Displaying publications 521 - 540 of 701 in total

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  1. Fulltext (R)-(+)-α-lipoic acid protected NG108-15 cells against H₂O₂-induced cell death through PI3K-Akt/GSK-3β pathway and suppression of NF-κβ-cytokines
    Kamarudin MN, Mohd Raflee NA, Hussein SS, Lo JY, Supriady H, Abdul Kadir H
    Drug Des Devel Ther, 2014;8:1765-80.
    PMID: 25336920 DOI: 10.2147/DDDT.S67980
    Alpha-lipoic acid, a potent antioxidant with multifarious pharmacological benefits has been reported to be neuroprotective in several neuronal models and used to treat neurological disorders such as Alzheimer's disease. Nonetheless, conclusive mechanisms of alpha-lipoic acid for its protective effects particularly in NG108-15 cells have never been investigated. In this study, the intricate neuroprotective molecular mechanisms by (R)-(+)-alpha-lipoic acid (R-LA) against H2O2-induced cell death in an in vitro model of neurodegeneration were elucidated. Pretreatment with R-LA (2 hours) significantly increased NG108-15 cell viability as compared to H2O2-treated cells and mitigated the induction of apoptosis as evidenced by Hoechst 33342/propidium iodide staining. R-LA (12.5-50 μM) aggrandized the reduced glutathione over glutathione disulfide ratio followed by a reduction in the intracellular reactive oxygen species level and an increase in mitochondrial membrane potential following H2O2 exposure. Moreover, pretreatment with R-LA stimulated the activation of PI3K-Akt through mTORC1 and mTORC2 components (mTOR, rictor and raptor) and production of antiinflammatory cytokine, IL-10 which led to the inactivation of glycogen synthase kinase-3β (GSK-3β) and reduction of both Bax/Bcl2 and Bax/Bcl-xL ratios, accompanied by inhibition of the cleaved caspase-3. Additionally, this observation was preceded by the suppression of NF-κβ p65 translocation and production of proinflammatory cytokines (IL-6 and TNF-α). The current findings accentuate new mechanistic insight of R-LA against apoptogenic and brain inflammatory factors in a neuronal model. These results further advocate the therapeutic potential of R-LA for the treatment of neurodegenerative diseases.
    Matched MeSH terms: Signal Transduction/drug effects
  2. Fulltext Perturbation of PI3K/Akt signaling affected autophagy modulation in dystrophin-deficient myoblasts
    Yazid MD, Hung-Chih C
    Cell Commun Signal, 2021 10 27;19(1):105.
    PMID: 34706731 DOI: 10.1186/s12964-021-00785-0
    BACKGROUND: The absence of dystrophin has gave a massive impact on myotube development in Muscular Dystrophy pathogenesis. One of the conserved signaling pathways involved in skeletal muscle differentiation is the PI3K/Akt/mTOR pathway that plays a vital role in autophagy regulation. To further understand and establish targeted therapy in dystrophin-deficient myoblasts, protein expression profiling has been determined which provides information on perturbed autophagy modulation and activation.

    METHODS: In this study, a dystrophin-deficient myoblast cell line established from the skeletal muscle of a dystrophic (mdx) mouse was used as a model. The dfd13 (dystrophin-deficient) and C2C12 (non-dystrophic) myoblasts were cultured in low mitogen conditions for 10 days to induce differentiation. The cells were subjected to total protein extraction prior to Western blotting assay technique. Protein sub-fractionation has been conducted to determine protein localization. The live-cell analysis of autophagy assay was done using a flow cytometer.

    RESULTS: In our culture system, the dfd13 myoblasts did not achieve terminal differentiation. PTEN expression was profoundly increased in dfd13 myoblasts throughout the differentiation day subsequently indicates perturbation of PI3K/Akt/mTOR regulation. In addition, rictor-mTORC2 was also found inactivated in this event. This occurrence has caused FoxO3 misregulation leads to higher activation of autophagy-related genes in dfd13 myoblasts. Autophagosome formation was increased as LC3B-I/II showed accumulation upon differentiation. However, the ratio of LC3B lipidation and autophagic flux were shown decreased which exhibited dystrophic features.

    CONCLUSION: Perturbation of the PTEN-PI3K/Akt pathway triggers excessive autophagosome formation and subsequently reduced autophagic flux within dystrophin-deficient myoblasts where these findings are of importance to understand Duchenne Muscular Dystrophy (DMD) patients. We believe that some manipulation within its regulatory signaling reported in this study could help restore muscle homeostasis and attenuate disease progression. Video Abstract.

    Matched MeSH terms: Signal Transduction/genetics
  3. Fulltext Recent developments in β-cell differentiation of pluripotent stem cells induced by small and large molecules
    Kumar SS, Alarfaj AA, Munusamy MA, Singh AJ, Peng IC, Priya SP, et al.
    Int J Mol Sci, 2014;15(12):23418-47.
    PMID: 25526563 DOI: 10.3390/ijms151223418
    Human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), hold promise as novel therapeutic tools for diabetes treatment because of their self-renewal capacity and ability to differentiate into beta (β)-cells. Small and large molecules play important roles in each stage of β-cell differentiation from both hESCs and hiPSCs. The small and large molecules that are described in this review have significantly advanced efforts to cure diabetic disease. Lately, effective protocols have been implemented to induce hESCs and human mesenchymal stem cells (hMSCs) to differentiate into functional β-cells. Several small molecules, proteins, and growth factors promote pancreatic differentiation from hESCs and hMSCs. These small molecules (e.g., cyclopamine, wortmannin, retinoic acid, and sodium butyrate) and large molecules (e.g. activin A, betacellulin, bone morphogentic protein (BMP4), epidermal growth factor (EGF), fibroblast growth factor (FGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), noggin, transforming growth factor (TGF-α), and WNT3A) are thought to contribute from the initial stages of definitive endoderm formation to the final stages of maturation of functional endocrine cells. We discuss the importance of such small and large molecules in uniquely optimized protocols of β-cell differentiation from stem cells. A global understanding of various small and large molecules and their functions will help to establish an efficient protocol for β-cell differentiation.
    Matched MeSH terms: Signal Transduction
  4. Direct regulation of gonadotropin release by neurokinin B in tilapia (Oreochromis niloticus)
    Biran J, Golan M, Mizrahi N, Ogawa S, Parhar IS, Levavi-Sivan B
    Endocrinology, 2014 Dec;155(12):4831-42.
    PMID: 25211586 DOI: 10.1210/en.2013-2114
    Neurokinin B (NKB) was recently identified as a key regulator of reproduction in mammals and fish. Fish were found to possess a specific novel neurokinin termed NKF. To study the role of NKB/NKF in the regulation of fish reproduction and to investigate the role of NKB/NKF and their receptors in the piscine pituitary, we have identified the NKB/tachikinin 3 receptor (tac3r) system in tilapia. Bioinformatics and phylogenetic analyses have demonstrated that the tilapia holds 1 putative tac3 gene and 2 NKB receptor genes (tac3ra and tac3rb) that clustered with other piscine Tac3 and NKB receptor lineages. Furthermore, we found that in African cichlids, NKB peptides differ from other vertebrate NKBs in their C-terminal sequence, possessing isoleucine instead of valine as the X in the NKB FXGLM-NH2-terminal consensus sequence. Signal transduction analysis demonstrated that tilapia NKB (tiNKB), tiNKF, and human NKB activated both CRE-luc and SRE-luc transcriptional activity of both tilapia and human NKB receptors. Two hours after ip injection of tiNKB, the plasma levels of both FSH and LH were increased, whereas tiNKF was more effective in increasing LH levels. However, tiNKB was more effective than tiNKF in increasing both FSH and LH from tilapia pituitary dispersed cells. Using in situ hybridization and fluorescent immunohistochemistry, we have shown that LH cells possess tac3, tac3ra, and tac3rb mRNAs, whereas FSH cells possess mainly tac3rb and tac3ra and tac3 to a much lesser extent. These results suggest that the members of the NKB/tac3r system may serve as paracrine/autocrine regulators of gonadotropin release in fish pituitary.
    Matched MeSH terms: Signal Transduction
  5. Fulltext Hypoxic culture conditions as a solution for mesenchymal stem cell based regenerative therapy
    Haque N, Rahman MT, Abu Kasim NH, Alabsi AM
    ScientificWorldJournal, 2013;2013:632972.
    PMID: 24068884 DOI: 10.1155/2013/632972
    Cell-based regenerative therapies, based on in vitro propagation of stem cells, offer tremendous hope to many individuals suffering from degenerative diseases that were previously deemed untreatable. Due to the self-renewal capacity, multilineage potential, and immunosuppressive property, mesenchymal stem cells (MSCs) are considered as an attractive source of stem cells for regenerative therapies. However, poor growth kinetics, early senescence, and genetic instability during in vitro expansion and poor engraftment after transplantation are considered to be among the major disadvantages of MSC-based regenerative therapies. A number of complex inter- and intracellular interactive signaling systems control growth, multiplication, and differentiation of MSCs in their niche. Common laboratory conditions for stem cell culture involve ambient O₂ concentration (20%) in contrast to their niche where they usually reside in 2-9% O₂. Notably, O₂ plays an important role in maintaining stem cell fate in terms of proliferation and differentiation, by regulating hypoxia-inducible factor-1 (HIF-1) mediated expression of different genes. This paper aims to describe and compare the role of normoxia (20% O₂) and hypoxia (2-9% O₂) on the biology of MSCs. Finally it is concluded that a hypoxic environment can greatly improve growth kinetics, genetic stability, and expression of chemokine receptors during in vitro expansion and eventually can increase efficiency of MSC-based regenerative therapies.
    Matched MeSH terms: Signal Transduction
  6. Anti-hyperalgesic effect of a benzilidine-cyclohexanone analogue on a mouse model of chronic constriction injury-induced neuropathic pain: Participation of the κ-opioid receptor and KATP
    Ming-Tatt L, Khalivulla SI, Akhtar MN, Lajis N, Perimal EK, Akira A, et al.
    Pharmacol. Biochem. Behav., 2013 Dec;114-115:58-63.
    PMID: 24201054 DOI: 10.1016/j.pbb.2013.10.019
    The present study investigated the analgesic effect of a novel synthetic cyclohexanone derivative, 2,6-bis-4-(hydroxyl-3-methoxybenzilidine)-cyclohexanone or BHMC in a mouse model of chronic constriction injury-induced neuropathic pain. It was demonstrated that intraperitoneal administration of BHMC (0.03, 0.1, 0.3 and 1.0mg/kg) exhibited dose-dependent inhibition of chronic constriction injury-induced neuropathic pain in mice, when evaluated using Randall-Selitto mechanical analgesiometer. It was also demonstrated that pretreatment of naloxone (non-selective opioid receptor blocker), nor-binaltorphimine (nor-BNI, selective κ-opioid receptor blocker), but not β-funaltrexamine (β-FN, selective μ-opioid receptor blocker) and naltrindole hydrochloride (NTI, selective δ-opioid receptor blocker), reversed the anti-nociceptive effect of BHMC. In addition, the analgesic effect of BHMC was also reverted by pretreatment of 1H-[1,2,4]Oxadiazole[4,3-a]quinoxalin-1-one (ODQ, soluble guanosyl cyclase blocker) and glibenclamide (ATP-sensitive potassium channel blocker) but not Nω-nitro-l-arginine (l-NAME, a nitric oxide synthase blocker). Taken together, the present study demonstrated that the systemic administration of BHMC attenuated chronic constriction, injury-induced neuropathic pain. We also suggested that the possible mechanisms include κ-opioid receptor activation and nitric oxide-independent cyclic guanosine monophosphate activation of ATP-sensitive potassium channel opening.
    Matched MeSH terms: Signal Transduction
  7. In silico identification and characterization of a putative phosphatidylinositol 4-phosphate 5-kinase (PIP5K) gene in Eimeria tenella
    Ling KH, Loo SS, Rosli R, Shamsudin MN, Mohamed R, Wan KL
    In Silico Biol. (Gedrukt), 2007;7(1):115-21.
    PMID: 17688436
    Phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) play diverse roles in the cellular biology of many organisms, including signal transduction, secretion and vesicular trafficking, and regulation of cytoskeleton assembly. Discovery of the PIP5K gene in Eimeria tenella may shed light on its role in the biology of this avian protozoan, and afford further understanding of the cell-host interaction, particularly during the invasion process. In this study, we report the identification of the PIP5K coding region in the genome sequence of Eimeria tenella using in silico gene prediction approaches. Prediction of the PIP5K coding sequence was confirmed by mapping the full-length cDNA sequence, generated via the Rapid Amplification of cDNA Ends (RACE) method, to the genomic sequence. The putative PIP5K gene of Eimeria tenella is located on the complementary strand of the E1080B12.b1 contig, and comprises 12 exons. Further analysis showed that the coding region spans from exon 1 to exon 7, with all exons obeying the adopted 'gt...ag' splicing rule of intronic sequences. Consensus of the hexameric 5' donor-splice site was deduced as GTRDBB... and the consensus for the 3' acceptor-splice sites as ...BHDYAG. The gene encodes a 252-amino acid residue protein. Domain search and protein fold recognition analyses provide compelling evidences that the deduced protein is a PIP5K.
    Matched MeSH terms: Signal Transduction
  8. Fulltext Bixa orellana leaf extract suppresses histamine-induced endothelial hyperpermeability via the PLC-NO-cGMP signaling cascade
    Yong YK, Chiong HS, Somchit MN, Ahmad Z
    BMC Complement Altern Med, 2015;15:356.
    PMID: 26468073 DOI: 10.1186/s12906-015-0901-3
    Histamine is established as a potent inflammatory mediator and it is known to increased endothelial permeability by promoting gap formation between endothelial cells. Previous studies have shown that aqueous extract of Bixa orellana leaves (AEBO) exhibits antihistamine activity in vivo, yet the mechanism of its action on endothelial barrier function remains unclear. Therefore, the current study aimed to determine the protective effect of AEBO against histamine-induced hyperpermeability in vitro.
    Matched MeSH terms: Signal Transduction
  9. Fulltext Identification of four functionally important microRNA families with contrasting differential expression profiles between drought-tolerant and susceptible rice leaf at vegetative stage
    Cheah BH, Nadarajah K, Divate MD, Wickneswari R
    BMC Genomics, 2015;16:692.
    PMID: 26369665 DOI: 10.1186/s12864-015-1851-3
    Developing drought-tolerant rice varieties with higher yield under water stressed conditions provides a viable solution to serious yield-reduction impact of drought. Understanding the molecular regulation of this polygenic trait is crucial for the eventual success of rice molecular breeding programmes. microRNAs have received tremendous attention recently due to its importance in negative regulation. In plants, apart from regulating developmental and physiological processes, microRNAs have also been associated with different biotic and abiotic stresses. Hence here we chose to analyze the differential expression profiles of microRNAs in three drought treated rice varieties: Vandana (drought-tolerant), Aday Sel (drought-tolerant) and IR64 (drought-susceptible) in greenhouse conditions via high-throughput sequencing.
    Matched MeSH terms: Signal Transduction
  10. Immunomodulatory Effect of Cytokines in the Differentiation of Mesenchymal Stem Cells: A Review
    Zahari W, Hashim SN, Yusof MF, Osman ZF, Kannan TP, Mokhtar KI, et al.
    Curr Stem Cell Res Ther, 2017;12(3):197-206.
    PMID: 27306400 DOI: 10.2174/1574888X11666160614103404
    Mesenchymal stem cells (MSCs) are stromal origin cells with multilineage differentiation capacity. The immunoregulatory properties of MSCs can be interfered effectively by cytokines. Cytokines, produced by a broad range of cells, act at the systemic level to influence biological phenomena such as inflammation, wound healing, organogenesis and oncogenesis. Cytokines also play vital roles in the differentiation of MSCs into several cell lineages. This review summarizes on how cytokines can affect MSCs differentiation and their relative signaling pathways, which may serve to understand the possible underlying mechanisms. Also, this review reveals the potential clinical use of MSCs as promising therapeutic agents due to their special characteristics such as multipotent differentiation, immunomodulatory properties, and selfrestoration.
    Matched MeSH terms: Signal Transduction
  11. Fulltext Integrated pathway analysis of nasopharyngeal carcinoma implicates the axonemal dynein complex in the Malaysian cohort
    Chin YM, Tan LP, Abdul Aziz N, Mushiroda T, Kubo M, Mohd Kornain NK, et al.
    Int J Cancer, 2016 10 15;139(8):1731-9.
    PMID: 27236004 DOI: 10.1002/ijc.30207
    Nasopharyngeal carcinoma (NPC) is an epithelial squamous cell carcinoma on the mucosal lining of the nasopharynx. The etiology of NPC remains elusive despite many reported studies. Most studies employ a single platform approach, neglecting the cumulative influence of both the genome and transcriptome toward NPC development. We aim to employ an integrated pathway approach to identify dysregulated pathways linked to NPC. Our approach combines imputation NPC GWAS data from a Malaysian cohort as well as published expression data GSE12452 from both NPC and non-NPC nasopharynx tissues. Pathway association for GWAS data was performed using MAGENTA while for expression data, GSA-SNP was used with gene p values derived from differential expression values from GEO2R. Our study identified NPC association in the gene ontology (GO) axonemal dynein complex pathway (pGWAS-GSEA  = 1.98 × 10(-2) ; pExpr-GSEA  = 1.27 × 10(-24) ; pBonf-Combined  = 4.15 × 10(-21) ). This association was replicated in a separate cohort using gene expression data from NPC and non-NPC nasopharynx tissues (pAmpliSeq-GSEA  = 6.56 × 10(-4) ). Loss of function in the axonemal dynein complex causes impaired cilia function, leading to poor mucociliary clearance and subsequently upper or lower respiratory tract infection, the former of which includes the nasopharynx. Our approach illustrates the potential use of integrated pathway analysis in detecting gene sets involved in the development of NPC in the Malaysian cohort.
    Matched MeSH terms: Signal Transduction
  12. Fulltext Modulation of Hydrogen Peroxide-Induced Oxidative Stress in Human Neuronal Cells by Thymoquinone-Rich Fraction and Thymoquinone via Transcriptomic Regulation of Antioxidant and Apoptotic Signaling Genes
    Ismail N, Ismail M, Azmi NH, Abu Bakar MF, Basri H, Abdullah MA
    Oxid Med Cell Longev, 2016;2016:2528935.
    PMID: 26823946 DOI: 10.1155/2016/2528935
    Nigella sativa Linn. (N. sativa) and its bioactive constituent Thymoquinone (TQ) have demonstrated numerous pharmacological attributes. In the present study, the neuroprotective properties of Thymoquinone-rich fraction (TQRF) and TQ against hydrogen peroxide- (H2O2-) induced neurotoxicity in differentiated human SH-SY5Y cells were investigated. TQRF was extracted using supercritical fluid extraction while TQ was acquired commercially, and their effects on H2O2 were evaluated using cell viability assay, reactive oxygen species (ROS) assay, morphological observation, and multiplex gene expression. Both TQRF and TQ protected the cells against H2O2 by preserving the mitochondrial metabolic enzymes, reducing intracellular ROS levels, preserving morphological architecture, and modulating the expression of genes related to antioxidants (SOD1, SOD2, and catalase) and signaling genes (p53, AKT1, ERK1/2, p38 MAPK, JNK, and NF-κβ). In conclusion, the enhanced efficacy of TQRF over TQ was likely due to the synergism of multiple constituents in TQRF. The efficacy of TQRF was better than that of TQ alone when equal concentrations of TQ in TQRF were compared. In addition, TQRF also showed comparable effects to TQ when the same concentrations were tested. These findings provide further support for the use of TQRF as an alternative to combat oxidative stress insults in neurodegenerative diseases.
    Matched MeSH terms: Signal Transduction
  13. Fulltext Association of Whole-Genome and NETRIN1 Signaling Pathway-Derived Polygenic Risk Scores for Major Depressive Disorder and White Matter Microstructure in the UK Biobank
    Barbu MC, Zeng Y, Shen X, Cox SR, Clarke TK, Gibson J, et al.
    Biol Psychiatry Cogn Neurosci Neuroimaging, 2019 01;4(1):91-100.
    PMID: 30197049 DOI: 10.1016/j.bpsc.2018.07.006
    BACKGROUND: Major depressive disorder is a clinically heterogeneous psychiatric disorder with a polygenic architecture. Genome-wide association studies have identified a number of risk-associated variants across the genome and have reported growing evidence of NETRIN1 pathway involvement. Stratifying disease risk by genetic variation within the NETRIN1 pathway may provide important routes for identification of disease mechanisms by focusing on a specific process, excluding heterogeneous risk-associated variation in other pathways. Here, we sought to investigate whether major depressive disorder polygenic risk scores derived from the NETRIN1 signaling pathway (NETRIN1-PRSs) and the whole genome, excluding NETRIN1 pathway genes (genomic-PRSs), were associated with white matter microstructure.

    METHODS: We used two diffusion tensor imaging measures, fractional anisotropy (FA) and mean diffusivity (MD), in the most up-to-date UK Biobank neuroimaging data release (FA: n = 6401; MD: n = 6390).

    RESULTS: We found significantly lower FA in the superior longitudinal fasciculus (β = -.035, pcorrected = .029) and significantly higher MD in a global measure of thalamic radiations (β = .029, pcorrected = .021), as well as higher MD in the superior (β = .034, pcorrected = .039) and inferior (β = .029, pcorrected = .043) longitudinal fasciculus and in the anterior (β = .025, pcorrected = .046) and superior (β = .027, pcorrected = .043) thalamic radiation associated with NETRIN1-PRS. Genomic-PRS was also associated with lower FA and higher MD in several tracts.

    CONCLUSIONS: Our findings indicate that variation in the NETRIN1 signaling pathway may confer risk for major depressive disorder through effects on a number of white matter tracts.

    Matched MeSH terms: Signal Transduction
  14. Fulltext Thymoquinone regulates gene expression levels in the estrogen metabolic and interferon pathways in MCF7 breast cancer cells
    Motaghed M, Al-Hassan FM, Hamid SS
    Int J Mol Med, 2014 Jan;33(1):8-16.
    PMID: 24270600 DOI: 10.3892/ijmm.2013.1563
    New drugs are continuously being developed for the treatment of patients with estrogen receptor-positive breast cancer. Thymoquinone is one of the drugs that exhibits anticancer characteristics based on in vivo and in vitro models. This study further investigates the effects of thymoquinone on human gene expression using cDNA microarray technology. The quantification of RNA samples was carried out using an Agilent 2100 Bioanalyser to determine the RNA integrity number (RIN). The Agilent Low Input Quick Amplification Labelling kit was used to generate cRNA in two-color microarray analysis. Samples with RIN >9.0 were used in this study. The universal human reference RNA was used as the common reference. The samples were labelled with cyanine-3 (cye-3) CTP dye and the universal human reference was labelled with cyanine-5 (cye-5) CTP dye. cRNA was purified with the RNeasy Plus Mini kit and quantified using a NanoDrop 2000c spectrophotometer. The arrays were scanned data analysed using Feature Extraction and GeneSpring software. Two-step qRT-PCR was selected to determine the relative gene expression using the High Capacity RNA-to-cDNA kit. The results from Gene Ontology (GO) analysis, indicated that 8 GO terms were related to biological processes (84%) and molecular functions (16%). A total of 577 entities showed >2-fold change in expression. Of these entities, 45.2% showed an upregulation and 54.7% showed a downregulation in expression. The interpretation of single experiment analysis (SEA) revealed that the cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and UDP glucuronosyltransferase 1 family, polypeptide A8 (UGT1A8) genes in the estrogen metabolic pathway were downregulated significantly by 43- and 11‑fold, respectively. The solute carrier family 7 (anionic amino acid transporter light chain, xc-system), member 11 (SLC7A11) gene in the interferon pathway, reported to be involved in the development of chemoresistance, was downregulated by 15‑fold. The interferon-induced protein with tetratricopeptide repeats (IFIT)1, IFIT2, IFIT3, interferon, α-inducible protein (IFI)6 (also known as G1P3), interferon regulatory factor 9 (IRF9, ISGF3), 2'-5'-oligoadenylate synthetase 1, 40/46 kDa (OAS1) and signal transducer and activator of transcription 1 (STAT1) genes all showed changes in expression following treatment with thymoquinone. The caspase 10, apoptosis-related cysteine peptidase (CASP10) gene was activated and the protein tyrosine phosphatase, receptor type, R (PTPRR) and myocyte enhancer factor 2C (MEF2C) genes were upregulated in the classical MAPK and p38 MAPK pathways. These findings indicate that thymquinone targets specific genes in the estrogen metabolic and interferon pathways.
    Matched MeSH terms: Signal Transduction
  15. Fulltext MDA5 against enteric viruses through induction of interferon-like response partially via the JAK-STAT cascade
    Li Y, Yu P, Qu C, Li P, Li Y, Ma Z, et al.
    Antiviral Res, 2020 04;176:104743.
    PMID: 32057771 DOI: 10.1016/j.antiviral.2020.104743
    Enteric viruses including hepatitis E virus (HEV), human norovirus (HuNV), and rotavirus are causing global health issues. The host interferon (IFN) response constitutes the first-line defense against viral infections. Melanoma Differentiation-Associated protein 5 (MDA5) is an important cytoplasmic receptor sensing viral infection to trigger IFN production, and on the other hand it is also an IFN-stimulated gene (ISG). In this study, we investigated the effects and mode-of-action of MDA5 on the infection of enteric viruses. We found that MDA5 potently inhibited HEV, HuNV and rotavirus replication in multiple cell models. Overexpression of MDA5 induced transcription of important antiviral ISGs through IFN-like response, without triggering of functional IFN production. Interestingly, MDA5 activates the expression and phosphorylation of STAT1, which is a central component of the JAK-STAT cascade and a hallmark of antiviral IFN response. However, genetic silencing of STAT1 or pharmacological inhibition of the JAK-STAT cascade only partially attenuated the induction of ISG transcription and the antiviral function of MDA5. Thus, we have demonstrated that MDA5 effectively inhibits HEV, HuNV and rotavirus replication through provoking a non-canonical IFN-like response, which is partially dependent on JAK-STAT cascade.
    Matched MeSH terms: Signal Transduction
  16. Translational genomics and recent advances in oral squamous cell carcinoma
    Chai AWY, Lim KP, Cheong SC
    Semin Cancer Biol, 2020 04;61:71-83.
    PMID: 31542510 DOI: 10.1016/j.semcancer.2019.09.011
    Oral squamous cell carcinomas (OSCC) are a heterogeneous group of cancers arising from the mucosal lining of the oral cavity. A majority of these cancers are associated with lifestyle risk habits including smoking, excessive alcohol consumption and betel quid chewing. Cetuximab, targeting the epidermal growth factor receptor was approved for the treatment of OSCC in 2006, and remains the only molecular targeted therapy available for OSCC. Here, we reviewed the current findings from genomic analyses of OSCC and discuss how these studies inform on the biological mechanisms underlying OSCC. Exome sequencing revealed that the significantly mutated genes are mainly tumour suppressors. Mutations in FAT1, CASP8, CDKN2A, and NOTCH1 are more frequently found in OSCC when compared to non-OSCC head and neck cancers and other squamous cell carcinomas, and HRAS and PIK3CA are the only significantly mutated oncogenes. The distribution of these mutations also differs in populations with distinct risk habits. Gene expression-based molecular classification showed that OSCC can be divided into distinct subtypes and these have a preferential response to different types of therapies, suggesting that these classifications could have clinical implications. More recently, with the approval of checkpoint inhibitors for the treatment of cancers including OSCC, genomics studies also dissected the genetic signatures of the immune compartment to delineate immune-active and -exhausted subtypes that could inform on the immune status of OSCC patients and guide the development of novel therapies to improve response to immunotherapy. Taken together, genomics studies are informing on the biology of both the epithelial and stromal compartments underlying OSCC development, and we discuss the opportunities and challenges in using these to derive clinical benefit for OSCC patients.
    Matched MeSH terms: Signal Transduction
  17. Fulltext AP1S3 Mutations Cause Skin Autoinflammation by Disrupting Keratinocyte Autophagy and Up-Regulating IL-36 Production
    Mahil SK, Twelves S, Farkas K, Setta-Kaffetzi N, Burden AD, Gach JE, et al.
    J Invest Dermatol, 2016 11;136(11):2251-2259.
    PMID: 27388993 DOI: 10.1016/j.jid.2016.06.618
    Prominent skin involvement is a defining characteristic of autoinflammatory disorders caused by abnormal IL-1 signaling. However, the pathways and cell types that drive cutaneous autoinflammatory features remain poorly understood. We sought to address this issue by investigating the pathogenesis of pustular psoriasis, a model of autoinflammatory disorders with predominant cutaneous manifestations. We specifically characterized the impact of mutations affecting AP1S3, a disease gene previously identified by our group and validated here in a newly ascertained patient resource. We first showed that AP1S3 expression is distinctively elevated in keratinocytes. Because AP1S3 encodes a protein implicated in autophagosome formation, we next investigated the effects of gene silencing on this pathway. We found that AP1S3 knockout disrupts keratinocyte autophagy, causing abnormal accumulation of p62, an adaptor protein mediating NF-κB activation. We showed that as a consequence, AP1S3-deficient cells up-regulate IL-1 signaling and overexpress IL-36α, a cytokine that is emerging as an important mediator of skin inflammation. These abnormal immune profiles were recapitulated by pharmacological inhibition of autophagy and verified in patient keratinocytes, where they were reversed by IL-36 blockade. These findings show that keratinocytes play a key role in skin autoinflammation and identify autophagy modulation of IL-36 signaling as a therapeutic target.
    Matched MeSH terms: Signal Transduction
  18. Fulltext Monoamine oxidase A is down-regulated in EBV-associated nasopharyngeal carcinoma
    Lee HM, Sia APE, Li L, Sathasivam HP, Chan MSA, Rajadurai P, et al.
    Sci Rep, 2020 04 09;10(1):6115.
    PMID: 32273550 DOI: 10.1038/s41598-020-63150-0
    Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we identify for the first time a role for monoamine oxidase A (MAOA) in NPC. MAOA is a mitochondrial enzyme that catalyzes oxidative deamination of neurotransmitters and dietary amines. Depending on the cancer type, MAOA can either have a tumour-promoting or tumour-suppressive role. We show that MAOA is down-regulated in primary NPC tissues and its down-regulation enhances the migration of NPC cells. In addition, we found that EBV infection can down-regulate MAOA expression in both pre-malignant and malignant nasopharyngeal epithelial (NPE) cells. We further demonstrate that MAOA is down-regulated as a result of IL-6/IL-6R/STAT3 signalling and epigenetic mechanisms, effects that might be attributed to EBV infection in NPE cells. Taken together, our data point to a central role for EBV in mediating the tumour suppressive effects of MAOA and that loss of MAOA could be an important step in the pathogenesis of NPC.
    Matched MeSH terms: Signal Transduction
  19. Fulltext The Role of Tocotrienol in Protecting Against Metabolic Diseases
    Pang KL, Chin KY
    Molecules, 2019 Mar 06;24(5).
    PMID: 30845769 DOI: 10.3390/molecules24050923
    Obesity is a major risk factor for diabetes, and these two metabolic conditions cause significant healthcare burden worldwide. Chronic inflammation and increased oxidative stress due to exposure of cells to excess nutrients in obesity may trigger insulin resistance and pancreatic β-cell dysfunction. Tocotrienol, as a functional food component with anti-inflammatory, antioxidant, and cell signaling-mediating effects, may be a potential agent to complement the current management of obesity and diabetes. The review aimed to summarize the current evidence on the anti-obesity and antidiabetic effects of tocotrienol. Previous studies showed that tocotrienol could suppress adipogenesis and, subsequently, reduce body weight and fat mass in animals. This was achieved by regulating pathways of lipid metabolism and fatty acid biosynthesis. It could also reduce the expression of transcription factors regulating adipogenesis and increase apoptosis of adipocytes. In diabetic models, tocotrienol was shown to improve glucose homeostasis. Activation of peroxisome proliferator-activated receptors was suggested to be responsible for these effects. Tocotrienol also prevented multiple systemic complications due to obesity and diabetes in animal models through suppression of inflammation and oxidative stress. Several clinical trials have been conducted to validate the antidiabetic of tocotrienol, but the results were heterogeneous. There is no evidence showing the anti-obesity effects of tocotrienol in humans. Considering the limitations of the current studies, tocotrienol has the potential to be a functional food component to aid in the management of patients with obesity and diabetes.
    Matched MeSH terms: Signal Transduction
  20. Differential Analysis of Mycelial Proteins and Metabolites From Rigidoporus Microporus During In Vitro Interaction With Hevea Brasiliensis
    Fisol AFBC, Saidi NB, Al-Obaidi JR, Lamasudin DU, Atan S, Razali N, et al.
    Microb Ecol, 2021 Apr 22.
    PMID: 33890145 DOI: 10.1007/s00248-021-01757-0
    Rigidoporus microporus is the fungus accountable for the white root rot disease that is detrimental to the rubber tree, Hevea brasiliensis. The pathogenicity mechanism of R. microporus and the identity of the fungal proteins and metabolites involved during the infection process remain unclear. In this study, the protein and metabolite profiles of two R. microporus isolates, Segamat (SEG) and Ayer Molek (AM), were investigated during an in vitro interaction with H. brasiliensis. The isolates were used to inoculate H. brasiliensis clone RRIM 2025, and mycelia adhering to the roots of the plant were collected for analysis. Transmission electron microscope (TEM) images acquired confirms the hyphae attachment and colonization of the mycelia on the root of the H. brasiliensis clones after 4 days of inoculation. The protein samples were subjected to 2-DE analysis and analyzed using MALDI-ToF MS/MS, while the metabolites were extracted using methanol and analyzed using LC/MS-QTOF. Based on the differential analyses, upregulation of proteins that are essential for fungal evolution such as malate dehydrogenase, fructose 1,6-biphosphate aldolase, and glyceraldehyde-3-phosphate dehydrogenase hints an indirect role in fungal pathogenicity, while metabolomic analysis suggests an increase in acidic compounds which may lead to increased cell wall degrading enzyme activity. Bioinformatics analyses revealed that the carbohydrate and amino acid metabolisms were prominently affected in response to the fungal pathogenicity. In addition to that, other pathways that were significantly affected include "Protein Ubiquitination Pathway," Unfolded Protein Response," "HIFα Signaling," and "Sirtuin Signaling Pathway." The identification of responsive proteins and metabolites from this study promotes a better understanding of mechanisms underlying R. microporus pathogenesis and provides a list of potential biological markers for early recognition of the white root rot disease.
    Matched MeSH terms: Signal Transduction
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