The role of BAFF and APRIL in rheumatoid arthritis

Development and activation of B cells quickly became clear after identifying new ligands and receptors in the tumor necrosis factor superfamily. B cell–activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are the members of membrane proteins Type 2 family released by proteolytic cleavage of furin to form active, soluble homotrimers. Except for B cells, ligands are expressed by all such immune cells like T cells, dendritic cells, monocytes, and macrophages. BAFF and APRIL have two common receptors, namely TNFR homolog transmembrane activator and Ca2+ modulator and CAML interactor (TACI) and B cell–maturation antigen. BAFF alone can also be coupled with a third receptor called BAFFR (also called BR3 or BLyS Receptor). These receptors are often expressed by immune cells in the B-cell lineage. The binding of BAFF or APRIL to their receptors supports B cells differentiation and proliferation, immunoglobulin production and the upregulation of B cell–effector molecules expression. It is possible that the overexpression of BAFF and APRIL contributes to the pathogenesis of autoimmune diseases. In BAFF transgenic mice, there is a pseudo-autoimmune manifestation, which is associated with an increase in B-lymphocytes, hyperglobulinemia, anti-single stranded DNA, and anti-double-stranded DNA antibodies, and immune complexes in their peripheral blood. Furthermore, overexpressing BAFF augments the number of peripheral B220+ B cells with a normal proliferation rate, high levels of Bcl2, and prolonged survival and hyperactivity. Therefore, in this review article, we studied BAFF and APRIL as important mediators in B-cell and discussed their role in rheumatoid arthritis.     

St. John's Wort inhibits insulin signaling in murine and human adipocytes

Adipocytes are insulin-sensitive cells that play a major role in energy homeostasis. Obesity is the primary disease of fat cells and a major risk factor for the development of Type 2 diabetes, cardiovascular disease, and metabolic syndrome. The use of botanicals in the treatment of metabolic diseases is an emerging area of research. In previous studies, we screened over 425 botanical extracts for their ability to modulate adipogenesis and insulin sensitivity. We identified St. John's Wort (SJW) extracts as inhibitors of adipogenesis of 3T3-L1 cells and demonstrated that these extracts also inhibited insulin-sensitive glucose uptake in mature fat cells. In these follow-up studies we have further characterized the effects of SJW on insulin action in both murine and human fat cells. We have shown that SJW also attenuates insulin-sensitive glucose uptake in human adipocytes. Moreover, SJW inhibits IRS-1 tyrosine phosphorylation in both murine and human fat cells. Botanical extracts are complex mixtures. Many bioactive compounds have been identified in SJW, including hypericin (HI) and hyperforin (HF). We have examined the ability of HI and HF, purified from SJW, to modulate adipocyte development and insulin action in mature adipocytes. Our novel studies indicate that the profound effects of SJW on adipogenesis, IRS-1 activation, and insulin-stimulated glucose uptake are not mediated by HI and/or HF. Nonetheless, we propose that extracts of SJW may contribute to adipocyte related diseases by limiting differentiation of preadipocytes and significantly inducing insulin resistance in mature fat cells.     

Unreduced gamete formation in wheat × <Emphasis Type="Italic">Aegilops</Emphasis> spp. hybrids is genotype specific and prevented by shared homologous subgenomes

Key message

The presence of homologous subgenomes inhibited unreduced gamete formation in wheat × Aegilops interspecific hybrids. Unreduced gamete rates were under the control of the wheat nuclear genome.

Abstract

Production of unreduced gametes is common among interspecific hybrids, and may be affected by parental genotypes and genomic similarity. In the present study, five cultivars of Triticum aestivum and two tetraploid Aegilops species (i.e. Ae. triuncialis and Ae. cylindrica) were reciprocally crossed to produce 20 interspecific hybrid combinations. These hybrids comprised two different types: T. aestivum × Aegilops triuncialis; 2n = ABDU^tC^t (which lack a common subgenome) and T. aestivum × Ae. cylindrica; 2n = ABDD^cC^c (which share a common subgenome). The frequency of unreduced gametes in F₁ hybrids was estimated in sporads from the frequency of dyads, and the frequency of viable pollen, germinated pollen and seed set were recorded. Different meiotic abnormalities recorded in the hybrids included precocious chromosome migration to the poles at metaphase I and II, laggards in anaphase I and II, micronuclei and chromosome stickiness, failure in cell wall formation, premature cytokinesis and microspore fusion. The mean frequency of restitution meiosis was 10.1 %, and the mean frequency of unreduced viable pollen was 4.84 % in T. aestivum × Ae. triuncialis hybrids. By contrast, in T. aestivum × Ae. cylindrica hybrids no meiotic restitution was observed, and a low rate of viable gametes (0.3 %) was recorded. This study present evidence that high levels of homologous pairing between the D and D^c subgenomes may interfere with meiotic restitution and the formation of unreduced gametes. Variation in unreduced gamete production was also observed between T. aestivum × Ae. triuncialis hybrid plants, suggesting genetic control of this trait.

     

Impact of iron reduction on the metabolism of Clostridium acetobutylicum

Iron is essential for most living organisms. In addition, its biogeochemical cycling influences important processes in the geosphere (e.g., the mobilization or immobilization of trace elements and contaminants). The reduction of Fe(III) to Fe(II) can be catalysed microbially, particularly by metal-respiring bacteria utilizing Fe(III) as a terminal electron acceptor. Furthermore, Gram-positive fermentative iron reducers are known to reduce Fe(III) by using it as a sink for excess reducing equivalents, as a form of enhanced fermentation. Here, we use the Gram-positive fermentative bacterium Clostridium acetobutylicum as a model system due to its ability to reduce heavy metals. We investigated the reduction of soluble and solid iron during fermentation. We found that exogenous (resazurin, resorufin, anthraquinone-2,6-disulfonate) as well as endogenous (riboflavin) electron mediators enhance solid iron reduction. In addition, iron reduction buffers the pH, and elicits a shift in the carbon and electron flow to less reduced products relative to fermentation. This study underscores the role fermentative bacteria can play in iron cycling and provides insights into the metabolic profile of coupled fermentation and iron reduction with laboratory experiments and metabolic network modelling.     

Increased efficiency of evolved group I intron spliceozymes by decreased side product formation

The group I intron ribozyme from Tetrahymena was recently reengineered into a trans-splicing variant that is able to remove 100-nt introns from pre-mRNA, analogous to the spliceosome. These spliceozymes were improved in this study by 10 rounds of evolution in Escherichia coli cells. One clone with increased activity in E. coli cells was analyzed in detail. Three of its 10 necessary mutations extended the substrate binding duplexes, which led to increased product formation and reduced cleavage at the 5′-splice site. One mutation in the conserved core of the spliceozyme led to a further reduction of cleavage at the 5′-splice site but an increase in cleavage side products at the 3′-splice site. The latter was partially reduced by six additional mutations. Together, the mutations increased product formation while reducing activity at the 5′-splice site and increasing activity at the 3′-splice site. These results show the adaptation of a ribozyme that evolved in nature for cis-splicing to trans-splicing, and they highlight the interdependent function of nucleotides within group I intron ribozymes. Implications for the possible use of spliceozymes as tools in research and therapy, and as a model for the evolution of the spliceosome, are discussed.     

Low Selection Pressure Aids the Evolution of Cooperative Ribozyme Mutations in Cells

Understanding the evolution of functional RNA molecules is important for our molecular understanding of biology. Here we tested experimentally how two evolutionary parameters, selection pressure and recombination, influenced the evolution of an evolving RNA population. This was done using four parallel evolution experiments that employed low or gradually increasing selection pressure, and recombination events either at the end or dispersed throughout the evolution. As model system, a trans-splicing group I intron ribozyme was evolved in Escherichia coli cells over 12 rounds of selection and amplification, including mutagenesis and recombination. The low selection pressure resulted in higher efficiency of the evolved ribozyme populations, whereas differences in recombination did not have a strong effect. Five mutations were responsible for the highest efficiency. The first mutation swept quickly through all four evolving populations, whereas the remaining four mutations accumulated later and more efficiently under low selection pressure. To determine why low selection pressure aided this evolution, all evolutionary intermediates between the wild type and the 5-mutation variant were constructed, and their activities at three different selection pressures were determined. The resulting fitness profiles showed a high cooperativity among the four late mutations, which can explain why high selection pressure led to inefficient evolution. These results show experimentally how low selection pressure can benefit the evolution of cooperative mutations in functional RNAs.     

A Significant Reduction in the Plasma Levels and Gene Expression of CCL2 in Patients with Osteoarthritis following Intervention with Krocina™

Background:inflammatory chemokines such as CCL2 and CCL5 are involved in the progress of osteoarthritis. Crocin with antioxidant and anti-inflammatory properties can reduce the symptoms of osteoarthritis (OA). This study was performed investigate the effect of Krocina™, on the gene expressions and plasma levels of CCL2 and CCL5 in OA patients.Methods:The study included 35 patients that were randomized in the Krocina™ and placebo groups. The intervention was Krocina™ 15mg daily for four months. Clinical and paraclinical parameters were measured. CCL2 and CCL5 genes expression and plasma levels were determined using the SYBR Green Real-Time RT-PCR and Enzyme-linked Immunosorbent Assay (ELISA) techniques.Results:The C-reactive protein (CRP) value in the Krocina™ group and the visual analogue scale (VAS) value in the Krocina™ and placebo groups decreased significantly after the intervention. The gene expression of CCL2 in the Krocina™ and placebo groups decreased significantly. On the contrary, the gene expression of CCL5 in the Krocina™ and placebo groups increased significantly. Moreover, the plasma levels of CCL2 in the Krocina™ and placebo groups decreased meaningfully. There was no difference regarding the plasma levels of CCL5 within the Krocina™ and placebo groups before and after the intervention in either of the groups.Conclusion:Administration of Krocina™ reduced the clinical signs of inflammation and CRP and VAS value. Also, Krocina™ significantly decreased the plasma levels and gene expression of CCL2 in osteoarthritis patients.Key Words: CCL2, CCL5, Krocina™, Osteoarthritis     

Clinical governance implementation in a selected teaching emergency department: a systems approach

ABSTRACT: BACKGROUND: Clinical governance (CG) is among the different frameworks proposed to improve the quality of healthcare. Iran, like many other countries, has put healthcare quality improvement in its top health policy priorities. In November 2009, implementation of CG became a task for all hospitals across the country. However, it has been a challenge to clarify the notion of CG and the way to implement it in Iran. The purpose of this action research study is to understand how CG can be defined and implemented in a selected teaching emergency department (ED).Methods/designWe will use Soft Systems Methodology for both designing the study and inquiring into its content. As we considered a complex problem situation regarding the quality of care in the selected ED, we initially conceptualized CG as a cyclic set of purposeful activities designed to explore the situation and find relevant changes to improve the quality of care. Then, implementation of CG will conceptually be to carry out that set of purposeful activities. The activities will be about: understanding the situation and finding out relevant issues concerning the quality of care; exploring different stakeholders' views and ideas about the situation and how it can be improved; and defining actions to improve the quality of care through structured debates and development of accommodations among stakeholders. We will flexibly use qualitative methods of data collection and analysis in the course of the study. To ensure the study rigor, we will use different strategies. DISCUSSION: Successful implementation of CG, like other quality improvement frameworks, requires special consideration of underlying complexities. We believe that addressing the complex situation and reflections on involvement in this action research will make it possible to understand the concept of CG and its implementation in the selected setting. By describing the context and executed flexible methods of implementation, the results of this study would contribute to the development of implementation science and be employed by boards and executives governing other clinical settings to facilitate CG implementation.     

St. John’s Wort inhibits adipocyte differentiation and induces insulin resistance in adipocytes

Adipocytes are insulin sensitive cells that play a major role in energy homeostasis. Obesity is the primary disease of fat cells and a major risk factor for the development of Type II diabetes, cardiovascular disease, and metabolic syndrome. Obesity and its related disorders result in dysregulation of the mechanisms that control adipocyte gene expression and function. To identify potential novel therapeutic modulators of adipocytes, we screened 425 botanical extracts for their ability to modulate adipogenesis and insulin sensitivity. We observed that less than 2% of the extracts had substantial effects on adipocyte differentiation of 3T3-L1 cells. Two of the botanical extracts that inhibited adipogenesis were extracts from St. John’s Wort (SJW). Our studies revealed that leaf and flower, but not root, extracts isolated from SJW inhibited adipogenesis as judged by examining PPARγ and adiponectin levels. We also examined the effects of these SJW extracts on insulin sensitivity in mature 3T3-L1 adipocytes. Both leaf and flower extracts isolated from SJW substantially inhibited insulin sensitive glucose uptake. The specificity of the observed effects was demonstrated by showing that treatment with SJW flower extract resulted in a time and dose dependent inhibition of insulin stimulated glucose uptake. SJW is commonly used in the treatment of depression. However, our studies have revealed that SJW may have a negative impact on adipocyte related diseases by limiting differentiation of preadipocytes and significantly inducing insulin resistance in mature fat cells.     

DCK is frequently inactivated in acquired gemcitabine-resistant human cancer cells

Although gemcitabine is the most effective chemotherapeutic agent against pancreatic cancer, a growing concern is that a substantial number of patients acquire gemcitabine chemoresistance. To elucidate the mechanisms of acquisition of gemcitabine resistance, we developed gemcitabine-resistant cell lines from six human cancer cell lines; three pancreatic, one gastric, one colon, and one bile duct cancer. We first analyzed gemcitabine uptake using three paired parental and gemcitabine resistant pancreatic cancer cell lines (PK-1 and RPK-1, PK-9 and RPK-9, PK-59 and RPK-59) and found that uptake of gemcitabine was rapid. However, no DNA damage was induced in resistant cells. We further examined the microarray-based expression profiles of the cells to identify genes associated with gemcitabine resistance and found a remarkable reduction in the expression of deoxycytidine kinase (DCK). DCK is a key enzyme that activates gemcitabine by phosphorylation. Genetic alterations and expression of DCK were studied in these paired parental and derived gemcitabine-resistant cell lines, and inactivating mutations were found only in gemcitabine-resistant cell lines. Furthermore, siRNA-mediated knockdown of DCK in the parental cell lines yielded gemcitabine resistance, and introduction of DCK into gemcitabine-resistant cell lines invariably restored gemcitabine sensitivities. Mutation analyses were expanded to three other different paired cell lines, DLD-1 and RDLD-1 (colon cancer cell line), MKN-28 and RMKN-28 (gastric cancer cell line), and TFK-1 and RTFK -1 (cholangiocarcinoma cell line). We found inactivating mutations in RDLD-1 and RTFK-1 and decreased expression of DCK in RMKN-28. These results indicate that the inactivation of DCK is one of the crucial mechanisms in acquisition of gemcitabine resistance.