Regulation of Epithelial-Mesenchymal Transition of A549 Cells by Prostaglandin D2.

BACKGROUND/AIMS: Despite significant advances in diagnostic and operative techniques, lung cancer remains one of the most lethal malignancies worldwide. Since prostaglandins such as prostaglandin D2 (PGD2) is involved in various pathophysiological process, including inflammation and tumorigenesis, this study aims to investigate the role of PGD2 during the process of epithelial-mesenchymal transition (EMT) in A549 cells. METHODS: A549 cells were stimulated with PGD2 and expression of EMT markers was analyzed by immunoblotting and immunofluorescence. EMT-related gene, Slug expression was evaluated using quantitative real-time polymerase chain reaction (qPCR). Migration and invasion abilities of A549 cells were determined in chemotaxis and Matrigel invasion assays, respectively. We also inhibited the TGF/Smad signaling pathway using a receptor inhibitor or silencing of TGF-ß1 and TGFß type I receptor (TGFßRI), and protein expression was assessed by immunoblotting and immunofluorescence. RESULTS: Here, we found that stimulation of A549 cells with PGD2 resulted in morphological changes into a mesenchymal-like phenotype under low serum conditions. Stimulation of A549 cells with PGD2 resulted in a significant reduction in proliferation, whereas invasion and migration were enhanced. The expression of E-cadherin was markedly downregulated, while Vimentin expression was upregulated after treatment of A549 cells with PGD2. Slug expression was markedly upregulated by stimulating A549 cells with PGD2, and stimulation of A549 cells with PGD2 significantly enhanced TGF-ß1 expression, and silencing of TGF-ß1 significantly blocked PGD2-induced EMT and Smad2 phosphorylation. In addition, PGD2-induced Smad2 phosphorylation and EMT were significantly abrogated by either pharmacological inhibition or silencing of TGFßRI. PGD2-induced expression of Slug and EMT were significantly augmented in low nutrient and low serum conditions. Finally, the subsequent culture of mesenchymal type of A549 cells under normal culture conditions reverted the cell's phenotype to an epithelial type. CONCLUSION: Given these results, we suggest that tumor microenvironmental factors such as PGD2, nutrition, and growth factors could be possible therapeutic targets for treating metastatic cancers.

Phospholipase D1 is upregulated by vorinostat and confers resistance to vorinostat in glioblastoma.

Glioblastoma (GBM) is an aggressive brain tumor and drug resistance remains a major barrier for therapeutics. Epigenetic alterations are implicated in GBM pathogenesis, and epigenetic modulators including histone deacetylase (HDAC) inhibitors are exploited as promising anticancer therapies. Here, we demonstrate that phospholipase D1 (PLD1) is a transcriptional target of HDAC inhibitors and confers resistance to HDAC inhibitor in GBM. Treatment of vorinostat upregulates PLD1 through PKCζ-Sp1 axis. Vorinostat induces dynamic changes in the chromatin structure and transcriptional machinery associated with PLD1 promoter region. Cotreatment of vorinostat with PLD1 inhibitor further attenuates invasion, angiogenesis, colony-forming capacity, and self-renewal capacity, compared with those of either treatment. PLD1 inhibitor overcomes resistance to vorinostat in GBM cells intracranial GBM tumors. Our finding provides new insight into the role of PLD1 as a target of resistance to vorinostat, and PLD1 inhibitor might provide the basis for therapeutic combinations with improved efficacy of HDAC inhibitor.

PLD1 and PLD2 differentially regulate the balance of macrophage polarization in inflammation and tissue injury.

Phospholipase D (PLD) isoforms PLD1 and PLD2 serve as the primary nodes where diverse signaling pathways converge. However, their isoform-specific functions remain unclear. We showed that PLD1 and PLD2 selectively couple to toll-like receptor 4 (TLR4) and interleukin 4 receptor (IL-4R) and differentially regulate macrophage polarization of M1 and M2 via the LPS-MyD88 axis and the IL-4-JAK3 signaling, respectively. Lipopolysaccharide (LPS) enhanced TLR4 or MyD88 interaction with PLD1; IL-4 induced IL-4R or JAK3 association with PLD2, indicating isozyme-specific signaling events. PLD1 and PLD2 are indispensable for M1 polarization and M2 polarization, respectively. Genetic and pharmacological targeting of PLD1 conferred protection against LPS-induced sepsis, cardiotoxin-induced muscle injury, and skin injury by promoting the shift toward M2; PLD2 ablation intensified disease severity by promoting the shift toward M1. Enhanced Foxp3+ regulatory T cell recruitment also influenced the anti-inflammatory phenotype of Pld1LyzCre macrophages. We reveal a previously uncharacterized role of PLD isoforms in macrophage polarization, signifying potential pharmacological interventions for macrophage modulation.

Cellular and subcellular localization of endogenous phospholipase D6 in seminiferous tubules of mouse testes.

Phospholipase D6 (PLD6) plays pivotal roles in mitochondrial dynamics and spermatogenesis, but the cellular and subcellular localization of endogenous PLD6 in testis germ cells is poorly defined. We examined the distribution and subcellular localization of PLD6 in mouse testes using validated specific anti-PLD6 antibodies. Ectopically expressed PLD6 protein was detected in the mitochondria of PLD6-transfected cells, but endogenous PLD6 expression in mouse testes was localized to the perinuclear region of pachytene spermatocytes, and more prominently, to the round (Golgi and cap phases) and elongating spermatids (acrosomal phase); these results suggest that PLD6 is localized to the Golgi apparatus. The distribution of PLD6 in the round spermatids partially overlapped with that of the cis-Golgi marker GM130, indicating that the PLD6 expression corresponded to the GM130-positive subdomains of the Golgi apparatus. Correlative light and electron microscopy revealed that PLD6 expression in developing spermatids was localized almost exclusively to several flattened cisternae, and these structures might correspond to the medial Golgi subcompartment; neither the trans-Golgi networks nor the developing acrosomal system expressed PLD6. Further, we observed that PLD6 interacted with tesmin, a testis-specific transcript necessary for successful spermatogenesis in mouse testes. To our knowledge, these results provide the first evidence of PLD6 as a Golgi-localized protein of pachytene spermatocytes and developing spermatids and suggest that its subcompartment-specific distribution within the Golgi apparatus may be related to the specific functions of this organelle during spermatogenesis.

Nitration of protein phosphatase 2A increases via Epac1/PLCε/CaMKII/HDAC5/iNOS cascade in human endometrial stromal cell decidualization.

Decidualization of the endometrial stroma is an essential differentiation process for embryo implantation and maintenance of pregnancy. We previously reported that protein phosphatase 2A (PP2A) acts as a key mediator during cAMP-induced decidualization of human endometrial stromal cells (hESCs). However, the mechanism underlying its activation has remained obscure in hESCs. In the present study, we aimed to reveal the mechanism that induces the nitration of PP2A catalytic subunit (PP2Ac) during cAMP-induced decidualization of hESCs. First, cAMP-induced PP2Ac nitration was significantly repressed using L-NAME, an inhibitor of nitric oxide synthase (NOS). Among several NOS isoforms, only inducible NOS (iNOS) was highly expressed in hESCs, indicating that iNOS directly induces the nitration of PP2Ac. Second, cAMP-induced iNOS expression and PP2Ac nitration were decreased by treatment with TSA, an inhibitor of histone deacetylase 5 (HDAC5). cAMP-induced phosphorylation of CaMKII and HDAC5 was suppressed by treatment with U73122 (an inhibitor of phospholipase C) or transfection of PLCε siRNA. Finally, small G protein Rap1 and its guanine nucleotide exchange factor Epac1 were found to be involved in cAMP-induced PP2A activation. Taken together, our results suggest that PP2Ac nitration during cAMP-induced decidualization of hESCs is induced through the Epac1-Rap1-PLCε-CaMKII-HDAC5-iNOS signaling pathway.

Preparation and Evaluation of Colon-Targeted Prodrugs of the Microbial Metabolite 3-Indolepropionic Acid as an Anticolitic Agent.

Microbial metabolites play a critical role in mucosal homeostasis by mediating physiological communication between the host and colonic microbes, whose perturbation may lead to gut inflammation. The microbial metabolite 3-indolepropionic acid (3-IPA) is one such communication mediator with potent antioxidative and anti-inflammatory activity. To apply the metabolite for the treatment of colitis, 3-IPA was coupled with acidic amino acids to yield colon-targeted 3-IPA, 3-IPA-aspartic acid (IPA-AA) and 3-IPA-glutamic acid (IPA-GA). Both conjugates were activated to 3-IPA in the cecal contents, which occurred faster for IPA-AA. Oral gavage of IPA-AA (oral IPA-AA) delivered a millimolar concentration of IPA-AA to the cecum, liberating 3-IPA. In a 2,4-dinitrobenzene sulfonic acid (DNBS)-induced rat colitis model, oral IPA-AA ameliorated rat colitis and was less effective than sulfasalazine (SSZ), a current anti-inflammatory bowel disease drug. To enhance the anticolitic activity of 3-IPA, it was azo-linked with the GPR109 agonist 5-aminonicotinic acid (5-ANA) to yield IPA-azo-ANA, expecting a mutual anticolitic action. IPA-azo-ANA (activated to 5-ANA and 2-amino-3-IPA) exhibited colon specificity in in vitro and in vivo experiments. Oral IPA-azo-ANA mitigated colonic damage and inflammation and was more effective than SSZ. These results suggest that colon-targeted 3-IPA ameliorated rat colitis and its anticolitic activity could be enhanced by codelivery of the GPR109A agonist 5-ANA.

Phospholipase D1 inhibition sensitizes glioblastoma to temozolomide and suppresses its tumorigenicity.

Resistance of glioblastoma to the chemotherapeutic compound temozolomide is associated with the presence of glioblastoma stem cells in glioblastoma and is a key obstacle for the poor prognosis of glioblastoma. Here, we show that phospholipase D1 is elevated in CD44High glioblastoma stem cells and in glioblastoma, especially recurring glioblastoma. Phospholipase D1 elevation positively correlated with the level of CD44 and poor prognosis in glioblastoma patients. Temozolomide significantly upregulated the expression of phospholipase D1 in the low and moderate CD44 populations of glioblastoma stem cells, but not in the CD44High population in which phospholipase D1 is highly expressed. Phospholipase D1 conferred resistance to temozolomide in CD44High glioblastoma stem cells and increased their self-renewal capacity and maintenance. Phospholipase D1 expression significantly correlated with levels of temozolomide resistance factors, which were suppressed by microRNA-320a and -4496 induced by phospholipase D1 inhibition. Genetic and pharmacological targeting of phospholipase D1 attenuated glioblastoma stem cell-derived intracranial tumors of glioblastoma using the microRNAs, and improved survival. Treatment solely with temozolomide produced no benefits on the glioblastoma, whereas in combination, phospholipase D1 inhibition sensitized glioblastoma stem cells to temozolomide and reduced glioblastoma tumorigenesis. Together, these findings indicate that phospholipase D1 inhibition might overcome resistance to temozolomide and represents a potential treatment strategy for glioblastoma. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Integrating binding and expression data to predict transcription factors combined function.

BACKGROUND: Transcription factor binding to the regulatory region of a gene induces or represses its gene expression. Transcription factors share their binding sites with other factors, co-factors and/or DNA-binding proteins. These proteins form complexes which bind to the DNA as one-units. The binding of two factors to a shared site does not always lead to a functional interaction. RESULTS: We propose a method to predict the combined functions of two factors using comparable binding and expression data (target). We based this method on binding and expression target analysis (BETA), which we re-implemented in R and extended for this purpose. target ranks the factor's targets by importance and predicts the dominant type of interaction between two transcription factors. We applied the method to simulated and real datasets of transcription factor-binding sites and gene expression under perturbation of factors. We found that Yin Yang 1 transcription factor (YY1) and YY2 have antagonistic and independent regulatory targets in HeLa cells, but they may cooperate on a few shared targets. CONCLUSION: We developed an R package and a web application to integrate binding (ChIP-seq) and expression (microarrays or RNA-seq) data to determine the cooperative or competitive combined function of two transcription factors.

ß-Catenin-RAS interaction serves as a molecular switch for RAS degradation via GSK3ß.

RAS proteins play critical roles in various cellular processes, including growth and transformation. RAS proteins are subjected to protein stability regulation via the Wnt/ß-catenin pathway, and glycogen synthase kinase 3 beta (GSK3ß) is a key player for the phosphorylation-dependent RAS degradation through proteasomes. GSK3ß-mediated RAS degradation does not occur in cells that express a nondegradable mutant (MT) ß-catenin. Here, we show that ß-catenin directly interacts with RAS at the α-interface region that contains the GSK3ß phosphorylation sites, threonine 144 and threonine 148 residues. Exposure of these sites by prior ß-catenin degradation is required for RAS degradation. The introduction of a peptide that blocks the ß-catenin-RAS interaction by binding to ß-catenin rescues the GSK3ß-mediated RAS degradation in colorectal cancer (CRC) cells that express MT ß-catenin. The coregulation of ß-catenin and RAS stabilities by the modulation of their interaction provides a mechanism for Wnt/ß-catenin and RAS-ERK pathway cross-talk and the synergistic transformation of CRC by both APC and KRAS mutations.

Inhibition of phospholipase D2 augments histone deacetylase inhibitor-induced cell death in breast cancer cells.

BACKGROUND: Histone deacetylase (HDAC) inhibitors are promising anticancer drugs but their effect on tumor treatment has been disappointing mainly due to the acquisition of HDAC inhibitor resistance. However, the mechanisms underlying such resistance remain unclear. METHODS: In this study, we performed Western blot, q-PCR, and promoter assay to examine the expression of HDAC inhibitor-induced phospholipase D2 (PLD2) in MDA-MB231and MDA-MB435 breast cancer cells. Apoptosis and proliferation were analyzed by flow cytometry. In addition to invasion and migration assay, angiogenesis was further measured using in vitro tube formation and chick embryo chorioallantoic membrane model. RESULTS: HDAC inhibitors including suberoylanilide hydroxamic acid (SAHA), trichostatin, and apicidin, induce expression of PLD2 in a transcriptional level. SAHA upregulates expression of PLD2 via protein kinase C-ζ in breast cancer cells and increases the enzymatic activity of PLD. The combination treatment of SAHA with PLD2 inhibitor significantly enhances cell death in breast cancer cells. Phosphatidic acid, a product of PLD activity, prevented apoptosis promoted by cotreatment with SAHA and PLD2 inhibitor, suggesting that SAHA-induced PLD2 expression and subsequent activation of PLD2 might confers resistance of breast cancer cells to HDAC inhibitor. The combinational treatment of the drugs significantly suppressed invasion, migration, and angiogenesis, compared with that of either treatment. CONCLUSION: These findings provide further insight into elucidating the advantages of combination therapy with HDAC and PLD2 inhibitors over single-agent strategies for the treatment of cancer.

Targeting of Phospholipase D1 Ameliorates Collagen-Induced Arthritis via Modulation of Treg and Th17 Cell Imbalance and Suppression of Osteoclastogenesis.

Phospholipase D1 (PLD1) plays a crucial role in various inflammatory and autoimmune diseases. Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease. However, the role of PLD1 in the pathogenesis of RA remains unknown. Here, we first investigated the role and effects of PLD1 in collagen-induced arthritis (CIA) and found that genetic and pharmacological inhibition of PLD1 in DBA1/J mice with CIA reduced the incidence of CIA, decreased the clinical score, and abrogated disease symptoms including infiltration of leukocytes, synovial inflammation, bone erosion, and cartilage destruction. Moreover, ablation and inhibition of PLD1 suppressed the production of type II collagen-specific IgG2a autoantibody and proinflammatory cytokines, accompanied by an increase in the regulatory T (Treg) cell population and a decrease in the Th17 cell population in CIA mice. The PLD1 inhibitor also promoted differentiation of Treg cells and suppressed differentiation of Th17 cells in vitro. Furthermore, the PLD1 inhibitor attenuated pathologic bone destruction in CIA mice by suppressing osteoclastogenesis and bone resorption. Thus, our findings indicate that the targeting of PLD1 can ameliorate CIA by modulating the imbalance of Treg and Th17 cells and suppressing osteoclastogenesis, which might be a novel strategy to treat autoimmune diseases, such as RA.

WDR76 degrades RAS and suppresses cancer stem cell activation in colorectal cancer.

BACKGROUND: Stabilization of RAS is a key event for the hyper-activation of Wnt/ß-catenin signaling and activation of cancer stem cell (CSC) in colorectal cancer (CRC). WD Repeat protein 76 (WDR76) mediates the polyubiquitination-dependent degradation of RAS in hepatocellular carcinoma (HCC). We investigated whether WDR76 destabilizes RAS and acts as a tumor suppressor inhibiting CSC activation in CRC. METHODS: We generated mice with deletion of Wdr76 (Wdr76-/-) and crosses of Wdr76-/- with ApcMin/+ (Wdr76-/-; ApcMin/+) and compared them with wildtype mice (Wdr76+/+) and ApcMin/+ mice (Wdr76+/+; ApcMin/+), respectively. Intestinal crypt lengthening, tumorigenesis and CSC activation were analyzed by histology, immunohistochemistry, and immunoblotting. CRC cell line was engineered to stably express or knockdown WDR76 or control vector and was analyzed after spheroid culture. RESULTS: Wdr76-/- mice, with increased Ras level, displayed crypt elongation and hyper-proliferation. Wdr76-/-; ApcMin/+ mice developed more tumors with bigger sizes than ApcMin/+ mice and their tumors showed increased proliferation and CSC activation with elevated RAS and ß-catenin levels. In CRC cells, overexpression or knockdown of WDR76 decreased or increased the numbers and sizes of CRC spheroids with inhibition or activation of CSC markers, respectively. In human CRC, lower level of WDR76 was associated with poor patient survival. CONCLUSIONS: In analyses of mice with deletion of Wdr76 and CRC spheroids, we found that RAS stability plays important roles in tumorigenesis by affecting proliferation and CSC activation. Our results suggest that destabilization of RAS by WDR76 is a potential strategy for targeting malignant CRC involving CSC activation.

Small-molecule binding of the axin RGS domain promotes ß-catenin and Ras degradation.

Both the Wnt/ß-catenin and Ras pathways are aberrantly activated in most human colorectal cancers (CRCs) and interact cooperatively in tumor promotion. Inhibition of these signaling may therefore be an ideal strategy for treating CRC. We identified KY1220, a compound that destabilizes both ß-catenin and Ras, via targeting the Wnt/ß-catenin pathway, and synthesized its derivative KYA1797K. KYA1797K bound directly to the regulators of G-protein signaling domain of axin, initiating ß-catenin and Ras degradation through enhancement of the ß-catenin destruction complex activating GSK3ß. KYA1797K effectively suppressed the growth of CRCs harboring APC and KRAS mutations, as shown by various in vitro studies and by in vivo studies using xenograft and transgenic mouse models of tumors induced by APC and KRAS mutations. Destabilization of both ß-catenin and Ras via targeting axin is a potential therapeutic strategy for treatment of CRC and other type cancers activated Wnt/ß-catenin and Ras pathways.

MicroRNA-320a and microRNA-4496 attenuate Helicobacter pylori cytotoxin-associated gene A (CagA)-induced cancer-initiating potential and chemoresistance by targeting ß-catenin and ATP-binding cassette, subfamily G, member 2.

Infection with Helicobacter pylori is closely linked to an increased risk of gastric cancer. Although cytotoxin-associated gene A (CagA), a major virulence factor of H. pylori, is known to be a causal factor for gastric carcinogenesis, the molecular link between CagA and gastric cancer-initiating cell (CIC)-like properties remains elusive. Here, we demonstrate that CagA is required for increased expression of ß-catenin and its target CIC markers via downregulation of microRNA (miR)-320a and miR-4496. CagA promoted gastric CIC properties and was responsible for chemoresistance. miR-320a and miR-4496 attenuated the in vitro self-renewal and tumour-initiating capacity of CagA-expressing CICs by targeting ß-catenin. Moreover, miR-320a and miR-4496 decreased CagA-induced chemoresistance by targeting ATP-binding cassette, subfamily G, member 2 (ABCG2) at the transcriptional and post-transcriptional levels, respectively. Combination therapy with 5-fluorouracil and miR-320a/miR-4496 suppressed gastric tumourigenesis and metastatic potential in an orthotopic mouse model, probably via suppression of CagA-induced CIC properties and chemoresistance. Our results provide novel evidence that CIC properties, chemoresistance and tumourigenesis associated with H. pylori are linked to CagA-induced upregulation of ß-catenin and ABCG2. These data provide novel insights into the molecular mechanisms of CagA-induced carcinogenisis and the therapeutic potential of of miR-320a and miR-4496. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Rebamipide induces the gastric mucosal protective factor, cyclooxygenase-2, via activation of 5'-AMP-activated protein kinase.

Rebamipide, an amino acid derivative of 2(1H)-quinolinone, has been used for mucosal protection, healing of gastroduodenal ulcers, and treatment of gastritis. Induction of cyclooxygenase (COX)-2, a gastric mucosal protective factor, by rebamipide has been suggested as the major mechanism of the drug action. However, how rebamipide induces COX-2 at the molecular level needs further investigation. In this study, the molecular mechanism underlying the induction of COX-2 by rebamipide was investigated. In gastric carcinoma cells and macrophage cells, rebamipide induced phosphorylation of AMP-activated protein kinase (AMPK), leading to phosphorylation of acetyl-CoA carboxylase (ACC), a substrate of AMPK. The induction of COX-2 by rebamipide was dependent on AMPK activation because compound C, an AMPK inhibitor, abolished COX-2 induction by rebamipide. In a mouse ulcer model, rebamipide protected against hydrochloric acid/ethanol-induced gastric ulcer, and these protective effects were deterred by co-administration of compound C. In parallel, in the gastric tissues, rebamipide increased the phosphorylation AMPK, whereas compound C reduced the levels of COX-2 and phosphorylated ACC, which were increased by rebamipide. Taken together, the activation of AMPK by rebamipide may be a molecular mechanism that contributes to induction of COX-2, probably resulting in protection against gastric ulcers.

Minoxidil Induction of VEGF Is Mediated by Inhibition of HIF-Prolyl Hydroxylase.

The topical application of minoxidil may achieve millimolar concentrations in the skin. We investigated whether millimolar minoxidil could induce vascular endothelial growth factor (VEGF), a possible effector for minoxidil-mediated hair growth, and how it occurred at the molecular level. Cell-based experiments were performed to investigate a molecular mechanism underlying the millimolar minoxidil induction of VEGF. The inhibitory effect of minoxidil on hypoxia-inducible factor (HIF) prolyl hydroxylase-2 (PHD-2) was tested by an in vitro von Hippel-Lindau protein (VHL) binding assay. To examine the angiogenic potential of millimolar minoxidil, a chorioallantoic membrane (CAM) assay was used. In human keratinocytes and dermal papilla cells, millimolar minoxidil increased the secretion of VEGF, which was not attenuated by a specific adenosine receptor antagonist that inhibits the micromolar minoxidil induction of VEGF. Millimolar minoxidil induced hypoxia-inducible factor-1α (HIF-1α), and the induction of VEGF was dependent on HIF-1. Moreover, minoxidil applied to the dorsal area of mice increased HIF-1α and VEGF in the skin. In an in vitro VHL binding assay, minoxidil directly inhibited PHD-2, thus preventing the hydroxylation of cellular HIF-1α and VHL-dependent proteasome degradation and resulting in the stabilization of HIF-1α protein. Minoxidil inhibition of PHD-2 was reversed by ascorbate, a cofactor of PHD-2, and the minoxidil induction of cellular HIF-1α was abrogated by the cofactor. Millimolar minoxidil promoted angiogenesis in the CAM assay, an in vivo angiogenic test, and this was nullified by the specific inhibition of VEGF. Our data demonstrate that PHD may be the molecular target for millimolar minoxidil-mediated VEGF induction via HIF-1.

CXXC5 plays a role as a transcription activator for myelin genes on oligodendrocyte differentiation.

Myelination in corpus callosum plays important role for normal brain functions by transferring neurological information between various brain regions. However, the factors controlling expression of myelin genes in myelination are poorly understood. Here, CXXC5, a recently identified protein with CXXC-type zinc finger DNA binding motif, was characterized as a transcriptional activator of major myelin genes. We identified expression of CXXC5 expression was increased by Wnt/ß-catenin signaling. CXXC5 specifically expressed in the white matter induced expression of myelin genes through the direct binding of CXXC DNA-binding motif of CXXC5 on the MBP promoter. During the differentiation of neural stem cells (NSCs) of CXXC5(-/-) mice, the expressions of myelin genes were simultaneously reduced. The CXXC5(-/-) mice exhibited severely reduction of myelin genes expression in corpus callosum as well as abnormalities in myelin structure. The disrupted structural integrity of myelin in the CXXC5(-/-) mice resulted in reduced electrical conduction amplitudes at corpus callosum. These findings indicate that the regulation of myelin genes expression by CXXC5 is important for forming myelin structure involved with axonal electrical signal transfer in the corpus callosum.

A translocator protein 18 kDa ligand, Ro5-4864, inhibits ATP-induced NLRP3 inflammasome activation.

Ro5-4864 and PK11195, prototypical synthetic ligands of translocator protein 18 kDa (TSPO), have shown anti-inflammatory effects in several models of inflammatory diseases; however, their biochemical mechanisms remain poorly understood. Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation as a part of the innate immune system, has been implicated in a variety of inflammatory diseases. Here, we demonstrate for the first time that TSPO ligands, especially Ro5-4864, potently suppressed ATP-induced NLRP3 inflammasome activation in THP-1 and BMDM cells. Detailed action mechanism was further investigated in THP-1 cells. Ro5-4864 efficiently attenuated NLRP3 translocation to mitochondria, inflammasome assembly/oligomerization, activation of caspase-1, and subsequent secretion of the mature forms of interleukin-1ß and -18. Ro5-4864 also reduced the production of mitochondrial superoxide and preserved the mitochondrial membrane potential in ATP-treated cells, suggesting that Ro5-4864 may act on mitochondria or more upstream targets in NLRP3 inflammasome signaling. We also observed the distinct effects of the TSPO ligands between THP-1 monocytes and macrophages, which suggested different NLRP3 inflammasome signaling depending on cell type. Collectively, our novel findings demonstrate that Ro5-4864 effectively inhibited ATP-induced NLRP3 inflammasome activation through the prevention of mitochondrial perturbation. Our results indicate Ro5-4864 as a promising candidate for the treatment of NLRP3 inflammasome-related diseases.

Hepatitis C virus core protein enhances hepatocellular carcinoma cells to be susceptible to oncolytic vesicular stomatitis virus through down-regulation of HDAC4.

Since hepatitis C virus (HCV) core protein is known to possess potential oncogenic activity, we explored whether oncolytic vesicular stomatitis virus (VSV) could efficiently induce cytolysis in hepatocellular carcinoma cells stably expressing HCV core protein (Hep3B-Core). We found that Hep3B-Core cells were more susceptible to VSV as compared to control (Hep3B-Vec) cells owing to core-mediated inactivation of STAT1 and STAT2 proteins. Core expression induced lower phosphorylation levels of type I IFN signaling proteins such as Tyk2 and Jak1, and a reduced response to exogenous IFN-α, which resulted in susceptibility to VSV. Furthermore, as STAT1 acetylation by switching phosphorylation regulated its activity, the role of STAT1 acetylation in susceptibility of Hep3B-Core cells to VSV was investigated. Treatment with trichostatin A, an inhibitor of histone deacetylase (HDAC), increased STAT1 acetylation but blocked IFN-α-induced phosphorylation of STAT1, leading to increase of susceptibility to VSV. Interestingly, the core protein decreased HDCA4 transcript levels, leading to down-regulation of HDAC4 protein. However, ectopic expression of HDAC4 conversely enforced phosphorylation of STAT1 and hindered VSV replication, indicating that core-mediated reduction of HDAC4 provides a suitable intracellular circumstance for VSV replication. Collectively, we suggest that VSV treatment will be a useful therapeutic strategy for HCV-infected hepatocellular carcinoma cells because HCV core protein suppresses the anti-viral threshold by down-regulation of the STAT1-HDAC4 signaling axis.

Polygonum aviculare L. and its active compounds, quercitrin hydrate, caffeic acid, and rutin, activate the Wnt/ß-catenin pathway and induce cutaneous wound healing.

Polygonum aviculare L. is a member of the Polygonaceae family of plants, which has been known for its antioxidant and anti-obesity effects. However, the wound healing function of P. aviculare extract has not been assessed. In this study, we identified a novel property of P. aviculare extract as a Wnt/ß-catenin pathway activator based on a screen of 350 plant extracts using HEK293-TOP cells retaining the Wnt/ß-catenin signaling reporter gene. P. aviculare extract accelerated the migration of HaCaT keratinocytes without showing significant cytotoxicity. Moreover, P. aviculare extract efficiently re-epithelized wounds generated on mice. Additionally, ingredients of P. aviculare extract, such as quercitrin hydrate, caffeic acid, and rutin, also accelerated the motility of HaCaT keratinocytes with the activation of Wnt/ß-catenin signaling. Therefore, based on our findings, P. aviculare extract and its active ingredients could be potential therapeutic agents for wound healing. Copyright © 2016 John Wiley & Sons, Ltd.