Depletion of DNMT3A Suppressed Cell Proliferation and Restored PTEN in Hepatocellular Carcinoma Cell

Promoter hypermethylation mediated by DNA methyltransferases (DNMTs) is the main reason for epigenetic inactivation of tumor suppressor genes (TSGs). Previous studies showed that DNMT1 and DNMT3B play an important role in CpG island methylation in tumorigenesis. Little is known about the role of DNMT3A in this process, especially in hepatocellular carcinoma (HCC). In the present study, increased DNMT3A expression in 3 out of 6 HCC cell lines and 16/25 (64%) HCC tissues implied that DNMT3A is involved in hepatocellular carcinogenesis. Depletion of DNMT3A in HCC cell line SMMC-7721 inhibited cell proliferation and decreased the colony formation (about 65%). Microarray data revealed that 153 genes were upregulated in DNMT3A knockdown cells and that almost 71% (109/153) of them contain CpG islands in their 5′ region. 13 of them including PTEN, a crucial tumor suppressor gene in HCC, are genes involved in cell cycle and cell proliferation. Demethylation of PTEN promoter was observed in DNMT3A-depleted cells implying that DNMT3A silenced PTEN via DNA methylation. These results provide insights into the mechanisms of DNMT3A to regulate TSGs by an epigenetic approach in HCC

The Natural Occurring Compounds Targeting Endoplasmic Reticulum Stress

ER stress has been implicated in pathophysiological development of many diseases. Persistent overwhelming stimuli trigger ER stress to initiate apoptosis, autophagy, and cell death. IRE1-JNK and eIF2α-CHOP signaling pathways are the two important players of ER stress, which is also modulated by ROS production, calcium disturbance, and inflammatory factors. ER stress has been developed as a novel strategy for diseases management. Recently, a vast of research focuses on the natural occurring compounds targeting ER stress, which results in medical benefits to human diseases. These small reported molecules mainly include polyphenols, alkaloids, and saponins. Many of them have been developed for use in clinical applications. To better understand the pharmacological mechanism of these molecules in ER stress in diseases, efforts have been made to discover and deliver medical merits. In this paper, we will summarize the natural occurring compounds targeting ER stress

Fetal haemoglobin response to hydroxycarbamide treatment and sar1a promoter polymorphisms in sickle cell anaemia

The hydroxycarbamide (HC)-inducible small guanosine triphosphate (GTP)-binding protein, secretion-associated and RAS-related (SAR) protein has recently been shown to play a pivotal role in HBG induction and erythroid maturation by causing cell apoptosis and G1/S-phase arrest. Our preliminary analysis indicated that HC inducibility is transcriptionally regulated by elements within the SAR1A promoter. This study aimed to assess whether polymorphisms in the SAR1A promoter are associated with differences Hb F levels or HC therapeutic responses among sickle cell disease (SCD) patients. We studied 386 individuals with SCD comprised of 269 adults treated with or without HC and 117 newborns with SCD identified from a newborn screening program. Three previously unknown single nucleotide polymorphisms (SNPs) in the upstream 5′UTR (−809 C>T, −502 G>T and −385 C>A) were significantly associated with the fetal haemoglobin (HbF) response in Hb SS patients treated with HC (P < 0·05). In addition, four SNPs (rs2310991, −809 C>T, −385 C>A and rs4282891) were significantly associated with the change in absolute HbF after 2 years of treatment with HC. These data suggest that variation within SAR1A regulatory elements might contribute to inter-individual differences in regulation of HbF expression and patient responses to HC in SCD

The Multifunctional Effects of Nobiletin and Its Metabolites In Vivo

Nobiletin (NOB) chemically known as 5,6,7,8,3′,4′-hexamethoxyflavone is a dietary polymethoxylated flavonoid found in Citrus fruits. Recent evidences show that NOB is a multifunctional pharmaceutical agent. The various pharmacological activities of NOB include neuroprotection, cardiovascular protection, antimetabolic disorder, anticancer, anti-inflammation, and antioxidation. These events may be underpinned by modulation of signaling cascades, including PKA/ERK/MEK/CREB, NF-κB, MAPK, Ca2+/CaMKII, PI3K/Akt1/2, HIF-1α, and TGFβ signaling pathways. The metabolites may exhibit stronger beneficial effects than NOB on diseases pathogenesis. The biological activities of NOB have been clarified on many systems. This review aims to discuss the pharmacological effects of NOB with specific mechanisms of actions. NOB may become a promising candidate for potential drug development. However, further investigations of NOB on specific intracellular targets and clinical trials are still needed, especially for in vivo medical applications

Combination of Human Leukocyte Antigen and Killer Cell Immunoglobulin-Like Receptor Genetic Background Influences the Onset Age of Hepatocellular Carcinoma in Male Patients with Hepatitis B Virus Infection

To investigate whether killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) genetic background could influence the onset age of hepatocellular carcinoma (HCC) in patients with hepatitis B virus (HBV) infection, one hundred and seventy-one males with HBV-related HCC were enrolled. The presence of 12 loci of KIR was detected individually. HLA-A, -B, and -C loci were genotyped with high resolution by a routine sequence-based typing method. The effect of each KIR locus, HLA ligand, and HLA-KIR combination was examined individually by Kaplan-Meier (KM) analysis. Multivariate Cox hazard regression model was also applied. We identified C1C1-KIR2DS2/2DL2 as an independent risk factor for earlier onset age of HCC (median onset age was 44 for C1C1-KIR2DS2/2DL2 positive patients compared to 50 for negative patients, P=0.04 for KM analysis; HR = 1.70, P=0.004 for multivariate Cox model). We conclude that KIR and HLA genetic background can influence the onset age of HCC in male patients with HBV infection. This study may be useful to improve the current HCC surveillance program in HBV-infected patients. Our findings also suggest an important role of natural killer cells (or other KIR-expressing cells) in the progress of HBV-related HCC development

KIR and HLA Loci Are Associated with Hepatocellular Carcinoma Development in Patients with Hepatitis B Virus Infection: A Case-Control Study

BACKGROUND: Natural killer (NK) cells activation has been reported to contribute to inflammation and liver injury during hepatitis B virus (HBV) infection both in transgenic mice and in patients. However, the role of NK cells in the process of HBV-associated hepatocellular carcinoma (HCC) development has not been addressed. Killer cell immunoglobulin-like receptors (KIRs) are involved in regulating NK cell activation through recognition of specific human leukocyte antigen (HLA) class I allotypes. METHODOLOGY/PRINCIPAL FINDINGS: To investigate whether KIR and HLA genes could influence the risk of HBV-associated HCC development, 144 HBV-infected patients with HCC and 189 well-matched HBV infectors with chronic hepatitis or cirrhosis as non-HCC controls were enrolled in this study. The presence of 12 loci of KIR was detected individually. HLA-A, -B, -C loci were genotyped with high-resolution. HLA-C group 1 homozygote (OR = 2.02; p = 0.005), HLA-Bw4-80I (OR = 2.67; p = 2.0E-04) and combination of full-length form and 22 bp-deleted form of KIR2DS4 (KIR2DS4/1D) (OR = 1.89; p = 0.017) were found associated with HCC incidence. When the combined effects of these three genetic factors were evaluated, more risk factors were observed correlating with higher odds ratios for HCC incidence (P trend = 7.4E-05). Because all the risk factors we found have been reported to result in high NK cell functional potential by previous studies, our observations suggest that NK cell activation may contribute to HBV-associated HCC development. CONCLUSIONS/SIGNIFICANCE: In conclusion, this study has identified significant associations that suggest an important role for NK cells in HCC incidence in HBV-infected patients. Our study is useful for HCC surveillance and has implications for novel personalized therapy strategy development aiming at HCC prevention in HBV-infected patients

Étude de deux gènes effecteurs de la voie Toll impliqués dans la résilience et la résistance aux infections microbiennes chez Drosophila melanogaster

La réponse immunitaire systémique de la drosophile contre de nombreuses bactéries et champignons à Grampositif est assurée par la voie Toll. La façon dont les effecteurs régulés par la voie Toll remplissent réellement ce rôle reste mal connue car les gènes des peptides antimicrobiens régulés par cette voie ne sont actifs que contre les champignons filamenteux et non contre les bactéries à Gram-positif ou les levures. Ce travail a porté sur l’élucidation de la fonction biologique dans la défense de l’hôte contre les infections microbiennes de deux effecteurs sécrétés de la voie Toll, BaramicinA et GNBP-like3. L’analyse génétique de BaraA présentée ici révèle un rôle pour BaraA dans la résilience contre deux infections spécifiques, la bactérie à Gram-positif Enterococcus faecalis et le champignon entomopathogène Metarhizium robertsii. Pourtant, une analyse protéomique basée sur l’électrophorèse sur gel bidimensionnel a révélé que GNBP-like 3 était l’une des protéines les plus induites par une infection fongique, en accord avec une fonction effectrice potentielle. Ici, nous avons démontré une fonction protectrice de BaraA contre deux toxines l’EnterocinV de E. faecalis et la Destruxin A de M. robertsii. Il serait intéressant de déterminer si ces toxines sont constamment sécrétées au cours de l’infection ou si une dose initiale est suffisante pour atteindre un seuil de dommages chez les mutants de BaraA. En revanche, les mutants de GNBP-like3 présentent une charge en Candida glabrata nettement accrue au cours de l’infection. Cependant, il faudra déterminer si GNBP-like 3 fonctionne comme un véritable peptide antimicrobien. Ce travail ouvre de nouvelles directions de recherche et certaines des questions en suspens sont évoquées dans la discussion finale.The Drosophila systemic immune response against many Gram-positive bacteria and fungi is mediated by theToll pathway. How Toll-regulated effectors actually fulfill this role remains poorly understood as the knownToll-regulated antimicrobial peptide (AMP) genes are active only against filamentous fungi and not Grampositive bacteria or yeasts. This work has focused on the elucidation of the biological function in host defense against microbial infections of two secreted effectors of the Toll pathway, BaramicinA and GNBP-like 3. The genetic analysis of BaraA presented here reveals a role for BaraA in resilience against two specific infections, the Gram-positive bacterium Enterococcus faecalis and the entomopathogenic fungus Metarhizium robertsii. A proteomics analysis relying on 2D-gel electrophoresis revealed that GNBP-like 3 was one of the most induced protein upon a fungal challenge, in keeping with a potential effector function. Here, we have demonstrated a protective function of BaraA against two toxins EnterocinV from E. faecalis and Destruxin A from M. robertsii. It would be interesting to determine whether these toxins are constantly secreted during infection or whether just an initial dose is sufficient to reach a threshold level of damages in BaraA mutants. In contrast, GNBP-like 3 mutants exhibit a clearly increased C. glabrata load during the infection. However, whether GNBP-like 3 functions as a genuine AMP needs to be assessed. This work opens novel research directions and some of the outstanding issues are outlined in the concluding discussion

Characterization of summertime aerosols at Ny-Ålesund in the Arctic

Characteristics of atmospheric aerosols have implications for aerosol radiative forcing, aerosol-cloud interactions, heterogeneous chemistry, and climate. To characterize summertime aerosols in the Arctic, aerosol samples were collected at Ny-Ålesund in July of 2011 and 2012. The specific objectives were: (1) to determine aerosol compositions, (2) to investigate the sources and deposition of selected aerosol components, (3) to identify the effects of ship emissions on aerosol concentrations, and (4) to investigate the formation of secondary inorganic aerosols (SIAs), aerosol acidity and chloride (Cl−) depletion. The results showed that the mean equivalent black carbon (EBC) concentration was 17 ng m-3 at the Ny-Ålesund settlement, higher than the mean value of 5.4 ng m-3 observed outside the Ny-Ålesund settlement in July 2011. The average local emission rate of EBC was 8.1 g h-1, with an uncertainty of approximately a factor of two. The EBC plumes from local emissions were confined to 10 km downwind, with the total EBC deposition estimated to be 6.4–44 ng m-2 h-1. When two cruise ships with more than 1500 passengers visited Ny-Ålesund in July 2012, the concentrations of the nc-V, nc-Ni and nss-SO42− were 0.976 ng m−3, 0.572 ng m−3 and 203 ng m−3, which were 38-fold, 8-fold and 2-fold higher than their median values of the sampling period. In July 2012, the mean SIAs concentration, defined as the sum of nss-SO42−, NO3− and NH4+, was 158 ng m−3, accounted for 33% of the total mass of ionic species. The mean neutralization ratio (NR) was 0.53, indicating that SO42− and NO3− was not fully neutralized by NH4+. The Cl− depletion occurred in samples that had high concentrations of [nss-SO42− + NO3− − NH4+] and sea salt, indicating that the Cl− depletion could be affected by interactions of acidic species (SO42−, NO3−) with sea salt. Results from this study fill the data gap of the chemical properties of summertime aerosols and the effects of local emissions on air quality at Ny-Ålesund in the Arctic. These results may serve for future research that seeks to assess aerosol radiative forcing and for developing emission reduction strategies in the Arctic.Ph.D.Includes bibliographical referencesIncludes vitaby Jianqiong Zha

Étude de deux gènes effecteurs de la voie Toll impliqués dans la résilience et la résistance aux infections microbiennes chez Drosophila melanogaster

La réponse immunitaire systémique de la drosophile contre de nombreuses bactéries et champignons à Grampositif est assurée par la voie Toll. La façon dont les effecteurs régulés par la voie Toll remplissent réellement ce rôle reste mal connue car les gènes des peptides antimicrobiens régulés par cette voie ne sont actifs que contre les champignons filamenteux et non contre les bactéries à Gram-positif ou les levures. Ce travail a porté sur l’élucidation de la fonction biologique dans la défense de l’hôte contre les infections microbiennes de deux effecteurs sécrétés de la voie Toll, BaramicinA et GNBP-like3. L’analyse génétique de BaraA présentée ici révèle un rôle pour BaraA dans la résilience contre deux infections spécifiques, la bactérie à Gram-positif Enterococcus faecalis et le champignon entomopathogène Metarhizium robertsii. Pourtant, une analyse protéomique basée sur l’électrophorèse sur gel bidimensionnel a révélé que GNBP-like 3 était l’une des protéines les plus induites par une infection fongique, en accord avec une fonction effectrice potentielle. Ici, nous avons démontré une fonction protectrice de BaraA contre deux toxines l’EnterocinV de E. faecalis et la Destruxin A de M. robertsii. Il serait intéressant de déterminer si ces toxines sont constamment sécrétées au cours de l’infection ou si une dose initiale est suffisante pour atteindre un seuil de dommages chez les mutants de BaraA. En revanche, les mutants de GNBP-like3 présentent une charge en Candida glabrata nettement accrue au cours de l’infection. Cependant, il faudra déterminer si GNBP-like 3 fonctionne comme un véritable peptide antimicrobien. Ce travail ouvre de nouvelles directions de recherche et certaines des questions en suspens sont évoquées dans la discussion finale.The Drosophila systemic immune response against many Gram-positive bacteria and fungi is mediated by theToll pathway. How Toll-regulated effectors actually fulfill this role remains poorly understood as the knownToll-regulated antimicrobial peptide (AMP) genes are active only against filamentous fungi and not Grampositive bacteria or yeasts. This work has focused on the elucidation of the biological function in host defense against microbial infections of two secreted effectors of the Toll pathway, BaramicinA and GNBP-like 3. The genetic analysis of BaraA presented here reveals a role for BaraA in resilience against two specific infections, the Gram-positive bacterium Enterococcus faecalis and the entomopathogenic fungus Metarhizium robertsii. A proteomics analysis relying on 2D-gel electrophoresis revealed that GNBP-like 3 was one of the most induced protein upon a fungal challenge, in keeping with a potential effector function. Here, we have demonstrated a protective function of BaraA against two toxins EnterocinV from E. faecalis and Destruxin A from M. robertsii. It would be interesting to determine whether these toxins are constantly secreted during infection or whether just an initial dose is sufficient to reach a threshold level of damages in BaraA mutants. In contrast, GNBP-like 3 mutants exhibit a clearly increased C. glabrata load during the infection. However, whether GNBP-like 3 functions as a genuine AMP needs to be assessed. This work opens novel research directions and some of the outstanding issues are outlined in the concluding discussion