Monophosphate Response Element Research Articles

Hepatitis B Virus X Protein Modulates p90 Ribosomal S6 Kinase 2 by ERK to Promote Growth of Hepatoma Cells.

Hepatitis B virus (HBV) infection is a leading cause of hepatocellular carcinoma (HCC), one of the most prevalent malignant tumors worldwide that poses a significant threat to human health. The multifunctional regulator known as Hepatitis B virus X-protein (HBx) interacts with host factors, modulating gene transcription and signaling pathways and contributing to hepatocellular carcinogenesis. The p90 ribosomal S6 kinase 2 (RSK2) is a member of the 90 kDa ribosomal S6 kinase family involved in various intracellular processes and cancer pathogenesis. At present, the role and mechanism of RSK2 in the development of HBx-induced HCC are not yet clear. In this study, we found that HBx upregulates the expression of RSK2 in HBV-HCC tissues, HepG2, and SMMC-7721 cells. We further observed that reducing the expression of RSK2 inhibited HCC cell proliferation. In HCC cell lines with stable HBx expression, RSK2 knockdown impaired the ability of HBx to promote cell proliferation. The extracellularly regulated protein kinases (ERK) 1/2 signaling pathway, rather than the p38 signaling pathway, mediated HBx-induced upregulation of RSK2 expression. Additionally, RSK2 and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) were highly expressed and positively correlated in HBV-HCC tissues and associated with tumor size. This study showed that HBx upregulates the expression of RSK2 and CREB by activating the ERK1/2 signaling pathway, promoting the proliferation of HCC cells. Furthermore, we identified RSK2 and CREB as potential prognostic markers for HCC patients.

Identification of key transcription factors and their functional role involved in Salmonella typhimurium infection in chicken using integrated transcriptome analysis and bioinformatics approach

Salmonella enterica serovar typhimurium is the cause of significant morbidity and mortality worldwide that causes economic losses to poultry and is able to cause infection in humans. Indigenous chicken breeds are a potential source of animal protein and have the added advantage of being disease resistant. An indigenous chicken, Kashmir favorella and commercial broiler were selected for understanding the mechanism of disease resistance. Following infection in Kashmir favorella, three differentially expressed genes Nuclear Factor Kappa B (NF-κB1), Forkhead Box Protein O3 (FOXO3) and Paired box 5 (Pax5) were identified. FOXO3, a transcriptional activator, is the potential marker of host resistance in Salmonella infection. NF-κB1 is an inducible transcription factor which lays the foundation for studying gene network of the innate immune response of Salmonella infection in chicken. Pax5 is essential for differentiation of pre-B cells into mature B cell. The real time PCR analysis showed that in response to Salmonella Typhimurium infection a remarkable increase of NF-κB1 (P˂0.01), FOXO3 (P˂0.01) gene expression in liver and Pax5 (P˂0.01) gene expression in spleen of Kashmir favorella was observed. The protein–protein interaction (PPI) and protein-TF interaction network by STRINGDB analysis suggests that FOXO3 is a hub gene in the network and is closely related to Salmonella infection along with NF-κB1. All the three differentially expressed genes (NF-κB1, FOXO3 and PaX5) showed their influence on 12 interacting proteins and 16 TFs, where cyclic adenosine monophosphate Response Element Binding protein (CREBBP), erythroblast transformation-specific (ETSI), Tumour-protein 53(TP53I), IKKBK, lymphoid enhancer-binding factor-1 (LEF1), and interferon regulatory factor-4 (IRF4) play role in immune responses. This study shall pave the way for newer strategies for treatment and prevention of Salmonella infection and may help in increasing the innate disease resistance.

A unique melanocortin-4-receptor signaling profile for obesity-associated constitutively active variants.

The melanocortin-4 receptor (MC4R) plays a critical role in regulating energy homeostasis. Studies on obesogenic human MC4R (hMC4R) variants have not yet revealed how hMC4R maintains body weight. Here, we identified a signaling profile for obesogenic constitutively active H76R and L250Q hMC4R variants transfected in HEK293 cells that included constitutive activity for adenylyl cyclase (AC), cyclic adenosine monophosphate (cAMP) response element (CRE)-driven transcription, and calcium mobilization but not phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) activity. Importantly, the signaling profile included impaired α-melanocyte-stimulating hormone-induced CRE-driven transcription but not impaired α-melanocyte-stimulating hormone-induced AC, calcium, or pERK1/2. This profile was not observed for transfected H158R, a constitutively active hMC4R variant associated with overweight but not obesity. We concluded that there is potential for α-melanocyte-stimulating hormone-induced CRE-driven transcription in HEK293 cells transfected with obesogenic hMC4R variants to be the key predictive tool for determining whether they exhibit loss of function. Furthermore, in vivo, α-melanocyte-stimulating hormone-induced hMC4R CRE-driven transcription may be key for maintaining body weight.

Abstract 3907: Targeting adaptive resistance to EGFR and KRAS G12C inhibitors by TT125-802, a novel and specific CBP/p300 bromodomain inhibitor

Abstract Resistance to targeted therapies is a major challenge in oncology. Disease progression is caused by multiple resistance mechanisms. Besides pre-existing and acquired genetic alternations, adaptive non-mutational reprogramming as well as modulation of phenotypic plasticity have emerged as drivers of disease progression. For example, in epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) patients who were treated with osimertinib, ~50% of progressive disease could not be attributed to genetic mutations (Leonetti et al., BJC 2019). Similarly, in ~ 40% of patients suffering from KRAS G12C-mutated NSCLC and colorectal cancer (CRC), disease progressed under sotorasib treatment without identifiable acquired mutations (Zhao et al., Nature 2021). Thus, targeting non-genetic adaptive resistance mechanism such as drug-induced transcriptional reprogramming might be of great therapeutic benefit. Here we identified small molecules, that interfere with cancer drug-induced transcriptional escape mechanisms using a phenotypic screen based on an SRY-Box Transcription Factor 2 (SOX2) reporter system. The screen led to the development of TT125-802, a highly specific and potent, orally available small molecule inhibitor of the bromodomain of the transcriptional and epigenetic regulator CBP [cyclic adenosine monophosphate response element binding protein (CREB) binding protein] and its paralogue p300. TT125-802 dose-dependently prevented osimertinib resistance development in EGFR-mutated NSCLC cell lines HCC827 and HCC4006, as well as sotorasib resistance development in KRAS G12C-mutated NCI-H358 (NSCLC), SW837 and SNU-1411 (CRCs) as assessed by label-free long-term live microscopy assays. Data generated in mouse xenograft studies confirmed the ability of TT125-802 increasing response rates and prolonging the duration of response to osimertinib and sotorasib in vivo. In cells and tumours which were already resistant to osimertinib or sotorasib, TT125-802 could still delay cell or tumor growth. Complementary and longitudinal analysis of transcriptional changes using RNA sequencing in vitro and in vivo identified several early adaptive and late acquired resistance signatures that were reversed by TT125-802. A first-in-human study of TT125-802 in cancer patients is on track to start in 2023. Citation Format: Thomas Bohnacker, Dorothea Gruber, Sara Laudato, Martin Schwill, Charles-Henry Fabritius, Raquel Herrador, Katrin Westritschnig, Thushara Pattupara, Vikram Ayinampudi, Stefanie Flückiger-Mangual. Targeting adaptive resistance to EGFR and KRAS G12C inhibitors by TT125-802, a novel and specific CBP/p300 bromodomain inhibitor. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3907.

Myokine Musclin Is Critical for Exercise-Induced Cardiac Conditioning.

This study investigates the role and mechanisms by which the myokine musclin promotes exercise-induced cardiac conditioning. Exercise is one of the most powerful triggers of cardiac conditioning with proven benefits for healthy and diseased hearts. There is an emerging understanding that muscles produce and secrete myokines, which mediate local and systemic "crosstalk" to promote exercise tolerance and overall health, including cardiac conditioning. The myokine musclin, highly conserved across animal species, has been shown to be upregulated in response to physical activity. However, musclin effects on exercise-induced cardiac conditioning are not established. Following completion of a treadmill exercise protocol, wild type (WT) mice and mice with disruption of the musclin-encoding gene, Ostn, had their hearts extracted and exposed to an ex vivo ischemia-reperfusion protocol or biochemical studies. Disruption of musclin signaling abolished the ability of exercise to mitigate cardiac ischemic injury. This impaired cardioprotection was associated with reduced mitochondrial content and function linked to blunted cyclic guanosine monophosphate (cGMP) signaling. Genetic deletion of musclin reduced the nuclear abundance of protein kinase G (PKGI) and cyclic adenosine monophosphate (cAMP) response element binding (CREB), resulting in suppression of the master regulator of mitochondrial biogenesis, peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), and its downstream targets in response to physical activity. Synthetic musclin peptide pharmacokinetic parameters were defined and used to calculate the infusion rate necessary to maintain its plasma level comparable to that observed after exercise. This infusion was found to reproduce the cardioprotective benefits of exercise in sedentary WT and Ostn-KO mice. Musclin is essential for exercise-induced cardiac protection. Boosting musclin signaling might serve as a novel therapeutic strategy for cardioprotection.

Effects of brain-derived neurotrophic factor and adeno-associated viral vector on morphine-induced condition through target concentration changes in the ventral tegmental area and nucleus accumbens

Morphine remains the standard analgesic for severe pain. However, the clinical use of morphine is limited by the innate tendency of opiates to become addictive. Brain-derived neurotrophic factor (BDNF) is a growth factor that is protective against many mental disorders. This study aimed to evaluate the protective function of BDNF on morphine addiction based on the behavioural sensitisation (BS) model and assess potential changes in downstream molecular tropomyosin-related kinase receptor B (TrkB) and cyclic adenosine monophosphate response element binding protein (CREB) expression caused by overexpression of BDNF. We divided 64 male C57BL/6 J mice into saline, morphine, morphine plus adeno-associated viral vector (AAV), and morphine plus BDNF groups. After administering the treatments, behavioural tests were conducted during the development and expression phases of BS, followed by a western blot analysis. All data were analysed by one- or two-way analysis of variance. The overexpression of BDNF in the ventral tegmental area (VTA) caused by BDNF-AAV injection decreased the total distance of locomotion in mice who underwent morphine-induced BS and increased the concentrations of BDNF, TrkB, and CREB in the VTA and nucleus accumbens (NAc). BDNF exerts protective effects against morphine-induced BS by altering target gene expression in the VTA and NAc.

Cullin-5 deficiency orchestrates the tumor microenvironment to promote mammary tumor development through CREB1-CCL2 signaling.

Breast cancer-associated gene 1 (Brca1) deficiency induces the onset of breast cancer formation, accompanied with extensive genetic alterations. Here, we used both the sleeping beauty transposon mutagenesis system and CRISPR-Cas9-mediated genome-wide screening in mice to identify potential genetic alterations that act synergistically with Brca1 deficiency to promote tumorignesis. Both approaches identified Cullin-5 as a tumor suppressor, whose mutation enabled Brca1-deficient cell survival and accelerated tumorigenesis by orchestrating tumor microenvironment. Cullin-5 suppresses cell growth through ubiquitylating and degrading adenosine 3',5'-monophosphate-responsive element binding protein 1 (CREB1), especially under protein damage condition. Meanwhile, Cullin-5 deficiency activated CREB1-CCL2 signaling and resulted in the accumulation of monocytes and polymorphonuclear myeloid-derived suppressor cells, reduction of T cells that benefit tumor progression in both Brca1-deficient cells and wild-type cells. Blocking CREB1 activity either through gene knockout or specific inhibitor treatment suppressed changes in the tumor microenvironment caused by Cullin-5 deficiency and blocked tumor progression.

Sex-Dependent Effect of Chronic Piromelatine Treatment on Prenatal Stress-Induced Memory Deficits in Rats.

Prenatal stress impairs cognitive function in rats, while Piromelatine treatment corrects memory decline in male rats with chronic mild stress. In the present study, we aimed to evaluate the effect of chronic treatment with the melatonin analogue Piromelatine on the associative and spatial hippocampus-dependent memory of male and female offspring with a history of prenatal stress (PNS). We report that male and female young adult offspring with PNS treated with a vehicle had reduced memory responses in an object recognition test (ORT). However, the cognitive performance in the radial arm maze test (RAM) was worsened only in the male offspring. The 32-day treatment with Piromelatine (20 mg/kg, i.p.) of male and female offspring with PNS attenuated the impaired responses in the ORT task. Furthermore, the melatonin analogue corrected the disturbed spatial memory in the male offspring. While the ratio of phosphorylated and nonphosphorylated adenosine monophosphate response element binding protein (pCREB/CREB) was reduced in the two sexes with PNS and treated with a vehicle, the melatonin analogue elevated the ratio of these signaling molecules in the hippocampus of the male rats only. Our results suggest that Piromelatine exerts a beneficial effect on PNS-induced spatial memory impairment in a sex-dependent manner that might be mediated via the pCREB/CREB pathway.

Novel role of AMPK in cocaine reinforcement via regulating CRTC1

Repeated cocaine exposure causes compensatory neuroadaptations in neurons in the nucleus accumbens (NAc), a region that mediates reinforcing effects of drugs. Previous studies suggested a role for adenosine monophosphate-activated protein kinase (AMPK), a cellular energy sensor, in modulating neuronal morphology and membrane excitability. However, the potential involvement of AMPK in cocaine use disorder is still unclear. The present study employed a cocaine self-administration model in rats to investigate the effect of AMPK and its target cyclic adenosine monophosphate response element binding protein-regulated transcriptional co-activator 1 (CRTC1) on cocaine reinforcement and the motivation for cocaine. We found that intravenous cocaine self-administration significantly decreased AMPK activity in the NAc shell (NAcsh), which persisted for at least 7 days of withdrawal. Cocaine reinforcement, reflected by self-administration behavior, was significantly prevented or enhanced by augmenting or suppressing AMPK activity pharmacologically and genetically, respectively. No difference in sucrose self-administration behavior was found after the same manipulations. The inhibition of AMPK activity in the NAcsh also increased the motivation for cocaine in progressive-ratio schedules of reinforcement, whereas the activation of AMPK had no effect. The knockdown of CRTC1 in the NAcsh significantly impaired cocaine reinforcement, which was rescued by pharmacologically increasing AMPK activity. Altogether, these results indicate that AMPK in the NAcsh is critical for cocaine reinforcement, possibly via the regulation of CRTC1 signaling. These findings may help reveal potential therapeutic targets and have important implications for the treatment of cocaine use disorder and relapse.

Butyrate Attenuates Hepatic Steatosis Induced by a High-Fat and Fiber-Deficient Diet via the Hepatic GPR41/43-CaMKII/HDAC1-CREB Pathway.

Hepatic steatosis is a major health issue that can be attenuated by a healthy diet. This study investigates the effects and molecular mechanisms of butyrate, a dietary fiber metabolite of gut microbiota, on lipid metabolism in hepatocytes. This study examines the effects of butyrate (0-8mM) on lipid metabolism in primary hepatocytes. The results show that butyrate (2mM) consistently inhibits lipogenic genes and activates lipid oxidation-related gene expression in hepatocytes. Furthermore, butyrate modulates lipid metabolism genes, reduces fat droplet accumulation, and activates the calcium/calmodulin-dependent protein kinase II (CaMKII)/histone deacetylase 1 (HDAC1)-cyclic adenosine monophosphate response element binding protein (CREB) signaling pathway in the primary hepatocytes and liver of wild-type (WT) mice, but not in G-protein-coupled receptor 41 (GPR41) knockout and 43 (GPR43) knockout mice. This suggests that butyrate regulated hepatic lipid metabolism requires GPR41 and GPR43. Finally, the study finds that dietary butyrate supplementation (5%) ameliorates hepatic steatosis and abnormal lipid metabolism in the liver of mice fed a high-fat and fiber-deficient diet for 15 weeks. This work reveals that butyrate improves hepatic lipid metabolism through the GPR41/43-CaMKII/HDAC1-CREB pathway, providing support for consideration of butyrate as a dietary supplement to prevent the progression of NAFLD induced by the Western-style diet.

The antidepressant effects and serum metabonomics of bifid triple viable capsule in a rat model of chronic unpredictable mild stress.

BackgroundProbiotics have shown potential antidepressant effects. This study evaluated the effect and probable mechanisms of bifid triple viable capsules (BTVCs) on a rat model of chronic unpredictable mild stress (CUMS).Materials and methodsRats were randomly divided into Normal, CUMS model, fluoxetine hydrochloride (FLX), BTVCs, and FLX+BTVCs groups. Depressive-like behaviours, pathological changes in the hippocampus, changes in serum metabolites and potential biomarkers, and metabolic pathways were detected via behavioural tests, haematoxylin-eosin staining, nissl staining, non-targetted metabolomics, and ingenuity pathway analysis (IPA).ResultsThe rats displayed depressive-like behaviours after CUMS exposure, but BTVCs ameliorated the depressive-like behaviours. In addition, the pathological results showed that the hippocampal tissue was damaged in rats after CUMS exposure and that the damage was effectively alleviated by treatment with BTVCs. A total of 20 potential biomarkers were identified. Treatment with BTVCs regulated D-phenylalanine, methoxyeugenol, (±)-myristoylcarnitine, 18:3 (6Z, 9Z, 12Z) /P-18:1 (11Z), propionyl-L-carnitine, and arachidonic acid (AA) concentrations, all compounds that are involved with biosynthesis of unsaturated fatty acids, glycerophospholipid metabolism, linoleic acid metabolism and AA metabolism. The IPA demonstrated that endothelin-1 signalling and cyclic adenosine monophosphate response element binding protein (CREB) signalling in neurons may be involved in the development of depression.ConclusionOur findings suggest that BTVCs can alleviate depressive-like behaviours, restore damage to the hippocampus in CUMS rats and regulate serum metabolism, which may be related to endothelin-1 signalling or CREB signalling in neurons.

RhoB Promotes Endometrial Stromal Cells Decidualization Via Semaphorin3A/PlexinA4 Signaling in Early Pregnancy.

Endometrial decidualization refers to a series of morphological changes and functional remodeling of the uterine endometrium to accept the embryo under the effect of estrogen and progesterone secreted by ovaries after ovulation. During decidualization, endometrial stromal cells (ESCs) proliferate and differentiate into decidual stromal cells, undergoing cytoskeletal rearrangement-mediated morphological changes and expressing decidualization markers, such as insulin-like growth factor-binding protein-1 and prolactin. Ras homology (Rho) proteins, a family of small G proteins, are well known as regulators of cellular morphology and involved in multiple other cellular processes. In this study, we found ras homolog family member B (RHOB) was the most significantly upregulated gene in the Rho protein family after the in vitro decidualization of human primary ESCs. RhoB expression was induced mainly by 3',5'-cyclic adenosine 5'-monophosphate (cAMP) / protein kinase A (PKA) / cyclic adenosine monophosphate-response element binding protein signaling and partly by progesterone signaling. Knockdown of RhoB in ESCs greatly inhibited actin cytoskeletal rearrangement, cell morphological transformation, and upregulation of insulin-like growth factor-binding protein-1, suggesting an indispensable role of RhoB in decidualization. Mechanistically, the downstream target of RhoB was semaphorin3A (Sema3A), which mediated its signaling via interacting with the receptor, plexinA4. More importantly, decreased expression of RhoB, Sema3A, and plexinA4 were detected in deciduas from patients with unexplained spontaneous miscarriage. Collectively, our results indicate that RhoB/Sema3A/plexinA4 signaling plays a positive role in endometrial decidualization and relates to unexplained spontaneous miscarriage, which is worthy of further exploration so as to provide new insights into therapeutic strategies for pregnancy diseases associated with poor decidualization.

Activation of the N-methyl-D-aspartate receptor contributes to orofacial neuropathic and inflammatory allodynia by facilitating calcium-calmodulin-dependent protein kinase II phosphorylation in mice

Neuropathic and inflammatory pain are major clinical challenges due to their ambiguous mechanisms and limited treatment approaches. N-methyl-D-aspartate receptor (NMDAR) and calcium-calmodulin-dependent protein kinase II (CaMKII) are responsible for nerve system sensation and are required for the induction and maintenance of pain. However, the roles of NMDAR and CaMKII in regulating orofacial pain are still less well known. Here, we established a neuropathic pain model by transecting a mouse inferior alveolar nerve (IAN) and an inflammatory pain model by injecting complete Freund’s adjuvant (CFA) into its whisker pad. The Cre/loxp site-specific recombination system was used to conditionally knock out (KO) NR2B in the trigeminal ganglion (TG). Von Frey filament behavioral tests showed that IANX and CFA-induced mechanical allodynia were altered in NR2B-deficient mice. CFA upregulated CaMKIIα and CaMKIIβ in the mouse TG and spinal trigeminal caudate nucleus (SpVc). CaMKIIα first decreased and then increased in the TG after IANX, and CaMKIIβ decreased in the TG and SpVc. CFA and IANX both greatly enhanced the expression of phospho (p)-NR2B, p-CaMKII, cyclic adenosine monophosphate (cAMP), p-ERK, and p-cAMP response element binding protein (CREB) in the TG and SpVc. These neurochemical signal pathway alterations were reversed by the conditional KO of NR2B and inhibition of CaMKII. Similarly, IANX- and CFA-related behavioral alterations were reversed by intra-ganglionic (i.g.) -application of inhibitors of CaMKII, cAMP, and ERK. These findings revealed novel molecular signaling pathways (NR2B-CaMKII-cAMP-ERK-CREB) in the TG- and SpVc-derived latent subsequent peripheral and spinal central sensitization under nerve injury and inflammation, which might be beneficial for the treatment of orofacial allodynia.

A Polymorphism in the BDNF Gene (rs11030101) is Associated With Negative Symptoms in Chinese Han Patients With Schizophrenia.

Objective: This study aimed to investigate the association between brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate response element binding protein (CREB) gene polymorphisms and schizophrenia. Methods: This study used a case-control design, and diagnoses were made based on the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition criteria. One hundred and thirty-four patients with schizophrenia were recruited from the Third People’s Hospital of Zhongshan City from January 2018 to April 2020. Sixty-four healthy controls were recruited from the same region. Genotypes at the BDNF gene single nucleotide polymorphisms rs11030101, rs2030324, and rs6265 and the CREB gene single nucleotide polymorphisms rs6740584 and rs2551640 were determined using a MassARRAY mass spectrometer. Linkage disequilibrium and haplotype analyses were performed, and genotype and allele frequencies were compared between groups. The positive and negative symptom scale (PANSS) was used to evaluate the association between the BDNF and CREB gene polymorphisms and schizophrenic symptoms. Results: There was no significant difference in genotype or allele frequencies for rs11030101, rs2030324, rs6265, rs6740584, or rs2551640 between schizophrenic patients and controls (p > 0.05). In addition, there were no significant differences in rs11030101, rs2030324, rs6265, rs6740584, or rs2551640 genotype frequencies between the two groups in the dominant, recessive, or over-dominant models (p > 0.05). Three loci in the BDNF gene and two loci in the CREB gene were in a state of strong linkage disequilibrium. The frequency of haplotype AAC (rs11030101/rs2030324/rs626), composed of three loci in the BDNF gene, was significantly increased in schizophrenic patients compared with control subjects. There were significant differences in the subscores of PANSSS for negative symptoms, in patients with different rs11030101 genotypes of the BDNF gene (p < 0.05). There was also significant differences in the PANSS scores for the general symptom G12 (judgment and lack of insight) in patients with different rs6265 genotypes of the BDNF gene (p < 0.05). Conclusion: The BDNF gene rs11030101/rs2030324/rs6265 AAC haplotype was potentially associated with an increased risk of schizophrenia. In addition, genotypes at the rs11030101 and rs6265 loci may affect the negative symptoms and general symptoms of schizophrenic patients, respectively.

Hippocampal NR6A1 impairs CREB-BDNF signaling and leads to the development of depression-like behaviors in mice

Chronic stress exposure is a risk factor that can induce the development of depression-like behaviors by impairing the hippocampal cyclic adenosine monophosphate-response element binding protein (CREB)-brain-derived neurotrophic factor (BDNF) signaling, but its underlying mechanisms remain largely unknown. We identified an orphan receptor that can suppress the activity of CREB, nuclear receptor sub-family 6, group A, member 1 (NR6A1), in mouse brain neurons. Given the critical role of the impaired CREB-BDNF signaling in depression, we speculate that the neuronal NR6A1 may mediate the pathogenesis of depression. Results showed that chronic unpredictable stress (CUS) markedly increased the expression levels of hippocampal NR6A1 protein, which reduced hippocampal CREB phosphorylation and BDNF protein expression. Overexpression of hippocampal NR6A1 in stress-naïve mice simulated chronic stress, inducing depression-like behaviors in the tail suspension test, forced swimming test, and sucrose preference test, and impairing the hippocampal CREB-BDNF signaling cascade. Genetic knockdown of hippocampal NR6A1 did not affect mouse behaviors but prevented the CUS-induced depression-like behaviors in mice and impairment in hippocampal CREB-BDNF signaling. Furthermore, genetic knockdown of hippocampal CREB or BDNF abrogated the preventive effect of hippocampal NR6A1 down-regulation on CUS-induced depression-like behaviors in mice. Collectively, these results for the first time identified a nuclear expression of NR6A1 in mouse brain neurons, and showed that the abnormally increased NR6A1 protein in the hippocampus in mice treated with or without chronic stress can impair the CREB-BDNF signaling cascade and lead to the development of depression-like behaviors. Hippocampal NR6A1 could be a novel target for the development of antidepressants.

Effects of endoplasmic reticulum stress-mediated CREB3L1 on apoptosis of glioma cells.

The association between endoplasmic reticulum stress (ERS) and apoptosis has been extensively studied. Cyclic adenosine monophosphate responsive element binding protein 3 like 1 (CREB3L1) has an important role in the development of glioma. In the present study, the potential association between ERS-induced apoptosis and CREB3L1 and its clinical implications were investigated. From a total of 30 cases, brain gliomas with different pathological grades surgically resected at the Department of Neurosurgery of the Affiliated Hospital of Guizhou Medical University (Guiyang, China) between January 2018 and January 2019 were collected. The expression of CREB3L1 and ERS-related proteins in gliomas with different degrees of malignancy was detected by immunohistochemistry. Furthermore, U87-MG glioma cells were cultured in vitro and treated with different concentrations of ERS inducer thapsigargin (TG). The Cell Counting Kit-8 (CCK-8) assay was performed to detect changes in cell activity at different incubation times and drug concentrations. Cell apoptosis was detected by Annexin Ⅴ-FITC/propidium iodide double staining and the protein expression levels of CREB3L1 and ERS were detected by western blot analysis. Immunohistochemical analysis suggested that the expression levels of CREB3L1, glucose-regulated protein, 78 kDa (GRP78) and C/EBP-homologous protein (CHOP) in World Health Organization (WHO) grade I glioma were higher than those in WHO grade Ⅱ-Ⅳ (all P<0.01). The results of the CCK-8 assay suggested that the activity of U87-MG glioma cells was significantly decreased after treatment with TG (all P<0.05), and this effect was time- and drug concentration-dependent. Flow cytometric analysis indicated that the apoptotic rate of the cells was increased, which was significant when the concentration of TG was 0.1 µmol/l (P<0.01). Furthermore, the protein expression of CREB3L1, GRP78 and CHOP in glioma cells treated with TG was increased (P<0.05). However, the expression level of Bcl-2 decreased (P<0.05). In conclusion, ERS may reduce the cell proliferative activity and promote apoptosis through mediating CREB3L1 expression. CREB3L1 may be a novel potential target for glioma therapy.

Perfluorooctanoic acid-induced lipid metabolism disorder in SD rat liver and its effect on the expression of fatty acid metabolism-related proteins.

Perfluorooctanoic acid (PFOA) can cause lipid metabolism disorders in animal body and affect the lipolysis and synthesis of fatty acids. Peroxisome proliferators-activated receptor (PPAR) plays an extremely important role in this process. This study aims to explore the effects of PFOA on liver lipid metabolism disorders in Sprague Dewley (SD) rats and the expression of PPAR. A total of 40 male SD rats were randomly divided into 4 groups (n=10 in each group): a control group (ddH2O), a low-dose PFOA group [PFOA 1.25 mg/(kg·d)], a middle-dose PFOA group [PFOA 5.00 mg/(kg·d)], and a high-dose PFOA group [PFOA 20.00 mg/(kg·d)]. The rats were fed with normal diet, and PFOA exposure were performed by oral gavage for 14 days, and the rats were observed, weighted and recorded every day during the exposure. After the exposure, the blood was collected, and the livers were quickly stripped after the rats were killed. Part of the liver tissues were fixed in 4% paraformaldehyde for periodic acid-schiff (PAS) staining; the contents of HDLC, LDLC, TG, TC in serum and liver tissues, as well as the activities of their related enzymes were assayed; The expression levels of cyclic adenosine monophosphate-response element binding protein (Cbp), general control of amino acid synthesis 5-like 2 (Gcn5L2), peroxidation peroxisome proliferation factor activated receptor γ (PPAR), silent information regulator 1 (Sirt1) and human retinoid X receptor alpha 2 (Rxrα2) ) were detected by Western blotting. After 14 days of PFOA exposure, the PAS staining positive particles in the cytoplasm and nucleus of SD rats in the medium and high dose groups were significantly reduced compared with the control group. The serum levels of LDLC and TC in the low-dose and middle-dose groups were significantly reduced compared with the control group (all P<0.05), while the high-dose group showed an increasing tendency, without siginificant difference (P>0.05), there was no significant difference in HDLC and TG (both P>0.05). The activities of alkaline phosphatase (AKP) and alanine aminotransferase (ALT) were increased significantly (both P<0.05) compared with control group; the ratio of ALT/aspartate aminotransferase (AST) in the high-dose group was increased significantly (P<0.05), there was no significant difference in LDH and TG (both P>0.05); the HDLC content in the liver tissues in the high-dose group was significantly reduced, compared with the control group (P<0.05); the TC contents in the liver tissues in the low, medium and high-dose groups were significantly increased (all P<0.05), there was no significant difference in LDLC and TG (both P>0.05); the AKP activity in the livers in the medium and high-dose groups was significantly increased (both P<0.05), there was no siginificant difference in LDH, ALT, and the ratio of ALT/AST (all P>0.05); the protein expression levels of Ppar γ, Cbp and Rxrα2 in the liver in the high dose groups were significantly down-regulated compared with the control group (all P<0.05), while the protein expression levels of Sirt1 were significantly up-regulated (all P<0.05). PFOA exposure can cause lipid metabolism disorder and glycogen reduction in SD rat livers, which may be related to the activation of Sirt1 and inhibition of Ppar γ expression, leading to affecting the normal metabolism of fatty acids and promoting glycolysis.

Retrieval of olfactory fear memory alters cell proliferation and expression of pCREB and pMAPK in the corticomedial amygdala and piriform cortex.

The brain forms robust associations between odors and emotionally salient memories, making odors especially effective at triggering fearful or traumatic memories. Using Pavlovian olfactory fear conditioning (OFC), a variant of the traditional tone-shock paradigm, this study explored the changes involved in its processing. We assessed the expression of neuronal plasticity markers phosphorylated cyclic adenosine monophosphate response element binding protein (pCREB) and phosphorylated mitogen-activated protein kinase (pMAPK) 24 h and 14 days following OFC, in newborn neurons (EdU+) and in brain regions associated with olfactory memory processing; the olfactory bulb, piriform cortex, amygdale, and hippocampus. Here, we show that all proliferating neurons in the dentate gyrus of the hippocampus and glomerular layer of the olfactory bulb were colocalized with pCREB at 24 h and 14 days post-conditioning, and the number of proliferating neurons at both time points were statistically similar. This suggests the occurrence of long-term potentiation within the neurons of this pathway. Finally, OFC significantly increased the density of pCREB- and pMAPK-positive immunoreactive neurons in the medial and cortical subnuclei of the amygdala and the posterior piriform cortex, suggesting their key involvement in its processing. Together, our investigation identifies changes in neuroplasticity within critical neural circuits responsible for olfactory fear memory.

Pharmacological Actions of Myricetin in the Nervous System: A Comprehensive Review of Preclinical Studies in Animals and Cell Models.

Myricetin is a natural flavonoid extracted from a variety of plants, such as medicinal herbs, vegetables, berries, and tea leaves. A growing body of evidence has reported that myricetin supplementation display therapeutic activities in a lot of nervous system disorders, such as cerebral ischemia, Alzheimer’s disease, Parkinson’s disease, epilepsy, and glioblastoma. Myricetin supplementation can also protect against pathological changes and behavioral impairment induced by multiple sclerosis and chronic stress. On the basis of these pharmacological actions, myricetin could be developed as a potential drug for the prevention and/or treatment of nervous system disorders. Mechanistic studies have shown that inhibition of oxidative stress, cellular apoptosis, and neuroinflammatory response are common mechanisms for the neuroprotective actions of myricetin. Other mechanisms, including the activation of the nuclear factor E2-related factor 2 (Nrf2), extracellular signal-regulated kinase 1/2 (ERK1/2), protein kinase B (Akt), cyclic adenosine monophosphate-response element binding protein (CREB), and brain-derived neurotrophic factor (BDNF) signaling, inhibition of intracellular Ca2+ increase, inhibition of c-Jun N-terminal kinase (JNK)-p38 activation, and suppression of mutant protein aggregation, may also mediate the neuroprotective effects of myricetin. Furthermore, myricetin treatment has been shown to promote the activation of the inhibitory neurons in the hypothalamic paraventricular nucleus, which subsequently produces anti-epilepsy effects. In this review, we make a comprehensive understanding about the pharmacological effects of myricetin in the nervous system, aiming to push the development of myricetin as a novel drug for the treatment of nervous system disorders.

Cannabinoid receptor 2 engagement promotes group 2 innate lymphoid cell expansion and enhances airway hyperreactivity

Cannabinoids modulate the activation of immune cells and physiologic processes in the lungs. Group 2 innate lymphoid cells (ILC2s) are central players in type 2 asthma, but how cannabinoids modulate ILC2 activation remains to be elucidated. Our goal was to investigate the effects of cannabinoids on ILC2s and their role in asthma. A combination of cannabinoid receptor (CB)2 knockout (KO) mice, CB2 antagonist and agonist were used in the mouse models of IL-33, IL-25, and Alternaria alternata ILC2-dependent airway inflammation. RNA sequencing was performed to assess transcriptomic changes in ILC2s, and humanized mice were used to assess the role of CB2 signaling in human ILC2s. We provide evidence that CB2 signaling in ILC2s is important for the development of ILC2-driven airway inflammation in both mice and human. We showed that both naive and activated murine pulmonary ILC2s express CB2. CB2 signaling did not affect ILC2 homeostasis at steady state, but strikingly it stimulated ILC2 proliferation and function upon activation. As a result, ILC2s lacking CB2 induced lower lung inflammation, as we made similar observations using a CB2 antagonist. Conversely, CB2 agonism remarkably exacerbated ILC2-driven airway hyperreactivity and lung inflammation. Mechanistically, transcriptomic and protein analysis revealed that CB2 signaling induced cyclic adenosine monophosphate-response element binding protein (CREB) phosphorylation in ILC2s. Human ILC2s expressed CB2, as CB2 antagonism and agonism showed opposing effects on ILC2 effector function and development of airway hyperreactivity in humanized mice. Collectively, our results define CB2 signalinginILC2s as an important modulator of airway inflammation.