Classical Signaling Pathways Research Articles

Mitochondrial Permeability Transition Induces Atrophy in C2C12 Myotubes

INTRODUCTIONIn advanced age (>75 yrs), muscle atrophy can lead to physical frailty, impaired mobility, and increased mortality. Impairment and functional decline of mitochondria within skeletal muscle are seen with aging, including a sensitization to mitochondrial permeability transition (MPT). MPT is an established pathological mechanism causing ischemic organ damage and has been observed in aged motoneurons and skeletal muscle. However, the role of MPT in age‐related muscle atrophy has not been determined. To better understand how MPT may induce skeletal muscle atrophy, we determined the impact of inducing MPT on myotube size in a cell culture model and the impact of modulating MPT on classical atrophy signaling transcripts. We hypothesized that induction of MPT in myotubes would cause atrophy, and MPT would modulate atrophy‐related signaling pathways.METHODSTo determine if MPT can induce myotube atrophy, C2C12 myotubes were treated with doxorubicin (Dox; 1 μM), a known inducer of MPT, or DMSO (vehicle, 1 μM) on day 4 post‐differentiation for 12, 24, and 48 h. At each time point, cells were fixed/permeabilized in icecold methanol/acetone (1:1), blocked, and incubated with a primary antibody against sarcomeric myosin (MF‐20). Cells were incubated with a fluorescent secondary antibody and imaged at 20X on an inverted fluorescent microscope. Images (n=4 per well, 5 wells/treatment) were analyzed to quantify MF20+ area (myotube area) using a custom written program in CellProfiler.To assess signaling mechanisms downstream of MPT, C2C12 myotubes were treated with Dox (1μM), Dox + an inhibitor of MPT (bongkrekic acid [BA]; DOX+BA, each 1 μM), or DMSO (vehicle;1 μM) for 12 h on day 4 post‐differentiation (n=3 biological replicates; n=4 technical replicates per treatment). At 12 h post‐treatment, cells were collected in TRIzol and their RNA isolated for RT‐PCR analysis of transcriptional regulators of muscle atrophy (FOXO1, NfKB1, Gadd45a, ATF4), an autophagy‐regulating gene (p62/SQSTM), and E3 ubiquitin ligases (Mafbx, MuRF). The comparative threshold cycle (CT) method was used to calculate fold changes in expression with 18s as an endogenous control. Relative fold changes in expression are presented as 2−ΔΔCT and normalized to DMSO‐treated samples.Two‐tailed Student’s t‐tests were used to assess differences between DOX vs. DMSO, and DOX vs. DOX+BA, respectively. Significance was accepted at P<0.05.RESULTSDOX treatment significantly reduced myotube area by 24 h post‐treatment, and this persisted through 48 h (P<0.05). Inhibiting MPT with BA attenuated mRNA levels of transcription factors FOXO1 and ATF4, Gadd45a, the atrogene MuRF1, and the autophagy regulating gene p62 at 12 h post‐treatment (P<0.05 for all). There was no difference between DOX vs. DOX+BA for MAFbx (P=0.076) or NfKB1 (0.692) expression.DISCUSSIONConsistent with our hypothesis, induction of MPT with DOX caused myotube atrophy. Additionally, inhibiting MPT in the presence of DOX attenuated mRNA levels of classical atrophy signaling pathway components, including FOXO1, ATF4, Gadd45α, MuRF1 and p62. Thus, our results suggest that MPT is a cause of atrophy in aging skeletal muscle.Support or Funding InformationSB is supported by a T32 from the National Institute of Child Health and Human Development Grant T32HD043730.

The functional differentiation of four smad4 paralogs in TGF-β signaling pathway of Japanese flounder (Paralichthys olivaceus)

As a classical signaling pathway, transforming growth factor β (TGF-β) has been studied in various animals for more than decade years. However, the members of TGF-β were markedly expanded in teleost specific third and fourth rounds of whole genome duplication (WGD). Here, four smad4s named Posmad4a, Posmad4b, Posmad4c and Posmad4d were identified in Japanese flounder. Our study showed that four flounder smad4s had distinct properties in terms of their protein structure, expression pattern, protein interaction and subcellular localization. PoSMAD4a/b were mainly located in the cytoplasm, and could co-localize in the nucleus with PoSMAD3a after TGF-β activator stimulation. PoSMAD4c was mainly located in nucleus, whereas PoSMAD4d distributed in the whole cell. Both PoSMAD4c and PoSMAD4d could co-localize in the nucleus with PoSMAD3b after TGF-β activator stimulation. Furthermore, Posmad4c responded most strongly to TGF-β signal stimulation. Dual-luciferase reporter assay also showed that Posmad4c could specifically up-regulate the TGF-β signal luciferase reporter gene, Posmad4b could enhance Wnt signal luciferase reporter gene, while both Posmad4b and Posmad4d could markedly up-regulate Notch signal reporter gene. All results indicated that Posmad4a/b/c/d had significantly functional differences among TGF-β, Notch and Wnt signaling pathways. Our study provided important understanding to the biology of smad4s and its pathway crosstalk in teleost.

Chlorzoxazone, a small molecule drug, augments immunosuppressive capacity of mesenchymal stem cells via modulation of FOXO3 phosphorylation

Nowadays, immune diseases are a large burden in healthcare. Mesenchymal stem cells (MSCs) have prominent ability in immunomodulation and have been applicated on treating many immune-related diseases. However, the clinical outcomes can be disparate and sometimes completely counterproductive beyond explanation of cell heterogeneity. The theory of immunomodulation plasticity in MSCs has then emerged to explain that MSCs can be induced into proinflammatory MSC1 or anti-inflammatory MSC2 responding to different immune environment. It would be safer and more efficient if we could induce MSCs into a certain immune phenotype, in most cases MSC2, prior to medical treatment. In this study, we screened and identified a classical FDA-approved drug, chlorzoxazone (CZ). Unlike traditional method induced by IFN-γ, CZ can induce MSC into MSC2 phenotype and enhance the immunosuppressive capacity without elevation of immunogenicity of MSCs. CZ-treated MSCs can better inhibit T cells activation and proliferation, promote expression of IDO and other immune mediators in vitro, and alleviate inflammatory infiltration and tissue damage in acute kidney injury rat model more effectively. Moreover, we discovered that CZ modulates phosphorylation of transcriptional factor forkhead box O3 (FOXO3) independent of classical AKT or ERK signaling pathways, to promote expression of downstream immune-related genes, therefore contributing to augmentation of MSCs immunosuppressive capacity. Our study established a novel and effective approach to induce MSC2, which is ready for clinical application.

An Overview of Embryogenesis: External Morphology and Transcriptome Profiling in the Hemipteran Insect Nilaparvata lugens

During embryogenesis of insects, the morphological and transcriptional changes are important signatures to obtain a better understanding of insect patterning and evolution. The brown planthopper Nilaparvata lugens is a serious insect pest of rice plants, but its embryogenesis has not uncovered. Here, we described embryonic development process of the pest and found it belongs to an intermediate-germ mode. The RNA-seq data from different times (6, 30, 96, and 150 h, after egg laying) of embryogenesis were then analyzed, and a total of 10,895 genes were determined as differentially expressed genes (DEGs) based on pairwise comparisons. Afterward, 1,898 genes, differentially expressed in at least two comparisons of adjacent embryonic stages were divided into 10 clusters using K means cluster analysis (KMCA). Eight-gene modules were established using a weighted gene co-expression network analysis (WGCNA). Gene expression patterns in the different embryonic stages were identified by combining the functional enrichments of the stage-specific clusters and modules, which displayed the expression level and reprogramming of multiple developmental genes during embryogenesis. The “hub” genes at each embryonic stage with possible crucial roles were identified. Notably, we found a “center” set of genes that were related to overall membrane functions and might play important roles in the embryogenesis process. After parental RNAi of the MSTRG.3372, the hub gene, the embryo was observed as abnormal. Furthermore, some homologous genes in classic embryonic development processes and signaling pathways were also involved in embryogenesis of this insect. An improved comprehensive finding of embryogenesis within the N. lugens reveals better information on genetic and genomic studies of embryonic development and might be a potential target for RNAi-based control of this insect pest.

Crocin Alleviates Pain Hyperalgesia in AIA Rats by Inhibiting the Spinal Wnt5a/β-Catenin Signaling Pathway and Glial Activation.

At present, most of the drugs have little effect on the pathological process of rheumatoid arthritis (RA). Analgesia is an important measure in the treatment of RA and is also one of the criteria to determine the therapeutic effects of the disease. Some studies have found that crocin, a kind of Chinese medicine, can effectively alleviate pain sensitization in pain model rats, but the mechanism is not clear. Emerging evidence indicates that crocin may inhibit the metastasis of lung and liver cancer cells from the breast by inhibiting Wnt/β-catenin and the Wnt signaling pathway is closely related to RA. Wnt5a belongs to the Wnt protein family and was previously thought to be involved only in nonclassical Wnt signaling pathways. Recent studies have shown that Wnt5a has both stimulatory and inhibitory effects on the classical Wnt signaling pathway, and so, Wnt5a has attracted increasing attention. This study demonstrated that crocin significantly increased the mechanical thresholds of adjuvant-induced arthritis (AIA) rats, suggesting that crocin can alleviate neuropathic pain. Crocin significantly decreased the levels of pain-related factors and glial activation. Foxy5, activator of Wnt5a, inhibited the above effects of crocin in AIA rats. In addition, intrathecal injection of a Wnt5a inhibitor significantly decreased hyperalgesia in AIA rats. This research shows that crocin may alleviate neuropathic pain in AIA rats by inhibiting the expression of pain-related molecules through the Wnt5a/β-catenin pathway, elucidating the mechanism by which crocin relieves neuropathic pain and provides a new way of thinking for the treatment of AIA pain.

Loss of Arp1, a putative actin-related protein, triggers filamentous and invasive growth and impairs pathogenicity in Candida albicans

The polymorphous cellular shape of Candida albicans, in particular the transition from a yeast to a filamentous form, is crucial for either commensalism or life-threatening infections of the host. Various external or internal stimuli, including serum and nutrition starvation, have been shown to regulate filamentous growth primarily through two classical signaling pathways, the cAMP-PKA and the MAPK pathways. Genotoxic stress also induces filamentous growth, but through independent pathways, and little is known about negative regulation during this reversible morphological transition. In this study, we established that ARP1 in C. albicans, similar to its homolog in S. cerevisiae, has a role in nuclei separation and spindle orientation. Deletion of ARP1 generated filamentous and invasive growth as well as increased biofilm formation, accompanied by up-regulation of hyphae specific genes, such as HWP1, UME6 and ALS3. The filamentous and invasive growth of the ARP1 deletion strain was independent of transcription factors Efg1, Cph1 and Ume6, but was suppressed by deleting checkpoint BUB2 or overexpressing NRG1. Deletion of ARP1 impaired the colonization of Candida cells in mice and also attenuated virulence in a mouse model. All the data suggest that loss of ARP1 activates filamentous and invasive growth in vitro, and that it positively regulates virulence in vivo, which provides insight into actin-related morphology and pathogenicity in C. albicans.

NF-κB Signaling Regulates Physiological and Pathological Chondrogenesis.

The nuclear factor-κB (NF-κB) is a transcription factor that regulates the expression of genes that control cell proliferation and apoptosis, as well as genes that respond to inflammation and immune responses. There are two means of NF-κB activation: the classical pathway, which involves the degradation of the inhibitor of κBα (IκBα), and the alternative pathway, which involves the NF-κB-inducing kinase (NIK, also known as MAP3K14). The mouse growth plate consists of the resting zone, proliferative zone, prehypertrophic zone, and hypertrophic zone. The p65 (RelA), which plays a central role in the classical pathway, is expressed throughout the cartilage layer, from the resting zone to the hypertrophic zone. Inhibiting the classical NF-κB signaling pathway blocks growth hormone (GH) or insulin-like growth factor (IGF-1) signaling, suppresses cell proliferation, and suppresses bone morphogenetic protein 2 (BMP2) expression, thereby promoting apoptosis. Since the production of autoantibodies and inflammatory cytokines, such as tumor necrosis factor-α (TNFα), interleukin (IL)-1β, IL-6, and IL-17, are regulated by the classical pathways and are increased in rheumatoid arthritis (RA), NF-κB inhibitors are used to suppress inflammation and joint destruction in RA models. In osteoarthritis (OA) models, the strength of NF-κB-activation is found to regulate the facilitation or suppression of OA. On the other hand, RelB is involved in the alternative pathway, and is expressed in the periarticular zone during the embryonic period of development. The alternative pathway is involved in the generation of chondrocytes in the proliferative zone during physiological conditions, and in the development of RA and OA during pathological conditions. Thus, NF-κB is an important molecule that controls normal development and the pathological destruction of cartilage.

MiR-491 functions as a tumor suppressor through Wnt3a/β-catenin signaling in the development of glioma.

Glioma is the most frequent brain tumor that has high invasion and usually disperses to the whole brain through blood and basement membranes. MicroRNA-491 (miR-491) has been reported to have low expression and act as a tumor suppressor in several cancers. The Wnt/β-catenin signaling is a classic signaling pathway that participated in several biological processes. Our purpose was to detect the molecular mechanism of miR-491 in regulating the growth and metastasis of glioma. Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was applied to calculate the mRNA level of miR-491 and target gene. The protein expression of special genes was assessed by Western blot. The proliferation and invasive abilities were measured by the Cell Counting Kit-8 (CCK-8) and transwell assays. The Kaplan-Meier method was conducted to evaluate the association between the expressions of miR-491 with the overall survival of glioma patients. We discovered that miR-491 was lowly expressed in glioma and downregulation of miR-491 predicted poor outcome of glioma patients. Similarly, a high expression of miR-491 suppressed the growth and metastasis in glioma cell line LN229. MiR-491 high expression inhibited the growth of glioma in a mouse xenograft model. Moreover, Wnt3a was a target gene of miR-491 and miR-491 mediated the invasion-mediated epithelial-mesenchymal transition (EMT) by regulating the expression of Wnt3a. Additionally, miR-491 regulated the proliferation through the Wnt/β-Catenin pathway by targeting Wnt3a. MiR-491 overexpression inhibited the proliferation through the Wnt3a/β-catenin pathway and invasion-mediated EMT in glioma. The newly identified miR-491/Wnt3a/β-catenin axis provides novel insight into the pathogenesis of glioma.

Low BCL9 expression inhibited ovarian epithelial malignant tumor progression by decreasing proliferation, migration, and increasing apoptosis to cancer cells

BackgroundAbnormal activation of the classic Wnt signaling pathway is closely related to the occurrence of epithelial cancers. B-cell lymphoma 9 (BCL9), a transcription factor, is a novel oncogene discovered in the classic Wnt pathway and promotes the occurrence and development of various tumors. Ovarian cancer is the gynecological malignant tumor with the highest mortality because it is difficult to diagnose early, and easy to relapse and metastasis. The expression and role of BCL9 in epithelial ovarian cancer (EOC) have not been studied. Thus, in this research, we aimed to investigate the expression and clinical significance of BCL9 in EOC tissues and its effect on the malignant biological behavior of human ovarian cancer cells.MethodsWe detect the expression of BCL9 in ovarian epithelial tumor tissues and normal ovarian tissues using immunohistochemistry and analyzed the relationship between it and clinicopathological parameters and patient prognosis. The expression of proteins was detected by Western blot. The MTT assay, flow cytometry, the scratch assay, and the transwell assay were used to detect cell proliferation, apoptosis, migration, and invasion, respectively. A total of 374 ovarian cancer tissue samples were collected using TCGA database. A gene set enrichment analysis of BCL9 was performed.ResultsBCL9 was overexpressed in EOC tissues. The level of BCL9 expression was correlated with the 5-year progression-free survival rate and overall survival rate in ovarian cancer patients and independently predicted the risk of ovarian cancer recurrence. Low BCL9 expression inhibited proliferation, invasion and migration of EOC cells, decreased MMP2 and MMP9 expression of ES-2 cell line, increased the BAX/BCL2 ratio and promoted apoptosis of EOC cells.ConclusionBCL9 is overexpressed in epithelial ovarian tumors, resulting in a poor prognosis for ovarian cancer patients. Low BCL9 expression can promote ovarian cancer cell apoptosis, inhibit proliferation and migration. BCL9 promotes the development of ovarian cancer.

Silence of S1 RNA binding domain 1 represses cell growth and promotes apoptosis in human non-small cell lung cancer cells.

To investigate the expression of S1 RNA binding domain 1 (SRBD1) in non-small cell lung cancer tissue and the effects of SRBD1 silencing on the biological behaviors of human non-small cell lung cancer cells, and to explore the molecular mechanism of SRBD1functions in human non-small cell lung cancer cells. Expressions of SRBD1 in human non-small cell lung cancer tissues and cell lines were examined by immunostaining and RT-PCR. shRNAs of SRBD1 were chemically synthesized and transfected into A549 and NCI-H1299 cells by lentivirus. Cell proliferation was assayed by cell counting, MTT and clone formation. Cell apoptosis was assayed by flow cytometry. Tumorigenicity was assessed by cell injection into BALB/c athymic nude mouse. Gene chip analysis was employed to explore genomic changes in A549 cells. Potential classical signaling pathways, upstream regulators and gene interaction networks were analyzed by Ingenuity Pathway Analysis, and verified by western blot analysis. SRBD1 was specifically expressed in human squamous cell carcinoma and highly expressed in lung cancer cell lines, NCI-H1299, A549 and NCI-H1975. SRBD1 directed-shRNA (shSRBD1) effectively reduced the expression of SRBD1 in A549 and NCI-H1299 cells. SRBD1 silencing inhibited cell proliferation, and promoted cell apoptosis in non-small cell lung cancer cells, and suppressed tumorigenesis in a nude mouse model. In addition, we found silencing of SRBD1 expression resulted in marked changes in gene expression in A549 cells. Besides, in shSRBD1 group, the protein levels of EPS 15, IGF1R, MYC, PYCR1 and HNRNPA0 were downregulated, and the expressions of several classical factors involved in the growth and apoptosis of cancer cells were also decreased. We found that SRBD1 were specifically expressed in non-small cell lung cancer tissue. Silencing of SRBD1 inhibits cell growth and promotes cell apoptosis in non-small cell lung cancer cells, and suppresses tumorigenesis in vivo, suggesting that SRBD1 may be a new diagnostic indicator and therapeutic target of non-small cell lung cancer.

Abstract A133: Role of CXCR2 in the acquisition of pan-resistant phenotype in high grade serous ovarian cancer cells

Abstract Epithelial ovarian cancer (EOC) remains the most lethal gynecologic malignancy. Indeed, EOC epidemiological scenario is partially due to its late diagnosis, when most of tumor cells have acquired metastatic and chemoresistant phenotype. Despite the initial satisfactory response of EOC cells to platinum/taxanes-based therapy, chemoresistance emerges in an uncontrolled pace, specifically when the patient carries a high-grade serous adenocarcinoma (HGS-AC). Therefore, EOC clinic urges for novel treatment possibilities, aiming the reversal of chemoresistance, the improvement of patients’ quality of life, and their survival rates. cDNA microarray data from our group demonstrated that chemokines secreted to the tumor microenvironment, as CXCL2, IL-6, and IL-8 likely play a crucial role in EOC cells chemoresistance. Thereafter, the present study focused on the role of CXCL2, which binds to its receptor CXCR2 in the membrane of target cells. Nonetheless its function in HGS-AC is unclear. Our study model was based in two HGS-AC lineages: chemosensitive A2780, and its pan-resistant derived ACRP (IC50 to cisplatin 7.3uM vs. 26,56uM, p<0.001; to doxuribicin 0.07uM vs. 1.5uM, p<0.0001, and to paclitaxel 0.22uM vs. 1.7uM, p<0.0001, respectively). CXCR2 was knockdown (KD), and its expression was decreased to 0.6-fold as compared to control cells (p= 0.0015). As compared to the control experimental condition (100%), CXCR2 KD HGS-AC cells described compromised cellular proliferation and metabolic viability (BrdU and Presto blue/SRB assays: A2780 21% vs. ACRP 23%, p<0.0001), and lower cell viability (clonogenic assay: A2780 70% vs. ACRP 49%, p<0.0001). Although angiogenesis does not seem to influence our observations, chicken embryo chorioallantoic membrane assay revealed that CXCR2 KD ACRP-induced tumors shrunk by 3.3-fold in comparison the control condition. Intriguingly, similar results were not observed when cells were treated with the pharmacological inhibitor of CXCR2. We lately discovered that the receptor was anomalously expressed in the cells nucleus, thus justifying our observations while opening novel avenues for future investigations in the field. We, then, argued whether CXCR2 KD would modulate carcinogenic classic signaling pathways. We observed a biological tendency of less P-AKT (0.5- fold, p=0.09), but not P-ERK (0.3-fold, p=0.7) when compared to control. We also investigated the involvement of EMT in our studied phenomena. Our findings demonstrated significative decline in the expression of SLUG (0.9-fold vs. control, p=0.022) and SNAIL (1.1-fold vs. control, p=0.005) in CXCR2 KD ACRP cells. Finally, in silico analysis including over 200 HGS-AC cases revealed that overexpression of CXCR2 is robustly correlated to the worse disease prognosis and patients’ overall survival rate, specially in late stage disease (p=0.035). Altogether, our results present innovative strategy to fight pan-chemoresistant HGS-AC by silencing anomalously overexpressed CXCR2. Citation Format: Taciane Henriques, Diandra dos Santos, Isabella Guimaraes, Nayara Tessarollo, Paulo Lyra, Patricia Mesquisa, Diana Padua, Ana Luisa Amaral, Luisa Pereira, Bruno Cavadas, Ian Silva, Raquel Almeida, Leticia Rangel. Role of CXCR2 in the acquisition of pan-resistant phenotype in high grade serous ovarian cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A133. doi:10.1158/1535-7163.TARG-19-A133

Mapping Stem Cell Dependencies in Cancer Heterogeneity and Therapy Resistance

Our research focuses on the signals that control stem cell self-renewal and how these signals are hijacked in cancer. Using a series of genetic models, we have studied how classic developmental signaling pathways play key roles in hematopoietic stem cell growth and regeneration and are dysregulated during leukemia development. Through this work we have identified Hedgehog and Wnt signaling, and more recently the cell fate determinant Musashi, as critical players in driving progression of hematologic malignancies and as targets for therapy. To search for new regulators of myeloid leukemia, we have carried out a focused screen of surface molecules that may enable leukemia cells to receive supportive cues from the microenvironment. This screen identified key new adhesion signals that are critical to leukemia growth, drug resistance and dissemination. Using high resolution in vivo imaging we have mapped how these mediate the interactions that leukemia cells make within their microenvironment. To complement this focused screen, we have also carried out a genome wide CRISPR screen to more generally define the biological determinants of myeloid leukemia establishment and propagation. This screen identified a large number of new genes and programs critically required for leukemia, including those essential for chromatin remodeling and spliceosomal assembly. Among these, RNA binding proteins (RBPs) in general, and the chromatin binding sub-family of RBPs in particular, emerged as key new dependencies of myeloid leukemia. The talk will focus in part on these new regulators. Disclosures No relevant conflicts of interest to declare.

JAK2/STAT3 Pathway is Required for α7nAChR-Dependent Expression of POMC and AGRP Neuropeptides in Male Mice.

Cholinergic signalling mediated by the activation of muscarinic and nicotinic receptors has been described in the literature as a classic and important signalling pathway in the regulation of the inflammatory response. Recent research has investigated the role of acetylcholine, the physiological agonist of these receptors, in the control of energy homeostasis at the central level. Studies have shown that mice that do not express acetylcholine in brain regions regulating energy homeostasis present with excessive weight gain and hyperphagia. However, it has not yet been well-described in the literature which cholinergic receptor subunits are involved in this response; moreover, the signalling pathways responsible for the observed effects are not fully delineated. The hypothalamus is the regulating centre of energy homeostasis, and the α7 subunit of the nicotinic acetylcholine receptor (α7nAChR) is highly expressed in this region. When active, α7nAChR recruits proteins such as JAK2/STAT3 to mediate its signalling; the same intracellular components are required by leptin, an anorexigenic hormone. The aim of the present study was to evaluate the role of the hypothalamic α7nAChR in the control of energy homeostasis. The work was performed on Swiss male mice. Initially, using immunofluorescent staining on brain sections, the presence of α7nAChR in hypothalamic cells regulating energy homeostasis was evaluated. Animals were submitted to stereotaxis in the lateral ventricle and intracerebroventricular stimulation (ICV) was used for the administration of an agonist (PNU) or antagonist (α-bungarotoxin) of α7nAChR. Metabolic parameters were evaluated and the expression of neuropeptides was evaluated in the hypothalamus by real-time PCR and western blot. The expression of hypothalamic neuropeptides was evaluated in mice treated with siRNA or inhibitors of JAK2/STAT3 (AG490 and STATTIC) proteins. We also evaluated food intake in α7nAChR knockout animals (α7KO). Additionally, in mouse hypothalamic cell culture (the mypHoA-POMC/GFP lineage), we evaluated the expression of neuropeptides and pSTAT3 after stimulation with PNU. Our results indicate co-localisation of α7nAChR with α-MSH, AgRP and NPY in hypothalamic cells. Pharmacological activation of α7nAChR reduced food intake and increased hypothalamic POMC expression and decreased NPY and AgRP mRNA levels and the protein content of pAMPK. Inhibition of α7nAChR with an antagonist increased the mRNA content of NPY and AgRP. Inhibition of α7nAChR with siRNA led to the suppression of POMC expression and an increase in AgRP mRNA levels. α7KO mice showed no changes in food intake. Inhibition of proteins involved in the JAK2/STAT3 signalling pathway reversed the effects observed after PNU stimulation. POMC-GFP cells, when treated with PNU, showed increased POMC expression and nuclear translocation of pSTAT3. Thus, selective activation of α7nAChR is able to modulate important markers of the response to food intake, suggesting that α7nAChR activation can suppress the expression of orexigenic markers and favour the expression of anorexics using the intracellular JAK2/STAT3 machinery.

Bioinformatics analysis of inhibitory mechanism of vitamin K2 combined with phosphatidylcholine on human hepatocellular carcinoma cells

Objective To explore the molecular mechanism of vitamin K2 (vk2) combined with phosphatidylcholine (pc) inhibiting human hepatocellular carcinoma cells. Methods Vitamin K2 combined with phosphatidylcholine was used to treat human hepatocellular carcinoma cells (SMMC-7721) for 48 hours. The expression of microRNA (miRNA, miR) in the treated human hepatocellular carcinoma cells was detected by microarray. Bioinformatics was used to predict the functional classification and cell signaling pathway and target genes of miRNA. Finally, the key proteins of cell signaling pathway were verified by Western blotting. Results A total of 65 miRNAs were significantly up-regulated or down-regulated by more than two folds. The variation of the expression level of miRNA16 was the greatest, up-regulated by 8 171.07 folds compared with the control group (t=6.238, P<0.01). There were 8 to 326 targeting genes in 65 miRNAs, which were mainly distributed in up-regulation and biological processes. Among them, there were 164 targeting genes in miR-16. After mapping the target genes to the signaling pathways, Wnt signaling pathway enriched the target genes most significantly, with 58 target genes (t=8.753, P<0.01). The low expression of WNT3A and phosphorylated β-catenin in Western blotting confirmed that the classical Wnt signaling pathway was involved significantly in the human hepatocellular carcinoma cells inhibited by vitamin K2 combined with phosphatidylcholine (t=5.354, P<0.01). Conclusion Vitamin K2 combined with phosphatidylcholine can inhibit the Wnt signaling pathway by up-regulating the expression of miR-16 in human hepatocellular carcinoma cells. Key words: Vitamin K2; Phosphatidylcholine; Hepatocellular carcinoma cell; Bioinformatics; WNT3A; MicroRNA-16

Occlusal trauma inhibits osteoblast differentiation and bone formation through IKK‐NF‐κB signaling

Occlusal trauma is an important factor promoting bone loss caused by periodontal diseases. Although there are reports of traumatic force promoting bone resorption in periodontal diseases, no studies examining the inhibition of bone formation by traumatic force and the underlying mechanism have been reported. The aim of this study was to investigate the mechanism whereby traumatic force inhibits bone formation. MC3T3-E1 cells were induced to undergo osteogenic differentiation and subjected to cyclic uniaxial compressive stress with or without stimulation with Pg. LPS. The expression of osteoblast markers and the activation of IKK-NF-κB signaling were evaluated in vitro. Then, MC3T3-E1 cells were induced to undergo osteogenic differentiation and subjected to cyclic uniaxial compressive stress with or without IKK-2 Inhibitor VI. The expression of osteoblast markers was determined. Then, the classic Wnt signaling pathway (β-catenin, Gsk3β, p-Gsk3β, and Dkk1) was further evaluated in vitro. Finally, occlusal trauma was induced in Wistar rats with or without the injection of IKK-2 Inhibitor VI, to evaluate changes in bone mass and IKK-NF-κB and Wnt/β-catenin signaling in vivo. After stimulation with Pg. LPS and traumatic force, IKK-NF-κB signaling was significantly activated in vitro. The expression of osteoblast markers and the activity of alkaline phosphatase in MC3T3-E1 cells declined after traumatic force loading and were rescued when IKK-NF-κB signaling was blocked. Wnt/β-catenin signaling was accordingly inhibited upon force loading, but this inhibition was reversed when IKK-NF-κB was antagonized in vitro. X-ray and Micro-CT analysis of the mandibles of the rats as well as HE and TRAP staining showed that bone loss induced by occlusal trauma declined after IKK-NF-κB was inhibited. The expression of p65 and IκBα was increased when occlusal trauma was induced in Wistar rats, whereas β-catenin, OCN, and Runx2 levels were decreased. After blocking IKK-NF-κB, significant upregulation of β-catenin, OCN, and Runx2 was observed in rats suffering from occlusal trauma. IKK-NF-κB signaling could be activated by traumatic force or occlusal trauma. Its activation promoted the degradation of β-catenin, ultimately inhibiting osteogenic differentiation in vitro and bone formation in vivo.

Pattern of triptans use: a retrospective prescription study in Calabria, Italy

A large number of chemokines, cytokines, other trophic factors and the extracellular matrix molecules form a favorable microenvironment for peripheral nerve regeneration. This microenvironment is one of the major factors for regenerative success. Therefore, it is important to investigate the key molecules and regulators affecting nerve regeneration after peripheral nerve injury. However, the identities of specific cytokines at various time points after sciatic nerve injury have not been determined. The study was performed by transecting the sciatic nerve to establish a model of peripheral nerve injury and to analyze, by protein microarray, the expression of different cytokines in the distal nerve after injury. Results showed a large number of cytokines were up-regulated at different time points post injury and several cytokines, e.g., ciliary neurotrophic factor, were downregulated. The construction of a protein-protein interaction network was used to screen how the proteins interacted with differentially expressed cytokines. Kyoto Encyclopedia of Genes and Genomes pathway and Gene ontology analyses indicated that the differentially expressed cytokines were significantly associated with chemokine signaling pathways, Janus kinase/signal transducers and activators of transcription, phosphoinositide 3-kinase/protein kinase B, and notch signaling pathway. The cytokines involved in inflammation, immune response and cell chemotaxis were up-regulated initially and the cytokines involved in neuronal apoptotic processes, cell-cell adhesion, and cell proliferation were up-regulated at 28 days after injury. Western blot analysis showed that the expression and changes of hepatocyte growth factor, glial cell line-derived neurotrophic factor and ciliary neurotrophic factor were consistent with the results of protein microarray analysis. The results provide a comprehensive understanding of changes in cytokine expression and changes in these cytokines and classical signaling pathways and biological functions during Wallerian degeneration, as well as a basis for potential treatments of peripheral nerve injury. The study was approved by the Institutional Animal Care and Use Committee of the Chinese PLA General Hospital, China (approval number: 2016-x9-07) in September 2016.

Anti-inflammation effects of injectable platelet-rich fibrin via macrophages and dendritic cells.

Immune response to implantation materials plays a critical role during early local inflammation and biomaterial-induced regeneration or restoration. A novel platelet concentrate termed i-PRF (injectable platelet-rich fibrin) has recently been developed without any additives by low centrifugation speeds. To date, scientists have investigated the capability of releasing growth factors to improve regeneration but have ignored whether i-PRF can inhibit the inflammatory effect around the wound. The present study investigated the anti-inflammation effects of i-PRF on immune response-related cells, especially macrophages and dendric cells. We found that i-PRF reduced pro-inflammatory M1 phenotype of macrophages and activated dendritic cells around muscle defect that was injected with bacterial suspension. Moreover, in vitro experiments showed similar results. i-PRF deleted inflammatory response caused by lipopolysaccharide to some extent. We determined that TLR4, an activator of inflammatory stimulation and p-p65, a key factor belongs to classical inflammatory related NF-κB signal pathway, can be inhibited by use of i-PRF. Results indicate the potential anti-inflammatory role of i-PRF during regeneration and restoration.

GNAQ Negatively Regulates Antiviral Innate Immune Responses in a Calcineurin-Dependent Manner.

Although guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) constitute the largest cell surface membrane receptor family and transduce thousands of extracellular signals into the cytoplasm, only four kinds of G protein α subunits (Gαs, Gαi/o, Gαq/11, and Gα12/13) are coupled to regulate cAMP or phosphatidylinositol signals. Growing evidence suggests that viruses tend to hijack GPCRs and harness their activated intracellular signaling pathways. Thus, understanding the roles of G protein signaling will further uncover the GPCR signaling pathways that are exploited by viruses. In this study, we demonstrate that the expression of GNAQ (Gq α subunit) was downregulated during viral infection and that small interfering RNA-mediated GNAQ knockdown protected host cells from both vesicular stomatitis virus (VSV) and HSV type 1 infection. Meanwhile, VSV and HSV type 1 replication was reduced significantly in Gnaq-deficient macrophages. Accordingly, the VSV distribution in the liver, spleen, and lung was reduced in Gnaq-deficient mice during VSV infection, and Gnaq-deficient mice were much more resistant to VSV infection than wild-type mice. Mechanistically, GNAQ limits type I IFN production through the canonical PLC-β/Ca2+/CALNA signaling pathway, which has been demonstrated to dephosphorylate virus-activated TANK-binding kinase 1 (TBK1). Thus, our data demonstrate that GNAQ negatively regulates the antiviral innate immune responses in a calcineurin-dependent manner. These findings also provide insights into the function and cross-talk of the classic GPCR signaling pathway with antiviral innate immune responses and suggest a potential therapeutic role for GNAQ in controlling viral diseases.

Novel Microglia Cell Line Expressing the Human EP2 Receptor.

Recently, EP2 signaling pathways were shown to regulate the classical activation and death of microglia in rat primary microglial culture. The study of microglial cells has been challenging because they are time-consuming to isolate in culture, they are demanding in their growth requirements, and they have a limited lifespan. To circumvent these difficulties, we created a murine BV2 microglial cell line stably expressing human EP2 receptors (BV2-hEP2) and further explored EP2 modulation of microglial functions. The BV2-hEP2 cells displayed cAMP elevation when exposed to the selective EP2 receptor agonists (ONO-AE1-259-1 and CP544326), and this response was competitively inhibited by TG4-155, a selective EP2 antagonist (Schild KB = 2.6 nM). By contrast, untransfected BV2 cells were unresponsive to selective EP2 agonists. Similar to the case of rat primary microglia, BV2-hEP2 microglia treated with lipopolysaccharide (LPS) (100 ng/mL) displayed rapid and robust induction of the inflammatory mediators COX-2, IL-1β, TNFα, and IL-6. EP2 activation depressed TNFα induction but exacerbated that of the other inflammatory mediators. Like primary microglia, classically activated BV2 microglia phagocytose fluorescent-labeled latex microspheres. The presence of EP2, but not its activation by agonists, in BV2-hEP2 microglia reduced phagocytosis and proliferation by 65% and 32%, respectively, compared to BV2 microglia. Thus, BV2-hEP2 is the first microglial cell line that retains the EP2 modulation of immune regulation and phagocytic ability of native microglia. Suppression of phagocytosis by the EP2 protein appears unrelated to classical EP2 signaling pathways, which has implications for therapeutic development of EP2 antagonists.

Transcriptomic perspective on extracellular ATP signaling: a few curious trifles

ABSTRACTExtracellular ATP is perceived by the purinoceptor P2K1, leading to induction of defense response in plants. Previously, we described the transcriptomic response to extracellular ATP in wild-type Arabidopsis seedlings and mutants of classical defense hormone signaling pathways (Jewell et al., 2019, Plant Physiol. 179: 1144–58), in which extracellular ATP was found to induce defense-related genes independently and also along with other defense signaling pathways. In the present study, we provide further analysis and discussion of the data that we neglected to describe in the previous transcriptomics report. Briefly, we describe transcriptomic differences between a P2K1 knockout mutant (dorn1) and wild-type seedlings in the absence of exogenous ATP as well as an analysis of genes more responsive to extracellular ATP in a P2K1 overexpression line. Finally, we describe an exaggerated response to extracellular ATP in the ein2 mutant and suggest testable explanations of this phenomenon.