Serum metabolomics reveals irreversible inhibition of fatty acid beta-oxidation through the suppression of PPARalpha activation as a contributing mechanism of acetaminophen-induced hepatotoxicity

Metabolic bioactivation, glutathione depletion, and covalent binding are the early hallmark events after acetaminophen (APAP) overdose. However, the subsequent metabolic consequences contributing to APAP-induced hepatic necrosis and apoptosis have not been fully elucidated. In this study, serum metabolomes of control and APAP-treated wild-type and Cyp2e1-null mice were examined by liquid chromatography-mass spectrometry (LC-MS) and multivariate data analysis. A dose-response study showed that the accumulation of long-chain acylcarnitines in serum contributes to the separation of wild-type mice undergoing APAP-induced hepatotoxicity from other mouse groups in a multivariate model. This observation, in conjunction with the increase of triglycerides and free fatty acids in the serum of APAP-treated wild-type mice, suggested that APAP treatment can disrupt fatty acid beta-oxidation. A time-course study further indicated that both wild-type and Cyp2e1-null mice had their serum acylcarnitine levels markedly elevated within the early hours of APAP treatment. While remaining high in wild-type mice, serum acylcarnitine levels gradually returned to normal in Cyp2e1-null mice at the end of the 24 h treatment. Distinct from serum aminotransferase activity and hepatic glutathione levels, the pattern of serum acylcarnitine accumulation suggested that acylcarnitines can function as complementary biomarkers for monitoring the APAP-induced hepatotoxicity. An essential role for peroxisome proliferator-activated receptor alpha (PPARalpha) in the regulation of serum acylcarnitine levels was established by comparing the metabolomic responses of wild-type and Ppara-null mice to a fasting challenge. The upregulation of PPARalpha activity following APAP treatment was transient in wild-type mice but was much more prolonged in Cyp2e1-null mice. Overall, serum metabolomics of APAP-induced hepatotoxicity revealed that the CYP2E1-mediated metabolic activation and oxidative stress following APAP treatment can cause irreversible inhibition of fatty acid oxidation, potentially through suppression of PPARalpha-regulated pathways.

BCL6 suppression of BCL2 via Miz1 and its disruption in diffuse large B cell lymphoma

The BCL6 proto-oncogene encodes a transcriptional repressor that is required for germinal center (GC) formation and whose deregulation by genomic lesions is implicated in the pathogenesis of GC-derived diffuse large B cell lymphoma (DLBCL) and, less frequently, follicular lymphoma (FL). The biological function of BCL6 is only partially understood because no more than a few genes have been functionally characterized as direct targets of BCL6 transrepression activity. Here we report that the anti-apoptotic proto-oncogene BCL2 is a direct target of BCL6 in GC B cells. BCL6 binds to the BCL2 promoter region by interacting with the transcriptional activator Miz1 and suppresses Miz1-induced activation of BCL2 expression. BCL6-mediated suppression of BCL2 is lost in FL and DLBCL, where the 2 proteins are pathologically coexpressed, because of BCL2 chromosomal translocations and other mechanisms, including Miz1 deregulation and somatic mutations in the BCL2 promoter region. These results identify an important function for BCL6 in facilitating apoptosis of GC B cells via suppression of BCL2, and suggest that blocking this pathway is critical for lymphomagenesis.

Systematic Functional Analysis of BicD Serine Phosphorylation and Intragenic Suppression of a Female Sterile Allele of BicD

Protein phosphorylation is involved in posttranslational control of essentially all biological processes. Using mass spectrometry, recent analyses of whole phosphoproteomes led to the identification of numerous new phosphorylation sites. However, the function of most of these sites remained unknown. We chose the Drosophila Bicaudal-D protein to estimate the importance of individual phosphorylation events. Being involved in different cellular processes, BicD is required for oocyte determination, for RNA transport during oogenesis and embryogenesis, and for photoreceptor nuclei migration in the developing eye. The numerous roles of BicD and the available evidence for functional importance of BicD phosphorylation led us to identify eight phosphorylation sites of BicD, and we tested a total of 14 identified and suspected phosphoserine residues for their functional importance in vivo in flies. Surprisingly, all these serines turned out to be dispensable for providing sufficient basal BicD activity for normal growth and development. However, in a genetically sensitized background where the BicD(A40V) protein variant provides only partial activity, serine 103 substitutions are not neutral anymore, but show surprising differences. The S103D substitution completely inactivates the protein, whereas S103A behaves neutral, and the S103F substitution, isolated in a genetic screen, restores BicD(A40V) function. Our results suggest that many BicD phosphorylation events may either be fortuitous or play a modulating function as shown for Ser(103). Remarkably, amongst the Drosophila serines we found phosphorylated, Ser(103) is the only one that is fully conserved in mammalian BicD.

Age-dependent suppression of SERCA2a mRNA in pediatric atrial myocardium

Differential expression of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban (PLB) has been shown in heart failure and atrial arrhythmias. We investigated the influence of volume overload and age on their expression in pediatric atrial myocardium. Right atrial specimens from 18 children with volume overloaded right atrium (VO) and 12 patients without overload were studied. Each group was further divided into patients less than and older than 12 months of age. Only in the younger patients SERCA2a was significantly reduced in the VO group. In younger patients PLB mRNA level tended to be lower in VO. The PLB:SERCA protein ratio was significantly reduced in the VO group. Age itself did not influence the SERCA2a and PLB expression, if the hemodynamic overload was not taken into account. This study is the first to show a combined influence of volume overload and age on atrial SERCA2a expression.

REVERSIBLE SUPPRESSION OF NITRIC OXIDE SYSTEM IN ESSENTIAL HYPERTENSION

Despite enormous research in the field of hypertension, its pathophysiology still remains largely unresolved and appears to be multifactorial. In the present communication, we have analyzed the status of nitric oxide (NO) in the patients with essential hypertension and age matched controls. We have found that the levels of NO are lowered in essential hypertension. The normalization of blood pressure by administration of antihypertensive therapy causes rise in the NO level indicating that perturbed NO status in essential hypertension is reversible. Addition of antioxidant to the antihypertensive drugs causes a further, though non significant, rise in the levels of NO, suggesting that antioxidants may be combined with antihypertensive drugs as adjunct in the management of essential hypertension.

Modeling and Vibration Suppression for Telescopic Systems of Structural Members with Clearance

Telescopic systems of structural members with clearance are found in many applications, e.g., mobile cranes, rack feeders, fork lifters, stacker cranes (see Figure 1). Operating these machines, undesirable vibrations may reduce the performance and increase safety problems. Therefore, this contribution has the aim to reduce these harmful vibrations. For a better understanding, the dynamic behaviour of these constructions is analysed. The main interest is the overlapping area of each two sections of the above described systems (see markings in Figure 1) which is investigated by measurements and by computations. A test rig is constructed to determine the dynamic behaviour by measuring fundamental vibrations and higher frequent oscillations, damping coefficients, special appearances and more. For an appropriate physical model, the governing boundary value problem is derived by applying Hamilton’s principle and a classical discretisation procedure is used to generate a coupled system of nonlinear ordinary differential equations as the corresponding truncated mathematical model. On the basis of this model, a controller concept for preventing harmful vibrations is developed.

Suppression of OCT4B enhances sensitivity of lung adenocarcinoma A549 cells to cisplatin via increased apoptosis

BACKGROUND Resistance to chemotherapy in lung adenocarcinoma remains a major obstacle. We examined the potential role of Octamer-binding transcription factor-4B (OCT4B) in enhancing sensitivity of lung adenocarcinoma cells to cisplatin. MATERIALS AND METHODS RNAi interference was used to examine the role of OCT4B in cisplatin-treated A549 cells. Cells were transfected with OCT4B siRNA prior to a 48-h cisplatin treatment. Propidium iodide (PI) and caspase-3 staining were used to determine cell viability and apoptosis. Cell-cycle analysis was performed to evaluate alterations in phase distribution. RESULTS OCT4B suppression in cells increased the number of non-viable, PI(+), and apoptotic, caspase-3(+) cells in the presence and absence of cisplatin treatment. Importantly, cisplatin treatment of OCT4B-suppressed cells resulted in a marked transition of cells from G0/G1 to G2/M phase. CONCLUSION Silencing of OCT4B confers sensitivity to cisplatin treatment in A549 cells via cell-cycle regulation, increased proliferation and enhancement of cisplatin-induced apoptosis. OCT4B clearly protects A549 cells from apoptosis.

Higher CNS Penetration-Effectiveness of Long-term Combination Antiretroviral Therapy Is Associated With Better HIV-1 Viral Suppression in Cerebrospinal Fluid

Objectives: To determine HIV-1 RNA in cerebrospinal fluid (CSF) of successfully treated patients and to evaluate if combination antiretroviral treatments with higher central nervous system penetration-effectiveness (CPE) achieve better CSF viral suppression. Methods: Viral loads (VLs) and drug concentrations of lopinavir, atazanavir, and efavirenz were measured in plasma and CSF. The CPE was calculated using 2 different methods. Results: The authors analyzed 87 CSF samples of 60 patients. In 4 CSF samples, HIV-1 RNA was detectable with 43–82 copies per milliliter. Median CPE in patients with detectable CSF VL was significantly lower compared with individuals with undetectable VL: CPE of 1.0 (range, 1.0–1.5) versus 2.3 (range, 1.0–3.5) using the method of 2008 (P = 0.011) and CPE of 6 (range, 6–8) versus 8 (range, 5–12) using the method of 2010 (P = 0.022). The extrapolated CSF trough levels for atazanavir (n = 12) were clearly above the 50% inhibitory concentration (IC50) in only 25% of samples; both patients on atazanavir/ritonavir with detectable CSF HIV-1 RNA had trough levels in the range of the presumed IC50. The extrapolated CSF trough level for lopinavir (n = 42) and efavirenz (n = 18) were above the IC50 in 98% and 78%, respectively, of samples, including the patients with detectable CSF HIV-1 RNA. Conclusions: This study suggests that treatment regimens with high intracerebral efficacy reflected by a high CPE score are essential to achieve CSF HIV-1 RNA suppression. The CPE score including all drug components was a better predictor for treatment failure in the CSF than the sole concentrations of protease inhibitor or nonnucleoside reverse transcriptase inhibitor in plasma or CSF.

Entwicklung eines Screening-Instruments zu Rumination und Suppression RS-8

Rumination und Suppression sind 2 maladaptive Emotionsregulationsstrategien, die im Zusammenhang mit pathologischem Verhalten wie übermäßigem Essen oder Trinken stehen. Ein Messinstrument, welches beide Strategien in Kurzform erfasst, fehlt bisher. Der RS-8 erfasst mit 8 Items die beiden Dimensionen Rumination und Suppression. Anhand von 2 klinischen (Patienten mit Alkoholabhängigkeit [n = 79], Patienten mit Adipositas [n = 53]) und einer nichtklinischen Stichprobe (n = 133) wurde die psychometrische Qualität der Skala überprüft. Die Ergebnisse zeigen, dass der RS-8 ein valides und reliables Messinstrument ist. Die interne Konsistenz kann als gut und die faktorielle Validität als sehr gut bewertet werden. Der RS-8 ist ein ökonomisches Screening-Instrument, welches bei klinischen und nicht-klinischen Stichproben eingesetzt werden kann.

Platelet-activating factor is crucial in psoralen and ultraviolet A-induced immune suppression, inflammation, and apoptosis.

Psoralen plus UVA (PUVA) is used as a very effective treatment modality for various diseases, including psoriasis and cutaneous T-cell lymphoma. PUVA-induced immune suppression and/or apoptosis are thought to be responsible for the therapeutic action. However, the molecular mechanisms by which PUVA acts are not well understood. We have previously identified platelet-activating factor (PAF), a potent phospholipid mediator, as a crucial substance triggering ultraviolet B radiation-induced immune suppression. In this study, we used PAF receptor knockout mice, a selective PAF receptor antagonist, a COX-2 inhibitor (presumably blocking downstream effects of PAF), and PAF-like molecules to test the role of PAF receptor binding in PUVA treatment. We found that activation of the PAF pathway is crucial for PUVA-induced immune suppression (as measured by suppression of delayed type hypersensitivity to Candida albicans) and that it plays a role in skin inflammation and apoptosis. Downstream of PAF, interleukin-10 was involved in PUVA-induced immune suppression but not inflammation. Better understanding of PUVA's mechanisms may offer the opportunity to dissect the therapeutic from the detrimental (ie, carcinogenic) effects and/or to develop new drugs (eg, using the PAF pathway) that act like PUVA but have fewer side effects.

IL-2 REGULATION OF IL-24 EXPRESSION LEADS TO GROWTH SUPPRESSION OF MELANOMA CELLS

Melanoma is known to be highly resistant to chemotherapy. Treatment with high dose IL-2 has shown significant clinical benefit in a minority of metastatic melanoma patients and has lead to long term survival in a few cases. However, this treatment is associated with excessive multiorgan toxicities, which severely limits its use. We hypothesize that one mechanism of effective IL-2 therapy is through the direct upregulation of IL-24 production in melanoma tumors and subsequent IL-24 mediated tumor growth suppression. Five melanoma cell lines were treated with high dose recombinant hIL-2 at 1000U/ml. Three of the cell lines (A375, WM1341, WM793) showed statistically significant increases in their levels of IL-24 protein when measured by Western blotting, while the remaining two lines (WM35, MeWo) remained negative for IL-24 message and protein. This increase in IL-24 was abolished by either preincubating with an anti-IL-2 antibody or by blocking the IL-2 receptor directly with antibodies against the receptor chains. We also demonstrated by ELISA that these three cell lines secrete IL-24 protein in higher amounts when stimulated with IL-2 than do untreated cells. These cells were found to contain IL-2R beta and gamma message by RT-PCR and also expressed higher levels of IL-24 when treated with IL-15, which shares the IL-2R beta chain. Thus we propose that IL-2 is signaling through IL-2R beta on some melanoma cells to upregulate IL-24 protein expression. To address the biological function of IL-2 in melanoma cells, five cell lines were treated with IL-2 and cell viability determined. Cell growth was found to be significantly decreased by day 4 in the IL-24 positive cell lines while no effect on growth was seen in WM35 or MeWo. Incubating the cells with anti-IL-24 antibody or transfecting with IL-24 siRNA effectively negated the growth suppression seen with IL-2. These data support our hypothesis that in addition to its immunotherapeutic effects, IL-2 also acts directly on some melanoma tumors and that the IL-24 and IL-2R beta status of a tumor may be useful in predicting patient response to high dose IL-2.

E2F1 AND TUMOR SUPPRESSION: THE ROLE OF p21, miRNAS, AND THE DNA DAMAGE RESPONSE

E2F1 is a multi-faceted protein that has roles in a number of important cellular processes including cell cycle regulation, apoptosis, proliferation, and the DNA damage response (DDR). Moreover, E2F1 has opposing roles in tumor development, acting as either a tumor suppressor or an oncogene depending on the context. In human cancer, E2F1 is often deregulated through aberrations in the Rb-p16INK4a-cyclin D1 pathway. In these studies we examined three mechanisms by which E2F1 might mediate its tumor suppressive properties: p21-induced senescence, miRNAs, and the DNA damage response. We found that E2F1 acts as a tumor suppressor in response to ras activation through a non-apoptotic mechanism requiring ARF and p53, but not p21. However, p21-loss inhibited two-stage chemical carcinogenesis in FVB mice. In response to E2F1 overexpression, we found that 22 miRNAs are differentially regulated in mouse epidermis, including let-7a, let-7c, and miR-301. Additionally, regulation of miR-301 involves binding of E2F1 to its promoter. Finally, our data indicate a role for E2F1 at sites of DNA damage requiring E2F1’s phosphorylation at serine 31 which may involve DNA repair. Further, this role in the DDR may affect tumor aggressiveness and multiplicity. In all, we have explored three mechanisms for E2F1-induced tumor suppression and identified E2F1’s role in the DNA damage response as a likely contributor to this phenomenon.

rIFN-gamma-mediated growth suppression of platinum-sensitive and -resistant ovarian tumor cell lines not dependent upon arginase inhibition.

BACKGROUND: Arginine metabolism in tumor cell lines can be influenced by various cytokines, including recombinant human interferon-gamma (rIFN-gamma), a cytokine that shows promising clinical activity in epithelial ovarian cancer (EOC). METHODS: We examined EOC cell lines for the expression of arginase in an enzymatic assay and for transcripts of arginase I and II, inducible nitric oxide synthase (iNOS), and indoleamine 2,3-dioxygenase (IDO) by reverse transcription-polymerase chain reaction. The effects of rIFN-gamma on arginase activity and on tumor cell growth inhibition were determined by measuring [3H]thymidine uptake. RESULTS: Elevated arginase activity was detected in 5 of 8 tumor cell lines, and analysis at the transcriptional level showed that arginase II was involved but arginase I was not. rIFN-gamma reduced arginase activity in 3 EOC cell lines but increased activity in the 2008 cell line and its platinum-resistant subline, 2008.C13. iNOS transcripts were not detected in rIFN-gamma-treated or untreated cell lines. In contrast, IDO activity was induced or increased by rIFN-gamma. Suppression of arginase activity by rIFN-gamma in certain cell lines suggested that such inhibition might contribute to its antiproliferative effects. However, supplementation of the medium with polyamine pathway products did not interfere with the growth-inhibitory effects of rIFN-gamma EOC cells. CONCLUSIONS: Increased arginase activity, specifically identified with arginase II, is present in most of the tested EOC cell lines. rIFN-gamma inhibits or stimulates arginase activity in certain EOC cell lines, though the decrease in arginase activity does not appear to be associated with the in vitro antiproliferative activity of rIFN-gamma. Since cells within the stroma of EOC tissues could also contribute to arginine metabolism following treatment with rIFN-gamma or rIFN-gamma-inducers, it would be helpful to examine these effects in vivo.