Astrocyte-specific inhibition of sigma-1 receptor leads to depressive-like behaviors in mice via activation of NF-κB-induced neuroinflammation.

Major depressive disorder (MDD) is a global health burden characterized by persistent low mood, deprivation of pleasure, recurrent thoughts of death, and physical and cognitive deficits. The current understanding of the pathophysiology of MDD is lacking, resulting in few rapid and effective antidepressant therapies. Recent studies have pointed to the sigma-1 (σ-1) receptor as a potential rapid antidepressant target; σ-1 agonists have shown promise in a variety of preclinical depression models. Hypidone hydrochloride (YL-0919), an independently developed antidepressant by our institute with faster onset of action and low rate of side effects, has recently emerged as a highly selective σ-1 receptor agonist; however, its underlying astrocyte-specific mechanism is unknown. In this study, we investigated the effect of YL-0919 treatment on gene expression in the prefrontal cortex of depressive-like mice by single-cell RNA sequencing. Furthermore, we knocked down σ-1 receptors on astrocytes in the medial prefrontal cortex of mice to explore the effects of YL-0919 on depressive-like behavior and neuroinflammation in mice. Our results demonstrated that astrocyte-specific knockdown of σ-1 receptor resulted in depressive-like behavior in mice, which was reversed by YL-0919 administration. In addition, astrocytic σ-1 receptor deficiency led to activation of the NF-κB inflammatory pathway, and crosstalk between reactive astrocytes and activated microglia amplified neuroinflammation, exacerbating stress-induced neuronal apoptosis. Furthermore, the depressive-like behavior induced by astrocyte-specific knockdown of the σ-1 receptor was improved by a selective NF-κB inhibitor, JSH-23, in mice. Our study not only reaffirms the σ-1 receptor as a key target of the faster antidepressant effect of YL-0919, but also contributes to the development of astrocytic σ-1 receptor-based novel drugs.

[Single mini-incision combined with honeycomb titanium plate in treatment of acute acromioclavicular joint dislocation].

OBJECTIVE: To explore clinical effect of single small incision with honeycomb titanium plate in treating acute acromioclavicular dislocation. METHODS: The clinical data of 40 patients with acute acromioclavicular dislocation admitted from December 2019 to December 2021 were retrospectively analyzed and divided into two groups according to different surgical methods. Among them, 20 patients were fixed with single small incision with honeycomb titanium plate (titanium plate group), including 11 males and 9 females, aged from 23 to 65 years old with an average of (47.40±12.58) years old;12 patients on the left side, 8 patients on the right side;11 patients with type Ⅲ, 3 patients with type Ⅳ, and 6 patients with type Ⅴ according to Rockwood classification. Twenty patients were fixed with clavicular hook plate (clavicular hook group), including 8 males and 12 females, aged from 24 to 65 years old with an average of (48.40±12.08) years old;12 patients on the left side, 8 patients on the right side;10 patients with type Ⅲ, 2 patients with type Ⅳ, and 8 patients with type Ⅴ according to Rockwood classification. Operative time, incision length, intraoperative blood loss, hospital stay, visual analogue scale (VAS) and Constant-Murley score of shoulder joint function were compared between two groups. Anteroposterior radiographs of the affected shoulder joint were recorded before, immediately and 6 months after surgery, and the coracoclavicular distance was measured and compared. RESULTS: Both groups of patients were successfully completed operation without serious complications. All patients were followed up for 6 to 15 months with an average of (11.9±4.8) months. There were no incisional infection, internal plant fracture or failure, bone tunnel fracture and other complications occurred. The incision length of titanium plate group (35.90±3.14) mm was significantly shorter than that of clavicular hook group (49.30±3.79) mm (P<0.05). There were no significant difference in operative time, intraoperative blood loss and hospital stay between two groups (P>0.05). At 1 and 3 months after operation, VAS of titanium plate group was lower than that of clavicular hook group (P<0.05). Connstant-Murley scores in titanium plate group at 1, 3 and 6 months after operation were (86.80±1.36), (91.60±2.32) and (94.90±2.22), respectively;and in clavicular hook group were (78.45±5.47), (85.55±2.01) and (90.25±1.92), which were higher than that of clavicular hook group (P<0.05). There was no significant difference in coracoclavicular distance between two groups immediately and 6 months after operation(P>0.05). CONCLUSION: For the treatment of acute acromioclavicular joint dislocation, single small incision combined with honeycomb titanium plate have advantages of shorter incision, fast recovery of shoulder joint function without the second operation, and has good satisfaction of patient.

Statin-mediated reduction in mitochondrial cholesterol primes an anti-inflammatory response in macrophages by upregulating Jmjd3.

Statins are known to be anti-inflammatory, but the mechanism remains poorly understood. Here, we show that macrophages, either treated with statin in vitro or from statin-treated mice, have reduced cholesterol levels and higher expression of Jmjd3, a H3K27me3 demethylase. We provide evidence that lowering cholesterol levels in macrophages suppresses the adenosine triphosphate (ATP) synthase in the inner mitochondrial membrane and changes the proton gradient in the mitochondria. This activates nuclear factor kappa-B (NF-κB) and Jmjd3 expression, which removes the repressive marker H3K27me3. Accordingly, the epigenome is altered by the cholesterol reduction. When subsequently challenged by the inflammatory stimulus lipopolysaccharide (M1), macrophages, either treated with statins in vitro or isolated from statin-fed mice, express lower levels proinflammatory cytokines than controls, while augmenting anti-inflammatory Il10 expression. On the other hand, when macrophages are alternatively activated by IL-4 (M2), statins promote the expression of Arg1, Ym1, and Mrc1. The enhanced expression is correlated with the statin-induced removal of H3K27me3 from these genes prior to activation. In addition, Jmjd3 and its demethylase activity are necessary for cholesterol to modulate both M1 and M2 activation. We conclude that upregulation of Jmjd3 is a key event for the anti-inflammatory function of statins on macrophages.

Activation of σ-1 receptor mitigates estrogen withdrawal-induced anxiety/depressive-like behavior in mice via restoration of GABA/glutamate signaling and neuroplasticity in the hippocampus.

Postpartum depression (PPD) is a significant contributor to maternal morbidity and mortality. The Sigma-1 (σ-1) receptor has received increasing attention in recent years because of its ability to link different signaling systems and exert its function in the brain through chaperone actions, especially in neuropsychiatric disorders. YL-0919, a novel σ-1 receptor agonist developed by our institute, has shown antidepressive and anxiolytic effects in a variety of animal models, but effects on PPD have not been revealed. In the present study, excitatory/inhibitory signaling in the hippocampus was reflected by GABA and glutamate and their associated excitatory-inhibitory receptor proteins, the HPA axis hormones in the hippocampus were assessed by ELISA. Finally, immunofluorescence for markers of newborn neuron were undertaken in the dentate gyri, along with dendritic spine staining and dendritic arborization tracing. YL-0919 rapidly improves anxiety and depressive-like behavior in PPD-like mice within one week, along with normalizing the excitation/inhibition signaling as well as the HPA axis activity. YL-0919 rescued the decrease in hippocampal dendritic complexity and spine density induced by estrogen withdrawal. The study results suggest that YL-0919 elicits a therapeutic effect on PPD-like mice; therefore, the σ-1 receptor may be a novel promising target for PPD treatment in the future.

Long-Term Outcomes of dMMR/MSI-H Rectal Cancer Treated With Anti-PD-1-Based Immunotherapy as Curative-Intent Treatment.

BACKGROUND: Neoadjuvant anti-PD-1 therapy has shown encouraging efficacy in patients with deficient DNA mismatch repair (dMMR)/microsatellite instability-high (MSI-H) locally advanced rectal cancer (LARC), which suggests its potential as a curative-intent therapy and a promising treatment option for organ preservation. We aimed to investigate the long-term outcomes of patients with dMMR/MSI-H LARC who experienced clinical complete response (cCR) after anti-PD-1 therapy. METHODS: We retrospectively analyzed patients with dMMR/MSI-H LARC who achieved cCR and received nonoperative management following neoadjuvant anti-PD-1-based treatment from 4 Chinese medical centers. Patients were followed up for at least 1 year after they achieved cCR, their clinical data were collected, and survival outcomes were analyzed using the Kaplan-Meier method. RESULTS: A total of 24 patients who achieved cCR and received nonoperative management from March 2018 to May 2022 were included, with a median age of 51.0 years (range, 19.0-77.0 years). The median treatment course to reach cCR was 6.0 (range, 1.0-12.0). Fifteen patients (62.5%) continued their treatments after experiencing cCR, and the median treatment course was 17.0 (range, 3.0-36.0). No local regrowth or distant metastasis was observed in a median follow-up time of 29.1 months (range, 12.6-48.5 months) after cCR. The 3-year disease-free and overall survivals were both 100%. CONCLUSIONS: Patients with dMMR/MSI-H locally advanced or low-lying rectal cancer who achieved cCR following anti-PD-1-based therapy had promising long-term outcomes. A prospective clinical trial with a larger sample size is required to further validate these findings.

Expression and significance of SIRT6 in human peritoneal dialysis effluents and peritoneal mesothelial cells.

Sirtuin 6 (SIRT6) can inhibit the fibrosis of many organs. However, the relationship between SIRT6 and peritoneal fibrosis (PF) in peritoneal dialysis (PD) remains unclear. We collected 110 PD patients with a duration of PD for more than 3 months and studied the influence of PD duration and history of peritonitis on SIRT6 levels in PD effluents (PDEs). We also analyzed the relationship between SIRT6 levels in PDEs and transforming growth factor beta 1 (TGF-ß1), IL-6, PD duration, peritoneal function, PD ultrafiltration (UF), and glucose exposure. We extracted human peritoneal mesothelial cells (HPMCs) from PDEs and measured the protein and gene expression levels of SIRT6, E-cadherin, vimentin, and TGF-ß1 in these cells. Based on the clinical results, we used human peritoneal mesothelial cells lines (HMrSV5) to observe the changes in SIRT6 levels and mesothelial-to-mesenchymal transition (MMT) after intervention with PD fluid. By overexpressing and knocking down SIRT6 expression, we investigated the effect of SIRT6 expression on E-cadherin, vimentin, and TGF-ß1 expression to elucidate the role of SIRT6 in mesothelial-to-epithelial transition in PMCs. Results: (1) With the extension of PD duration, the influence of infection on SIRT6 levels in PDEs increased. Patients with the PD duration of more than 5 years and a history of peritonitis had the lowest SIRT6 levels. (2) SIRT6 levels in PDEs were negatively correlated with PD duration, total glucose exposure, TGF-ß1, IL-6 levels, and the dialysate-to-plasma ratio of creatinine (Cr4hD/P), but positively correlated with UF. This indicates that SIRT6 has a protective effect on the peritoneum. (3) The short-term group (PD ≤ 1 year) had higher SIRT6 and E-cadherin gene and protein levels than the mid-term group (1 year < PD ≤ 5 years) and long-term group (PD > 5 years) in PMCs, while vimentin and TGF-ß1 levels were lower in the mid-term group and long-term group. Patients with a history of peritonitis had lower SIRT6 and E-cadherin levels than those without such a history. (4) After 4.25% PD fluid intervention for HPMCs, longer intervention time resulted in lower SIRT6 levels. (5) Overexpressing SIRT6 can lead to increased E-cadherin expression and decreased vimentin and TGF-ß1 expression in HPMCs. Knocking down SIRT6 expression resulted in decreased E-cadherin expression and increased vimentin and TGF-ß1 expression in HPMCs. This indicates that SIRT6 expression can inhibit MMT in HPMCs, alleviate PF associated with PD, and have a protective effect on the peritoneum.

STAMENLESS1 activates SUPERWOMAN 1 and FLORAL ORGAN NUMBER 1 to control floral organ identities and meristem fate in rice.

Floral patterns are unique to rice and contribute significantly to its reproductive success. SL1 encodes a C2H2 transcription factor that plays a critical role in flower development in rice, but the molecular mechanism regulated by it remains poorly understood. Here, we describe interactions of the SL1 with floral homeotic genes, SPW1, and DL in specifying floral organ identities and floral meristem fate. First, the sl1 spw1 double mutant exhibited a stamen-to-pistil transition similar to that of sl1, spw1, suggesting that SL1 and SPW1 may located in the same pathway regulating stamen development. Expression analysis revealed that SL1 is located upstream of SPW1 to maintain its high level of expression and that SPW1, in turn, activates the B-class genes OsMADS2 and OsMADS4 to suppress DL expression indirectly. Secondly, sl1 dl displayed a severe loss of floral meristem determinacy and produced amorphous tissues in the third/fourth whorl. Expression analysis revealed that the meristem identity gene OSH1 was ectopically expressed in sl1 dl in the fourth whorl, suggesting that SL1 and DL synergistically terminate the floral meristem fate. Another meristem identity gene, FON1, was significantly decreased in expression in sl1 background mutants, suggesting that SL1 may directly activate its expression to regulate floral meristem fate. Finally, molecular evidence supported the direct genomic binding of SL1 to SPW1 and FON1 and the subsequent activation of their expression. In conclusion, we present a model to illustrate the roles of SL1, SPW1, and DL in floral organ specification and regulation of floral meristem fate in rice.

Anxiolytic-like effects of YL-IPA08, a potent ligand for the translocator protein (18 kDa) via regulating the synaptic plasticity in hippocampus.

TSPO, translocator protein (18 kDa) ligands have demonstrated consistent antidepression and anxiolytic effects in several preclinical studies. This study aimed to examine whether YL-IPA08[N-ethyl-N-(2-pyridinylmethyl)-2-(3,4-ichlorophenyl) -7-methylimidazo [1,2-a] pyridine-3-acetamide hydrochloride], a potent and selective TSPO ligand synthesized by our institute, could alleviate anxiety-related behaviors induced by electric shock (ES) and investigate its underlying mechanism. As expected, we showed that chronic treatment with YL-IPA08 significantly reversed anxiety-related behaviors induced by electrical stimulation (0.5 mA, 12 times, duration 1s, interval 10s) exposure. Using the analysis of RNA-sequencing (RNA-seq) technology, it was found that the differential genes associated with the anxiolytic effect of YL-IPA08 were mainly related to synaptic plasticity. Furthermore, YL-IPA08 restored the decreased levels of brain-derived neurotrophic factor (BDNF), synapse-related protein (e.g. synapsin-1 and post-synaptic density95, PSD95), and the number of doublecortin (DCX) + neurons in the hippocampus of post-ES mice. In addition, YL-IPA08 also enhanced the dendritic complexity and dendritic spine density of hippocampal dentate gyrus (DG) granule neurons. Meanwhile, the induction of long-term potentiation (LTP) was significantly enhanced by YL-IPA08. In summary, the findings from the current study showed that YL-IPA08 exerted a clear anxiolytic effect, which might be partially mediated by promoting hippocampal neuroplasticity.

Multi-Omics Characteristics of Ferroptosis Associated with Colon Adenocarcinoma Typing and Survival.

BACKGROUND: Ferroptosis, an iron-dependent form of cell death, plays a crucial role in the progression of various cancers, including colon adenocarcinoma (COAD). However, the multi-omics signatures relevant to ferroptosis regulation in COAD diagnosis remain to be elucidated. METHODS: The transcriptomic, miRNAomic, and methylomic profiles of COAD patients were acquired from the Cancer Genome Atlas (TCGA). Ferroptosis activity in these patients was determined, represented by a ferroptosis score (FS), using single-sample gene set enrichment analysis (ssGSEA) based on the expression of ferroptosis-related genes. RESULTS: Results showed that the COAD patients with high-FS displayed favorable survival outcomes and heightened drug sensitivity. They also exhibited an up-regulation of genes involved in immune-related pathways (e.g., tumor necrosis factor signaling pathway), suggesting a correlation between immunity and ferroptosis in COAD progression. Furthermore, three survival prediction models were established based on 10 CpGs, 12 long non-coding RNAs (lncRNAs), and 14 microRNAs (miRNAs), respectively. These models demonstrated high accuracy in predicting COAD survival, achieving areas under the curve (AUC) >0.7. The variables used in the three models also showed strong correlations at different omics levels and were effective at discriminating between high-FS and low-FS COAD patients (AUC >0.7). CONCLUSIONS: This study identified different DNA methylation (DNAm), lncRNA, and miRNA characteristics between COAD patients with high and low ferroptosis activity. Furthermore, ferroptosis-related multi-omics signatures were established for COAD prognosis and classification. These insights present new opportunities for improving the efficacy of COAD therapy.

A rate-limiting step in antidepressants onset: Excitation of glutamatergic pyramidal neurons in medial prefrontal cortex of rodents.

Although clinical antidepressants have varied mechanisms of action, it remains unclear whether they may have a common mechanism underlying their antidepressant effects. We investigated the behavioral effects of five different antidepressants (differing in target, chemical structure, and rate of onset) and their effects on the firing activities of glutamatergic pyramidal neurons in the medial prefrontal cortex (mPFC) using the forced swimming test (FST) and electrophysiological techniques (in vivo). We employed fiber photometry recordings to validate the effects of antidepressants on the firing activity of pyramidal neurons. Additionally, multichannel electrophysiological recordings were conducted in mice exhibiting depressive-like behaviors induced by chronic restraint stress (CRS) to investigate whether antidepressants exert similar effects on pyramidal neurons in depressed mice. Behavioral tests were utilized for evaluating the depression model. We found that fluoxetine, duloxetine, vilazodone, YL-0919, and ketamine all increase the firing activities of glutamatergic pyramidal neurons (at least 57%) while exerting their initial onset of antidepressant effects. Fiber photometry revealed an increase in the calcium activity of pyramidal neurons in the mPFC at the onset of antidepressant effects. Furthermore, a significant reduction was observed in the firing activity of pyramidal neurons in the mPFC of CRS-exposed mice, which was reversed by antidepressants. Taken together, our findings suggested that five pharmacologically distinct classes of antidepressants share the common ability to increase the firing activity of pyramidal neurons, just different time, which might be a rate-limiting step in antidepressants onset. The study contributes to the body of knowledge of the mechanisms underlying antidepressant effects and paves the way for developing rapid-acting antidepressants.

A first-in-human study of Brozopentyl Sodium, following single and multiple ascending intravenous infusion in Chinese healthy volunteers.

BACKGROUND: Brozopentyl Sodium (BZP), a novel agent for ischemic stroke, has shown promising results in preclinical pharmacological studies, prompting the initiation of the first-in-human investigation. PURPOSE: This study aimed to assess the safety, tolerability, and pharmacokinetic (PK) characteristics of BZP in Chinese healthy volunteers. METHODS: The study consisted of two parts. Part I was a single-center, randomized, single-blinded, placebo-controlled, single-ascending study with six BZP dose cohorts (SAD: 25, 50, 100, 200, 300, and 400 mg). Part II was a single-center, randomized, single-blinded, placebo-controlled, multi-dose- and dose-elevated study with three BZP dose cohorts (MAD: 50, 100, and 200 mg). Doses were administered once daily on days 1 and 7 and twice daily on days 2-6. The PK properties of BZP and its bioactive metabolites, BNBP, were assessed. Safety and tolerability evaluations were also conducted. RESULTS: In the SAD study, BZP reached peak plasma concentrations (Tmax) at the end of administration, with median Tmax values ranging from 1 to 1.03 h, while BNBP reached Tmax between 1.25 to 1.38 h. The terminal half-lives (T1/2) were approximately 8 h for BZP and 15 h for BNBP. In the MAD study, steady-state plasma concentrations of BZP were reached by day 5. There was minimal accumulation of both BZP and BNBP after 7 days of administration. The area under the plasma concentration-time curve from 0 to time of the last measurable concentration (AUC0-t) and maximum plasma drug concentration (Cmax) showed dose-proportional increases for BZP but not for BNBP in both study parts. Single and multiple doses of BZP demonstrated a good safety profile and were well-tolerated. CONCLUSION: BZP displayed safety, good tolerability and predictable PK characteristics following both single and multiple ascending intravenous administrations. These findings provide a basis for further clinical development of BZP for ischemic stroke patients.

Gamma oscillations in the mPFC: A potential predictive biomarker of depression and antidepressant effects.

Gamma oscillations have attracted much attention in the field of mood disorders, but their role in depression remains poorly understood. This study aimed to investigate whether gamma oscillations in the medial prefrontal cortex (mPFC) could serve as a predictive biomarker of depression. Chronic restraint stress (CRS) or lipopolysaccharide (LPS) were used to induce depression-like behaviors in mice; local field potentials (LFPs) in the mPFC were recorded by electrophysiological techniques; We found that both CRS and LPS induced significant depression-like behaviors in mice, including increasing immobility durations in the forced swimming test (FST) and tail suspension test (TST) and increasing the latency to feed in the novelty-suppressed feeding test (NSFT). Electrophysiological results suggested that CRS and LPS significantly reduced low and high gamma oscillations in the mPFC. Furthermore, a single injection of ketamine or scopolamine for 24 h significantly increased gamma oscillations and elicited rapid-acting antidepressant-like effects. In addition, fluoxetine treatment for 21 days significantly increased gamma oscillations and elicited antidepressant-like effects. Taken together, our findings suggest that gamma oscillations are strongly associated with depression, yielding new insights into investigating the predictive biomarkers of depression and the time course of antidepressant effects.

Sigma-1 receptor activation mediates the sustained antidepressant effect of ketamine in mice via increasing BDNF levels.

Sigma-1 receptor (S1R) is a unique multi-tasking chaperone protein in the endoplasmic reticulum. Since S1R agonists exhibit potent antidepressant-like activity, S1R has become a novel target for antidepression therapy. With a rapid and sustained antidepressant effect, ketamine may also interact with S1R. In this study, we investigated whether the antidepressant action of ketamine was related to S1R activation. Depression state was evaluated in the tail suspension test (TST) and a chronic corticosterone (CORT) procedure was used to induce despair-like behavior in mice. The neuronal activities and structural changes of pyramidal neurons in medial prefrontal cortex (mPFC) were assessed using fiber-optic recording and immunofluorescence staining, respectively. We showed that pharmacological manipulation of S1R modulated ketamine-induced behavioral effect. Furthermore, pretreatment with an S1R antagonist BD1047 (3 mg·kg-1·d-1, i.p., for 3 consecutive days) significantly weakened the structural and functional restoration of pyramidal neuron in mPFC caused by ketamine (10 mg·kg-1, i.p., once). Ketamine indirectly triggered the activation of S1R and subsequently increased the level of BDNF. Pretreatment with an S1R agonist SA4503 (1 mg·kg-1·d-1, i.p., for 3 consecutive days) enhanced the sustained antidepressant effect of ketamine, which was eliminated by knockdown of BDNF in mPFC. These results reveal a critical role of S1R in the sustained antidepressant effect of ketamine, and suggest that a combination of ketamine and S1R agonists may be more beneficial for depression patients.

Effects of human umbilical cord blood mononuclear cells on ovalbumin-induced asthma in mice.

Background: Umbilical cord blood mononuclear cells (UCMNCs) show broad immune-modulation effects, which may be helpful for treating asthma. Effects of UCMNCs on asthma were investigated with mouse model in present study. Methods: Asthma was induced in BALB/c mice by ovalbumin (OVA) immunization and challenge. Asthmatic mice were then treated on days 7 and 20 with intravenous injections of UCMNCs in doses of 4×105, 2×106, and 107 cells per mouse for the low-dose UCMNC (UCMNCL), medium-dose UCMNC (UCMNCM), and high-dose UCMNC (UCMNCH) groups, respectively. Fetal mouse blood mononuclear cells (FMMNCs) were administered to FMMNC group at a dose of 2×106 cells per mouse as approximate allograft control. Airway hyperresponsiveness (AHR), airway inflammation indexes, and CD4/CD8 T cell subsets were measured at day 25. Results: Compared with the model group, AHR in the UCMNCL group, inflammation score of lung tissue in the UCMNCM group, interleukin (IL)-5 in bronchoalveolar lavage fluid (BALF) in UCMNCL group, IL-5 and IL-13 in BALF in UCMNCM group, and IL-17 in serum in UCMNCH group were significantly inhibited. Compared with the model group, CD4+CD8+ T cells were reduced in the UCMNCL group, while decrease of CD4-CD8- T cells and increase of CD4+CD8- T cells were further strengthened in UCMNCM group. FMMNC treatment significantly reduced the IL-13 and IL-17 in serum, decreased CD4-CD8- and CD4+CD8- T cells, and increased the CD4+CD8+ and CD4-CD8+ T cells in BALF. Conclusions: UCMNCs can modulate AHR, T-helper (Th)2 inflammation, and airway injury in experimental asthma at appropriate dose.

Corrigendum: Essential role of microglia in the fast antidepressant action of ketamine and hypidone hydrochloride (YL-0919).

[This corrects the article DOI: 10.3389/fphar.2023.1122541.].

Essential role of microglia in the fast antidepressant action of ketamine and hypidone hydrochloride (YL-0919).

Introduction: Intracerebral microglia play a vital role in mediating central immune response, neuronal repair and synaptic pruning, but its precise role and mechanism in fast action of antidepressants have remained unknown. In this study, we identified that the microglia contributed to the rapid action of antidepressants ketamine and YL-0919. Methods: The depletion of microglia was achieved with the diet containing the colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 in mice. The tail suspension test (TST), forced swimming test (FST) and novelty suppressed feeding test (NSFT) were employed to evaluate the rapid acting antidepressant behavior of ketamine and YL-0919 in the microglia depletion model. The number of microglia in the prefrontal cortex (PFC) was assayed by the immunofluorescence staining. The expressions of synaptic proteins (synapsin-1, PSD-95, GluA1) and brain-derived neurotrophic factor (BDNF) in the PFC were tested by Western blot. Results: The immobility duration in FST and the latency to feed in NSFT were shortened 24 h after an intraperitoneal (i.p.) injection of ketamine (10 mg/kg). The microglial depletion of PLX3397 blocked the rapid antidepressant-like effect of ketamine in mice. In addition, the immobility time in TST and FST as well as latency to feed in NSFT were reduced 24 h after the intragastric (i.g.) administration of YL-0919 (2.5 mg/kg), and the rapid antidepressant effect of YL-0919 was also blocked by the microglial depletion using PLX5622. About 92% of microglia in the prefrontal cortex was depleted in PLX5622 diet-fed mice, while both ketamine and YL-0919 promoted proliferation on the remaining microglia. YL-0919 significantly increased the protein expressions of synapsin-1, PSD-95, GluA1 and BDNF in the PFC, all of which could be blocked by PLX5622. Conclusion: These results suggested the microglia underlying the rapid antidepressant-like effect of ketamine and YL-0919, and microglia would likely constitute in the rapid enhancing impact of synaptic plasticity in the prefrontal cortex by YL-0919.

New Loss-of-Function Mutations in PCSK9 Reduce Plasma LDL Cholesterol.

BACKGROUND: Lower plasma levels of LDL (low-density lipoprotein) cholesterol (LDL-C) can reduce the risk of atherosclerotic cardiovascular disease. The loss-of-function mutations in PCSK9 (proprotein convertase subtilisin/kexin type 9) have been known to associate with low LDL-C in many human populations. PCSK9 genetic variants in Chinese Uyghurs who are at high risk of atherosclerotic cardiovascular disease due to their dietary habits have not been reported. METHODS: The study involved the whole-exome and target sequencing of college students from Uyghur and other ethnic groups in Xinjiang, China, for the association of PCSK9 loss-of-function mutations with low plasma levels of LDL-C. The mechanisms by which the identified mutations affect the function of PCSK9 were investigated in cultured cells using biochemical and cell assays. The causal effects of the identified PCSK9 mutations on LDL-C levels were verified in mice injected with adeno-associated virus expressing different forms of PCSK9 and fed a high-cholesterol diet. RESULTS: We identified 2 PCSK9 mutations-E144K and C378W-in Chinese Uyghurs with low plasma levels of LDL-C. The E144K and C378W mutations impaired the maturation and secretion of the PCSK9 protein, respectively. Adeno-associated virus-mediated expression of E144K and C378W mutants in Pcsk9 KO (knockout) mice fed a high-cholesterol diet also hampered PCSK9 secretion into the serum, resulting in elevated levels of LDL receptor in the liver and reduced levels of LDL-C in the serum. CONCLUSIONS: Our study shows that E144K and C378W are PCSK9 loss-of-function mutations causing low LDL-C levels in mice and probably in humans as well.

Inulin-type oligosaccharides of Morinda officinalis exerted antidepressant effects by reducing hippocampal inflammation.

Neuroinflammation contributes to the pathogenesis of depression. Inulin-type oligosaccharides of Morinda officinalis (IOMO) exert antidepressant-like effects in rodents and patients with depression, while the underlying mechanisms remain unclear. This study used chronic restraint stress (CRS) and lipopolysaccharide (LPS) to induce depression-like behaviors in mice. Western blotting and ELISA analysis were used to investigate the effects of IOMO on inflammatory cytokine levels. Immunofluorescence analysis was used to investigate the effects of IOMO on hippocampal NLRP3 inflammasome and microglial cells. The results suggested that 6 weeks of CRS induced significant depression-like behaviors based on the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST), which were accompanied by increases in the expression of IL-6 and the activation of hippocampal microglial cells. Chronic treatment with IOMO (25 mg/kg, i.g.) for 28 days significantly reversed these depression-like behaviors and inhibited the activation of microglial cells. Furthermore, LPS (0.5 mg/kg, i.p.) also significantly induced depression-like behaviors in the TST, FST, and novelty-suppressed feeding test (NSFT), as well as increased the expression of IL-1ß and caspase-1, and activated the microglial cells and the NLRP3 inflammasome in the hippocampus. Treatment with IOMO for 9 days significantly reversed these depression-like behaviors and normalized the LPS-induced activation of the microglial cells and NLRP3 inflammasome. Taken together, these results suggested that IOMO exerted antidepressant-like effects via hippocampal microglial NLRP3 inflammasome mediation followed by caspase-1 inhibition and the production of IL-1ß. These findings provide a basis for developing new antidepressants targeting the microglial NLRP3 inflammasome.