Humid heat environment causes anxiety-like disorder via impairing gut microbiota and bile acid metabolism in mice.

Climate and environmental changes threaten human mental health, but the impacts of specific environmental conditions on neuropsychiatric disorders remain largely unclear. Here, we show the impact of a humid heat environment on the brain and the gut microbiota using a conditioned housing male mouse model. We demonstrate that a humid heat environment can cause anxiety-like behaviour in male mice. Microbial 16 S rRNA sequencing analysis reveals that a humid heat environment caused gut microbiota dysbiosis (e.g., decreased abundance of Lactobacillus murinus), and metabolomics reveals an increase in serum levels of secondary bile acids (e.g., lithocholic acid). Moreover, increased neuroinflammation is indicated by the elevated expression of proinflammatory cytokines in the serum and cortex, activated PI3K/AKT/NF-κB signalling and a microglial response in the cortex. Strikingly, transplantation of the microbiota from mice reared in a humid heat environment readily recapitulates these abnormalities in germ-free mice, and these abnormalities are markedly reversed by Lactobacillus murinus administration. Human samples collected during the humid heat season also show a decrease in Lactobacillus murinus abundance and an increase in the serum lithocholic acid concentration. In conclusion, gut microbiota dysbiosis induced by a humid heat environment drives the progression of anxiety disorders by impairing bile acid metabolism and enhancing neuroinflammation, and probiotic administration is a potential therapeutic strategy for these disorders.

Predicting haemorrhagic transformation through serum biochemical indices for patients after endovascular treatment: a retrospective study.

INTRODUCTION: The aim of this study was to determine the serum biochemical markers that can predict the risk of haemorrhagic transformation (HT) before and after endovascular treatment (EVT). MATERIAL AND METHODS: This study included patients with anterior circulation large vessel occlusion (ACLVO) who underwent EVT within six hours of symptom onset between September 2017 and September 2022. These patients were retrospectively categorised into two groups: an HT group and a No-HT group. RESULTS: A total of 180 patients were included in the study, of whom 55 (30.6%) had HT. The monocyte count before EVT (p = = 0.005, OR = 0.694, 95% CI 0.536-0.898), the activated partial thromboplastin time before EVT (p = 0.009, OR = 0.186, 95% CI 0.699-0.952), and the eosinophil count after EVT (p = 0.038, OR = 0.001, 95% CI 0.000-0.018) were all found to be independent predictors of HT, with warning values of 6.65%, 22.95 seconds, and 0.035*10^9/L, respectively. When compared to prediction using only demographic data [AUC = 0.662,95% CI (0.545, 0.780)], adding biochemical indices before EVT [AUC = 0.719,95% CI (0.617, 0.821)], adding biochemical indices after EVT [AUC = 0.670,95% CI (0.566, 0.773)], and adding both [AUC = 0.778,95% CI (0.686, 0.870)], the prediction efficiency of HT was improved among all three combinations, with no statistical significance. CONCLUSIONS: The levels of serum biochemical markers were found to show significant changes before and after EVT in ACLVO patients. A combination of demographic data and serum biochemical markers proved to be effective in predicting the occurrence of HT in patients with ACLVO who underwent EVT.

Celsr3 is required for Purkinje cell maturation and regulates cerebellar postsynaptic plasticity.

Atypical cadherin Celsr3 is critical for brain embryonic development, and its role in the postnatal cerebellum remains unknown. Using Celsr3-GFP mice, Celsr3 shows high expression in postnatal Purkinje cells (PCs). Mice with conditional knockout (cKO) of Celsr3 in postnatal PCs exhibit deficit in motor coordination and learning, atrophic PC dendrites, and decreased synapses. Whole-PC recording in cerebellar slices discloses a reduction frequency of mEPSC and defective postsynaptic plasticity (LTP and LTD) in Celsr3 cKO mutants. Wnt5a perfusion enhances LTP formation, which could be occluded by cAMP agonist and diminished by cAMP antagonist in control, but not in Celsr3 cKO or Fzd3 cKO cerebellar slices. Celsr3 cKO resulted in the failure of mGluR1 agonist-induced LTD and paired stimulation-induced PKCα overexpression in PC dendrites, and downregulation of mGluR1 expression compvared to controls. In conclusion, Celsr3 is required for PCs maturation and regulates postsynaptic LTP and LTD through Wnt5a/cAMP and mGluR1/PKCα signaling respectively.

Protein kinase A mediates scopolamine-induced mTOR activation and an antidepressant response.

BACKGROUND: Clinical reports have shown that scopolamine produces a rapid (3-4 d) and potent anti-depressive response without severe adverse effects. Animal experiments have proven that scopolamine induces mTOR pathway activation in an AMPAR dependent manner. The present study aimed to determine the role of PKA in scopolamine-induced potentiation of AMPAR, as well as in mTOR pathway activation and rapid antidepressant effects. METHODS: We utilized electrophysiological recording, Western blotting, and behavior tests to examine the effects of scopolamine, the selective M2 cholinergic receptor antagonist methoctramine, and H89, a PKA specific inhibitor on AMPAR potentiation, mTOR pathway activation, and behavioral responses in a rat depression model of learned helplessness. RESULTS: Scopolamine (1µM) rapidly increased AMPAR-fEPSP amplitudes and membrane GluA1 expression in CA1 region of hippocampal slices, both of which were abolished by H89. Moreover, scopolamine promoted AMPAR phosphorylation on GluA1 ser845, a PKA site involved in GluA1 membrane insertion. H89 disrupted both GluA1 ser845 phosphorylation and mTOR activation, as well as the antidepressant effects of scopolamine as determined via forced swim test. Additionally, methoctramine mimicked the effects of scopolamine on phosphorylation and counter-depressive action in a PKA-dependent manner. LIMITATIONS: Only one test was used to evaluate depressive behavior, and gene knock-out rats were not yet utilized to refine our hypotheses. CONCLUSION: Our findings revealed that PKA pathway is necessary for scopolamine-induced synaptic plasticity and mTOR pathway activation, and indicated that a potential M2-PKA mechanism underlies scopolamine's antidepressant effects. Such findings suggest that GluA1 ser845 phosphorylation may be a trigger event for scopolamine's actions, and that PKA may represent a novel target for the treatment of depressive symptoms.

Synaptic potentiation mediated by L-type voltage-dependent calcium channels mediates the antidepressive effects of lateral habenula stimulation.

Although deep-brain stimulation (DBS) of the lateral habenula (LHb) has been successfully applied to treatment-resistant depression for years, the mechanism is still unclear. Previous researches have demonstrated that LHb-DBS elevates brain monoamine neurotransmitters. However, these changes do not account for the treatment efficacy on treatment-resistant depression, or the rapid behavioral effects in rats; the evidence suggests that altered synaptic potentiation may contribute to the treatment effects. We applied LHb-DBS in a rat model of learned helplessness (LH) and analyzed mammalian target of rapamycin (mTOR) phosphorylation. We also assessed related electrophysiological changes after LHb-DBS in vitro. LHb-DBS reversed depression-like behaviors in sucrose preference and forced swim tests in rats with LH. Additionally, mTOR phosphorylation significantly increased and field population excitatory postsynaptic potentials increased in the hippocampus. These effects were blocked by the L-type voltage-dependent calcium channel (L-VDCC) antagonist, nifedipine. Furthermore, in vitro LHb-DBS increased both the frequency and width of spontaneous spikes generated by CA1 pyramidal neurons, which contribute to Ca2+ influx through L-VDCC. Our findings suggest that L-VDCC-mediated synaptic potentiation underlies the antidepressant effects of LHb-DBS, and suggest that astrocytic regulation of Ca2+ influx and associated synaptic changes maybe novel targets for developing antidepressant treatments.

Differential Mechanisms Underlying Antidepressant Responses of Ketamine and Imipramine.

BACKGROUND & OBJECTIVE: Ketamine, a noncompetitive NMDA receptor antagonist, exhibits rapid antidepressant actions, but the underlying mechanism remains obscure. AMPA receptor and cAMP response element-binding protein (CREB) are involved in the antidepressant actions of Ketamine and imipramine, a traditional tricyclic antidepressant. However, ketamine exerts its therapeutic actions much faster than imipramine. Understanding the discrepancy of antidepressant efficiency between ketamine and the traditional antidepressant is important for elucidating the mechanism underlying ketamine's fast-acting antidepressant responses as well as designing new rapid antidepressants. RESULTS: Here we show that the enhancement of the phosphorylation of CREB Ser133 and expression of CREB and glutamate receptor 1 (GluR1) are necessary for both ketamine's and imipramine's antidepressant actions, but the enhancements at early stage may account for the faster onset of ketamine's antidepressant action than imipramine. Notably, ketamine but not imipramine enhances CREBregulated transcription coactivator-1 (CRTC1) expression and induces potentiation of excitatory synaptic transmission at Schaffer collateral CA1 synapses, which indicates critical targets for unveiling ketamine's rapid antidepressant actions. CONCLUSION: Our study suggests that differential regulation of CRTC1 expression may contribute to the discrepancy of antidepressant efficacy between ketamine and imipramine, which may lead to a better understanding of ketamine's fast antidepressant responses.

Effects of quercetin on LPS-induced disseminated intravascular coagulation (DIC) in rabbits.

INTRODUCTION: Quercetin is widely distributed in plants and has been reported to have effects of anti-inflammation and anti-thrombosis. In this study, we evaluated the protective effect of quercetin on LPS-induced experimental DIC in rabbits, and tried to clarify its mechanism against DIC. MATERIALS AND METHODS: LPS-induced DIC model in rabbits was established through continuous infusion of 100 ug · kg(-1) · h(-1) LPS for a period of 6h. Six groups were divided: quercetin-treated groups (0.5, 1.0, and 2.0 mg·kg(-1) · h(-1), respectively), LPS-control group, heparin-control group (100 IU · kg(-1) · h(-1)), and saline-control group. APTT, PT, and plasma FIB level were measured, the plasma levels of ALT, BUN, and TNF-α were detected, and the activity of Protein C and ATIII was recorded. RESULTS: A continuous injection of LPS induced a gradual impairment of hemostatic parameters, a rise in plasma level of TNF-α, and damage in renal and hepatic function. The intravenous administration of quercetin significantly attenuated the increase of APTT, PT, ALT, BUN, and TNF-α, and the decrease of plasma FIB level and activity of Protein C and ATIII. CONCLUSION: Quercetin may have a protective effect against LPS-induced DIC in rabbits through anti-inflammation and anticoagulation.