Background
Oxidative injury to retinal pigment epithelium (RPE) and retinal photoreceptors has been linked to a number of retinal diseases, including age-related macular degeneration (AMD). Reactive oxygen species (ROS)-mediated gene expression has been extensively studied at transcriptional levels. Also, the post-transcriptional control of gene expression at the level of translational regulation has been recently reported. However, the microRNA (miRNA/miR)-mediated post-transcriptional regulation in human RPE cells has not been thoroughly looked at. Increasing evidence points to a potential role of miRNAs in diverse physiological processes.
Methodology/Principal Findings
We demonstrated for the first time in a human retinal pigment epithelial cell line (ARPE-19) that the post-transcriptional control of gene expression via miRNA modulation regulates human catalase, an important and potent component of cell's antioxidant defensive network, which detoxifies hydrogen peroxide (H2O2) radicals. Exposure to several stress-inducing agents including H2O2 has been reported to alter miRNA expression profile. Here, we demonstrated that a sublethal dose of H2O2 (200 µM) up-regulated the expression of miR-30b, a member of the miR-30 family, which inhibited the expression of endogenous catalase both at the transcript and protein levels. However, antisense (antagomirs) of miR-30b was not only found to suppress the miR-30b mimics-mediated inhibitions, but also to dramatically increase the expression of catalase even under an oxidant environment.
Conclusions/Significance
We propose that a microRNA antisense approach could enhance cytoprotective mechanisms against oxidative stress by increasing the antioxidant defense system.
Eyes gather information and color forms an extremely important component of the information, more so in the case of animals to forage and navigate within their immediate environment. By using the ONIOM (QM/MM) method, we report a comprehensive theoretical analysis of the structure and molecular mechanism of spectral tuning of monkey-red and green-sensitive visual pigments. We show that, interaction of retinal with three hydroxyl-bearing amino acids near the β-ionone ring part of the retinal in opsin, A164S, F261Y and A269T, increases the electron delocalization, decreases the BLA of the retinal and leads to variation in the wavelength of maximal absorbance in the red- and green-sensitive visual pigments. Based on the analysis, we propose the “OH-site” rule for seeing red and green. This rule is also shown to account for the spectral shifts obtained from hydroxyl-bearing amino acids near the Schiff base in different visual pigments: at site 292 (A292S, A292Y, and A292T) in bovine and at site 111 (Y111) in squid opsins. Therefore, the OH-site rule is shown to be site-specific and not pigment-specific and thus can be used for tracking spectral shifts in any visual pigment.
Recent experimental and theoretical studies on the dynamics of the reactions of methane with F and Cl atoms have modified our understanding of mode-selective chemical reactivity. The O + methane reaction is also an important candidate to extend our knowledge on the rules of reactivity. Here, we report a unique full-dimensional ab initio potential energy surface for the O(3P) + methane reaction, which opens the door for accurate dynamics calculations using this surface. Quasiclassical trajectory calculations of the angular and vibrational distributions for the ground state and CH stretching excited O + CHD3(v1 = 0,1) → OH + CD3 reactions are in excellent agreement with the experiment. Our theory confirms what was proposed experimentally: The mechanistic origin of the vibrational enhancement is that the CH-stretching excitation enlarges the reactive cone of acceptance.
by
Matthew A. Kutny;
Barry K. Moser;
Kristina Laumann;
James H. Feusner;
Alan Gamis;
John Gregory;
Richard A. Larson;
Bayard L. Powell;
Wendy Stock;
Cheryl L. Willman;
William G Woods;
Soheil Meshinchi
Background: FLT3 mutations (FLT3/Mut) are prevalent in de novo AML and are associated with early relapse. The prevalence and prognostic significance of FLT3/Mut have not been well defined in childhood acute promyelocytic leukemia (APL). Procedure: Diagnostic specimens from 104 pediatric APL patients were screened for FLT3/Mut (FLT3/ITD or FLT3/ALM). FLT3/Mut status was correlated with disease characteristics and clinical outcome for patients treated on CALGB C9710 (n=50). Results: Forty-two of the 104 patients (40%) had either FLT3/ITD (n=28, 27%) or FLT3/ALM (n=15, 14%). Median diagnostic WBC count was 23,400cells/μl vs. 3,600cells/μl for those with and without FLT3/Mut (P<0.001), and similar results for the cohort of 50 patients treated on C9710 (P<0.001). In patients treated on C9710, presence of a FLT3 mutation was highly correlated with diagnostic WBC count >10,000 (P=0.004), microgranular variant histology (P=0.035), and a lower remission rate (P=0.009). In patients who received ATRA (C9710 or CCG-2911, n=58), those with FLT3/Mut had an induction death rate of 30% (7/23) compared to 3% (1/35) in FLT3/WT patients (P=0.005). In patients with high WBC counts (>10,000), those with FLT3/Mut had a significantly higher risk of induction death versus FLT3/WT patients (47% vs. 0%, P=0.05). FLT3/Mut was not associated with adverse outcome in those who survived induction therapy. Conclusions: FLT3/Mut are prevalent in pediatric APL and are associated with high WBC count and increased induction death. This study provides further evidence for testing APL patients for FLT3/Mut and the potential role for FLT3 inhibitors in this disease.
by
Christine E. Schnitzler;
Kevin Pang;
Meghan L. Powers;
Adam M. Reitzel;
Joseph F. Ryan;
David Simmons;
Takashi Tada;
Morgan Park;
Jyoti Gupta;
Shelise Y. Brooks;
Robert W. Blakesley;
Shozo Yokoyama;
Steven H.D. Haddock;
Mark Q. Martindale;
Andreas D. Baxevanis
Background
Calcium-activated photoproteins are luciferase variants found in photocyte cells of bioluminescent jellyfish (Phylum Cnidaria) and comb jellies (Phylum Ctenophora). The complete genomic sequence from the ctenophore Mnemiopsis leidyi, a representative of the earliest branch of animals that emit light, provided an opportunity to examine the genome of an organism that uses this class of luciferase for bioluminescence and to look for genes involved in light reception. To determine when photoprotein genes first arose, we examined the genomic sequence from other early-branching taxa. We combined our genomic survey with gene trees, developmental expression patterns, and functional protein assays of photoproteins and opsins to provide a comprehensive view of light production and light reception in Mnemiopsis.
Results
The Mnemiopsis genome has 10 full-length photoprotein genes situated within two genomic clusters with high sequence conservation that are maintained due to strong purifying selection and concerted evolution. Photoprotein-like genes were also identified in the genomes of the non-luminescent sponge Amphimedon queenslandica and the non-luminescent cnidarian Nematostella vectensis, and phylogenomic analysis demonstrated that photoprotein genes arose at the base of all animals. Photoprotein gene expression in Mnemiopsis embryos begins during gastrulation in migrating precursors to photocytes and persists throughout development in the canals where photocytes reside. We identified three putative opsin genes in the Mnemiopsis genome and show that they do not group with well-known bilaterian opsin subfamilies. Interestingly, photoprotein transcripts are co-expressed with two of the putative opsins in developing photocytes. Opsin expression is also seen in the apical sensory organ. We present evidence that one opsin functions as a photopigment in vitro, absorbing light at wavelengths that overlap with peak photoprotein light emission, raising the hypothesis that light production and light reception may be functionally connected in ctenophore photocytes. We also present genomic evidence of a complete ciliary phototransduction cascade in Mnemiopsis.
Conclusions
This study elucidates the genomic organization, evolutionary history, and developmental expression of photoprotein and opsin genes in the ctenophore Mnemiopsis leidyi, introduces a novel dual role for ctenophore photocytes in both bioluminescence and phototransduction, and raises the possibility that light production and light reception are linked in this early-branching non-bilaterian animal.
To investigate reversal effects of pantoprazole (PPZ) on multidrug resistance (MDR) in human gastric adenocarcinoma cells in vivo and in vitro. Human gastric adenocarcinoma cell SGC7901 was cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum and antibiotics in a humidified 5% CO2 atmosphere at 37°C. Adriamycin (ADR)-resistant cells were cultured with addition of 0.8μg/ml of ADR maintaining MDR phenotype. ADR was used to calculate ADR releasing index; CCK-8 Assay was performed to evaluate the cytotoxicity of anti-tumor drugs; BCECF-AM pH-sensitive fluorescent probe was used to measure intracellular pH (pHi) value of cells, whereas pH value of medium was considered as extracellular pH (pHe) value; Western blotting and immunofluorescent staining analyses were employed to determine protein expressions and intracellular distributions of vacuolar H+-ATPases (V-ATPases), mTOR, HIF-1α, P-glycoprotein (P-gp), and multidrug resistant protein 1 (MRP1); SGC7901 and SGC7901/ADR cells were inoculated in athymic nude mice. Thereafter, effects of ADR with or without PPZ pretreatment were compared by determining the tumor size and weight, apoptotic cells in tumor tissues were detected by TUNEL assay. At concentrations greater than 20μg/ml, PPZ pretreatment reduced ADR releasing index and significantly enhanced intracellular ADR concentration of SGC7901 (P<0.01). Similarly, PPZ pretreatment significantly decreased ADR releasing index of SGC7901/ADR dose-dependently (P<0.01). PPZ pretreatment also decreased cell viabilities of SGG7901 and SGC7901/ADR dose-dependently. After 24-h PPZ pretreatment, administration of chemotherapeutic agents demonstrated maximal cytotoxic effects on SGC7901 and SGC7901/ADR cells (P<0.05). The resistance index in PPZ pretreatment group was significantly lower than that in non-PPZ pretreatment group (3.71 vs. 14.80). PPZ at concentration >10μg/ml significantly decreased pHi in SGC7901 and SGC7901/ADR cells and diminished or reversed transmembrane pH gradient (P<0.05). PPZ pretreatment also significantly inhibited protein expressions of V-ATPases, mTOR, HIF-1α, P-gp, and MRP1, and alter intracellular expressions in parent and ADR-resistant cells (P<0.05). In vivo experiments further confirmed that PPZ pretreatment could enhance anti-tumor effects of ADR on xenografted tumor of nude mice and also improve the apoptotic index in xenografted tumor tissues. PPZ pretreatment enhances the cytotoxic effects of anti-tumor drugs on SGC7901 and reverse MDR of SGC7901/ADR by downregulating the V-ATPases/mTOR/HIF-1α/P-gp and MRP1 signaling pathway.
by
David J. Adelstein;
John A. Ridge;
David M. Brizel;
F. Christopher Holsinger;
Bruce H. Haughey;
Brian O'Sullivan;
Eric M. Genden;
Jonathan Beitler;
Gregory S. Weinstein;
Harry Quon;
Douglas B. Chepeha;
Robert L. Ferris;
Randal S. Weber;
Benjamin Movsas;
John Waldron;
Val Lowe;
Scott Ramsey;
Judith Manola;
Bevan Yueh;
Thomas E. Carey;
Justin E. Bekelman;
Andre A. Konski;
Eric Moore;
Arlene Forastiere;
David E. Schuller;
Jean Lynn;
Claudio Dansky Ullmann
To determine among children with acute myeloid leukemia, whether the proportions of life-threatening or fatal infections differed according to the intensity of induction or type of intensification treatment.
Participants were children enrolled to the Children's Cancer Group (CCG) 2891 with de novo acute myeloid leukemia. In phase 1 (induction) patients were randomized to 4 cycles of chemotherapy either administered as intensive or standard timing. In phase 2 (intensification), those achieving remission were allocated to allogeneic stem cell transplantation (SCT) if a suitable family donor was available while the remainder were randomized to autologous SCT or chemotherapy. Each infection was classified prospectively as nonlife-threatening, life-threatening, or fatal.
The proportion of all infections that were considered life-threatening or fatal was higher with intensive timing compared with standard timing induction (60.3% vs. 37.3%, P<0.0001). Infections caused by Gram-positive and Gram-negative bacteria and fungi were significantly more likely to be severe during intensive compared with standard timing induction. Most molds were life-threatening or fatal. Chemotherapy intensification was not associated with less severe infections compared with SCT. Intensive timing was associated with more severe infections compared with standard timing induction. Prophylactic strategies are likely more important with intensive induction regimens.