Molecular characterisation and expression analysis of interferon gamma in response to natural chlamydia infection in the koala, phascolarctos cinereus

Interferon gamma (IFNγ) is a key Th1 cytokine, with a principal role in the immune response against intracellular organisms such as Chlamydia. Along with being responsible for significant morbidity in human populations, Chlamydia is also responsible for wide spread infection and disease in many animal hosts, with reports that many Australian koala subpopulations are endemically infected. An understanding of the role played by IFNγ in koala chlamydial diseases is important for the establishment of better prophylactic and therapeutic approaches against chlamydial infection in this host. A limited number of IFNγ sequences have been published from marsupials and no immune reagents to measure expression have been developed. Through preliminary analysis of the koala transcriptome, we have identified the full coding sequence of the koala IFNγ gene. Transcripts were identified in spleen and lymph node tissue samples. Phylogenetic analysis demonstrated that koala IFNγ is closely related to other marsupial IFNγ sequences and more distantly related to eutherian mammals. To begin to characterise the role of this important cytokine in the koala's response to chlamydial infection, we developed a quantitative real time PCR assay and applied it to a small cohort of koalas with and without active chlamydial disease, revealing significant differences in expression patterns between the groups. Description of the IFNγ sequence from the koala will not only assist in understanding this species' response to its most important pathogen but will also provide further insight into the evolution of the marsupial immune system

Protective effects of sweroside on human MG-63 cells and rat osteoblasts

Herbal Fructus Corni is a folk medicine with a long history of safe use for treating osteoporosis in postmenopausal women or elderly men in Asia. Sweroside is a bioactive herbal ingredient isolated from Fructus Corni, which has been widely used for the treatment of osteoporosis in traditional Chinese medicine (TCM). Unfortunately, the working mechanisms of this compound are difficult to determine and thus remain unclear. The aim of the study was performed to determine the potential molecular mechanism of the anti-osteoporotic effect of sweroside on the human MG-63 cells and rat osteoblasts. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was used to observe the effect of sweroside on cell proliferation. The activity of alkaline phosphatase (ALP) and the amount of osteocalcin were also assayed the cell differentiation. Sweroside significantly increased the proliferation of human MG-63 cells and rat osteoblasts (P<0.01). It increased the activity of ALP, and osteocalcin was also elevated in response to sweroside (P<0.05). Of note, flowcytometer assay showed that sweroside can attenuate and inhibit apoptosis. Sweroside has a direct osteogenic effect on the proliferation and differentiation of cultured human MG-63 cells and rat osteoblasts in vitro. These data will help in understanding the molecular mechanisms of therapeutic efficacy of sweroside, and highlight insights into drug discovery. In the current study, sweroside has been suggested to be a promising osteoporosis therapeutic natural product.

Investigation of the role of the GABRG2 gene variant in migraine

Migraine is the most common neurological disorder worldwide affecting about 12% of the worldwide population. This disorder has been classed into two main types of migraine—with and without aura. While a number of factors can influence the onset of migraine, a major factor is that of genetics. The GABAA gene encodes for the GABAA receptor. Along with other receptors, the GABAA receptor is involved in the mediation of neuronal activities. In this study, a GABRG2 gene (GABAA receptor gamma-2-subunit) SNP (rs211037) was genotyped on a migraine case–control population of 546 (273 affected and an equal number of healthy) individuals. Using specifically designed primers, a high resolution melt (HRM) assay was carried out in the genotyping process. After genotyping, results were compared in the case and control populations. Analysis of results showed no significant differences in the allele frequencies between case and control populations. Similarly no differences were detected for subtypes or for a specific gender of migraine (p > 0.05). Although this gene has been previously found to be involved in febrile seizures and there is some co-morbidity between epilepsy and migraine, we decided to investigate this marker for involvement in migraine. The results did not support a role for the tested GABRG2 variant in migraine.

Investigation of the [−/A]8 and C1236T genetic variations within the human toll-like receptor 3 gene for association with multiple sclerosis

Multiple sclerosis (MS) is a serious cause of neurological disability among young adults. The clinical course remains difficult to predict, and the pathogenesis of the disease is still modestly understood. Autoimmunity is thought to be a key aspect of the disease, with autoreactive T cells thought to mediate central nervous system (CNS) inflammation to some extent. Toll-like receptors are known to mediate cellular recognition of pathogens by way of patterns of molecular presentation. Toll-like receptor 3 is coded by the gene TLR3 and is recognized as an important factor in virus recognition and is known to be involved in the expression of neuroprotective mediators. We set out to investigate two variations within the TLR3 gene, an 8 bp insertion-deletion \[-/A](8) and a single base-pair variation C1236T, in subjects with MS and matched healthy controls to determine whether significant differences exist in these markers in an Australian population. We used capillary gel electrophoresis and TaqMan genotyping assay techniques to resolve genotypes for each marker, respectively. Our work found no significant difference between frequencies for TLR3 \[-/A](8) by genotype (chi(2)=1.03, p=0.60) or allele (chi(2)=1.09, p=0.30). Similarly, we found no evidence for the association of TLR3 C1236T by genotype (chi(2)=0.35, p=0.84) or allele frequency (chi(2)=0.31, p=0.58). This work reveals no evidence to suggest that these markers are associated with MS in the tested population. Although the role of TLR3 and the wider toll-like receptor family remain significant in neurological and CNS inflammatory disorders, our current work does not support a role for the two tested variants in this gene with regard to MS susceptibility.

PEGylation of lysine residues reduces the pro-migratory activity of IGF-I

Background: The insulin-like growth factor (IGF) system is composed of ligands and receptors which regulate cell proliferation, survival, differentiation and migration. Some functions are regulated via intracellular signaling cascades, others by involvement of the extracellular milieu, including binding proteins and other extracellular matrix proteins. However, understanding of their functions and the exact nature of these interactions remains incomplete. Methods: IGF-I was PEGylated at its lysine sites - K27, K65 and K68. Binding of PEG-IGF-I to the IGFBPs was analyzed using BIAcore and its ability to activate the IGF-IR was assessed using IGF-IR phosphorylation assay. Furthermore, functional consequences of PEGylating the lysine residues of IGF-I was investigated using cell viability and cell migration assays. In addition, particular downstream signaling pathways regularly implicated in these mechanisms were also dissected using phospho-AKT and phospho-ERK1/2 assays. Results: In this study, IGF-I specifically PEGylated at lysine 27 (PEG-K27), 65 (PEG-K65) or 68 (PEG-K68) were employed. Receptor phosphorylation was only reduced by 2-fold with PEG-K65 and PEG-K68 over all the time points tested, and as observed in two cell types, 3T3 fibroblasts and MCF-7 breast cancer cells. PEGylation at K27 resulted in a much larger effect, with more than 10-fold lower activation for 3T3 fibroblasts and a ~3 fold reduced IGF-IR activation for MCF-7 breast cancer cells over 15 minutes. In addition, all PEG-IGF-I variants demonstrated a ten-fold reduction in the association rate to IGF binding proteins (IGFBPs). Functionally, all PEG variants completely lost their ability to induce cell migration in the presence of IGFBP-3/vitronectin (VN) complexes as compared to IGF-I; in contrast, cell viability was fully preserved. Further investigations into the downstream signaling pathways revealed that the PI3-K/AKT pathway was preferentially affected upon treatment with the PEG-IGF-I variants compared to the MAPK/ERK pathway. Conclusion: PEGylation of IGF-I has an impact on cell migration but not cell viability. General significance: PEG-IGF-I may differentially modulate IGF-I mediated functions that are dependent on its interaction with its receptor as well as key extracellular proteins such as VN and IGFBPs.

Acetylcholine receptor antibody in the diagnosis of myasthenia gravis

The acetylcholine receptor (AchR) antibody assay has a key role in the diagnosis of myasthenia gravis. In this article, the role of AchR antibody assay in the diagnosis of ocular and generalized myasthenia gravis is reviewed, and compared to standard means of diagnosing the disease by clinical and electrophysiological methods.

Acetylcholine receptor antibody in the diagnosis and management of myasthenia gravis

The relationship of acetylcholine receptor (AchR) antibodies to disease activity in myasthenia gravis (MG) is controversial. Some authors claim a direct correlation with disease activity and treatment, in particular plasmapheresis therapy, whereas others have commented on the poor overall correlation of antibody levels with clinical state. Antibody levels were examined in a population of MG patients and correlated with disease activity and response to treatment. Antibodies to skeletal muscle AchR were found in most patients with generalised MG (24/25) and in about half of the patients with purely ocular MG (6/10) and in neither of 2 patients with congenital MG. There was scant correlation with disease activity or response to treatment. It is concluded that the assay is more useful for diagnosis than for management of MG.

Dengue fever viral exposure rates among blood donors during outbreaks in North Queensland

Introduction: Dengue poses a problem for safe transfusion of blood components with confirmed reports of transfusion-transmission in Hong Kong and Singapore. The largest outbreak in 50 years occurred in North Queensland during 2008/2009 with more than 1,000 confirmed cases in Cairns and Townsville. During this outbreak, supplementary questioning for all donors was implemented, and fresh components were not manufactured from at risk donors. We aim to determine the seroprevalence of dengue exposure in this population during this epidemic. Methods: Samples were collected from blood donors during the 2008/2009 epidemic and 3 months after the last confirmed case. These samples were tested for anti-Dengue IgM, IgG and NS1 antigen with commercially available ELISA based assay kits from PanBio. Results: Initial analyses revealed 2.7% of samples from deferred donors were IgM repeat reactive. Of these, 16% were also positive for anti-dengue IgG, while none of these were positive for the NS1 viral antigen. However, two NS1 positives were found in samples collected from deferred donors. Conclusions: This initial analysis represents recent and cumulative past exposure in a presumed asymptomatic population, and will provide documentation of the rate of asymptomatic dengue infection during the epidemic. This data can also be used to assess the risk of dengue becoming endemic in North Queensland given that the mosquito vector is established in this region.

A high-throughput panel for identifying clinically relevant mutation profiles in melanoma

Success with molecular-based targeted drugs in the treatment of cancer has ignited extensive research efforts within the field of personalized therapeutics. However, successful application of such therapies is dependent on the presence or absence of mutations within the patient's tumor that can confer clinical efficacy or drug resistance. Building on these findings, we developed a high-throughput mutation panel for the identification of frequently occurring and clinically relevant mutations in melanoma. An extensive literature search and interrogation of the Catalogue of Somatic Mutations in Cancer database identified more than 1,000 melanoma mutations. Applying a filtering strategy to focus on mutations amenable to the development of targeted drugs, we initially screened 120 known mutations in 271 samples using the Sequenom MassARRAY system. A total of 252 mutations were detected in 17 genes, the highest frequency occurred in BRAF (n = 154, 57%), NRAS (n = 55, 20%), CDK4 (n = 8, 3%), PTK2B (n = 7, 2.5%), and ERBB4 (n = 5, 2%). Based on this initial discovery screen, a total of 46 assays interrogating 39 mutations in 20 genes were designed to develop a melanoma-specific panel. These assays were distributed in multiplexes over 8 wells using strict assay design parameters optimized for sensitive mutation detection. The final melanoma-specific mutation panel is a cost effective, sensitive, high-throughput approach for identifying mutations of clinical relevance to molecular-based therapeutics for the treatment of melanoma. When used in a clinical research setting, the panel may rapidly and accurately identify potentially effective treatment strategies using novel or existing molecularly targeted drugs

A cohort study of Chlamydia trachomatis treatment failure in women : a study protocol

Background Chlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection in the developed world and diagnosis rates have increased dramatically over the last decade. Repeat infections of chlamydia are very common and may represent re-infection from an untreated partner or treatment failure. The aim of this cohort study is to estimate the proportion of women infected with chlamydia who experience treatment failure after treatment with 1 gram azithromycin. Methods/design This cohort study will follow women diagnosed with chlamydia for up to 56 days post treatment. Women will provide weekly genital specimens for further assay. The primary outcome is the proportion of women who are classified as having treatment failure 28, 42 or 56 days after recruitment. Comprehensive sexual behavior data collection and the detection of Y chromosome DNA and high discriminatory chlamydial genotyping will be used to differentiate between chlamydia re-infection and treatment failure. Azithromycin levels in high-vaginal specimens will be measured using a validated liquid chromatography – tandem mass spectrometry method to assess whether poor azithromycin absorption could be a cause of treatment failure. Chlamydia culture and minimal inhibitory concentrations will be performed to further characterize the chlamydia infections. Discussion Distinguishing between treatment failure and re-infection is important in order to refine treatment recommendations and focus infection control mechanisms. If a large proportion of repeat chlamydia infections are due to antibiotic treatment failure, then international recommendations on chlamydia treatment may need to be re-evaluated. If most are re-infections, then strategies to expedite partner treatment are necessary.

Osteocyte-induced angiogenesis via VEGF–MAPK-dependent pathways in endothelial cells

Recently, it has been suggested osteocytes control the activities of bone formation (osteoblasts) and resorption (osteoclast), indicating their important regulatory role in bone remodelling. However, to date, the role of osteocytes in controlling bone vascularisation remains unknown. Our aim was to investigate the interaction between endothelial cells and osteocytes and to explore the possible molecular mechanisms during angiogenesis. To model osteocyte/endothelial cell interactions, we co-cultured osteocyte cell line (MLOY4) with endothelial cell line (HUVECs). Co-cultures were performed in 1:1 mixture of osteocytes and endothelial cells or by using the conditioned media (CM) transfer method. Real-time cell migration of HUVECs was measured with the transwell migration assay and xCELLigence system. Expression levels of angiogenesis- related genes were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The effect of vascular endothelial growth factor (VEGF) and mitogen-activated phosphorylated kinase (MAPK) signaling were monitored by western blotting using relevant antibodies and inhibitors. During the bone formation, it was noted that osteocyte dendritic processes were closely connected to the blood vessels. The CM generated from MLOY4 cells-activated proliferation, migration, tube-like structure formation, and upregulation of angiogenic genes in endothelial cells suggesting that secretory factor(s) from osteocytes could be responsible for angiogenesis. Furthermore, we identified that VEGF secreted from MLOY4-activated VEGFR2–MAPK–ERK-signaling pathways in HUVECs. Inhibiting VEGF and/or MAPK–ERK pathways abrogated osteocyte-mediated angiogenesis in HUVEC cells. Our data suggest an important role of osteocytes in regulating angiogenesis.

Endothelin-1 is a novel prognostic factor in non-small cell lung cancer

Endothelin-1 (ET-1) is a potent vasoactive peptide and a hypoxia-inducible angiogenic growth factor associated with the development and growth of solid tumours. This study evaluated the expression of big endothelin-1 (big ET-1), a stable precursor of ET-1, and ET-1 in non-small cell lung cancer (NSCLC). Big ET-1 expression was evaluated in paraffin-embedded tissue sections from 10 NSCLC tumours using immunohistochemistry and in situ hybridisation. The production of big ET-1 and ET-1 was studied in six established NSCLC cell lines. The plasma concentrations of big ET-1 were measured in 30 patients with proven NSCLC prior to chemotherapy by means of a sandwich enzyme-linked immunoassay and compared to levels in 20 normal controls. Big ET-1 immunostaining was detected in the cancer cells of all tumours studied. Using in situ hybridisation, tumour cell big ET-1 mRNA expression was demonstrated in all samples. All six NSCLC cell lines expressed ET-1, with big ET-1 being detected in three. The median big ET-1 plasma level in patients with NSCLC was 5.4 pg/mL (range 0-22.7 pg/mL) and was significantly elevated compared to median big ET-1 plasma levels in controls, 2.1 pg/mL (1.2-13.4 pg/mL) (p=0.0001). Furthermore, patients with plasma big ET-1 levels above the normal range (upper tertile) had a worse outcome (p=0.01). In conclusion, big ET-1/ET-1 is expressed by resected NSCLC specimens and tumour cell lines. Plasma big ET-1 levels are elevated in NSCLC patients compared to controls with levels >7.8 pg/mL being associated with a worse outcome. The development of selective ET-1 antagonists such as Atrasentan indicates that ET-1 may be a therapeutic target in NSCLC. © 2004 Wichtig Editore.

IL-20 is epigenetically regulated in NSCLC and down regulates the expression of VEGF

Background IL-20 is a pleiotrophic member of the IL-10 family and plays a role in skin biology and the development of haematopoietic cells. Recently, IL-20 has been demonstrated to have potential anti-angiogenic effects in non-small cell lung cancer (NSCLC) by down regulating COX-2. Methods The expression of IL-20 and its cognate receptors (IL-20RA/B and IL-22R1) was examined in a series of resected fresh frozen NSCLC tumours. Additionally, the expression and epigenetic regulation of this family was examined in normal bronchial epithelial and NSCLC cell lines. Furthermore, the effect of IL-20 on VEGF family members was examined. Results The expression of IL-20 and its receptors are frequently dysregulated in NSCLC. IL-20RB mRNA was significantly elevated in NSCLC tumours (p < 0.01). Protein levels of the receptors, IL-20RB and IL-22R1, were significantly increased (p < 0.01) in the tumours of NSCLC patients. IL-20 and its receptors were found to be epigenetically regulated through histone post-translational modifications and DNA CpG residue methylation. In addition, treatment with recombinant IL-20 resulted in decreased expression of the VEGF family members at the mRNA level. Conclusions This family of genes are dysregulated in NSCLC and are subject to epigenetic regulation. Whilst the anti-angiogenic properties of IL-20 require further clarification, targeting this family via epigenetic means may be a viable therapeutic option in lung cancer treatment. © 2011 Elsevier Ltd. All rights reserved.

IL-23 is pro-proliferative, epigenetically regulated and modulated by chemotherapy in non-small cell lung cancer

Background IL-23 is a member of the IL-6 super-family and plays key roles in cancer. Very little is currently known about the role of IL-23 in non-small cell lung cancer (NSCLC). Methods RT-PCR and chromatin immunopreciptiation (ChIP) were used to examine the levels, epigenetic regulation and effects of various drugs (DNA methyltransferase inhibitors, Histone Deacetylase inhibitors and Gemcitabine) on IL-23 expression in NSCLC cells and macrophages. The effects of recombinant IL-23 protein on cellular proliferation were examined by MTT assay. Statistical analysis consisted of Student's t-test or one way analysis of variance (ANOVA) where groups in the experiment were three or more. Results In a cohort of primary non-small cell lung cancer (NSCLC) tumours, IL-23A expression was significantly elevated in patient tumour samples (p<0.05). IL-23A expression is epigenetically regulated through histone post-translational modifications and DNA CpG methylation. Gemcitabine, a chemotherapy drug indicated for first-line treatment of NSCLC also induced IL-23A expression. Recombinant IL-23 significantly increased cellular proliferation in NSCLC cell lines. Conclusions These results may therefore have important implications for treating NSCLC patients with either epigenetic targeted therapies or Gemcitabine. © 2012 Elsevier Ireland Ltd.

Do pioneer cells exist?

Most mathematical models of collective cell spreading make the standard assumption that the cell diffusivity and cell proliferation rate are constants that do not vary across the cell population. Here we present a combined experimental and mathematical modeling study which aims to investigate how differences in the cell diffusivity and cell proliferation rate amongst a population of cells can impact the collective behavior of the population. We present data from a three–dimensional transwell migration assay which suggests that the cell diffusivity of some groups of cells within the population can be as much as three times higher than the cell diffusivity of other groups of cells within the population. Using this information, we explore the consequences of explicitly representing this variability in a mathematical model of a scratch assay where we treat the total population of cells as two, possibly distinct, subpopulations. Our results show that when we make the standard assumption that all cells within the population behave identically we observe the formation of moving fronts of cells where both subpopulations are well–mixed and indistinguishable. In contrast, when we consider the same system where the two subpopulations are distinct, we observe a very different outcome where the spreading population becomes spatially organized with the more motile subpopulation dominating at the leading edge while the less motile subpopulation is practically absent from the leading edge. These modeling predictions are consistent with previous experimental observations and suggest that standard mathematical approaches, where we treat the cell diffusivity and cell proliferation rate as constants, might not be appropriate.