Displaying publications 281 - 300 of 701 in total

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  1. In vitro and in vivo anti-colon cancer effects of Garcinia mangostana xanthones extract
    Aisha AF, Abu-Salah KM, Ismail Z, Majid AM
    BMC Complement Altern Med, 2012;12:104.
    PMID: 22818000
    BACKGROUND: Xanthones are a group of oxygen-containing heterocyclic compounds with remarkable pharmacological effects such as anti-cancer, antioxidant, anti-inflammatory, and antimicrobial activities.
    METHODS: A xanthones extract (81% α-mangostin and 16% γ-mangostin), was prepared by crystallization of a toluene extract of G. mangostana fruit rinds and was analyzed by LC-MS. Anti-colon cancer effect was investigated on HCT 116 human colorectal carcinoma cells including cytotoxicity, apoptosis, anti-tumorigenicity, and effect on cell signalling pathways. The in vivo anti-colon cancer activity was also investigated on subcutaneous tumors established in nude mice.
    RESULTS: The extract showed potent cytotoxicity (median inhibitory concentration 6.5 ± 1.0 μg/ml), due to induction of the mitochondrial pathway of apoptosis. Three key steps in tumor metastasis including the cell migration, cell invasion and clonogenicity, were also inhibited. The extract and α-mangostin up-regulate the MAPK/ERK, c-Myc/Max, and p53 cell signalling pathways. The xanthones extract, when fed to nude mice, caused significant growth inhibition of the subcutaneous tumor of HCT 116 colorectal carcinoma cells.
    CONCLUSIONS: Our data suggest new mechanisms of action of α-mangostin and the G. mangostana xanthones, and suggest the xanthones extract of as a potential anti-colon cancer candidate.
    Matched MeSH terms: Signal Transduction/drug effects
  2. Microarray profiling of secretory-phase endometrium from patients with recurrent miscarriage
    Othman R, Omar MH, Shan LP, Shafiee MN, Jamal R, Mokhtar NM
    Reprod Biol, 2012 Jul;12(2):183-99.
    PMID: 22850470
    The aim of the present study was to identify differentially expressed genes and their related biological pathways in the secretory phase endometrium from patients with recurrent miscarriage (RM) and fertile subjects. Endometrial samples from RM and fertile patients were analyzed using the Affymetrix GeneChip® ST Array. The bioinformatic analysis using the Partek Genomic Suite revealed 346 genes (175 up-regulated and 171 down-regulated) that were differentially expressed in the endometrium of RM patients compared to the fertile subjects (fold change ≥1.5, p<0.005). Validation step using quantitative real-time polymerase chain reaction (qPCR) confirmed a similar expression pattern of four exemplary genes: one up-regulated gene (fibroblast growth factor 9, FGF9) and three down-regulated genes: integrin β3 (ITGB3), colony stimulating factor 1 (CSF1) and matrix-metalloproteinases 19 (MMP19). The Gene Set Enrichment Analysis (GSEA) and the Pathway Studio software have found 101 signaling pathways (p<0.05) associated with the affected genes including the FGFR3 /signal transducer and activator of transcription (STAT) pathway and the CSF1R/STAT pathway. Cell adhesion, cell differentiation and angiogenesis were among biological processes indicated by this system. In conclusion, microarray technique is a useful tool to study gene expression in the secretory phase-endometrium of RM patients. The differences in endometrial gene expressions between healthy and RM subjects contribute to an increase in our knowledge on molecular mechanisms of RM development and may improve the outcome of pregnancies in high-risk women with RM.
    Matched MeSH terms: Signal Transduction/genetics*
  3. Fulltext Tamarindus indica extract alters release of alpha enolase, apolipoprotein A-I, transthyretin and Rab GDP dissociation inhibitor beta from HepG2 cells
    Chong UR, Abdul-Rahman PS, Abdul-Aziz A, Hashim OH, Junit SM
    PLoS One, 2012;7(6):e39476.
    PMID: 22724021 DOI: 10.1371/journal.pone.0039476
    The plasma cholesterol and triacylglycerol lowering effects of Tamarindus indica extract have been previously described. We have also shown that the methanol extract of T. indica fruit pulp altered the expression of lipid-associated genes including ABCG5 and APOAI in HepG2 cells. In the present study, effects of the same extract on the release of proteins from the cells were investigated using the proteomics approach.
    Matched MeSH terms: Signal Transduction/drug effects
  4. Fulltext alpha-Mangostin enhances betulinic acid cytotoxicity and inhibits cisplatin cytotoxicity on HCT 116 colorectal carcinoma cells
    Aisha AF, Abu-Salah KM, Ismail Z, Majid AM
    Molecules, 2012;17(3):2939-54.
    PMID: 22402764 DOI: 10.3390/molecules17032939
    Despite the progress in colon cancer treatment, relapse is still a major obstacle. Hence, new drugs or drug combinations are required in the battle against colon cancer. α-Mangostin and betulinic acid (BA) are cytotoxic compounds that work by inducing the mitochondrial apoptosis pathway, and cisplatin is one of the most potent broad spectrum anti-tumor agents. This study aims to investigate the enhancement of BA cytotoxicity by α-mangostin, and the cytoprotection effect of α-mangostin and BA on cisplatin-induced cytotoxicity on HCT 116 human colorectal carcinoma cells. Cytotoxicity was investigated by the XTT cell proliferation test, and the apoptotic effects were investigated on early and late markers including caspases-3/7, mitochondrial membrane potential, cytoplasmic shrinkage, and chromatin condensation. The effect of α-mangostin on four signalling pathways was also investigated by the luciferase assay. α-Mangostin and BA were more cytotoxic to the colon cancer cells than to the normal colonic cells, and both compounds showed a cytoprotective effect against cisplatin-induced cytotoxicity. On the other hand, α-mangostin enhanced the cytotoxic and apoptotic effects of BA. Combination therapy hits multiple targets, which may improve the overall response to the treatment, and may reduce the likelihood of developing drug resistance by the tumor cells. Therefore, α-mangostin and BA may provide a novel combination for the treatment of colorectal carcinoma. The cytoprotective effect of the compounds against cisplatin-induced cytotoxicity may find applications as chemopreventive agents against carcinogens, irradiation and oxidative stress, or to neutralize cisplatin side effects.
    Matched MeSH terms: Signal Transduction/drug effects
  5. Is vitamin E toxic to neuron cells?
    Then SM, Mazlan M, Mat Top G, Wan Ngah WZ
    Cell Mol Neurobiol, 2009 Jun;29(4):485-96.
    PMID: 19172392 DOI: 10.1007/s10571-008-9340-8
    Besides acting as potent free radical scavengers, tocopherols and tocotrienols have been known to have non-antioxidant properties such as the involvement of alpha-tocopherol (alphaT) in PKC pathway and the anti-cancer properties of gamma-tocotrienol (gammaT3). This study aims to elucidate whether protective effects shown by alphaT and gammaT3 in H(2)O(2)-induced neuron cultures have anti-apoptotic or pro-apoptotic tendency toward the initiation of neuronal apoptosis. H(2)O(2) is used to induce apoptosis in primary cerebellar neuron cultures which is attenuated by pretreatment of alphaT or gammaT3 at concentrations < or =10 microM. Similar to our previous work, gammaT3 was found to be neurotoxic at concentrations > or =100 microM, whereas alphaT showed no neurotoxicity. Cellular uptake of gammaT3 was higher than that of alphaT. Treating cells simultaneously with either gammaT3 or alphaT and with then H(2)O(2) led to higher expression of Bax and Bcl-2 than in neurons exposed to H(2)O(2) alone. Analysis of Bcl-2/Bax ratio as 'survival index' showed that both pretreatment of gammaT3 and alphaT followed by H(2)O(2) increase the 'survival index' of Bcl-2/Bax ratio compared to H(2)O(2)-treated cells, while treatment of gammaT3 alone decrease the ratio compared to unchanged Bcl2/Bax ratio of similar treatment with alphaT alone. Similar treatment of gammaT3 decreased p53 expression and activates p38 MAPK phosphorylation, whereas alphaT did not alter its expression compared to H(2)O(2)-treated cells. Treating neurons with only gammaT3 or alphaT increased the expression of Bax, Bcl-2, p53, and p38 MAPK compared to control with gammaT3 exerting stronger expression for proteins involved than alphaT. In conclusion, low doses of gammaT3 and alphaT confer neuroprotection to H(2)O(2)-treated neurons via their antioxidant mechanism but gammaT3 has stronger pro-apoptosis tendency than alphaT by activating molecules involved in the neuronal apoptotic pathway in the absence of H(2)O(2).
    Matched MeSH terms: Signal Transduction/physiology
  6. Gene expression profiling of p53(+/-) knockout and wild-type mice following diethylstilbestrol administration
    Salleh MN, Ismail P, Abdullah AS, Taufiq-Yap YH, Carmichael P
    IUBMB Life, 2004 Jul;56(7):409-16.
    PMID: 15545218
    Studies with clastogenic carcinogen diethylstilbestrol (DES) resulted in a broad of spectrum of toxic and carcinogenic effects in humans and rodents, but the cellular and molecular mechanism(s) by which it induces cancer is not clear. To identify putative genetic targets for p53 in vivo, we applied the cDNA macroarray gene expression profiles associated with apoptosis by comparing p53+/- knockout mice and wild-type mice on the kidney and uterus of female mice. p53+/- knockout mice and wild-type mice were treated with DES (500 micromole kg(-1)) or vehicle i.p once daily for 4 days. Total RNAs were obtained from kidney and uterus of both control and DES-treated. The signal intensities of individual gene spots on the membrane were quantified and normalized to the expression level of the GAPDH gene as an internal control. Our results demonstrated that 16 genes; bad, bax, bcl-2, bcl-w, bcl-x, caspase-3, caspase-7, caspase-8, c-myc, E124, GADD45, mdm2, NKkappab1, p53, p21, Rb and trail were up-regulated and six genes; caspase-1, caspase-2, DR5, E2F1, FasL and iNOS did not changed in response to DES treatment in wild-type mice compared to p53+/- knockout mice. Most genes are involved in cell cycle regulation, signal transduction, apoptosis, or transcription. The greatest changes were seen in bad, bcl-x, mdm2, p53 and p21 gene expression in wild-type mice compared to p53+/- knockout mice. In comparing p53 and p21 gene expression in wild-type mice and p53+/- knockout mice, there was an 4.4-fold vs. 1.8-fold; 8-fold vs. 5.2-fold for kidney and 16-fold vs. 5.5-fold; 2.1-fold vs. 8.3-fold for uterus samples increase in induction (respectively). RT-PCR and densitometric analysis was used to confirm the biggest changes of p21, p53 and bax genes. Using this approach, we have identified apoptosis associated genes regulated in response to DES and have revealed putative differences between the isogenic parent strain and p53+/- knockout mice, which will contribute to a better understanding of toxicity/carcinogenicity mechanisms in this model.
    Matched MeSH terms: Signal Transduction/genetics
  7. Fulltext Draft genome sequence of the rubber tree Hevea brasiliensis
    Rahman AY, Usharraj AO, Misra BB, Thottathil GP, Jayasekaran K, Feng Y, et al.
    BMC Genomics, 2013;14:75.
    PMID: 23375136 DOI: 10.1186/1471-2164-14-75
    Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876.
    Matched MeSH terms: Signal Transduction/genetics
  8. Fulltext Genome analysis of Daldinia eschscholtzii strains UM 1400 and UM 1020, wood-decaying fungi isolated from human hosts
    Chan CL, Yew SM, Ngeow YF, Na SL, Lee KW, Hoh CC, et al.
    BMC Genomics, 2015 Nov 18;16:966.
    PMID: 26581579 DOI: 10.1186/s12864-015-2200-2
    BACKGROUND: Daldinia eschscholtzii is a wood-inhabiting fungus that causes wood decay under certain conditions. It has a broad host range and produces a large repertoire of potentially bioactive compounds. However, there is no extensive genome analysis on this fungal species.

    RESULTS: Two fungal isolates (UM 1400 and UM 1020) from human specimens were identified as Daldinia eschscholtzii by morphological features and ITS-based phylogenetic analysis. Both genomes were similar in size with 10,822 predicted genes in UM 1400 (35.8 Mb) and 11,120 predicted genes in UM 1020 (35.5 Mb). A total of 751 gene families were shared among both UM isolates, including gene families associated with fungus-host interactions. In the CAZyme comparative analysis, both genomes were found to contain arrays of CAZyme related to plant cell wall degradation. Genes encoding secreted peptidases were found in the genomes, which encode for the peptidases involved in the degradation of structural proteins in plant cell wall. In addition, arrays of secondary metabolite backbone genes were identified in both genomes, indicating of their potential to produce bioactive secondary metabolites. Both genomes also contained an abundance of gene encoding signaling components, with three proposed MAPK cascades involved in cell wall integrity, osmoregulation, and mating/filamentation. Besides genomic evidence for degrading capability, both isolates also harbored an array of genes encoding stress response proteins that are potentially significant for adaptation to living in the hostile environments.

    CONCLUSIONS: Our genomic studies provide further information for the biological understanding of the D. eschscholtzii and suggest that these wood-decaying fungi are also equipped for adaptation to adverse environments in the human host.

    Matched MeSH terms: Signal Transduction/genetics
  9. Cancer prevention and therapy through the modulation of transcription factors by bioactive natural compounds
    Shanmugam MK, Lee JH, Chai EZ, Kanchi MM, Kar S, Arfuso F, et al.
    Semin Cancer Biol, 2016 10;40-41:35-47.
    PMID: 27038646 DOI: 10.1016/j.semcancer.2016.03.005
    The association between chronic inflammation and cancer development has been well documented. One of the major obstacles in cancer treatment is the persistent autocrine and paracrine activation of pro-inflammatory transcription factors such as nuclear factor-κB, signal transducer and activator of transcription 3, activator protein 1, fork head box protein M1, and hypoxia-inducible factor 1α in a wide variety of tumor cell lines and patient specimens. This, in turn, leads to an accelerated production of cellular adhesion molecules, inflammatory cytokines, chemokines, anti-apoptotic molecules, and inducible nitric oxide synthase. Numerous medicinal plant-derived compounds have made a tremendous impact in drug discovery research endeavors, and have been reported to modulate the activation of diverse oncogenic transcription factors in various tumor models. Moreover, novel therapeutic combinations of standard chemotherapeutic drugs with these agents have significantly improved patient survival by making cancer cells more susceptible to chemotherapy and radiotherapy. In this review, we critically analyze the existing literature on the modulation of diverse transcription factors by various natural compounds and provide views on new directions for accelerating the discovery of novel drug candidates derived from Mother Nature.
    Matched MeSH terms: Signal Transduction/drug effects
  10. Fulltext Geranylated 4-Phenylcoumarins Exhibit Anticancer Effects against Human Prostate Cancer Cells through Caspase-Independent Mechanism
    Suparji NS, Chan G, Sapili H, Arshad NM, In LL, Awang K, et al.
    PLoS One, 2016;11(3):e0151472.
    PMID: 26974436 DOI: 10.1371/journal.pone.0151472
    Geranylated 4-phenylcoumarins, DMDP-1 & -2 isolated from Mesua elegans were investigated for anticancer potential against human prostate cancer cells. Treatment with DMDP-1 & -2 resulted in cell death in a time and dose dependent manner in an MTT assay on all cancer cell lines tested with the exception of lung adenocarcinoma cells. DMDP-1 showed highest cytotoxic efficacy in PC-3 cells while DMDP-2 was most potent in DU 145 cells. Flow cytometry indicated that both coumarins were successful to induce programmed cell death after 24 h treatment. Elucidation on the mode-of-action via protein arrays and western blotting demonstrated death induced without any significant expressions of caspases, Bcl-2 family proteins and cleaved PARP, thus suggesting the involvement of caspase-independent pathways. In identifying autophagy, analysis of GFP-LC3 showed increased punctate in PC-3 cells pre-treated with CQ and treated with DMDP-1. In these cells decreased expression of autophagosome protein, p62 and cathepsin B further confirmed autophagy. In contrary, the DU 145 cells pre-treated with CQ and treated with DMDP-2 has reduced GFP-LC3 punctate although the number of cells with obvious GFP-LC3 puncta was significantly increased in the inhibitor-treated cells. The increase level of p62 suggested leakage of cathepsin B into the cytosol to trigger potential downstream death mediators. This correlated with increased expression of cathepsin B and reduced expression after treatment with its inhibitor, CA074. Also auto-degradation of calpain-2 upon treatment with DMDP-1 &-2 and its inhibitor alone, calpeptin compared with the combination treatment, further confirmed involvement of calpain-2 in PC-3 and DU 145 cells. Treatment with DMDP-1 & -2 also showed up-regulation of total and phosphorylated p53 levels in a time dependent manner. Hence, DMDP-1 & -2 showed ability to activate multiple death pathways involving autophagy, lysosomal and endoplasmic reticulum death proteins which could potentially be manipulated to develop anti-cancer therapy in apoptosis resistant cells.
    Matched MeSH terms: Signal Transduction/drug effects
  11. An in silico approach towards the identification of novel inhibitors of the TLR-4 signaling pathway
    Mahita J, Harini K, Rao Pichika M, Sowdhamini R
    J Biomol Struct Dyn, 2016 Jun;34(6):1345-62.
    PMID: 26264972 DOI: 10.1080/07391102.2015.1079243
    Precise functioning and fine-tuning of Toll-like receptor 4 (TLR4) signaling is a critical requirement for the smooth functioning of the innate immune system, since aberrant TLR4 activation causes excessive production of pro-inflammatory cytokines and interferons. This can result in life threatening conditions such as septic shock and other inflammatory disorders. The TRIF-related adaptor molecule (TRAM) adaptor protein is unique to the TLR4 signaling pathway and abrogation of TRAM-mediated TLR4 signaling is a promising strategy for developing therapeutics aimed at disrupting TRAM interactions with other components of the TLR4 signaling complex. The VIPER motif from the vaccinia virus-producing protein, A46 has been reported to disrupt TRAM-TLR4 interactions. We have exploited this information, in combination with homology modeling and docking approaches, to identify a potential binding site on TRAM lined by the BB loop and αC helix. Virtual screening of commercially available small molecules targeting the binding site enabled to short-list 12 small molecules to abrogate TRAM-mediated TLR4 signaling. Molecular dynamics and molecular mechanics calculations have been performed for the analysis of these receptor-ligand interactions.
    Matched MeSH terms: Signal Transduction/drug effects
  12. Fulltext Nutlin-3 sensitizes nasopharyngeal carcinoma cells to cisplatin-induced cytotoxicity
    Voon YL, Ahmad M, Wong PF, Husaini R, Ng WT, Leong CO, et al.
    Oncol Rep, 2015 Oct;34(4):1692-700.
    PMID: 26252575 DOI: 10.3892/or.2015.4177
    The small-molecule inhibitor of p53-Mdm2 interaction, Nutlin-3, is known to be effective against cancers expressing wild-type (wt) p53. p53 mutations are rare in nasopharyngeal carcinoma (NPC), hence targeting disruption of p53-Mdm2 interaction to reactivate p53 may offer a promising therapeutic strategy for NPC. In the present study, the effects of Nutlin-3 alone or in combination with cisplatin, a standard chemotherapeutic agent, were tested on C666-1 cells, an Epstein-Barr virus (EBV)-positive NPC cell line bearing wt p53. Treatment with Nutlin-3 activated the p53 pathway and sensitized NPC cells to the cytotoxic effects of cisplatin. The combined treatment also markedly suppressed soft agar colony growth formation and increased apoptosis of NPC cells. The effect of Nutlin-3 on NPC cells was inhibited by knockdown of p53, suggesting that its effect was p53-dependent. Extended treatment with increasing concentrations of Nutlin-3 did not result in emergence of p53 mutations in the C666-1 cells. Collectively, the present study revealed supportive evidence of the effectiveness of combining cisplatin and Nutlin-3 as a potential therapy against NPC.
    Matched MeSH terms: Signal Transduction/drug effects
  13. Fulltext A blood-based gene expression and signaling pathway analysis to differentiate between high and low grade gliomas
    Ponnampalam SN, Kamaluddin NR, Zakaria Z, Matheneswaran V, Ganesan D, Haspani MS, et al.
    Oncol Rep, 2017 Jan;37(1):10-22.
    PMID: 28004117 DOI: 10.3892/or.2016.5285
    The aims of the present study were to undertake gene expression profiling of the blood of glioma patients to determine key genetic components of signaling pathways and to develop a panel of genes that could be used as a potential blood-based biomarker to differentiate between high and low grade gliomas, non-gliomas and control samples. In this study, blood samples were obtained from glioma patients, non-glioma and control subjects. Ten samples each were obtained from patients with high and low grade tumours, respectively, ten samples from non-glioma patients and twenty samples from control subjects. Total RNA was isolated from each sample after which first and second strand synthesis was performed. The resulting cRNA was then hybridized with the Agilent Whole Human Genome (4x44K) microarray chip according to the manufacturer's instructions. Universal Human Reference RNA and samples were labeled with Cy3 CTP and Cy5 CTP, respectively. Microarray data were analyzed by the Agilent Gene Spring 12.1V software using stringent criteria which included at least a 2-fold difference in gene expression between samples. Statistical analysis was performed using the unpaired Student's t-test with a p<0.01. Pathway enrichment was also performed, with key genes selected for validation using droplet digital polymerase chain reaction (ddPCR). The gene expression profiling indicated that were a substantial number of genes that were differentially expressed with more than a 2-fold change (p<0.01) between each of the four different conditions. We selected key genes within significant pathways that were analyzed through pathway enrichment. These key genes included regulators of cell proliferation, transcription factors, cytokines and tumour suppressor genes. In the present study, we showed that key genes involved in significant and well established pathways, could possibly be used as a potential blood-based biomarker to differentiate between high and low grade gliomas, non-gliomas and control samples.
    Matched MeSH terms: Signal Transduction/genetics
  14. Identifying Potential Therapeutics for Osteoporosis by Exploiting the Relationship between Mevalonate Pathway and Bone Metabolism
    Hasan WNW, Chin KY, Jolly JJ, Ghafar NA, Soelaiman IN
    Endocr Metab Immune Disord Drug Targets, 2018;18(5):450-457.
    PMID: 29683099 DOI: 10.2174/1871530318666180423122409
    BACKGROUND: Osteoporosis is a silent skeletal disease characterized by low bone mass and destruction of skeletal microarchitecture, leading to an increased fracture risk. This occurs due to an imbalance in bone remodelling, whereby the rate of bone resorption is greater than bone formation. Mevalonate pathway, previously known to involve in cholesterol synthesis, is an important regulatory pathway for bone remodelling.

    OBJECTIVE: This review aimed to provide an overview of the relationship between mevalonate pathway and bone metabolism, as well as agents which act through this pathway to achieve their therapeutic potential.

    DISCUSSION: Mevalonate pathway produces farnesyl pyrophosphate and geranylgeranyl pyrophosphate essential in protein prenylation. An increase in protein prenylation favours bone resorption over bone formation. Non-nitrogen containing bisphosphonates inhibit farnesyl diphosphate synthase which produces farnesyl pyrophosphate. They are used as the first line therapy for osteoporosis. Statins, a well-known class of cholesterol-lowering agents, inhibit 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, the rate-determining enzyme in the mevalonate pathway. It was shown to increase bone mineral density and prevent fracture in humans. Tocotrienol is a group of vitamin E commonly found in palm oil, rice bran and annatto bean. It causes degradation of HMG-CoA reductase. Many studies demonstrated that tocotrienol prevented bone loss in animal studies but its efficacy has not been tested in humans.

    CONCLUSION: Mevalonate pathway can be exploited to develop effective antiosteoporosis agents.

    Matched MeSH terms: Signal Transduction/drug effects
  15. Fulltext Emerging pathways to neurodegeneration: Dissecting the critical molecular mechanisms in Alzheimer's disease, Parkinson's disease
    Tan SH, Karri V, Tay NWR, Chang KH, Ah HY, Ng PQ, et al.
    Biomed Pharmacother, 2019 Mar;111:765-777.
    PMID: 30612001 DOI: 10.1016/j.biopha.2018.12.101
    Neurodegenerative diseases are usually sporadic in nature and commonly influenced by a wide range of genetic, life style and environmental factors. A unifying feature of Alzheimer's disease (AD) and Parkinson's disease (PD) is the abnormal accumulation and processing of mutant or damaged intra and extracellular proteins; this leads to neuronal vulnerability and dysfunction in the brain. Through a detailed review of ubiquitin proteasome, mRNA splicing, mitochondrial dysfunction, and oxidative stress pathway interrelation on neurodegeneration can improve the understanding of the disease mechanism. The identified pathways common to AD and PD nominate promising new targets for further studies, and as well as biomarkers. These insights suggested would likely provide major stimuli for developing unified treatment approaches to combat neurodegeneration. More broadly, pathways can serve as vehicles for integrating findings from diverse studies of neurodegeneration. The evidence examined in this review provides a brief overview of the current literature on significant pathways in promoting in AD, PD. Additionally, these insights suggest that biomarkers and treatment strategies may require simultaneous targeting of multiple components.
    Matched MeSH terms: Signal Transduction/physiology*
  16. Potential Neuroprotective Effect of the HMGB1 Inhibitor Glycyrrhizin in Neurological Disorders
    Paudel YN, Angelopoulou E, Semple B, Piperi C, Othman I, Shaikh MF
    ACS Chem Neurosci, 2020 02 19;11(4):485-500.
    PMID: 31972087 DOI: 10.1021/acschemneuro.9b00640
    Glycyrrhizin (glycyrrhizic acid), a bioactive triterpenoid saponin constituent of Glycyrrhiza glabra, is a traditional medicine possessing a plethora of pharmacological anti-inflammatory, antioxidant, antimicrobial, and antiaging properties. It is a known pharmacological inhibitor of high mobility group box 1 (HMGB1), a ubiquitous protein with proinflammatory cytokine-like activity. HMGB1 has been implicated in an array of inflammatory diseases when released extracellularly, mainly by activating intracellular signaling upon binding to the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4). HMGB1 neutralization strategies have demonstrated disease-modifying outcomes in several preclinical models of neurological disorders. Herein, we reveal the potential neuroprotective effects of glycyrrhizin against several neurological disorders. Emerging findings demonstrate the therapeutic potential of glycyrrhizin against several HMGB1-mediated pathological conditions including traumatic brain injury, neuroinflammation and associated conditions, epileptic seizures, Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Glycyrrhizin's effects in neurological disorders are mainly attributed to the attenuation of neuronal damage by inhibiting HMGB1 expression and translocation as well as by downregulating the expression of inflammatory cytokines. A large number of preclinical findings supports the notion that glycyrrhizin might be a promising therapeutic alternative to overcome the shortcomings of the mainstream therapeutic strategies against neurological disorders, mainly by halting disease progression. However, future research is warranted for a deeper exploration of the precise underlying molecular mechanism as well as for clinical translation.
    Matched MeSH terms: Signal Transduction/drug effects
  17. Future target molecules in antiglaucoma therapy: tgf-Beta may have a role to play
    Agarwal R, Agarwal P
    Ophthalmic Res, 2010;43(1):1-10.
    PMID: 19829006 DOI: 10.1159/000246571
    Glaucoma, a leading cause of irreversible blindness, is often associated with increased resistance to aqueous outflow in trabecular tissue. Increased outflow resistance has been attributed to increased extracellular matrix (ECM) deposition in trabecular tissue. A critical balance between the synthesis and breakdown of the components of extracellular tissue is important in keeping the intraocular pressure within the normal range. Multiple mechanisms have been shown to affect ECM turnover in trabecular tissue. In this review, we examine the related literature to understand the role of TGF-beta in ECM turnover, in the development and progression of glaucoma, and in possible therapeutic strategies that can be devised by targeting the TGF-beta signaling pathways.
    Matched MeSH terms: Signal Transduction/drug effects
  18. Fulltext Chimeric Virus-Like Particles of Prawn Nodavirus Displaying Hepatitis B Virus Immunodominant Region: Biophysical Properties and Cytokine Response
    Ninyio NN, Ho KL, Yong CY, Chee HY, Hamid M, Ong HK, et al.
    Int J Mol Sci, 2021 Feb 15;22(4).
    PMID: 33672018 DOI: 10.3390/ijms22041922
    Hepatitis B is a major global health challenge. In the absence of an effective treatment for the disease, hepatitis B vaccines provide protection against the viral infection. However, some individuals do not have positive immune responses after being vaccinated with the hepatitis B vaccines available in the market. Thus, it is important to develop a more protective vaccine. Previously, we showed that hepatitis B virus (HBV) 'a' determinant (aD) displayed on the prawn nodavirus capsid (Nc) and expressed in Spodoptera frugiperda (Sf9) cells (namely, Nc-aD-Sf9) self-assembled into virus-like particles (VLPs). Immunisation of BALB/c mice with the Nc-aD-Sf9 VLPs showed significant induction of humoral, cellular and memory B-cell immunity. In the present study, the biophysical properties of the Nc-aD-Sf9 VLPs were studied using dynamic light scattering (DLS) and circular dichroism (CD) spectroscopy. Enzyme-linked immunosorbent assay (ELISA) was used to determine the antigenicity of the Nc-aD-Sf9 VLPs, and multiplex ELISA was employed to quantify the cytokine response induced by the VLPs administered intramuscularly into BALB/c mice (n = 8). CD spectroscopy of Nc-aD-Sf9 VLPs showed that the secondary structure of the VLPs predominantly consisted of beta (β)-sheets (44.8%), and they were thermally stable up to ~52 °C. ELISA revealed that the aD epitope of the VLPs was significantly antigenic to anti-HBV surface antigen (HBsAg) antibodies. In addition, multiplex ELISA of serum samples from the vaccinated mice showed a significant induction (p < 0.001) of IFN-γ, IL-4, IL-5, IL-6, IL-10, and IL-12p70. This cytokine profile is indicative of natural killer cell, macrophage, dendritic cell and cytotoxic T-lymphocyte activities, which suggests a prophylactic innate and adaptive cellular immune response mediated by Nc-aD-Sf9 VLPs. Interestingly, Nc-aD-Sf9 induced a more robust release of the aforementioned cytokines than that of Nc-aD VLPs produced in Escherichia coli and a commercially used hepatitis B vaccine. Overall, Nc-aD-Sf9 VLPs are thermally stable and significantly antigenic, demonstrating their potential as an HBV vaccine candidate.
    Matched MeSH terms: Signal Transduction/immunology*
  19. Regulation of G protein signaling by the 70kDa heat shock protein
    Lim WK, Kanelakis KC, Neubig RR
    Cell Signal, 2013 Feb;25(2):389-96.
    PMID: 23153586 DOI: 10.1016/j.cellsig.2012.11.002
    G protein-coupled receptors (GPCRs) transduce extracellular signals to the interior of the cell by activating membrane-bound guanine nucleotide-binding regulatory proteins (G proteins). An increasing number of proteins have been reported to bind to and regulate GPCRs. We report a novel regulation of the alpha(2A) adrenergic receptor (α(2A)-R) by the ubiquitous stress-inducible 70kDa heat shock protein, hsp70. Hsp70, but not hsp90, attenuated G protein-dependent high affinity agonist binding to the α(2A)-R in Sf9 membranes. Antagonist binding was unchanged, suggesting that hsp70 uncouples G proteins from the receptor. As hsp70 did not bind G proteins but complexed with the α(2A)-R in intact cells, a direct interaction with the receptor seems likely. In the presence of hsp70, α(2A)-R-catalyzed [(35)S]GTPγS binding was reduced by approximately 70%. In contrast, approximately 50-fold higher concentrations of hsp70 were required to reduce agonist binding to the stress-inducible 5-hydroxytryptamine(1A) receptor (5-HT(1A)-R). In heat-stressed CHO cells, the α(2A)-R was significantly uncoupled from G proteins, coincident with an increased localization of hsp70 at the membrane. The contrasting effect of hsp70 on the α(2A)-R compared to the 5-HT(1A)-R suggests that during stress, upregulation of hsp70 may attenuate signaling from specific GPCRs as part of the stress response to foster survival.
    Matched MeSH terms: Signal Transduction/drug effects*
  20. RAGE and TLRs: relatives, friends or neighbours?
    Ibrahim ZA, Armour CL, Phipps S, Sukkar MB
    Mol Immunol, 2013 Dec;56(4):739-44.
    PMID: 23954397 DOI: 10.1016/j.molimm.2013.07.008
    The innate immune system forms the first line of protection against infectious and non-infectious tissue injury. Cells of the innate immune system detect pathogen-associated molecular patterns or endogenous molecules released as a result of tissue injury or inflammation through various innate immune receptors, collectively termed pattern-recognition receptors. Members of the Toll-like receptor (TLR) family of pattern-recognition receptors have well established roles in the host immune response to infection, while the receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor predominantly involved in the recognition of endogenous molecules released in the context of infection, physiological stress or chronic inflammation. RAGE and TLRs share common ligands and signaling pathways, and accumulating evidence points towards their co-operative interaction in the host immune response. At present however, little is known about the mechanisms that result in TLR versus RAGE signalling or RAGE-TLR cross-talk in response to their shared ligands. Here we review what is known in relation to the physicochemical basis of ligand interactions between TLRs and RAGE, focusing on three shared ligands of these receptors: HMGB1, S100A8/A9 and LPS. Our aim is to discuss what is known about differential ligand interactions with RAGE and TLRs and to highlight important areas for further investigation so that we may better understand the role of these receptors and their relationship in host defense.
    Matched MeSH terms: Signal Transduction/immunology*
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