Kdown of hnRNP H and F. Western blot (left) and corresponding
Kdown of hnRNP H and F. Western blot (left) and corresponding densitometric analysis (middle) demonstrating the actual 370-86-5 web silencing of hnRNP H and F proteins in RNAi experiments. (right) Relative expression levels of wild-type and pseudoexon-containing transcripts by qRT-PCR. The ratio between the two isoforms in samples silenced for either hnRNP F or H was 25033180 also calculated. (B) Transient overexpression of hnRNP F. (left) GeneMapper windows displaying fluorescence peaks corresponding to RT-PCR products obtained from the cDNA of cells transfected with constructs expressing the M minigene with or without hnRNP F overexpression. The fluorescence peak areas were measured by the GeneMapper v4.0 software. The X-axis represents data points (size standard peaks are also indicated) and the Y-axis represents fluorescence units. (right) Histograms represent the relative amount of transcripts including or skipping the pseudoexon, as assessed by calculating the ratio of the corresponding fluorescence peak areas (setting the sum of all peaks as 100 ). Bars represent mean 6 SD of 3 independent experiments, each performed in triplicate. The results were analyzed by unpaired t-test (*P,0.05; **P,0.01; ***P,0.001). doi:10.1371/journal.pone.0059333.gand Western blot assays, showing significantly lower levels of both endogenous hnRNP F mRNA and protein in HepG2 compared to HeLa cells (Figure S4). Contrary to what was observed for delG2 mutants, all single or combined deletions of G-runs outside the 25-bp region 374913-63-0 price resulted in a marked increase of pseudoexon splicing in both cell types, suggesting that G1 and G3 normally act as repressor elements (Figure 5). As the deletion of the G2 element alone does not
completely recapitulate the effect of the ablation of the entire 25-bp region, and considering that hnRNP F has three RNA-recognizing motifs arrayed in the same spacing that can bind to extended purine-rich elements [23], we produced an additional deleted construct (pTFGG-M-del8) lacking the very
last 8-bp purine-rich sequence of the 25-bp region. This mutant was transfected in both HeLa and HepG2 cells again showing 1081537 a cell-type specific response (Figure 5). In particular, in HepG2 cells the ablation of the 8-bp element ledto a significantly lower inclusion of the pseudoexon (from 77 to 51 of total FGG transcripts). Taken together, these results demonstrate that G-runs with opposite functions contribute in determining the levels of pseudoexon inclusion in FGG transcript, only in the presence of the IVS6-320A.T mutation.DiscussionDetailed knowledge on the structure of most vertebrate genes has highlighted the presence of a large number of pseudoexon sequences that are physiologically silenced by intrinsically defective splice sites [24], by the presence of silencer elements [25,26,27], or by the formation of inhibiting RNA secondary structures [28]. Even though pseudoexons are expected to be low in ESEs, the high degeneration of splicing enhancer motifs and their relative abundance also within introns [5] suggest that pseudoexons probably contain also a number of enhancer motifs,G-runs Regulating FGG Pseudoexon InclusionG-runs Regulating FGG Pseudoexon InclusionFigure 3. In-silico prediction of an ESE-enriched 25-bp sequence and identification of the interacting proteins. (A) Schematic representation of the minigene construct containing the 75-bp FGG pseudoexon activated by the IVS6-320A.T mutation (indicated by an arrow). (bottom) ESE elements predicted by the.Kdown of hnRNP H and F. Western blot (left) and corresponding densitometric analysis (middle) demonstrating the actual silencing of hnRNP H and F proteins in RNAi experiments. (right) Relative expression levels of wild-type and pseudoexon-containing transcripts by qRT-PCR. The ratio between the two isoforms in samples silenced for either hnRNP F or H was 25033180 also calculated. (B) Transient overexpression of hnRNP F. (left) GeneMapper windows displaying fluorescence peaks corresponding to RT-PCR products obtained from the cDNA of cells transfected with constructs expressing the M minigene with or without hnRNP F overexpression. The fluorescence peak areas were measured by the GeneMapper v4.0 software. The X-axis represents data points (size standard peaks are also indicated) and the Y-axis represents fluorescence units. (right) Histograms represent the relative amount of transcripts including or skipping the pseudoexon, as assessed by calculating the ratio of the corresponding fluorescence peak areas (setting the sum of all peaks as 100 ). Bars represent mean 6 SD of 3 independent experiments, each performed in triplicate. The results were analyzed by unpaired t-test (*P,0.05; **P,0.01; ***P,0.001). doi:10.1371/journal.pone.0059333.gand Western blot assays, showing significantly lower levels of both endogenous hnRNP F mRNA and protein in HepG2 compared to HeLa cells (Figure S4). Contrary to what was observed for delG2 mutants, all single or combined deletions of G-runs outside the 25-bp region resulted in a marked increase of pseudoexon splicing in both cell types, suggesting that G1 and G3 normally act as repressor elements (Figure 5). As the deletion of the G2 element alone does not completely recapitulate the effect of the ablation of the entire 25-bp region, and considering that hnRNP F has three RNA-recognizing motifs arrayed in the same spacing that can bind to extended purine-rich elements [23], we produced an additional deleted construct (pTFGG-M-del8) lacking the very last 8-bp purine-rich sequence of the 25-bp region. This mutant was transfected in both HeLa and HepG2 cells again showing 1081537 a cell-type specific response (Figure 5). In particular, in HepG2 cells the ablation of the 8-bp element ledto a significantly lower inclusion of the pseudoexon (from 77 to 51 of total FGG transcripts). Taken together, these results demonstrate that G-runs with opposite functions contribute in determining the levels of pseudoexon inclusion in FGG transcript, only in the presence of the IVS6-320A.T mutation.DiscussionDetailed knowledge on the structure of most vertebrate genes has highlighted the presence of a large number of pseudoexon sequences that are physiologically silenced by intrinsically defective splice sites [24], by the presence of silencer elements [25,26,27], or by the formation of inhibiting RNA secondary structures [28]. Even though pseudoexons are expected to be low in ESEs, the high degeneration of splicing enhancer motifs and their relative abundance also within introns [5] suggest that pseudoexons probably contain also a number of enhancer motifs,G-runs Regulating FGG Pseudoexon InclusionG-runs Regulating FGG Pseudoexon InclusionFigure 3. In-silico prediction of an ESE-enriched 25-bp sequence and identification of the interacting proteins. (A) Schematic representation of the minigene construct containing the 75-bp FGG pseudoexon activated by the IVS6-320A.T mutation (indicated by an arrow). (bottom) ESE elements predicted by the.
89.33 85.33 85.33 76.00 78.67 70.67 61.33 26.Accuracy 89.33 90.00 90.00 85.33 86.00 84.67 76.00 55.PPV 89.33 86.59 86.59 79.78 81.40 77.08 70.10 53.MCC 0.79 0.80 0.80 0.72 0.73 0.72 0.54 0.Reference This work This work This work [25] [23] [23] [23] [20]CS-AMPPred: The Cysteine-Stabilized AMPs PredictorTable 3. Benchmarking of prediction methods using the BS2.Model CS-AMPPred Linear CS-AMPPred Polynomial CS-AMPPred Radial ANFIS CAMP SVM CAMP Discriminant Analysis CAMP Random Forest SVM doi:10.1371/journal.pone.0051444.tSensitivity 69.81 77.36 79.25 100.00 88.68 90.57 96.23 98.Specificity 92.45 90.57 90.57 100.00 96.23 98.11 0.00 67.Accuracy 81.13 83.97 84.91 100.00 92.45 94.34 48.11 83.PPV 90.24 89.13 89.37 100.00 95.92 97.96 49.04 75.MCC 0.64 0.69 0.70 1.00 0.85 0.89 20.14 0.Reference This work This work This work [25] [23] [23] [23] [20]membrane portions [20,25]. In this work, a subset of PDB was used as a negative data set, since the proteins in PDB are overall more curated than in other databases. The construction of the NS was done in three steps. First, the proteins from PDB were selected by searching for the term “NOT Antimicrobial”; second, the redundant sequences were removed with a cutoff of 40 of identity, ensuring that the non-redundant sequences
is no warranty that a peptide has no antimicrobial activity, unless it had been already screened against several microorganisms. In the case of parigidinbr1, it does not show bactericidal activity, but it was not tested as fungicidal [8]. Another problem involved in antimicrobial activity prediction is the size variation of the sequences. In this study, the sequences in PS can vary from 16
in rich medium have no phenotype [4], under several stress conditions, including high salt, low pH, and low temperature,
Wild-type strains and strains deleted for mitochondrial COX2 display filamentous mitochondria. Strains with deletion or L247R-mutation of mitochondrial ATP6 display clustered mitochondria. Other OXPHOS-deficient strains (atp6-L183R, Datp12, r0) display filamentous and clustered mitochondria. (TIFF)AcknowledgmentsWe thank Nathalie Bonnefoy (Gif-sur-Yvette ?France), Agnes Delahodde ` (Orsay – France), Koji Okamoto (Okazaki ?Japan), Andreas Reichert (Frankfurt-am-Main – Germany), Benedikt Westermann (Bayreuth Germany) and Michael Zick (Munich ?Germany) for providing valuable reagents. We are grateful to Anne Devin, Stephen Manon and Claire Lordan for valuable advice and experimental assistance.Author ContributionsConceived and designed the experiments: CS SDC JPdR MR. Performed the experiments: CS SDC BS CD AML. Analyzed the data: CS SDC JPdR MR. Wrote the paper: MR.
were found for expressions of LDH-A and LDH-B in treated and control cells. GAPDH was used as a loading control. doi:10.1371/journal.pone.0056551.gaccelerated senescence [40,41]. The MDA-MB-231 cell line used in our study has mutated p53 gene and thus p53 activation was not likely the mechanism for the decreased metabolic flux observed. But it is possible that GAPDH intracellular translocation to the nucleus associated with DNA damage may contribute to a decrease in cytosolic GAPDH activity [42,43], and lead to a reduction of NAD+/NADH pool, and thus a reduction of pyruvate/lactate flux. It is also known that transformed neoplastic cells that lack functional p53 still have the capacity for accelerated senescence through other tumor suppressor or cell-cycle regulation pathways [39,44]. Although we observed a similar amount of apoptosis for the MDA-MB-231 cells in culture at 4 days post a 16 Gy dose of radiation as a prior study at 5 days post a 10 Gy dose [41], much higher cell senescence was observed in our study. The larger dose of radiation used in this study may be a possible reason behind this discrepancy. Further investigations are needed to elucidate the possible link between the radiation-induced senescence and
metabolic changes observed in this study. Other factors that may have directly impacted the observed change in apparent metabolic flux between hyperpolarized pyruvate and lactate such as tumor vascularity, tumor hypoxia, cellular membrane transport of the injected substrate, and the enzymes that facilitate this metabolic reaction were also investigated in this study. The small decrease in MVD and the significantly lower MCT4 expression in treated tumors suggested that less of the injected hyperpolarized pyruvate reached and entered the tumors cells to be metabolized, thus contributing to the lower metabolite (lactate) to substrate ratios in the treated group. LDH-B expression was also found to have significantly decreased post radiation and likely influenced the apparent metabolic flux after treatment. Although increased HIF1-a expression was observed post treatment and hypoxia can be associated with higher cellular lactate concentration (and potentially higher lactate to pyruvate ratios), the impact of any increase in tissue hypoxia on the observed imaging contrast was likely small as compared to other tissue and molecular changes, since lower lactate to pyruvate ratio was observed post therapy. Tumor response to ionizing radiation is a complex and dynamic phenomenon, and is a subject of active research. While effortswere made in this study to correlate the apparent change in metabolic flux between pyruvate and lactate to the cellular and molecular markers that have more immediate link to the observed imaging contrast (the transport and metabolism of the inj.Olic MRIFigure 5. Western blot analysis was used to assess cell membrane monocarboxylate transport and lactate dehydrogenase levels. Tissue hypoxia in the tumors was also assessed by HIF1-a expression. A) Western blots showed a decrease in MCT4 expression in MDA-MB-231 tumors radiation treated with radiation as compared to controls. The difference was significant (* P,0.03). B) A small decrease in MCT4 expression was observed in treated MDA-MB-231 cells in vitro. C) HIF1-a expression was higher for the treated tumors, but the difference was not significant. D) Expressions of lactate dehydrogenase isoforms B were significantly lower in treated tumors. E) Little changes were found for expressions of LDH-A and LDH-B in treated and control cells. GAPDH was used as a loading control. doi:10.1371/journal.pone.0056551.gaccelerated senescence [40,41]. The MDA-MB-231 cell line used in our study has mutated p53 gene and thus p53 activation was not likely the mechanism for the decreased metabolic flux observed. But it is possible that GAPDH intracellular translocation to the nucleus associated with DNA damage may contribute to a decrease in cytosolic GAPDH activity [42,43], and lead to a reduction of NAD+/NADH pool, and thus a reduction of pyruvate/lactate flux. It is also known that transformed neoplastic cells that lack functional p53 still have the capacity for accelerated senescence through other tumor suppressor or cell-cycle regulation pathways [39,44]. Although we observed a similar amount of apoptosis for the MDA-MB-231 cells in culture at 4 days post a 16 Gy dose of radiation as a prior study at 5 days post a 10 Gy dose [41], much higher cell senescence was observed in our study. The larger dose of radiation used in this study may be a possible reason behind this discrepancy. Further investigations are needed to elucidate the possible link between the radiation-induced senescence and metabolic changes observed in this study. Other factors that may have directly impacted the observed change in apparent metabolic flux between hyperpolarized pyruvate and lactate such as tumor vascularity, tumor hypoxia, cellular membrane transport of the injected substrate, and the enzymes that facilitate this metabolic reaction were also investigated in this study. The small decrease in MVD and the significantly lower MCT4 expression in treated tumors suggested that less of the injected hyperpolarized pyruvate reached and entered the tumors cells to be metabolized, thus contributing to the lower metabolite (lactate) to substrate ratios in the treated group. LDH-B expression was also found to have significantly decreased post radiation and likely influenced the apparent metabolic flux after treatment. Although increased HIF1-a expression was observed post treatment and hypoxia can be associated with higher cellular lactate concentration (and potentially higher lactate to pyruvate ratios), the impact of any increase in tissue hypoxia on the observed imaging contrast was likely small as compared to other tissue and molecular changes, since lower lactate to pyruvate ratio was observed post therapy. Tumor response to ionizing radiation is a complex and dynamic phenomenon, and is a subject of active research. While effortswere made in this study to correlate the apparent change in metabolic flux between pyruvate and lactate to the cellular and molecular markers that have more immediate link to the observed imaging contrast (the transport and metabolism of the inj.
assessments, the last of whom was included in May 2011. In the current study, we included those who had both OH measurements and available MRI scans with adequate scan quality.Assessment of Physical ComorbidityWe employed the “Cumulative Illness Rating Scale” (CIRS) for assessment of physical comorbidity. This instrument measures the chronic medical illness burden, while also taking into account the severity of chronic diseases. Scoring was done by an experienced geriatrician, in accordance with guidelines [35].MRIPatients were scanned at three different sites; Stavanger University Hospital, Haugesund Hospital, and Haraldsplass Deaconess Hospital (Bergen). 1.5 T scanners were used in all three centres (Philips Intera in Stavanger and Haugesund, and in
5D shows how these four regions are distributed as a function of activation and inactivation rates for a pacing frequency of 3 Hz. To further understand the presence of alternans when SR load does not alternate, we considered an idealized situation where: 1) stimulation was done using an action potential clamp, and 2) the SR calcium and 3) the subsarcolemmal calcium were fixed at a constant concentration at all times. This ensures that, if alternans still appears, the RyR2 dynamics is its only possible source. From a mathematical analysis of this case (see Section 2 in Appendix S1) we demonstrate the presence of an instability that gives rise to alternans, through a period-doubling bifurcation (Figure S4 in Appendix S1). The instability is inherent to the RyR2 dynamics and requires a stimulation period shorter than its recovery time from inactivation (Figure S5 in Appendix S1). We then
investigated how the stimulation frequency affects the relative
escape by negatively regulating anti-tumor T cells [2]. Thus, it would be desirable to correct DC impairments and restore anti-tumor activity of T cells in vivo. Systemic delivery of cytokines, e.g., GM-CSF or IFN-a2b to patients with cancer is aimed at the restoration of DC functions and the generation of more robust anti-tumor T-cell responses [11,12]. Therefore, IRX-2, a cell-derived biologic containing a well-defined mix of cytokines, was recently administered to the HNSCC patients enrolled in a phase II clinical trial. IRX-2 was injected locoregionally in the adjuvant setting with an expectation that it might enhance DC function in vivo [13]. The results showed a significant infiltration of tumors with activated T cells after IRX2 therapy which was associated with prolonged overall survival (OS) [14]. We have previously reported that IRX-2 is able to upregulate HLA-DR, CD86, CD40 and CCR7 expression and induce IL12p70 production, a cytokine necessary for Th1 polarization, in monocyte-derived DC generated from PBMC of healthy donors (HD) [15]. Although, we attributed the observed positive correlation between T-cell infiltration and OS to improved functions of DC after IRX-2 delivery, no information is available about the mechanisms through which the treatment of DC with IRX-2 might up-regulate T-cell anti-tumor activity. Here, we evaluate in vitro effects of IRX-2 on DC and, specifically, on the APM component expression in these cells which determines their potential to present TA to T cells. Our data show that IRX-2 not only enhances functions in mDC obtained from cancer patients and HD, but that it does so more efficiently than the conventional mix of IL-6, IL-1 and TNF-a broadly used for DC maturation. Thus, IRX-2 might be potentially beneficial as an immune therapeutic and a maturation biologic for the production of therapeutic DC.Figure 1. The conventionally matured mDC had higher expression of CD80, CD83 (p,0.01) and CD86 (p,0.05) than the IRX2-matured DC. On the other hand, the IRX-2-matured DC expressed significantly higher levels of CCR7 (p,0.01), CD11c (p,0.01) and CD40 (p,0.05) th.Responses.The APM consists of several intracellular proteins responsible for processing, transport and chaperoning of peptides derived mostly, but not exclusively, from endogenous proteins for crosspresentation. After cleavage of these proteins by the proteasome subunits, LMP-2 and LMP-7, the subunits of the transporter associated with antigen processing
cell surface, proper folding catalyzed by the chaperone molecules, BiP, calnexin, calreticulin, and ERp57, takes place in the ER [8]. HLA class I peptide complexes on the cell surface of APC are recognized by CD8+ T lymphocytes bearing cognate T cell receptors [8]. Recent studies suggest that up-regulation of the APM component expression correlates with the improved ability of DC to cross-present antigens and to cross-prime cytolytic T lymphocytes (CTL) [9,10]. Yet, APM component expression and its contribution to DCIRX-2 Up-Regulates DC Maturationfunction in cancer patients have been evaluated only to a limited extent. Impaired DC functions observed in cancer patients could potentially contribute to tumor escape by negatively regulating anti-tumor T cells [2]. Thus, it would be desirable to correct DC impairments and restore anti-tumor activity of T cells in vivo. Systemic delivery of cytokines, e.g., GM-CSF or IFN-a2b to patients with cancer is aimed at the restoration of DC functions and the generation of more robust anti-tumor T-cell responses [11,12]. Therefore, IRX-2, a cell-derived biologic containing a well-defined mix of cytokines, was recently administered to the HNSCC patients enrolled in a phase II clinical trial. IRX-2 was injected locoregionally in the adjuvant setting with an expectation that it might enhance DC function in vivo [13]. The results showed a significant infiltration of tumors with activated T cells after IRX2 therapy which was associated with prolonged overall survival (OS) [14]. We have previously reported that IRX-2 is able to upregulate HLA-DR, CD86, CD40 and CCR7 expression and induce IL12p70 production, a cytokine necessary for Th1 polarization, in monocyte-derived DC generated from PBMC of healthy donors (HD) [15]. Although, we attributed the observed positive correlation between T-cell infiltration and OS to improved functions of DC after IRX-2 delivery, no information is available about the mechanisms through which the treatment of DC with IRX-2 might up-regulate T-cell anti-tumor activity. Here, we evaluate in vitro effects of IRX-2 on DC and, specifically, on the APM component expression in these cells which determines their potential to present TA to T cells. Our data show that IRX-2 not only enhances functions in mDC obtained from cancer patients and HD, but that it does so more efficiently than the conventional mix of IL-6, IL-1 and TNF-a broadly used for DC maturation. Thus, IRX-2 might be potentially beneficial as an immune therapeutic and a maturation biologic for the production of therapeutic DC.Figure 1. The conventionally matured mDC had higher expression of CD80, CD83 (p,0.01) and CD86 (p,0.05) than the IRX2-matured DC. On the other hand, the IRX-2-matured DC expressed significantly higher levels of CCR7 (p,0.01), CD11c (p,0.01) and CD40 (p,0.05) th.