revealed that the AD cell model established by Aß was accompanied by the upregulation of Aß1-42, neuronal death, alternation of mitochondrial function and autophagy. M2-EXOs can be internalized by HT-22 cells and MAP2-positive neuronal cells in APP/PS1 mice, and exert neuroprotective functions. Specifically, the administration of M2-EXOs in the AD cell model partially increased cell viability, restored the destruction of mitochondrial membrane potential, and reduced the accumulation of reactive oxygen species inside the mitochondria and cells in a dose-dependent manner. Moreover, we demonstrated that PINK1/Parkin mediated mitophagy was enhanced, while incubation with M2-EXOs decreased beclin1, LC3II, PINK1, and Parkin expression levels. Finally, we observed that compared with APP/PS1 mice treated with PBS, the application of M2-EXOs could decrease Aß plaque deposition and minus Aß oligomer expression along with improved PINK1/Parkin pathway-mediated autophagy. Overall, our results imply that M2-EXOs play a protective role in the pathogenesis of AD by ameliorating PINK1/Parkin-mediated mitophagy, indicating that it may provide a novel therapeutic strategy to treat AD.

Effect of in vitro gastrointestinal digestion on the chemical composition and antioxidant properties of Ginkgo biloba leaves decoction and commercial capsules.

In this study Ginkgo biloba leaves (GBL) decoction and commercial capsules were digested using an in vitro model. Thirty-six active compounds were identified and quantified by HPLC-ESI-MS analysis based on the MS/MS patterns (precursor ions and product ions) and retention times, in comparison with reference standards. Most compounds in GBL showed a significant decrease during intestinal digestion, with an exception of vanillic acid and biflavonoids. Bioaccessibility values of chemical compositions varied between decoction and capsules samples. Also, significant reductions of total flavonoids and total phenolic content was observed after in vitro digestion. Both, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazo-line-6-sulfonic acid (ABTS) scavenging capacity decreased after gastric digestion, but increased during intestinal digestion. Nevertheless, different behaviour was observed in reducing antioxidant power (FRAP) assay. Compared to the pH of digestion, the influence of digestive enzymes on the chemical composition and antioxidant activity of GBL was relatively minor. Overall, these results may help provide a valid foundation for further investigations on bioactive compounds and the pharmacodynamics of GBL.

The p75 neurotrophin receptor as a novel intermediate in L-dopa-induced dyskinesia in experimental Parkinson's disease.

In Parkinson's disease (PD), long-term administration of L-dopa often leads to L-dopa-induced dyskinesia (LID), a debilitating motor complication. The p75 neurotrophin receptor (p75NTR) is likely to play a critical role in the regulation of dendritic spine density and morphology and appears to be associated with neuroinflammation, which previously has been identified as a crucial mechanism in LID. While aberrant modifications of p75NTR in neurological diseases have been extensively documented, only a few studies report p75NTR dysfunction in PD, and no data are available in LID. Here, we explored the functional role of p75NTR in LID. In LID rats, we identified that p75NTR was significantly increased in the lesioned striatum. In 6-hydroxydopamine (6-OHDA)-hemilesioned rats, specific knockdown of striatal p75NTR levels achieved by viral vector injection into the striatum prevented the development of LID and increased striatal structural plasticity. By contrast, we found that in 6-OHDA-hemilesioned rats, striatal p75NTR overexpression exacerbated LID and facilitated striatal dendritic spine losses. Moreover, we observed that the immunomodulatory drug fingolimod attenuated LID without lessening the therapeutic efficacy of L-dopa and normalized p75NTR levels. Together, these data demonstrate for the first time that p75NTR plays a pivotal role in the development of LID and that p75NTR may act as a potential novel target for the management of LID.

Systemic Inflammation Increases the Susceptibility to Levodopa-Induced Dyskinesia in 6-OHDA Lesioned Rats by Targeting the NR2B-Medicated PKC/MEK/ERK Pathway.

Background: The long-term administration of levodopa (L-dopa), the gold-standard treatment for Parkinson's disease (PD), is irreparably associated with L-dopa-induced dyskinesia (LID), which dramatically affects the quality of life of patients. However, the underlying molecular mechanisms of how LID exacerbates remain unknown. Neuroinflammation in the striatum plays an active role in LID. These findings prompt an investigation of non-neuronal mechanisms of LID. This study will examine the effects of systemic inflammation in the development and progression of LID. Methods: To evaluate the possible influence of systemic inflammation in the appearance of LID, the PD rats received an intraperitoneal (IP) injection of various concentrations of lipopolysaccharides (LPS, 1, 2, and 5 mg/kg) or saline. One day later, these PD rats started to receive daily treatment with L-dopa (6 mg/kg) along with benserazide (6 mg/kg) or saline for 21 days, and dyskinesia was evaluated at several time points. Moreover, the activation of microglia and astrocytes and the molecular changes in NR2B and mGLUR5 signaling pathways were measured. Results: We found that systemic inflammatory stimulation with LPS exacerbated the intensity of abnormal involuntary movements (AIMs) induced by L-dopa treatment in 6-hydroxydopamine (6-OHDA) lesioned rats. The LPS injection activated the gliocytes and increased the levels of proinflammatory cytokines in the striatum in LID rats. The PD rats that received the LPS injection showed the overexpression of p-NR2B and NR2B, as well as activated PKC/MEK/ERK and NF-κB signal pathways in response to the L-dopa administration. On the contrary, clodronate-encapsulated liposomes (Clo-lipo), which could suppress the inflammatory response induced by peripheral LPS injection, improved behavioral dysfunction, inhibited neuroinflammation, prevented NR2B overexpression, and decreased the phosphorylation of PKC/MEK/ERK and NF-κB signaling pathways. Conclusion: This study suggests that systemic inflammation, by exacerbating preexisting neuroinflammation and facilitating NR2B subunit activity, may play a crucial role in the development of LID. The administration of Clo-lipo restores the effects of LPS and decreases the susceptibility to LID in 6-OHDA lesioned rats.

Oculomotor Performances Are Associated With Motor and Non-motor Symptoms in Parkinson's Disease.

Background: Parkinson's disease (PD) patients exhibit deficits in oculomotor behavior, yet the results are inconsistent across studies. In addition, how these results are associated with clinical symptoms is unclear, especially in China. Methods: We designed a case-control study in China including 37 PD patients and 39 controls. Clinical manifestations in PD patients were recorded. Oculomotor performance was measured by a video-based eye tracker system. Results: We found that six oculomotor parameters, including fixation stability, saccadic latency, smooth pursuit gain, saccade frequency, viewing range, and saccade frequency during free-viewing context, were significantly different in PD patients and control group. Combining application of these six parameters could improve diagnostic accuracy to over 90%. Moreover, pursuit gain was significantly associated with PD duration, UPDRS III, in PD patients. Saccade latency was significantly associated with PD duration, Berg balance score, RBD score, and Total LEDD in PD patients. Conclusions: PD patients commonly exhibit oculomotor deficits in multiple behavioral contexts, which are associated with both motor and non-motor symptoms. Oculomotor test may provide a valuable tool for the clinical assessment of PD.

Partial Depletion of Peripheral M1 Macrophages Reverses Motor Deficits in MPTP-Treated Mouse by Suppressing Neuroinflammation and Dopaminergic Neurodegeneration.

Background: Neuroinflammation plays an important role in the pathogenesis of Parkinson's disease (PD). Inflammatory cytokines in the peripheral immune system can induce neuroinflammation in central nervous system (CNS). Whether the peripheral immune system is involved in PD is unclear. The present study investigated the contribution of the peripheral immune system to the neuronal loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP) model of PD. Methods: MPTP was intraperitoneally injected into mice to generate a PD model. Mice received clodronate liposomes every 3 days to deplete peripheral macrophages. The percentages of macrophages were measured by flow cytometry at 1, 3, and 7 days after MPTP injection. Neurobehavioral parameters, protein expression, inflammatory cytokines release, and microglia activation were measured by the open field test, western blotting, quantitative polymerase chain reaction (qPCR), and immunofluorescence staining, respectively at 7 days after MPTP injection. Results: Our study revealed that intraperitoneal injection of MPTP could increase peripheral M1 macrophages levels. It also can induce T cells infiltration and cytokine release. Depletion of M1 macrophages by clodronate liposomes suppressed these inflammatory effects and blunted the loss of TH+ nigral neurons and functional impairments caused by MPTP. Conclusion: Our results indicated the critical role of M1 macrophages in the pathogenesis of PD and proposed inhibition of M1 macrophages as a promising therapeutic approach for neurodegeneration.

Genetic analysis and clinical assessment of four patients with Glycogen Storage Disease Type IIIa in China.

BACKGROUND: Glycogen Storage Disease Type III (GSD III) is a rare autosomal recessive metabolic disorder caused by AGL gene mutation. There is significant heterogeneity between the clinical manifestations and the gene mutation of AGL among different ethnic groups. However, GSD III is rarely reported in Chinese population. CASE PRESENTATION: In this study, we aimed to study the genetic and clinical characteristics of four patients with GSD IIIa from China, especially the neurological manifestations. Meanwhile, we conducted a literature review of GSD IIIa cases reported in Chinese population to investigate the relationship between genotype and phenotype. CONCLUSIONS: Three different AGL gene mutations were identified in our patients: c.206dupA, c.1735 + 1G > T and c.2590 C>T. Moreover, progressive myopathy accompanied by elevated creatine kinase level was the main manifestation of our patients in adolescents. Our results showed that AGL c.206dupA was a novel mutation and caused severe clinical manifestations. AGL c.1735 + 1G > T might be a recurrent mutation in the Chinese population. Genetic analysis of AGL gene mutation combined with muscle magnetic resonance imaging (MRI) might provide greater benefit to the patient in diagnosing GSD IIIa, rather than an invasive diagnostic procedure of biopsy.

Thromboxane A2 receptor antagonist SQ29548 attenuates SH­SY5Y neuroblastoma cell impairments induced by oxidative stress.

Thromboxane A2 receptor (TXA2R) serves a vital role in numerous neurological disorders. Our previous study indicated that SQ29548, an antagonist of TXA2R, attenuated the induced neuron damage in cerebral infarction animals; however, the underlying mechanism remains unknown. Certain studies revealed a new role of TXA2R in the regulation of oxidative stress, which is one of the basic pathological processes in neurological disorders. Thus, the present study attempted to examine whether the inhibition of TXA2R with SQ29548 helped to protect the nerve cells against oxidative stress. SQ29548 was utilized as a TXA2R antagonist, and relevant assays were performed to detect the cell viability, cellular reactive oxygen species (ROS) level, cell apoptosis, expression levels of superoxide dismutase­2 (SOD2), catalase and caspases, and activation of mitogen­activated protein kinase (MAPK) pathways. It was observed that hydrogen peroxide (H2O2) dose­dependently reduced the viability of SH­SY5Y cells. In addition, H2O2 raised the level of ROS in cells, inhibited the expression levels of SOD2 and catalase, and potentially enhanced cell apoptosis and the expression of caspases via activating the MAPK pathways. Pretreatment with SQ29548 not only rescued the viability of SH­SY5Y cells, but also ameliorated the intracellular ROS level and the expression levels of SOD2 and catalase. Furthermore, it decreased the cell apoptosis and the expression of caspases, possibly via the inhibition of MAPK pathways. In conclusion, SQ29548, an antagonist of TXA2R, improved the antioxidant capacities of SH­SY5Y cells and reduced the cell apoptosis through the inhibition of MAPK pathways.

Idebenone Alleviates Neuroinflammation and Modulates Microglial Polarization in LPS-Stimulated BV2 Cells and MPTP-Induced Parkinson's Disease Mice.

Background: Idebenone is an antioxidant and a coenzyme Q10 analog that has been used to treat neurodegeneration disease. Some studies show idebenone exerts anti-inflammatory effects. However, whether idebenone can be used to reduce the neuroinflammation in Parkinson's disease (PD) has been little studied. Methods: The study investigated the potential anti-inflammatory effects of idebenone in vitro and in vivo, using cell models of Lipopolysaccharide (LPS)-simulated BV2 cells and animal models of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD with or without idebenone. To verify how idebenone exerts its effects on the BV2 cell activation and PD model, we performed the mechanistic studies in vitro and in vivo. Results: In vitro study showed that pretreatment with idebenone could attenuate the production of pro-inflammatory factors in LPS-stimulated BV2 cells and promoted a phenotypic switch from the M1 state to the M2 state. Mechanistically, idebenone reduced the activation of the MAPK and NF-κB signaling pathway upon LPS stimulation. Furthermore, in vivo experiments confirmed that pretreatment with idebenone could ameliorate MPTP-induced neurodegeneration and modulate microglia phenotypes through inhibition of the MAPK and NF-κB signaling pathway in the SN. Conclusion: These results suggest that idebenone ameliorates the neurological deficits related to PD and this effect is partly mediated by inhibiting the neuroinflammation and modulating microglia phenotypes.

Antidyskinetic Treatment with MTEP Affects Multiple Molecular Pathways in the Parkinsonian Striatum.

Parkinson's disease is characterized by dopaminergic neuron loss and dopamine (DA) depletion in the striatum. Standard treatment is still focused on the restoration of dopamine with exogenous L-Dopa, which however causes L-Dopa-induced dyskinesia (LID). Several studies have shown that antagonism of the metabotropic glutamate receptor 5 alleviates LID, but the underlying mechanisms have remained unclear. We set out to determine where this alleviation may depend on restoring the equilibrium between the two main striatofugal pathways. For this purpose, we examined molecular markers of direct and indirect pathway involvement (prodynorphin and proenkephalin, resp.) in a rat model of LID treated with the mGluR5 antagonist MTEP. Our results show that MTEP cotreatment significantly attenuates the upregulation of prodynorphin mRNA induced by L-Dopa while also decreasing the expression levels of proenkephalin mRNA. We also examined markers of the mGluR5-related PKC/MEK/ERK1/2 signaling pathway, finding that both the expression of PKC epsilon and the phosphorylation of MEK and ERK1/2 had decreased significantly in the MTEP-treated group. Taken together, our results show that pharmacological antagonism of mGluR5 normalizes several abnormal molecular responses in the striatum in this experimental model of LID.

Adjudin-preconditioned neural stem cells enhance neuroprotection after ischemia reperfusion in mice.

BACKGROUND: Transplantation of neural stem cells (NSCs) has been proposed as a promising therapeutic strategy for the treatment of ischemia/reperfusion (I/R)-induced brain injury. However, existing evidence has also challenged this therapy on its limitations, such as the difficulty for stem cells to survive after transplantation due to the unfavorable microenvironment in the ischemic brain. Herein, we have investigated whether preconditioning of NSCs with adjudin, a small molecule compound, could enhance their survivability and further improve the therapeutic effect for NSC-based stroke therapy. METHOD: We aimed to examine the effect of adjudin pretreatment on NSCs by measuring a panel of parameters after their transplantation into the infarct area of ipsilateral striatum 24 hours after I/R in mice. RESULTS: We found that pretreatment of NSCs with adjudin could enhance the viability of NSCs after their transplantation into the stroke-induced infarct area. Compared with the untreated NSC group, the adjudin-preconditioned group showed decreased infarct volume and neurobehavioral deficiency through ameliorating blood-brain barrier disruption and promoting the expression and secretion of brain-derived neurotrophic factor. We also employed H2O2-induced cell death model in vitro and found that adjudin preconditioning could promote NSC survival through inhibition of oxidative stress and activation of Akt signaling pathway. CONCLUSION: This study showed that adjudin could be used to precondition NSCs to enhance their survivability and improve recovery in the stroke model, unveiling the value of adjudin for stem cell-based stroke therapy.

Thromboxane A2 receptor antagonist SQ29548 suppresses the LPS­induced release of inflammatory cytokines in BV2 microglia cells via suppressing MAPK and NF­κB signaling pathways.

Inflammation in the brain, characterized by the activation of microglia, is hypothesized to participate in the pathogenesis of neuronal disorders. It is proposed that thromboxane A2 receptor (TXA2R) activation is involved in thrombosis/hemostasis and inflammation responses. In the present study, the anti­inflammatory effects of SQ29548 on lipopolysaccharide (LPS)­stimulated BV2 microglial cells and its molecular mechanisms were investigated. In the BV2 cell line, LPS­stimulated nitric oxide (NO) and inflammatory cytokine release, and the phosphorylation of mitogen­activated protein kinases (MAPKs) and the nuclear factor (NF)­κB were assessed using an NO assay kit, reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. In vitro studies demonstrated that SQ29548 inhibited LPS­stimulated BV2 activation and reduced the mRNA expression levels of interleukin (IL)­1ß, IL­6, tumor necrosis factor­α and inducible NO synthase via inhibition of MAPKs and the NF­κB signaling pathway. SQ29548 inhibited the LPS­induced inflammatory response by blocking MAPKs and NF­κB activation in BV2 microglial cells.

Thromboxane A2 receptor antagonist SQ29548 reduces ischemic stroke-induced microglia/macrophages activation and enrichment, and ameliorates brain injury.

Thromboxane A2 receptor (TXA2R) activation is thought to be involved in thrombosis/hemostasis and inflammation responses. We have previously shown that TXA2R antagonist SQ29548 attenuates BV2 microglia activation by suppression of ERK pathway, but its effect is not tested in vivo. The present study aims to explore the role of TXA2R on microglia/macrophages activation after ischemia/reperfusion brain injury in mice. Adult male ICR mice underwent 90-min transient middle cerebral artery occlusion (tMCAO). Immediately and 24 h after reperfusion, SQ29548 was administered twice to the ipsilateral ventricle (10 µl, 2.6 µmol/ml, per dose). Cerebral infarction volume, inflammatory cytokines release and microglia/macrophages activation were measured using the cresyl violet method, quantitative polymerase chain reaction (qPCR), and immunofluorescence double staining, respectively. Expression of TXA2R was significantly increased in the ipsilateral brain tissue after ischemia/reperfusion, which was also found to co-localize with activated microglia/macrophages in the infarct area. Administration of SQ29548 inhibited microglia/macrophages activation and enrichment, including both M1 and M2 phenotypes, and attenuated ischemia-induced IL-1ß, IL-6, and TNF-α up-regulation and iNOS release. TXA2R antagonist SQ29548 inhibited ischemia-induced inflammatory response and furthermore reduced microglia/macrophages activation and ischemic/reperfusion brain injury.

Relevance Study on Cerebral Infarction and Resistin Gene Polymorphism in Chinese Han Population.

Recent research on genome-wide associations has implicated that the serum resistin level and its gene polymorphism are associated with cerebral infarction (CI) morbidity and prognosis, and could thereby regulate CI. This study aimed to investigate the association between the resistin single nucleotide polymorphism (SNP) and the susceptibility to CI in the Chinese Han population. A total of 550 CI patients and 313 healthy controls were genotyped. Nine SNPs of the resistin gene previously shown were sequenced and assessed for an association with CI. The numbers of GG genotype carriers of rs3219175 and rs3486119 in the CI group were significantly higher than those in the control group among the middle-aged group (aged 45-65), at 76% vs 67.9% (P=0.025) and 75.5% vs 67.9% (P=0.031). rs3219175 and rs34861192 were associated with CI in the dominant and superdominant models according to the genetic model analysis (P<0.05). Meanwhile, there was strong linkage disequilibrium among the rs34124816, rs3219175, rs34861192, rs1862513, rs3745367, 180C/G and rs3745369 sites. In a haplotype analysis, the occurrence rate of the haplotype AGGCAGC was 1.97 times (P<0.05) higher in the patient group than in the control group. In addition, the numbers of GG genotype carriers of rs3219175 and rs3486119 in the middle-aged male CI patients and the middle-aged small artery occlusion (SAO) CI patients were higher than those in the control group (P<0.05). In the Chinese Han middle-aged population, the GG gene type carriers of the resistin gene sites rs3219175 and rs34861192 had a high risk for CI onset, especially in middle-aged male patients and SAO CI in all middle-aged patients.

Thromboxane A2 Receptor Stimulation Enhances Microglial Interleukin-1ß and NO Biosynthesis Mediated by the Activation of ERK Pathway.

BACKGROUND AND PURPOSE: Thromboxane A2 (TXA2) receptors (TP) interact with the ligand TXA2 to induce platelet aggregation and regulate hemostasis. Recently TP-mediated signaling has been suggested to function in multiple cell types in the brain. In this report, we aim to study the expression and physiological role of TP in microglia, in particular after brain ischemia. METHODS: Ischemic brain sections were analyzed for TP expression. Microglial cell line and primary microglia were cultured, or neuronal cell line co-culture system was used to determine the TP mediated signaling in inflammation and microglia activation. RESULTS: We found that the TP level was significantly increased in ipsilateral mouse brain tissue at 24 h after ischemia-reperfusion, which was also found to partly co-localize with CD11b, a marker for microglial and infiltrated monocyte/macrophage, in peri-infarct area. Immunofluorescence staining of primary microglia and microglial cell line BV2 revealed the predominant membrane distribution of TP. Conditioned culture media from TP agonist U46619-treated BV2 cells decreased neuronal SH-SY5Y cell viability and induced apoptotic morphological changes. Furthermore, U46619 enhanced IL-1ß, IL-6, and iNOS mRNA expression as well as IL-1ß and NO releases in BV2 cells or primary microglia. Such stimulation could be attenuated by TP antagonist SQ29548 or MEK inhibitor U0126. The dose- and time-dependent extracellular-signal-regulated kinase (ERK) phosphorylation induced by U46619 further demonstrated ERK signaling-mediated microglia activation by TP agonist. CONCLUSION: This study has shown a novel role of TP in microglia activation via the ERK signaling pathway, which provides insights for the management of neuroinflammation in diseases like cerebral infarction.