2015

Permanent URI for this collectionhttps://hdl.handle.net/1807/67552

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The SLC2A14 gene: genomic locus, tissue expression, splice variants, and subcellular localization of the protein
(Canadian Science Publishing, 2015-08-21) Amir Shaghaghi, Mandana; Murphy, Brent; Eck, Peter Karl
The SLC2A14 gene encodes for GLUT14, an orphan member of the facilitated membrane glucose transporter family, which was originally described to be exclusively expressed in human testis. However, genetic variations in SLC2A14 are associated to chronic diseases such as Alzheimerâ s disease and Inflammatory Bowel Disease, which cannot be explained by a strictly testicular expression. Therefore we analyzed available information on the SLC2A14 gene to update the knowledge on the locus and its encoded products. This report represents an expanded SLC2A14 gene locus and a more diverse tissue expression, concurring with existing evidence of disease associations. The exon utilization is tissue specific, with major expression in testis. When the two major testicular protein isoforms were expressed in mammalian cells, they located to the plasmalemma membrane, providing early evidence that GLUT14 could have a function as a membrane transporter.
The Quinone-Binding Site of Acidithiobacillus ferrooxidans Sulfide:Quinone Oxidoreductase Controls both Sulfide Oxidation and Quinone Reduction
(Canadian Science Publishing, 2015-11-27) Zhang, Yanfei; Qadri, Ali; Weiner, Joel
Sulfide:quinone oxidoreductase (SQR) is a peripheral membrane enzyme that catalyzes the oxidation of sulfide and the reduction of ubiquinone. Ubiquinone binds to a conserved hydrophobic domain and shuttles electrons from a non-covalent FAD cofactor to the membrane-bound quinone pool. Utilizing the structure of decylubiquinone bound to Acidithiobacillus ferrooxidans SQR, we combined site-directed mutagenesis and kinetic approaches to analyze quinone binding. SQR can reduce both benzoquinones and naphthoquinones. The alkyl side chain of ubiquinone derivatives enhances binding to SQR but limits the enzyme turnover. Pentachlorophenol and 2-n-heptyl-4-hydroxyquinoline-N-oxide are potent inhibitors of SQR with apparent inhibition constants (Ki) of 0.46 µM and 0.58 µM, respectively. The highly conserved amino acids surrounding the quinone binding site play an important role in quinone reduction. The phenyl sidechains of Phe357 and Phe391 sandwich the benzoquinone head group and are critical for quinone binding. Importantly, conserved amino acids that define the ubiquinone-binding site also play an important role in sulfide oxidation/flavin reduction.
Biocidal activity of chicken defensin-9 against microbial pathogens
(Canadian Science Publishing, 2015-11-27) Yacoub, Haitham A.; El-Hamidy, Salem M.; Mahmoud, Maged M.; Baeshen, Mohamed Nabih; Almehdar, Hussein A.; Uversky, Vladimir N.; Redwan, Elrashdy M.; Elazzazy , Ahmed M.
In this study we identified the expression patterns of β-defensin-9 in local chicken from Saudi Arabia, evaluated antimicrobial activities of the synthetic chicken β-defensin-9 (sAvBD-9) against pathogenic bacteria and fungi, and investigated the mode of sAvBD-9 action on the bacterial cells. The AvBD-9 gene of the local Saudi chicken encodes a polypeptide of 67 amino acids, which is highly similar to the duck, quail, and goose polypeptides (97%, 86%, and 87%, respectively) and shares a low sequence similarity with the mammalian defensins. AvBD-9 is expressed in various organs and tissues of the local chicken and is able to inhibit the growth of both Gram-negative and Gram-positive bacteria, as well as is active against unicellular and multicellular fungi, Aspergillus flavus, Aspergillus niger, and Candida albicans. The sAvBD-9 completely inhibited the growth of both Gram-positive and Gram-negative bacterial strains as well as Candida albicans. The haemolytic effects of sAvBD-9 were limited. The morphological analysis by TEM revealed that sAvBD-9 induces shortening and swelling of Staphylococcus aureus and Shigella sonni cells, opens holes and deep craters in their envelopes, and leads to the release of their cytoplasmic content. Our data shed light on the potential applications of sAvBD-9 in the pharmaceutical industry.
Mapping regions in Ste5 that support Msn5-dependent and -independent nuclear export
(Canadian Science Publishing, 2015-10-06) Hu, Zhenhua; Wang, Yunmei; Yu, Lu; Mahanty, Sanjoy K.; Mendoza, Natalia; Elion, Elaine A
Careful control of the available pool of the MAPK scaffold Ste5 is important for mating pathway activation and prevention of inappropriate mating differentiation in haploid S. cerevisiae. Ste5 shuttles constitutively through the nucleus where it is degraded by a ubiquitin-dependent mechanism triggered by G1 CDK phosphorylation. Here we narrow down regions of Ste5 that mediate nuclear export. Four regions in Ste5 relocalize SV40-TAgNLS-GFP-GFP from nucleus to cytoplasm. One region is N-terminal, dependent on exportin Msn5/Ste21/Kap142, and interacts with Msn5 in two hybrid assays independently of mating pheromone, Fus3, Kss1, Ptc1, the NLS/PM, and RING-H2. A second region overlaps the PH domain and Ste11 binding site and two others are on the vWA domain and include residues essential for MAPK activation. We find no evidence for dependence on Crm1/Xpo1 despite numerous potential nuclear export sequences (NESs) detected by LocNES and NETNES1.1 predictors. Thus, Msn5 (homolog of human Exportin-5) and one or more exportins or adapter molecules besides Crm1/Xpo1 may regulate Ste5 through multiple recognition sites.
Molecular modeling study on the drug resistance mechanism of NS5B polymerase to TMC647055
(Canadian Science Publishing, 2015-11-08) huiqun, wang; Wei, Cui; Chenchen, Guo; bo-zhen, Chen; mingjuan, ji
NS5B polymerase plays an important role in the viral replication machinery. TMC647055 is a novel and potent nonnucleoside inhibitor of the HCV NS5B polymerase. However, drug resistant mutations towards TMC647055 have been detected. In this study, we used Molecular dynamics (MD) simulations, binding free energy calculations and free energy decomposition to investigate the drug resistance mechanism of HCV to TMC647055 resulting from L392I and P495T/S/L in NS5B polymerase. From the calculated results we obtain that the decrease in the binding affinity between TMC647055 and NS5BL392I polymerase is mainly caused by the extra methyl group at the CB atom of Ile. The polarity of the side chain of residue 495 has no distinct influence on residue 495 binding with TMC. While the smaller size of the side chain of residue 495 makes the van der Walls interaction between TMC and residue 495 decrease greatly. And the longer length of the side chain of residue 495 has significant effect on the electrostatic interaction between TMC and Arg-503. Furthermore, we performed the same calculations and detailed analysis on other three mutations (L392V and P495V/I). The obtained results further confirm our conclusions. The computational results can not only disclose the drug resistance mechanism between TMC647055 and NS5B polymerase, but also provide valuable information for the rational design of more potent non-nucleoside inhibitors targeting HCV NS5B polymerase.
Transcript level of AKR1C3 is down-regulated in gastric cancer
(Canadian Science Publishing, 2015-12-08) Frycz, Bartosz Adam; Murawa, Dawid; Borejsza-Wysocki, Maciej; Wichtowski, Mateusz; Spychała, Arkadiusz; Marciniak, Ryszard; Murawa, Paweł; Drews, Michał; Jagodziński, Paweł Piotr
Steroid hormones are shown to play some role in gastric carcinogenesis. Large amounts of them are locally produced in peripheral tissues at both genders. Type 5 of 17β-hydroxysteroid dehydrogenase, encoded by AKR1C3 gene, plays a pivotal role in both androgen and estrogen metabolism and its deregulated expression was found in different cancers. In this study we measured AKR1C3 transcript and protein levels in nontumoral and primary tumoral gastric tissues and evaluated their association with some clinicopathological features of gastric cancer (GC). We found decreased AKR1C3 transcript (p
Environmental influences on the epigenomes of herpetofauna and fish
(Canadian Science Publishing, 2015-09-14) Hammond, S. Austin; Nelson, Christopher J; Helbing, Caren C.
Herpetofauna (amphibians and reptiles) and fish represent important sentinel and indicator species for environmental and ecosystem health. It is widely accepted that the epigenome plays an important role in gene expression regulation. Environmental stimuli, including temperature and pollutants, influence gene activity and growing evidence demonstrates that an important mechanism is through modulation of the epigenome. This has been primarily studied in human and mammalian models; relatively little is known about the impact of environmental conditions or pollutants on herpetofauna or fish epigenomes and the regulatory consequences of these changes on gene expression. Herein, we review recent studies that have begun to address this deficiency, which have mainly focused on limited specific epigenetic marks and individual genes or large-scale global changes in DNA methylation due to the comparative ease of measurement. Greater understanding of the epigenetic influences of these environmental factors will depend on increased availability of relevant species-specific genomic sequence information to facilitate chromatin immunoprecipitation and DNA methylation experiments.
Biochemical and biological activity of arginine deiminase from Streptococcus pyogenes M22.
(Canadian Science Publishing, 2015-09-25) Starikova, Eleonora A; Sokolov, Alexey; Vlasenko, Anna Yu; Burova, Larisa A; Freidlin, Irina S; Vasilyev, Vadim B
Streptococcus pyogenes (group A Streptococcus - GAS) is an important gram-positive extracellular bacterial pathogen responsible for a number of suppurative infections. This microorganism developed complex virulence mechanisms to avoid host defense. We have previously revealed that Supernatant of Destroyed Streptococcal Cells (SDSC) from GAS type M22 causes endothelial cells’ dysfunction, inhibits cellular adhesion, migration, metabolism and proliferation in a dose-dependent manner without affecting cells’ viability. The present work is aimed at isolation and characterization of a component from GAS type M22 supernatant that suppresses proliferation of endothelial cells EA.hy926. Isolating a protein possessing antiproliferative activity allowed identifying arginine deiminase (AD). Further study showed that the enzyme is most active at pH 6.8. Calculating Km and Vmax gave the values of 0.67 mM and 42 s-1, respectively. Distinctive feature of AD purified from GAS type M22 is the closest to neutral pH optimum of activity and the maximal rate of the catalytic process compared with such of the enzyme from other microorganisms. AD from GAS type M22 suppressed the proliferative activity of endothelial cells in a dose-dependent mode. At the same time in the presence of AD the share of cells in G0/G1 phase increased. When L-Arg was added at increasing concentrations to the culture medium containing 3 µg/ml AD, the enzyme’s capacity to inhibit cell proliferation became partly depressed. The proportion of cells in phases S/G2 increased concomitantly, though the cells did not fully recover their proliferation activity. All this allows regarding AD from GAS type M22 as a prospective pharmacy for suppression of excessive cell proliferation.
Effect of triiodothyronine (T3) excess on fatty acid metabolism in the soleus muscle from endurance-trained rats.Effect of triiodothyronine (T3) excess on fatty acid metabolism in the soleus muscle from endurance-trained rats.
(Canadian Science Publishing, 2015-10-19) Górecka, Monika; Synak, Marcin Hofman; Brzezińska, Zofia; Dąbrowski, Jan; Zernicka, Ewa
We studied whether short-term T3 administration at the end of endurance training will influence the rate of palmitic acid (PA) uptake and metabolism in rat soleus muscle in vitro. Training per se did not affect the rate of PA uptake by the soleus, however, T3 excess increased the rate of this process at 1.5mM PA and the rate of PA incorporation into intramuscular triacylglycerols (TG). In trained euthyroid rats the rate of TG synthesis was reduced after exercise (1.5mM PA). In all trained rats immediately after exercise the rate of PA oxidation was enhanced compared to sedentary value. Hyperthyroidism additionally increased the rate of this process at 1.5mM PA. After recovery the rate of PA oxidation returned to control value in both groups. High-energy phosphates content demonstrated that elevated PA oxidation after exercise-training in euthyroid rats was associated with stable ATP concentration and increased ADP and AMP content thus reducing energy cellular potential (ECP). In hyperthyroid rats ADP and AMP were increased in sedentary and exercise-trained rats. After recovery in hyperthyroid rats ECP was high resulting from high ATP and decreased ADP and AMP. In conclusion, already short-term hyperthyroidism accelerates PA utilization in well-trained soleus muscle.
RNA Polymerase II Pausing as a Context-Dependent Reader of the Genome.
(Canadian Science Publishing, 2015-08-31) Scheidegger, Adam; Nechaev, Sergei
The RNA polymerase II (Pol II) transcribes all mRNA genes in eukaryotes and is among the most highly regulated enzymes in the cell. The classic model of mRNA gene regulation involves recruitment of the RNA polymerase to gene promoters in response to environmental signals. Higher eukaryotes have an additional ability to generate multiple cell types. This extra level of regulation requires that each cell interpret the same genome by committing to one of the many possible transcription programs and executing it in a precise and robust manner. Whereas multiple mechanisms are implicated in cell type-specific transcriptional regulation, how one genome can give rise to distinct transcriptional programs and what mechanisms activate and maintain the appropriate program in each cell remains unclear. This review focuses on the process of promoter-proximal Pol II pausing during early transcription elongation as a key step in context-dependent interpretation of the metazoan genome. We highlight aspects of promoter-proximal Pol II pausing, including its interplay with epigenetic mechanisms, that may enable cell type-specific regulation, and emphasize some of the pertinent questions that remain unanswered and open for investigation.
Conformational Change in Individual Enzyme Molecules
(Canadian Science Publishing, 2015-09-25) Crawford, Jeremie J; Itzkow, Frannie; MacLean, Joanna; Craig, Douglas B
Single β-galactosidase molecule assays were performed using a capillary electrophoresis based protocol employing post-column laser-induced fluorescence detection. In a first set of experiments, the distribution of single β-galactosidase molecule catalytic rates and electrophoretic mobilities were determined from lysates of E. coli strains containing deletions for different heat shock proteins and grown under normal and heat shock conditions. There was no clear observed pattern of effect of heat shock protein expression on these distributions. In a second set of experiments, individual enzyme molecule catalytic rates were determined at 21°C before and after 2 sequential brief periods of incubation at 50, 28 and 10°C. The brief incubations at 50°C caused a change in the enzyme molecules resulting in a different catalytic rate. Any given molecules was just as likely to show an increase in rate as a decrease, resulting in no significant difference in the average rate of the population. The average change in individual molecule rate was dependent upon the temperature of the brief incubation period, with a lesser average change occurring at 28°C and negligible change at 10°C. A third set of experiments was similar to that of the second with the exception that it was electrophoretic mobility that was considered. This provided a similar result. Incubation at higher temperature resulted in a change in electrophoretic mobility. The probability of an individual molecules switching to a higher mobility was approximately equal to that of switching to a lower mobility, resulting in no net average change in the population. The magnitude of the changes in electrophoretic mobilities suggest that the associated conformational changes are subtle.
Hyperbaric oxygen enhances neutrophil apoptosis and their clearance by monocyte-derived macrophages
(Canadian Science Publishing, 2015-05-30) Almzaiel, Anwar; Billington, Richard; Smerdon, Gary; Moody, John
Neutrophil apoptosis and clearance by macrophages are essential for wound healing. Evidence suggests that hyperbaric oxygen (HBO) exposure may enhance neutrophil apoptosis, but HBO effects leading to neutrophil clearance by macrophages are still unclear. In the current study, bovine neutrophils and monocyte-derived macrophages (MDMФ) were co-cultured under HBO (97.9% O2, 2.1% CO2 at 2.4 ATA), hyperbaric normoxia (8.8% O2 at 2.4 ATA), normobaric hyperoxia (95% O2, 5% CO2), normoxia (air) and normobaric hypoxia (5% O2, 5% CO2). Phagocytosis of fresh and 22 h-aged neutrophils by MDMФ was increased after HBO pre-treatment, assessed using flow cytometry and light microscopy. Enhanced clearance of neutrophils was accompanied by an increase in H2O2 levels following HBO pre-treatment with up regulation of IL-10 (anti-inflammatory cytokine) mRNA expression in LPS-stimulated MDMФ that had ingested aged neutrophils. TNF-α (pro-inflammatory cytokine) gene expression did not change in LPS-stimulated MDMФ that had ingested fresh or aged neutrophils after HBO, pressure and hyperoxia. These findings suggest that HBO-activated MDMФ participate in the clearance of apoptotic cells. Uptake of neutrophils by MDMФ exposed to HBO may contribute to resolution of inflammation, because HBO induced up-regulation of IL-10 mRNA expression.
The Danger of Epigenetics Misconceptions (Epigenetics and Stuff…)
(Canadian Science Publishing, 2015-08-21) Georgel, Philippe T.
Within the past two decades, the fields of chromatin structure and function and transcription regulation research started to fuse and overlap, as evidences mounted to support a very strong regulatory role in gene expression was associated with histone post-translational modifications, DNA methylation, as well as various chromatin-associated proteins (the pillars of the “Epigenetics” building). The fusion and convergence of these complementary fields is now often simply referred to as “Epigenetics”. During these same 20 years, numerous new research groups have started to recognize the importance of the chromatin composition, conformation, and its plasticity. However, as the field started to grow exponentially, its growth came with the spreading of several important misconceptions, which have unfortunately led to improper or hasty conclusions. The goal of this short “opinion” piece is to attempt to minimize future mis-interpretations of experimental results and ensure that the right sets of experiment are used to reach the proper conclusion, at least as far as epigenetic mechanisms are concerned.
Histone H3K4 trimethylation: dynamic interplay with pre-mRNA splicing
(Canadian Science Publishing, 2015-06-23) Davie, James R.; Xu, Wayne; Delcuve, Genevieve P
Histone H3 lysine 4 trimethylation (H3K4me3) is often stated as a mark of transcriptionally active promoters. However, closer study of the positioning of H3K4me3 shows the mark locating primarily after the first exon at the 5’ splice site and overlapping with a CpG island in mammalian cells. There are several enzyme complexes that are involved in the placement of the H3K4me3 mark including multiple protein complexes containing SETD1A, SETD1B, MLL1 and MLL2 enzymes (writers). CXXC1, which is associated with SETD1A and SETD1B, target these enzymes to unmethylated CpG islands. Lysine demethylases (KDM5 family members, erasers) demethylate H3K4me3. The H3K4me3 mark is recognized by several proteins (readers), including lysine acetyltransferase complexes, chromatin remodelers, and RNA bound proteins involved in pre-mRNA splicing. Interestingly, attenuation of H3K4me3 impacts pre-mRNA splicing, and inhibition of pre-mRNA splicing attenuates H3K4me3.
Sulforaphane Modulates Telomerase Activity via Epigenetic Regulation in Prostate Cancer Cell Lines.
(Canadian Science Publishing, 2015-07-15) Abbas, Ata; Hall, Adam; Patterson, William Louis; Ho, Emily; Hsu, Anna; Al-Mulla, Fahd; Georgel, Philippe T.
Epidemiologic studies have revealed that diets rich in sulforaphane (SFN), an isothiocyanate present in cruciferous vegetables, are associated with a marked decrease in prostate cancer incidence. The chemo-preventive role of SFN is associated with its histone de-acetylase inhibitor activity. However, the effect of SFN on chromatin composition and dynamic folding, especially in relation to HDAC inhibitor activity, remains poorly understood. In this study, we found that SFN can inhibit the expression and activity of human Telomerase Reverse Transcriptase (hTERT), the catalytic subunit of telomerase, in two prostate cancer cell lines. This decrease in gene expression is correlated with SFN-induced changes in chromatin structure and composition. The SFN-mediated changes in levels of histone post-translational modifications, more specifically acetylation of histone H3 Lysine 18 and di-methylation of histone H3 Lysine 4, two modifications linked with high risk of prostate cancer recurrence, were associated with regulatory elements within the hTERT promoter region. Chromatin condensation may also play a role in SFN-mediated hTERT repression; since expression and recruitment of MeCP2, a known chromatin compactor, were altered in SFN treated prostate cancer cells. Chromatin immuno-precipitation (ChIP) of MeCP2 showed enrichment over regions of the hTERT promoter with increased nucleosome density. These combined results strongly support a role for SFN in the mediation of epigenetic events leading to the repression of hTERT in prostate cancer cells. This ability of SFN to modify chromatin composition and structure associated with target gene expression provides a new model by which dietary phytochemicals may exert their chemoprevention activity.
ClC-3 Chloride Channel Function as a Mechanical Sensitive Channel in Osteoblast
(Canadian Science Publishing, 2015-06-11) wang, huan; Wang, Rong; Liu, Qian; Wang, Zhe; Mao, Yong; Duan, Xiaohong
Mechanical stimulation usually causes the volume changes of osteoblasts. Whether this volume changes could be sensed by ClC-3 chloride channel, a volume sensitive ion channel, and further promotes the osteodifferentiation in osteoblasts remains to determine. In this study, we applied the persistent static compression on MC3T3-E1 cells to detect the expression changes of ClC-3, osteogenic markers as well as some molecules related with signaling transduction pathway. We tested the key role of ClC-3 in transferring the mechanical signal to osteoinduction by ClC-3 overexpressing and siRNA technique. We found that ClC-3 level was up regulated by mechanical stimulation in MC3T3-E1 cells. Mechanical force also up regulated the mRNA level of osteogenic markers such as alkaline phosphatase (Alp), bone sialoprotein (Bsp) and osteocalcin (Oc), which could be blocked or strengthened by Clcn3 siRNA or overexpressing, and Alp expression was more sensitive to the changes of ClC-3 level. We also found that runt-related transcription factor 2 (Runx2), transforming growth factor-beta 1 (TGF-β1) and Wnt pathway might be involved in ClC-3 mediated mechanical transduction in osteoblasts. The data from the current study suggest that ClC-3 chloride channel play as a mechanical sensitive channel to regulate osteodifferentiation in osteoblasts.
An Unusually Simple HP1 Gene Set in Hymenopteran Insects
(Canadian Science Publishing, 2015-07-16) Fang, Christopher; Schmitz, Lars; Ferree, Patrick Michael
The heterochromatin protein 1 (HP1) gene family includes a set of paralogs in higher eukaryotes that serve fundamental roles in heterochromatin structure and maintenance, and other chromatin-related functions. At least ten full and sixteen partial HP1 genes exist among Drosophila species, with multiple gene gains, losses and sub-functionalizations within this insect group. An important question is whether this diverse set of HP1 genes and their dynamic evolution represent the standard rule in eukaryotic groups. Here we have begun to address this question by bioinformatically identifying the HP1 family genes in representative species of the insect order Hymenoptera, which includes all ants, bees, wasps and sawflies. Compared to Drosophila species, hymenopterans have a much simpler set of HP1 genes, including one full and two partial HP1s. All three genes appear to have been present in the common ancestor of the hymenopterans and they derive from a Drosophila HP1B-like gene. In ants, a partial HP1 gene containing only a chromoshadow domain harbors amino acid changes at highly conserved sites within the PxVxL recognition region, suggesting that this gene has undergone sub-functionalization. In the jewel wasp Nasonia vitripennis the full HP1 and partial chromoshadow-only HP1 are expressed in both germ line and somatic tissues. However, the partial chromodomain-only HP1 is expressed exclusively in the ovary and testis, suggesting that it may have a specialized chromatin role during gametogenesis. Our findings demonstrate that the HP1 gene family is much simpler and evolutionarily less dynamic within the hymenopterans compared to the much younger Drosophila group, a pattern that may reflect major differences in the range of chromatin-related functions present in these and perhaps other insect groups.
Does epigenetic dysregulation of pancreatic islets contribute to impaired insulin secretion and type 2 diabetes?
(Canadian Science Publishing, 2015-06-25) Dayeh, Tasnim; Ling, Charlotte
Beta cell dysfunction is central to the development and progression of type 2 diabetes (T2D). T2D develops when beta cells are not able to compensate for the increasing demand for insulin caused by insulin resistance. Epigenetic modifications play an important role in establishing and maintaining beta cell identity and function in physiological conditions. On the other hand, epigenetic dysregulation can cause a loss of beta cell identity, which is characterized by reduced expression of genes that are important for beta cell function, ectopic expression of genes that are not supposed to be expressed in beta cells and loss of genetic imprinting. Consequently, this may lead to beta cell dysfunction and impaired insulin secretion. Risk factors that can cause epigenetic dysregulation include parental obesity, an adverse intrauterine environment, hyperglycemia, lipotoxicity, aging, physical inactivity and mitochondrial dysfunction. These risk factors can affect the epigenome at different time points throughout the lifetime of an individual and even before an individual is conceived. The plasticity of the epigenome enables it to change in response to environmental factors such as diet and exercise, and also makes the epigenome a good target for epigenetic drugs that may be used to enhance insulin secretion and potentially treat diabetes.
Lactoferrin attenuates fatty acid-induced lipotoxicity via Akt signaling in hepatocarcinoma cells
(Canadian Science Publishing, 2015-06-25) Morishita, Satoru; Tomita, Keiko; Ono, Tomoji; Murakoshi, Michiaki; Saito, Kenji; Sugiyama, Keikichi; Nishino, Hoyoku; Kato, Hisanori
Nonalcoholic fatty liver disease (NAFLD) describes a spectrum of lesions ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). The excess influx of fatty acids (FAs) into the liver is recognized as a main cause of simple steatosis formation and progression to NASH. Recently, administration of lactoferrin (LF), a glycoprotein present in milk, was suggested to prevent NAFLD development. However, the effect of LF on the contribution of FA to NAFLD development remains unclear. In this study, the effects of LF on FA mixture (FAm)-induced lipotoxicity using human hepatocarcinoma G2 cells were assessed. FAm significantly decreased cell viability and increased intracellular lipid accumulation, whereas LF significantly recovered cell viability without affecting lipid accumulation. FAm-induced lactic dehydrogenase (LDH) and caspase-3/7 activities were significantly decreased by LF and SP600125, a c-Jun N-terminal kinase (JNK) specific inhibitor. We also found that LF added to FAm-treated cells induced Akt phosphorylation which contributed to inhibition of JNK signaling pathway-dependent apoptosis. Akt inhibitor VIII, an allosteric Akt inhibitor, significantly attenuated the effect of LF on LDH activity and abrogated the ones on cell viability and caspase-3/7 activity. In summary, the present study has revealed that LF has a protective effect on FAm-induced lipotoxicity in a HepG2 model of NAFLD and identified the activation of the Akt signaling pathway as a possibly major mechanism.
Identification of MMP-9 as a biomarker for detecting progression of chronic obstructive pulmonary disease.
(Canadian Science Publishing, 2015-07-16) Abd El-Fatah, Marwa Fouad; Ghazy, Mohamed A; Mostafa, Mohamed Said; El-Attar, May Mahmoud; Egiza, Ahmed Osman
Chronic obstructive pulmonary disease (COPD) is a complex immunological disease with multiple pathological features that is primarily induced by smoking together with additional genetic risk factors. COPD is frequently underdiagnosed; forced expiratory volume in the first second (FEV1) is considered to be the main diagnostic measure for COPD, yet it is insufficiently sensitive to monitor disease progression. Biomarkers capable of monitoring COPD progression and severity are needed. In this report, we evaluated matrix metalloproteinase-9 (MMP-9) as an early marker for the detection and staging of COPD, by assessing the mRNA levels of MMP-9 in peripheral blood samples collected from 22 COPD patients, 6 asymptomatic smokers and 5 healthy controls. Our results demonstrate that the mRNA levels of MMP-9 increased more than two-folds in severe COPD relative to non-COPD smokers or moderate COPD groups. Moreover, in the very severe COPD group, MMP-9 mRNA levels showed a 4-fold increase relative to the non-COPD smokers or the moderate COPD groups, while there was a mild increase (~ 40%) when compared to the severe COPD group. Taken together, our results suggest that MMP-9 serves as a biomarker for the grade and severity of COPD.

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