BRD9 promotes the progression of gallbladder cancer via CST1 upregulation and interaction with FOXP1 through the PI3K/AKT pathway and represents a therapeutic target.

Gallbladder cancer (GBC) is highly aggressive and has poor prognosis, with most patients only diagnosed at an advanced stage. Furthermore, treatment options are limited, and their effect is unsatisfactory. Bromodomain-containing protein (BRD) is an epigenetic regulator that plays a carcinogenic role in several tumors, including squamous cell lung cancer, acute myeloid leukemia, synovial sarcoma, and malignant rhabdomyosarcoma. However, the expression, biological function, and molecular mechanisms of action of BRD9 in GBC are still unknown. Kaplan-Meier analysis, qRT-PCR, and analysis of clinical features were used to assess the clinical significance of BRD9 in GBC. Cell Counting Kit-8 and colony formation assays were performed to determine the effects of BRD9 on cell growth. The functional role of BRD9 in GBC was explored using qRT-PCR, western blotting, siRNA, and CHIP-qPCR. mRNA sequencing was performed to explore the underlying mechanisms of BRD9, and a nude mouse model of GBC was established to explore the anti-tumor effects of the BRD9 inhibitor I-BRD9 in vivo. BRD9 expression was elevated in GBC tissues compared with adjacent non-tumor tissues, and high BRD9 expression was associated with poor prognosis in patients with GBC. BRD9 knockdown by siRNA significantly decreased cell growth. Targeting BRD9 with I-BRD9 inhibited the proliferation of GBC cells without significant toxic effects. Additionally, I-BRD9 treatment suppressed CST1 expression in GBC cell lines, thereby inhibiting the PI3K-AKT pathway. The transcription factor FOXP1 was found to interact with BRD9 to regulate CST1 expression. Collectively, these results suggest that BRD9 may be a promising biomarker and therapeutic target for GBC.

Serotonergic transmission plays differentiated roles in the rapid and sustained antidepressant-like effects of ketamine.

BACKGROUND AND PURPOSE: The emerging antidepressant effects of ketamine have inspired tremendous interest in its underlying neurobiological mechanisms, although the involvement of 5-HT in the antidepressant effects of ketamine remains unclear. EXPERIMENTAL APPROACH: The chronic restraint stress procedure was performed to induce depression-like behaviours in mice. OFT, FST, TST, and NSFT tests were used to evaluate the antidepressant-like effects of ketamine. Tph2 knockout or depletion of 5-HT by PCPA and 5,7-DHT were used to manipulate the brain 5-HT system. ELISA and fibre photometry recordings were used to measure extracellular 5-HT levels in the brain. KEY RESULTS: 60 min after injection, ketamine (10 mg·kg-1, i.p.) produced rapid antidepressant-like effects and increased brain 5-HT levels. After 24 h, ketamine significantly reduced immobility time in TST and FST tests and increased brain 5-HT levels, as measured by ELISA and fibre photometry recordings. The sustained (24 h) but not rapid (60 min) antidepressant-like effects of ketamine were abrogated by PCPA and 5,7-DHT, or by Tph2 knockout. Importantly, NBQX (10 mg·kg-1, i.p.), an AMPA receptor antagonist, significantly inhibited the effect of ketamine on brain 5-HT levels and abolished the sustained antidepressant-like effects of ketamine in naïve or CRS-treated mice. CONCLUSION AND IMPLICATIONS: This study confirms the requirement of serotonergic neurotransmission for the sustained antidepressant-like effects of ketamine, which appears to involve AMPA receptors, and provides avenues to search for antidepressant pharmacological targets.

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.

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.

Role of luxS in Stress Tolerance and Adhesion Ability in Lactobacillus plantarum KLDS1.0391.

Lactobacillus plantarum, a probiotic, has a high survival rate and high colonization ability in the gastrointestinal tract. Tolerance to the gastrointestinal environment and adhesion to intestinal epithelial cells by some Lactobacillus species (excluding L. plantarum) are related to luxS/AI-2. Here, the role of luxS in tolerance to simulated digestive juice (SDJ) and adhesion to Caco-2 cells by L. plantarum KLDS1.0391 (hereafter, KLDS1.0391) was investigated. The KLDS1.0391 luxS mutant strain was constructed by homologous recombination. When luxS was deleted, acid and bile salt tolerance and survival rates in SDJ significantly decreased (p < 0.05 for all). The ability of the luxS deletion strain to adhere to Caco-2 cells was markedly lower than that of the wild-type strain (p < 0.05). The ability of the luxS mutant strain to adhere (competition, exclusion, and displacement) to Escherichia coli ATCC 25922 was significantly lower than that of the wild-type strain (p < 0.05 for all). A significant decrease was noted only in the exclusion adhesion inhibition of the luxS mutant strain to Salmonella typhimurium ATCC 14028 (p < 0.05). These results indicate that the luxS gene plays an important role in the gastrointestinal environment tolerance and adhesion ability of KLDS1.0391.

Role of the luxS gene in bacteriocin biosynthesis by Lactobacillus plantarum KLDS1.0391: A proteomic analysis.

Certain probiotic species of lactic acid bacteria, especially Lactobacillus plantarum, regulate bacteriocin synthesis through quorum sensing (QS) systems. In this study, we aimed to investigate the luxS-mediated molecular mechanisms of QS during bacteriocin synthesis by L. plantarum KLDS1.0391. In the absence of luxS, the 'spot-on-the-lawn' method showed that the bacteriocin production by L. plantarum KLDS1.0391 significantly decreased upon co-cultivation with L. helveticus KLDS1.9207 (P < 0.01) but did not change significantly when mono-cultivated. Furthermore, liquid chromatography-electrospray ionization tandem mass spectrometry analysis showed that, as a response to luxS deletion, L. plantarum KLDS1.0391 altered the expression level of proteins involved in carbohydrate metabolism, amino acid metabolism, fatty acid synthesis and metabolism, and the two-component regulatory system. In particular, the sensor histidine kinase AgrC (from the two-component system, LytTR family) was expressed differently between the luxS mutant and the wild-type strain during co-cultivation, whereas no significant differences in proteins related to bacteriocin biosynthesis were found upon mono-cultivation. In summary, we found that the production of bacteriocin was regulated by carbohydrate metabolism, amino acid metabolism, fatty acid synthesis and metabolism, and the two-component regulatory system. Furthermore, our results demonstrate the role of luxS-mediated molecular mechanisms in bacteriocin production.

Complete genome sequence of bacteriocin-producing Lactobacillus plantarum KLDS1.0391, a probiotic strain with gastrointestinal tract resistance and adhesion to the intestinal epithelial cells.

Lactobacillus plantarum KLDS1.0391 is a probiotic strain isolated from the traditional fermented dairy products and identified to produce bacteriocin against Gram-positive and Gram-negative bacteria. Previous studies showed that the strain has a high resistance to gastrointestinal stress and has a high adhesion ability to the intestinal epithelial cells (Caco-2). We reported the entire genome sequence of this strain, which contains a circular 2,886,607-bp chromosome and three circular plasmids. Genes, which are related to the biosynthesis of bacteriocins, the stress resistance to gastrointestinal tract environment and adhesive performance, were identified. Whole genome sequence of Lactobacillus plantarum KLDS1.0391 will be helpful for its applications in food industry.