PAG neuronal NMDARs activation mediated morphine-induced hyperalgesia by HMGB1-TLR4 dependent microglial inflammation.

Morphine is one of the most effective and widely used analgesic drugs. However, chronic morphine use caused opioid-induced hyperalgesia (OIH). The development of OIH limits the use of morphine. The mechanisms of OIH are not fully understood. Toll-like receptor4 (TLR4) and glutamate receptors in the periaqueductal gray (PAG) are critical in OIH, however, the association between TLR4 and N-methyl-D-aspartate Receptors (NMDARs) activation in PAG remains unclear. Microglia activation, increased TLR4/p65 nuclear factor-kappa B (p65 NF-κB) and proinflammatory cytokines in microglia, and phosphorylation of NMDAR1 subunit (NR1) and NMDAR2B subunit (NR2B) in neurons were observed in PAG of OIH mice. Up-regulations of TLR4/p65 NF-κB and proinflammatory cytokines (IL-1ß, IL-6, TNF-α) in BV2 cells were prevented by inhibiting and knocking down TLR4. By inhibiting myeloid differentiation factor 2 (MD2) and knocking down the High-mobility group box 1 (HMGB1), we found that morphine activated TLR4 by HMGB1 but not MD2. We co-cultured Neuro-2a (N2A) with BV2 microglial cell line and found that instead of directly phosphorylating NMDAR subunits, morphine increased the phosphorylation of NR1 and NR2B by inducing TLR4-mediated microglia inflammation. Knocking TLR4 out of PAG by Lentivirus-GFP-TLR4 shRNA reversed these changes and relieved OIH. Our findings suggested that the secretion of HMGB1 induced by morphine-activated TLR4 in microglia, and the proinflammatory factors released by activated microglia phosphorylated NR1 and NR2B of adjacent neurons, induced increased neuronal excitability. In conclusion, TLR4/NMDARs in PAG were involved in the development and maintenance of OIH and supported novel strategies for OIH treatment.

Chronic exposure of alcohol triggers microglia-mediated synaptic elimination inducing cognitive impairment.

BACKGROUND AND AIMS: Long-term alcohol intake leads to cognitive impairment and dementia. The impairment of the cerebral cortex and limbic structures in alcoholics is associated with the loss of synapses instead of neurons. Synapse loss is considered to be an early and key feature of many neurodegenerative diseases, in which microglia-mediated synapse elimination is vital. However, the underlying mechanisms of synapse loss and cognitive impairment caused by long-term alcohol intake are still largely unknown. METHODS: We investigated the relationship of synapse impairment, the microglial innate immune receptor-TREM2, and microglia-mediated synaptic elimination in long-term alcohol exposure. RESULTS: We found that long-term alcohol exposure increased expression of TREM2, decreased expression of synaptic proteins and glutamate receptor subunits, reduced dendrite spine density, and impaired long-term potentiation (LTP) in the hippocampus. Minocycline reduced the amount of the postsynaptic marker PSD95 in microglia, attenuated dendrite spine density loss, and slow down the forgetting process of already-formed memory. Furthermore, we found that TREM2 participated in microglia-mediated synapse elimination in chronic alcohol exposure in vivo. Significantly fewer PSD95 were detectable in microglial phagolysosomes in TREM2 knockdown mice. Besides, TREM2 gene silencing ameliorated synapse loss, LTP impairment, and forgetting of remote memories. CONCLUSIONS: Our data suggests that TREM2 is associated with synaptic plasticity impairment and memory deficits, indicating microglia-mediated synaptic pruning might be the underlying mechanism involved in synapse loss and memory impairment induced by long-term alcohol intake. These findings provide new evidence for the receptor's participation in neurodegeneration diseases.

Morphine-induced microglial immunosuppression via activation of insufficient mitophagy regulated by NLRX1.

BACKGROUND: Chronic morphine exposure induces immunosuppression in the peripheral and central nervous system, resulting in susceptibility of patients to invading pathogens. Mitophagy is a crucial regulator of inflammation, and dysregulated mitophagy may cause immunosuppression, but whether mitophagy is linked with morphine-induced immunosuppression in the brain remains unknown. NLRX1 is the only mitochondrially localized NOD family receptor protein which serves as a critical regulator in immunity and mitophagy activation, but it remains an enigma how NLRX1 functions in the crosstalk between microglial inflammatory defense and mitophagy in the presence of morphine. METHODS: Primary microglia and astrocytes, BV2 and MA cell lines were utilized. Mice were stimulated with repeated morphine treatment to mimic chronic morphine exposure, and activation of mitophagy, lysosomal functions, and inflammation were assayed in specific brain regions and immune organs with or without NLRX1-silencing. RESULTS: Morphine induced microglial mitophagy in a LC3 (microtubule-associated proteins light chain 3)-dependent manner, which was mediated by NLRX1. Contrastingly, morphine impaired lysosomal functions, including generation, acidification and mitophagosome-lysosome fusion, thus leading to insufficient mitophagy activation in microglia. NLRX1-silencing inhibited mitophagy activity and rescued lysosomal functions including generation and acidification in microglia. The NLRX1-mediated incomplete mitophagy in microglial cells contributed to immunosuppression and vulnerability towards pathogenic challenge after morphine treatment. In vivo, NLRX1-mediated microglial mitophagy activation by morphine was mainly located in the murine brain cortex, striatum, and cerebellum, where NLRX1 functioned as a negative immune regulator and facilitated septic shock. Collectively, microglial immune responses to septic shock were amenable to NLRX1 silencing in the brain with morphine treatment. CONCLUSION: Morphine activated insufficient mitophagy in microglia which was regulated by NLRX1, ultimately leading to host immunosuppression and susceptible conditions in the brain.

Validation and Factor Analysis of the Obsessive Compulsive Drinking Scale (OCDS) in the Chinese Population.

Obsessive Compulsive Drinking Scale (OCDS) was established and introduced to measure the craving for alcohol and the severity of alcohol dependence. However, the Chinese version of OCDS is still unavailable and has not been validated in the Chinese population. We tended to translate and validate the OCDS in Chinese. We translated original OCDS into Chinese through bi-direction translations and tested the reliability and validity. We found that Chinese OCDS had high internal consistency and good test-retest reliability. The Chinese OCDS also presented good internal structure to reflect the severity of alcohol dependence. The Chinese OCDS could be used in clinical studies and research among the Chinese population.

Effect of alteplase versus aspirin plus clopidogrel in acute minor stroke.

Background and purpose: The optimal treatment for acute ischemic stroke with mild neurologic deficits is unclear. We aimed to compare the efficacy and safety of alteplase versus dual-antiplatelet therapy in acute minor stroke.Methods: We performed a retrospective cohort study of patients with minor ischemic stroke and National Institutes of Health Stroke Scale scores ≤5 presenting within 24 h from last seen normal. Patients were divided into intravenous alteplase or dual-antiplatelet therapy group. The primary outcome was a modified Rankin Scale (mRS) score of 0 or 1 at 90 days. Secondary outcomes included mRS score at 7 days, and composite outcome of vascular events within 90 days. The safety outcome was any intracranial hemorrhage (ICH) according to the ECASS II criteria. Clinical outcomes were compared using a multivariable logistic regression after adjusting for confounding factors. We then performed the propensity score matching as a sensitivity analysis.Results: Two hundred twenty-eight patients met the eligibility criteria were included for analysis between January 2015 and September 2018. In the aspirin-clopidogrel group, 109 patients (91.6%) achieved a favorable functional outcome at 3-month versus 85(78.0%) in the alteplase group (OR 4.463, 95%CI 1.708-11.662, p = .002). The difference of the composite outcome of vascular events were not statistical significance between the two groups (p > .05). Asymptomatic ICH occurred in 0.8% patients who received aspirin-clopidogrel, as compared with 3.7% patients in alteplase group (p = .030).Conclusions: Patients treated with dual-antiplatelet therapy with acute minor ischemic stroke had greater functional outcome at 3 months compared with patients who received alteplase therapy.Classification of evidence: This study provides Class IV evidence that dual-antiplatelet therapy is superior to alteplase for achieving a better functional outcome and does not increase the risk of hemorrhage in acute minor ischemic stroke.

Reperfusion therapy for minor stroke: A systematic review and meta-analysis.

OBJECTIVES: Approximately, half of the acute stroke patients with minor symptoms were excluded from thrombolysis in some randomized controlled trials (RCTs). There is little evidence on treating minor strokes with rt-PA. Here, we performed a systematic review and meta-analysis to assess the safety and efficacy of thrombolysis in these patients. METHODS: PubMed, Embase, Web of Science, and Cochrane Library were searched in July 2018. All available RCTs and retrospective comparative studies that compared thrombolysis with nonthrombolysis' for acute minor stroke (NIHSS ≤ 5) with quantitative outcomes were included. RESULTS: Ten studies, including a total of 4,333 patients, were identified. The risk of intracranial hemorrhage (ICH) was higher in the rt-PA group as compared with that in the non-rt-PA group (3.8% vs. 0.6%; p = .0001). However, there is no significant difference in the rate of mortality between the two groups (p = .96). The pooled rate of a good outcome in 90 days was 67.8% in those with rt-PA and 63.3% in those without rt-PA (p = .07). Heterogeneity was 43% between the studies (p = .08). After adjusting for the heterogeneity, thrombolysis was associated with good outcome (68.3% vs. 63.0%, OR 1.47; 95% CI 1.14-1.89; p = .003). In post hoc analyses, including only RCTs, the pooled rate of good outcome had no significant differences between the two groups (86.6% vs. 85.7%, 95% CI 0.44-3.17, p = .74; 87.4% vs. 91.9%, 95% CI 0.35-1.41, p = .32; before and after adjusting separately). CONCLUSIONS: Although thrombolysis might increase the risk of ICH based on existing studies, patients with acute minor ischemic stroke could still benefit from thrombolysis at 3 months from the onset.

The efficacy of transcranial magnetic stimulation on migraine: a meta-analysis of randomized controlled trails.

OBJECTIVES: As a non-invasive therapy, whether transcranial magnetic stimulation (TMS) is effective on migraine. This article was aimed to assess the efficacy of TMS on migraine based on randomized controlled trails (RCTs). METHODS: We searched PubMed, Embase and Cochrane Library electronic databases for published studies which compared TMS group with sham group, conducted a meta-analysis of all RCTs. RESULTS: Five studies, consisting of 313 migraine patients, were identified. Single-pulse transcranial magnetic stimulation is effective for the acute treatment of migraine with aura after the first attack (p = 0.02). And, the efficacy of TMS on chronic migraine was not significant (OR 2.93; 95% CI 0.71-12.15; p = 0.14). CONCLUSIONS: TMS is effective for migraine based on the studies included in the article.