Publications by authors named "Hiromi Kudo"

30 Publications

  • Page 1 of 1

PD-1 blockade improves Kupffer cell bacterial clearance in acute liver injury.

J Clin Invest 2021 Feb;131(4)

Department of Metabolism, Digestion and Reproduction, Section of Hepatology and Gastroenterology, and.

Patients with acute liver failure (ALF) have systemic innate immune suppression and increased susceptibility to infections. Programmed cell death 1 (PD-1) expression by macrophages has been associated with immune suppression during sepsis and cancer. We therefore examined the role of the programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) pathway in regulating Kupffer cell (KC) inflammatory and antimicrobial responses in acetaminophen-induced (APAP-induced) acute liver injury. Using intravital imaging and flow cytometry, we found impaired KC bacterial clearance and systemic bacterial dissemination in mice with liver injury. We detected increased PD-1 and PD-L1 expression in KCs and lymphocyte subsets, respectively, during injury resolution. Gene expression profiling of PD-1+ KCs revealed an immune-suppressive profile and reduced pathogen responses. Compared with WT mice, PD-1-deficient mice and anti-PD-1-treated mice with liver injury showed improved KC bacterial clearance, a reduced tissue bacterial load, and protection from sepsis. Blood samples from patients with ALF revealed enhanced PD-1 and PD-L1 expression by monocytes and lymphocytes, respectively, and that soluble PD-L1 plasma levels could predict outcomes and sepsis. PD-1 in vitro blockade restored monocyte functionality. Our study describes a role for the PD-1/PD-L1 axis in suppressing KC and monocyte antimicrobial responses after liver injury and identifies anti-PD-1 immunotherapy as a strategy to reduce infection susceptibility in ALF.
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http://dx.doi.org/10.1172/JCI140196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7880414PMC
February 2021

Stat2 loss disrupts damage signalling and is protective in acute pancreatitis.

J Pathol 2020 Sep 23;252(1):41-52. Epub 2020 Jul 23.

Blizard Institute, Queen Mary, University of London, London, UK.

The severity of sterile inflammation, as seen in acute pancreatitis, is determined by damage-sensing receptors, signalling cascades and cytokine production. Stat2 is a type I interferon signalling mediator that also has interferon-independent roles in murine lipopolysaccharide-induced NF-κB-mediated sepsis. However, its role in sterile inflammation is unknown. We hypothesised that Stat2 determines the severity of non-infective inflammation in the pancreas. Wild type (WT) and Stat2 mice were injected i.p. with caerulein or l-arginine. Specific cytokine-blocking antibodies were used in some experiments. Pancreata and blood were harvested 1 and 24 h after the final dose of caerulein and up to 96 h post l-arginine. Whole-tissue phosphoproteomic changes were assessed using label-free mass spectrometry. Tissue-specific Stat2 effects were studied in WT/Stat2 bone marrow chimera and using Cre-lox recombination to delete Stat2 in pancreatic and duodenal homeobox 1 (Pdx1)-expressing cells. Stat2 mice were protected from caerulein- and l-arginine-induced pancreatitis. Protection was independent of type I interferon signalling. Stat2 mice had lower cytokine levels, including TNF-α and IL-10, and reduced NF-κB nuclear localisation in pancreatic tissue compared with WT. Inhibition of TNF-α improved (inhibition of IL-10 worsened) caerulein-induced pancreatitis in WT but not Stat2 mice. Phosphoproteomics showed downregulation of MAPK mediators but accumulation of Ser412-phosphorylated Tak1. Stat2 deletion in Pdx1-expressing acinar cells (Stat2 ) reduced pancreatic TNF-α expression, but not histological injury or serum amylase. WT/Stat2 bone marrow chimera mice were protected from pancreatitis irrespective of host or recipient genotype. Stat2 loss results in disrupted signalling in pancreatitis, upstream of NF-κB in non-acinar and/or bone marrow-derived cells. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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http://dx.doi.org/10.1002/path.5481DOI Listing
September 2020

Lipogenesis Alters the Phospholipidome of Esophageal Adenocarcinoma.

Cancer Res 2020 07 28;80(13):2764-2774. Epub 2020 Apr 28.

Department of Surgery and Cancer, Imperial College London, London, United Kingdom.

The incidence of esophageal adenocarcinoma is rising, survival remains poor, and new tools to improve early diagnosis and precise treatment are needed. Cancer phospholipidomes quantified with mass spectrometry imaging (MSI) can support objective diagnosis in minutes using a routine frozen tissue section. However, whether MSI can objectively identify primary esophageal adenocarcinoma is currently unknown and represents a significant challenge, as this microenvironment is complex with phenotypically similar tissue-types. Here, we used desorption electrospray ionization-MSI (DESI-MSI) and bespoke chemometrics to assess the phospholipidomes of esophageal adenocarcinoma and relevant control tissues. Multivariate models derived from phospholipid profiles of 117 patients were highly discriminant for esophageal adenocarcinoma both in discovery (AUC = 0.97) and validation cohorts (AUC = 1). Among many other changes, esophageal adenocarcinoma samples were markedly enriched for polyunsaturated phosphatidylglycerols with longer acyl chains, with stepwise enrichment in premalignant tissues. Expression of fatty acid and glycerophospholipid synthesis genes was significantly upregulated, and characteristics of fatty acid acyls matched glycerophospholipid acyls. Mechanistically, silencing the carbon switch in esophageal adenocarcinoma cells shortened glycerophospholipid chains, linking lipogenesis to the phospholipidome. Thus, DESI-MSI can objectively identify invasive esophageal adenocarcinoma from a number of premalignant tissues and unveils mechanisms of phospholipidomic reprogramming. SIGNIFICANCE: These results call for accelerated diagnosis studies using DESI-MSI in the upper gastrointestinal endoscopy suite, as well as functional studies to determine how polyunsaturated phosphatidylglycerols contribute to esophageal carcinogenesis.
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http://dx.doi.org/10.1158/0008-5472.CAN-19-4035DOI Listing
July 2020

The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron.

Front Public Health 2020 11;8:17. Epub 2020 Feb 11.

Nuclear Physics Laboratory, Faculty of Science, University of Yaounde I, Yaounde, Cameroon.

Radon (Rn), thoron (Tn), and thoron progeny (TnP) were measured in seven inhabited areas of the uranium and thorium bearing region of Lolodorf, located in southwestern Cameroon. Then the equilibrium factor (F) between thoron and its progeny was determined in order to show the importance of direct progeny measurements for correct estimation of effective dose due to radon, thoron and their progenies. A total of 220 RADUET detectors were used to measure indoor radon and thoron and 130 TnP monitors for thoron progeny indoors. The arithmetic and geometric mean concentrations of Rn, Tn, and TnP were 103 and 89 Bq m, 173, and 118 Bq m, 10.7, and 7.4 Bq m, respectively. Total effective dose determined from radon, thoron, and their progenies was estimated at 4.2 ± 0.5 mSv y. Thoron equilibrium factor varied according to seasons, the type of dwelling, building materials and localities. Thoron (Tn and TnP) contribution to effective dose ranged between 3 and 80% with the average value of 53%. Total effective dose estimated from the world average equilibrium factor of 0.02 given by UNSCEAR was 2.7 ± 0.2 mSv y. The effective dose due to thoron varied greatly according to the different values taken by F and was different from that determined directly using TnP concentrations. Thus, effective dose due to thoron determined from the equilibrium factor is unreliable. Therefore, the risk of public exposure due to thoron (Tn and TnP) may therefore be higher than that of radon (Rn and RnP) in many parts of the world if F is no longer used in estimating total effective dose. This is not in contradiction with the UNSCEAR conclusions. It is therefore important to directly measure the radon and thoron progeny for a correct estimate of effective dose.
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http://dx.doi.org/10.3389/fpubh.2020.00017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026246PMC
February 2020

Simultaneous measurements of indoor radon and thoron and inhalation dose assessment in Douala City, Cameroon.

Isotopes Environ Health Stud 2019 Oct 9;55(5):499-510. Epub 2019 Aug 9.

Nuclear Physics Laboratory, Faculty of Science, University of Yaoundé I , Yaoundé , Cameroon.

Radon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon-thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31 ± 1 to 436 ± 12 Bq m, 4 ± 7 to 246 ± 5 Bq m, and 1.5 ± 0.9 to 13.1 ± 9.4 Bq m. The mean value of the equilibrium factor for thoron is estimated at 0.11 ± 0.16. The annual effective dose due to exposure to indoor radon and progeny ranges from 0.6 to 9 mSv a with an average value of 2.6 ± 0.1 mSv a. The effective dose due to the exposure to thoron and progeny vary from 0.3 to 2.9 mSv a with an average value of 1.0 ± 0.4 mSv a. The contribution of thoron and its progeny to the total inhalation dose ranges from 7 to 60 % with an average value of 26 %; thus their contributions should not be neglected in the inhalation dose assessment.
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http://dx.doi.org/10.1080/10256016.2019.1649258DOI Listing
October 2019

Systemic silencing of PHD2 causes reversible immune regulatory dysfunction.

J Clin Invest 2019 06 4;129(9):3640-3656. Epub 2019 Jun 4.

Nuffield Department of Medicine Research Building, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.

Physiological effects of cellular hypoxia are sensed by prolyl hydroxylase (PHD) enzymes which regulate HIFs. Genetic interventions on HIF/PHD pathways reveal multiple phenotypes that extend the known biology of hypoxia. Recent studies unexpectedly implicate HIF in aspects of multiple immune and inflammatory pathways. However such studies are often limited by systemic lethal effects and/or use tissue-specific recombination systems, which are inherently irreversible, un-physiologically restricted and difficult to time. To study these processes better we developed recombinant mice which express tetracycline-regulated shRNAs broadly targeting the main components of the HIF/PHD pathway, permitting timed bi-directional intervention. We have shown that stabilization of HIF levels in adult mice through PHD2 enzyme silencing by RNA interference, or inducible recombination of floxed alleles, results in multi-lineage leukocytosis and features of autoimmunity. This phenotype was rapidly normalized on re-establishment of the hypoxia-sensing machinery when shRNA expression was discontinued. In both situations these effects were mediated principally through the Hif2a isoform. Assessment of cells bearing regulatory T cell markers from these mice revealed defective function and pro-inflammatory effects in vivo. We believe our findings have shown a new role for the PHD2/Hif2a couple in the reversible regulation of T cell and immune activity.
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http://dx.doi.org/10.1172/JCI124099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6715380PMC
June 2019

SIMULTANEOUS INDOOR RADON, THORON AND THORON PROGENY MEASUREMENTS IN BETARE-OYA GOLD MINING AREAS, EASTERN CAMEROON.

Radiat Prot Dosimetry 2019 Dec;185(3):391-401

Department of Radiation Physics, Hirosaki University, Institute of Radiation Emergency Medicine, 66-1 Honcho, Hirosaki-shi, Aomori 036-8564, Japan.

Indoor radon (Rn), thoron (Tn) and thoron progeny (TnP) were simultaneously measured in the gold mining areas of Betare-Oya using RADUET detectors and TnP monitors. Rn and Tn concentrations range between 88-282 and 4-383 Bq m-3, respectively, with the arithmetic means of 133 ± 39 and 93 ± 76 Bq m-3. The 76% of houses for Rn and 25% for Tn exceed the WHO reference level of 100 Bq m-3 and 3% of the houses exceed the ICRP threshold of 300 Bq m-3. The equilibrium equivalent thoron concentration ranges between 1 and 19 Bq m-3 with a mean value of 6 ± 4 Bq m-3. The thoron equilibrium factor ranges between 0.01 and 0.55 with arithmetic mean of 0.11, higher than the world average value of 0.02 given by UNSCEAR. The total inhalation dose due to Rn, Tn and their progeny ranges between 1.8 and 6.2 mSv y-1 with the arithmetic mean of 3.8 ± 1.1 mSv y-1.
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http://dx.doi.org/10.1093/rpd/ncz026DOI Listing
December 2019

siRNA Library Screening Identifies a Druggable Immune-Signature Driving Esophageal Adenocarcinoma Cell Growth.

Cell Mol Gastroenterol Hepatol 2018 31;5(4):569-590. Epub 2018 Jan 31.

Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, British Columbia, Canada.

Background & Aims: Effective therapeutic approaches are urgently required to tackle the alarmingly poor survival outcomes in esophageal adenocarcinoma (EAC) patients. EAC originates from within the intestinal-type metaplasia, Barrett's esophagus, a condition arising on a background of gastroesophageal reflux disease and associated inflammation.

Methods: This study used a druggable genome small interfering RNA (siRNA) screening library of 6022 siRNAs in conjunction with bioinformatics platforms, genomic studies of EAC tissues, somatic variation data of EAC from The Cancer Genome Atlas data of EAC, and pathologic and functional studies to define novel EAC-associated, and targetable, immune factors.

Results: By using a druggable genome library we defined genes that sustain EAC cell growth, which included an unexpected immunologic signature. Integrating Cancer Genome Atlas data with druggable siRNA targets showed a striking concordance and an EAC-specific gene amplification event associated with 7 druggable targets co-encoded at Chr6p21.1. Over-representation of immune pathway-associated genes supporting EAC cell growth included leukemia inhibitory factor, complement component 1, q subcomponent A chain (C1QA), and triggering receptor expressed on myeloid cells 2 (TREM2), which were validated further as targets sharing downstream signaling pathways through genomic and pathologic studies. Finally, targeting the triggering receptor expressed on myeloid cells 2-, C1q-, and leukemia inhibitory factor-activated signaling pathways (TYROBP-spleen tyrosine kinase and JAK-STAT3) with spleen tyrosine kinase and Janus-activated kinase inhibitor fostamatinib R788 triggered EAC cell death, growth arrest, and reduced tumor burden in NOD scid gamma mice.

Conclusions: These data highlight a subset of genes co-identified through siRNA targeting and genomic studies of expression and somatic variation, specifically highlighting the contribution that immune-related factors play in support of EAC development and suggesting their suitability as targets in the treatment of EAC.
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http://dx.doi.org/10.1016/j.jcmgh.2018.01.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6009761PMC
January 2018

The surgical intelligent knife distinguishes normal, borderline and malignant gynaecological tissues using rapid evaporative ionisation mass spectrometry (REIMS).

Br J Cancer 2018 05 19;118(10):1349-1358. Epub 2018 Apr 19.

Imperial College, London, UK.

Background: Survival from ovarian cancer (OC) is improved with surgery, but surgery can be complex and tumour identification, especially for borderline ovarian tumours (BOT), is challenging. The Rapid Evaporative Ionisation Mass Spectrometric (REIMS) technique reports tissue histology in real-time by analysing aerosolised tissue during electrosurgical dissection.

Methods: Aerosol produced during diathermy of tissues was sampled with the REIMS interface. Histological diagnosis and mass spectra featuring complex lipid species populated a reference database on which principal component, linear discriminant and leave-one-patient-out cross-validation analyses were performed.

Results: A total of 198 patients provided 335 tissue samples, yielding 3384 spectra. Cross-validated OC classification vs separate normal tissues was high (97·4% sensitivity, 100% specificity). BOT were readily distinguishable from OC (sensitivity 90.5%, specificity 89.7%). Validation with fresh tissue lead to excellent OC detection (100% accuracy). Histological agreement between iKnife and histopathologist was very good (kappa 0.84, P < 0.001, z = 3.3). Five predominantly phosphatidic acid (PA(36:2)) and phosphatidyl-ethanolamine (PE(34:2)) lipid species were identified as being significantly more abundant in OC compared to normal tissue or BOT (P < 0.001, q < 0.001).

Conclusions: The REIMS iKnife distinguishes gynaecological tissues by analysing mass-spectrometry-derived lipidomes from tissue diathermy aerosols. Rapid intra-operative gynaecological tissue diagnosis may improve surgical care when histology is unknown, leading to personalised operations tailored to the individual.
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http://dx.doi.org/10.1038/s41416-018-0048-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5959892PMC
May 2018

Genes Sufficient for Synthesizing Peptidoglycan are Retained in Gymnosperm Genomes, and MurE from Larix gmelinii can Rescue the Albino Phenotype of Arabidopsis MurE Mutation.

Plant Cell Physiol 2017 Mar;58(3):587-597

Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555 Japan.

The endosymbiotic theory states that plastids are derived from a single cyanobacterial ancestor that possessed a cell wall. Peptidoglycan (PG), the main component of the bacteria cell wall, gradually degraded during plastid evolution. PG-synthesizing Mur genes have been found to be retained in the genomes of basal streptophyte plants, although many of them have been lost from the genomes of angiosperms. The enzyme encoded by bacterial MurE genes catalyzes the formation of the UDP-N-acetylmuramic acid (UDP-MurNAc) tripeptide in bacterial PG biosynthesis. Knockout of the MurE gene in the moss Physcomitrella patens resulted in defects of chloroplast division, whereas T-DNA-tagged mutants of Arabidopsis thaliana for MurE revealed inhibition of chloroplast development but not of plastid division, suggesting that AtMurE is functionally divergent from the bacterial and moss MurE proteins. Here, we could identify 10 homologs of bacterial Mur genes, including MurE, in the recently sequenced genomes of Picea abies and Pinus taeda, suggesting the retention of the plastid PG system in gymnosperms. To investigate the function of gymnosperm MurE, we isolated an ortholog of MurE from the larch, Larix gmelinii (LgMurE) and confirmed its presence as a single copy per genome, as well as its abundant expression in the leaves of larch seedlings. Analysis with a fusion protein combining green fluorescent protein and LgMurE suggested that it localizes in chloroplasts. Cross-species complementation assay with MurE mutants of A. thaliana and P. patens showed that the expression of LgMurE cDNA completely rescued the albefaction defects in A. thaliana but did not rescue the macrochloroplast phenotype in P. patens. The evolution of plastid PG and the mechanism behind the functional divergence of MurE genes are discussed in the context of information about plant genomes at different evolutionary stages.
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http://dx.doi.org/10.1093/pcp/pcx005DOI Listing
March 2017

The immunoreceptor NKG2D promotes tumour growth in a model of hepatocellular carcinoma.

Nat Commun 2017 01 27;8:13930. Epub 2017 Jan 27.

Department of Life Sciences, Imperial College London, SW7 2AZ London, UK.

Inflammation is recognized as one of the drivers of cancer. Yet, the individual immune components that possess pro- and anti-tumorigenic functions in individual cancers remain largely unknown. NKG2D is a potent activating immunoreceptor that has emerged as an important player in inflammatory disorders besides its well-established function as tumour suppressor. Here, we provide genetic evidence of an unexpected tumour-promoting effect of NKG2D in a model of inflammation-driven liver cancer. Compared to NKG2D-deficient mice, NKG2D-sufficient mice display accelerated tumour growth associated with, an increased recruitment of memory CD8T cells to the liver and exacerbated pro-inflammatory milieu. In addition, we show that NKG2D contributes to liver damage and consequent hepatocyte proliferation known to favour tumorigenesis. Thus, the NKG2D/NKG2D-ligand pathway provides an additional mechanism linking chronic inflammation to tumour development in hepatocellular carcinoma. Our findings expose the need to selectively target the types of cancer that could benefit from NKG2D-based immunotherapy.
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http://dx.doi.org/10.1038/ncomms13930DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5290164PMC
January 2017

Radiation dose due to radon and thoron progeny inhalation in high-level natural radiation areas of Kerala, India.

J Radiol Prot 2017 Mar 21;37(1):111-126. Epub 2016 Dec 21.

Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. Current address: Department of Radiation Physics and Chemistry, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295, Japan.

In order to evaluate internal exposure to radon and thoron, concentrations for radon, thoron, and thoron progeny were measured for 259 dwellings located in high background radiation areas (HBRAs, outdoor external dose: 3-5 mGy y) and low background radiation areas (control areas, outdoor external dose: 1 mGy y) in Karunagappally Taluk, Kerala, India. The measurements were conducted using passive-type radon-thoron detectors and thoron progeny detectors over two six-month measurement periods from June 2010 to June 2011. The results showed no major differences in radon and thoron progeny concentrations between the HBRAs and the control areas. The geometric mean of the annual effective dose due to radon and thoron was calculated as 0.10 and 0.44 mSv, respectively. The doses were small, but not negligible compared with the external dose in the two areas.
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http://dx.doi.org/10.1088/1361-6498/37/1/111DOI Listing
March 2017

Characteristic of thoron (Rn) in environment.

Appl Radiat Isot 2017 02 22;120:7-10. Epub 2016 Nov 22.

Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan. Electronic address:

This paper describes importance of Rn (hereafter thoron) progeny measurement for the dose estimation. Although the spatial distribution of thoron activity concentration strongly depends on the distance from wall surface as an indoor thoron source), a homogeneous distribution was expected to be observed for Pb activity concentration which was one of thoron progeny. Furthermore, the mean equilibrium factor for thoron obtained by the recent measurements in several countries widely ranged from 0.008 to 0.07. Therefore the bronchial dose evaluated using the equilibrium factor and activity concentration of thoron instead of thoron progeny activity concentration may have a large uncertainty. Thus, the thoron progeny measurement should be investigated at each measurement point for the dose estimation for thoron.
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http://dx.doi.org/10.1016/j.apradiso.2016.11.014DOI Listing
February 2017

Imaging of Esophageal Lymph Node Metastases by Desorption Electrospray Ionization Mass Spectrometry.

Cancer Res 2016 10 30;76(19):5647-5656. Epub 2016 Jun 30.

Department of Surgery and Cancer, Imperial College London, 10th Floor QEQM Wing, St Mary's Hospital, London, United Kingdom.

Histopathological assessment of lymph node metastases (LNM) depends on subjective analysis of cellular morphology with inter-/intraobserver variability. In this study, LNM from esophageal adenocarcinoma was objectively detected using desorption electrospray ionization-mass spectrometry imaging (DESI-MSI). Ninety lymph nodes (LN) and their primary tumor biopsies from 11 esophago-gastrectomy specimens were examined and analyzed by DESI-MSI. Images from mass spectrometry and corresponding histology were coregistered and analyzed using multivariate statistical tools. The MSIs revealed consistent lipidomic profiles of individual tissue types found within LNs. Spatial mapping of the profiles showed identical distribution patterns as per the tissue types in matched IHC images. Lipidomic profile comparisons of LNM versus the primary tumor revealed a close association in contrast to benign LN tissue types. This similarity was used for the objective prediction of LNM in mass spectrometry images utilizing the average lipidomic profile of esophageal adenocarcinoma. The multivariate statistical algorithm developed for LNM identification demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 89.5%, 100%, 100%, and 97.2%, respectively, when compared with gold-standard IHC. DESI-MSI has the potential to be a diagnostic tool for perioperative identification of LNM and compares favorably with techniques currently used by histopathology experts. Cancer Res; 76(19); 5647-56. ©2016 AACR.
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http://dx.doi.org/10.1158/0008-5472.CAN-16-0699DOI Listing
October 2016

A Comparison of DESI-MS and LC-MS for the Lipidomic Profiling of Human Cancer Tissue.

J Am Soc Mass Spectrom 2016 Feb;27(2):255-64

Department of Surgery and Cancer, Imperial College London, 10th Floor QEQM Wing, St. Mary’s Hospital, London, W2 1NY, UK

In this study, we make a direct comparison between desorption electrospray ionization-mass spectrometry (DESI-MS) and ultraperformance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS) platforms for the profiling of glycerophospholipid (GPL) species in esophageal cancer tissue. In particular, we studied the similarities and differences in the range of GPLs detected and the congruency of their relative abundances as detected by each analytical platform. The main differences between mass spectra of the two modalities were found to be associated with the variance in adduct formation of common GPLs, rather than the presence of different GPL species. Phosphatidylcholines as formate adducts in UPLC-ESI-MS accounted for the majority of differences in negative ion mode and alkali metal adducts of phosphatidylcholines in DESI-MS for positive ion mode. Comparison of the relative abundance of GPLs, normalized to a common peak, revealed a correlation coefficient of 0.70 (P < 0.001). The GPL profile detected by DESI-MS is congruent to UPLC-ESI-MS, which reaffirms the role of DESI-MS for lipidomic profiling and a potential premise for quantification.
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http://dx.doi.org/10.1007/s13361-015-1278-8DOI Listing
February 2016

Estimation of external dose by car-borne survey in Kerala, India.

PLoS One 2015 17;10(4):e0124433. Epub 2015 Apr 17.

Hirosaki University Graduate School of Health Sciences, Aomori, Japan.

A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0124433PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4401755PMC
April 2016

Laser-induced tissue fluorescence in radiofrequency tissue-fusion characterization.

J Biomed Opt 2014 Jan;19(1):15007

Imperial College London, St. Mary's Hospital, Department of Surgery and Cancer, London W2 1NY, United KingdombUniversity of Liverpool, Department of Electrical Engineering and Electronics, Liverpool L69 3GJ, United Kingdom.

Heat-induced tissue fusion is an important procedure in modern surgery and can greatly reduce trauma, complications, and mortality during minimally invasive surgical blood vessel anastomosis, but it may also have further benefits if applied to other tissue types such as small and large intestine anastomoses. We present a tissue-fusion characterization technology using laser-induced fluorescence spectroscopy, which provides further insight into tissue constituent variations at the molecular level. In particular, an increase of fluorescence intensity in 450- to 550-nm range for 375- and 405-nm excitation suggests that the collagen cross-linking in fused tissues increased. Our experimental and statistical analyses showed that, by using fluorescence spectral data, good fusion could be differentiated from other cases with an accuracy of more than 95%. This suggests that the fluorescence spectroscopy could be potentially used as a feedback control method in online tissue-fusion monitoring.
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http://dx.doi.org/10.1117/1.JBO.19.1.015007DOI Listing
January 2014

Hirmi Valley liver disease: a disease associated with exposure to pyrrolizidine alkaloids and DDT.

J Hepatol 2014 Jan 20;60(1):96-102. Epub 2013 Aug 20.

Department of Medicine, Imperial College London, UK. Electronic address:

Background & Aims: Hirmi Valley liver disease was first reported in 2001 in Tigray, Ethiopia. 591 cases, including 228 deaths, were reported up to December 2009. The pyrrolizidine alkaloid acetyllycopsamine was detected in stored grain and residents reported adding the pesticide DDT (dichlorodiphenyldichloroethylene) directly to their food stores. We aimed to characterise the clinical features of the disease, and explore the role of these chemicals in its aetiology.

Methods: 32 cases were examined and full clinical histories taken. Nine cases underwent liver biopsy in hospitals. Serum and urine samples were collected from cases and controls. Urine was analysed for acetyllycopsamine by UPLC-MS. Total DDT in serum was measured by ELISA. Hepatotoxicity of DDT and acetyllycopsamine alone or in combination was explored in C57BL/6J mice.

Results: Clinical presentation included epigastric pain, abdominal swelling, bloody diarrhoea, hepatomegaly, splenomegaly, and ascites. Histology revealed acute injury characterised by centrilobular necrosis or chronic injury with bile ductular reaction, cytomegaly and fibrosis but no hepatic vein occlusion. Acetyllycopsamine was detected in urine samples taken in the affected area with significantly greater concentrations in 45 cases than in 43 controls (p=0.02). High levels of DDT (>125 ppb) were detected in 78% of serum samples. In mice, DDT (3 × 75 mg/kg) significantly increased the hepatotoxicity (plasma ALT, p=0.0065) of acetyllycopsamine (750 mg/kg), and in combination induced liver pathology similar to Hirmi Valley liver disease including centrilobular necrosis and cytomegaly.

Conclusions: This novel form of disease appears to be caused by co-exposure to acetyllycopsamine and DDT.
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http://dx.doi.org/10.1016/j.jhep.2013.07.039DOI Listing
January 2014

Radiofrequency-induced small bowel thermofusion: an ex vivo study of intestinal seal adequacy using mechanical and imaging modalities.

Surg Endosc 2013 Sep 10;27(9):3485-96. Epub 2013 Apr 10.

Division of Surgery, Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, 10th Floor, QEQM Building, South Wharf Road, London W2 1NY, UK.

Background: Bipolar radiofrequency (RF) induced tissue fusion is believed to have the potential to seal and anastomose intestinal tissue thereby providing an alternative to current techniques which are associated with technical and functional complications. This study examines the mechanical and cellular effects of RF energy and varying compressive pressures when applied to create ex vivo intestinal seals.

Methods: A total of 299 mucosa-to-mucosa fusions were formed on ex vivo porcine small bowel segments using a prototype bipolar RF device powered by a closed-loop, feedback-controlled RF generator. Compressive pressures were increased at 0.05 MPa intervals from 0.00 to 0.49 MPa and RF energy was applied for a set time period to achieve bowel tissue fusion. Seal strength was subsequently assessed using burst pressure and tensile strength testing, whilst morphological changes were determined through light microscopy. To further identify the subcellular tissue changes that occur as a result of RF energy application, the collagen matrix in the fused area of a single bowel segment sealed at an optimal pressure was examined using transmission electron microscopy (TEM).

Results: An optimal applied compressive pressure range was observed between 0.10 and 0.25 MPa. Light microscopy demonstrated a step change between fused and unfused tissues but was ineffective in distinguishing between pressure levels once tissues were sealed. Non uniform collagen damage was observed in the sealed tissue area using TEM, with some areas showing complete collagen denaturation and others showing none, despite the seal being complete. This finding has not been described previously in RF-fused tissue and may have implications for in vivo healing.

Conclusions: This study shows that both bipolar RF energy and optimal compressive pressures are needed to create strong intestinal seals. This finding suggests that RF fusion technology can be effectively applied for bowel sealing and may lead to the development of novel anastomosis tools.
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http://dx.doi.org/10.1007/s00464-013-2935-2DOI Listing
September 2013

Non-seasonal changes in the intensity of female mate preference and offspring sex ratio in the wild guppy Poecilia reticulata.

Zoolog Sci 2012 May;29(5):319-26

Department of Biology, Tokyo Gakugei University, 4-1-1, Nukui-kita, Koganei, Tokyo 184-8501, Japan.

It has been demonstrated that the exaggeration of male sexual ornaments and the intensity of female mate preferences of a wild guppy population change over a period of several months. However, the factors that determine the short-term changes in male ornaments and female preferences remained unclear. In this study, we examined the effect of season on these short-term changes by measuring these traits in the same seasons of different years for a wild guppy population in Okinawa, Japan. We also compared the characteristics of the offspring in each collection term, as female guppies are known to have the ability to control offspring characteristics, such as brood size and sex ratios, depending on their mates' attractiveness. Results showed that the total lengths of the males changed seasonally; males in the summer were larger than those in the spring. In contrast, the size of orange spots in males and the intensity of female mating preferences differed in the same seasons of different years. Brood size and offspring body size in each term showed seasonal changes. However, offspring sex ratios exhibited different patterns in the same seasons of different years. Females produced female-biased broods when attractive males with large orange spots were rare. These results suggest that short-term changes in some traits of adult male and female guppies as well as offspring sex ratios may be not determined by seasonal factors, and that these traits may be interrelated.
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http://dx.doi.org/10.2108/zsj.29.319DOI Listing
May 2012

Quantifying hepatic steatosis - more than meets the eye.

Histopathology 2012 May 28;60(6):971-81. Epub 2012 Feb 28.

Department of Histopathology, Imperial College Faculty of Medicine at St Mary's Hospital, London, UK.

Aims: The non-alcoholic fatty liver disease (NAFLD) activity score (NAS) is the histological tool used to assess disease severity based on steatosis, inflammation and hepatocyte ballooning. As steatosis contributes up to three of a potential eight points to NAS, it is important to quantify steatosis accurately. We sought to determine the optimum histological technique for identifying fat in tissue.

Methods And Results: Using tissue from a mouse model of NAFLD, with validation in human liver biopsies, the percentage steatosis and fat droplet size were assessed in haematoxylin and eosin (H&E)- and Oil Red-O (ORO)-stained sections by light microscopy and digital image analysis (DIA). Results were compared to biochemical tissue triglyceride content and MRI assessment of hepatic lipid content. H&E steatosis assessment correlated poorly with tissue triglyceride concentration. However, ORO DIA exhibited much higher sensitivity and specificity for steatosis and correlated very well with triglyceride concentration in mouse and human liver (R = 0.706, P = 0.001 and R = 0.894, P =0.041, respectively). MRI-based assessment of steatosis was inaccurate.

Conclusions: ORO DIA is the most accurate method for detecting and quantifying steatosis. Although H&E-based NAS remains clinically valid in both clinical research and experimental situations, ORO DIA is a more robust technique to assess liver steatosis accurately for NAS scoring.
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http://dx.doi.org/10.1111/j.1365-2559.2012.04193.xDOI Listing
May 2012

Multi-excitation fluorescence spectroscopy for analysis of non-alcoholic fatty liver disease.

Lasers Surg Med 2011 Jul;43(5):392-400

Department of Surgery and Cancer, Imperial College London, London SW72AZ, United Kingdom.

Background And Objectives: The increasing incidence of non-alcoholic fatty liver diseases (NAFLD) and the consequent progression to cirrhosis is expected to become a major cause of liver transplantation. This will exacerbate the organ donor shortage and mean that 'marginal' fatty liver grafts are more frequently used. Autofluorescence spectroscopy is a fast, objective, and non-destructive method to detect change in the endogenous fluorophores distribution and could prove to be a valuable tool for NAFLD diagnosis and transplant graft assessment.

Materials And Methods: A system was constructed consisting of a fibre probe with two laser diodes that provided excitation light at 375 and 405 nm, and an imaging spectrograph system. This was used to distinguish fluorescence spectra acquired from the harvested livers from mice with NAFLD of differing severity (healthy, mild steatotic and steatohepatitic). The fluorescence data were entered into a sparse multiclass probabilistic algorithm for disease classification. Histopathology, thiobarbituric acid reactive substances (TBARS) and alanine transaminase (ALT) assays were conducted in addition to the fluorescence measurements

Results: TBARS and ALT assays enabled differentiation of the steatohepatitic group from the mild steatosis and control groups (P ≤ 0.028) but failed to separate the mild steatotic group from the control group. The three groups were all clearly differentiated from each other using fluorescence spectroscopy, and classification accuracy was found to be 95%.

Conclusion: Fluorescence spectroscopy appears to be a promising approach for the analysis of diseased liver tissue.
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http://dx.doi.org/10.1002/lsm.21064DOI Listing
July 2011

Impact of pan-caspase inhibition in animal models of established steatosis and non-alcoholic steatohepatitis.

J Hepatol 2010 Sep 26;53(3):542-50. Epub 2010 May 26.

Department of Hepatology & Gastroenterology, St Mary's Hospital Campus, Imperial College London, UK.

Background & Aims: Non-alcoholic fatty liver disease is a progressive condition comprising steatosis, steatohepatitis, and cirrhosis. Caspase activation mediates apoptosis and the inflammatory response. Studies demonstrate increased apoptotic activity in NASH although its pathophysiological importance is uncertain. We sought to determine the effects of irreversible pan-caspase inhibition in murine models of established steatosis (high fat diet, HFD) and steatohepatitis (methionine-choline deficient diet, MCD).

Methods: In one study arm, male C3H/HeN mice were fed HFD; in the other, Db/Db mice were fed MCD. Once disease was established, animals were randomised to receive caspase inhibitor (VX-166), TPGS/PEG vehicle or no additional therapy until the end of the study. Biochemical and histological indices were examined to determine NASH activity and tissue oxidative stress. Apoptotic activity and cell turnover were assessed immunohistochemically by staining for caspase-cleaved CK-18 and PCNA.

Results: MCD and HFD significantly increased apoptosis, which was reduced by VX-166 treatment. VX-166 did not reduce steatosis but reduced histological inflammation, serum ALT levels, and oxidative stress, particularly in the MCD model. TPGS/PEG vehicle also exhibited some anti-inflammatory activity.

Conclusions: In both models, VX-166 inhibited apoptosis and reduced histological inflammatory infiltrate although there was a more modest impact on other indices of liver injury. In addition, TPGS/PEG vehicle also exhibited some anti-inflammatory activity, likely through the antioxidant effects of vitamin E and changes in gut flora/mucosal interactions. These data suggest that caspase inhibition may represent a valid therapeutic approach; however, further studies to assess the long-term value of more selective caspase inhibition are merited.
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http://dx.doi.org/10.1016/j.jhep.2010.03.016DOI Listing
September 2010

Is oil red-O staining and digital image analysis the gold standard for quantifying steatosis in the liver?

Hepatology 2010 May;51(5):1859; author reply 1859-60

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http://dx.doi.org/10.1002/hep.23551DOI Listing
May 2010

Role of cleavage by separase of the Rec8 kleisin subunit of cohesin during mammalian meiosis I.

J Cell Sci 2009 Aug;122(Pt 15):2686-98

Research Institute of Molecular Pathology, A-1030 Vienna, Austria.

Proteolytic activity of separase is required for chiasma resolution during meiosis I in mouse oocytes. Rec8, the meiosis-specific alpha-kleisin subunit of cohesin, is a key target of separase in yeast. Is the equivalent protein also a target in mammals? We show here that separase cleaves mouse Rec8 at three positions in vitro but only when the latter is hyper-phosphorylated. Expression of a Rec8 variant (Rec8-N) that cannot be cleaved in vitro at these sites causes sterility in male mice. Their seminiferous tubules lack a normal complement of 2 C secondary spermatocytes and 1 C spermatids and contain instead a high proportion of cells with enlarged nuclei. Chromosome spreads reveal that Rec8-N expression has no effect in primary spermatocytes but produces secondary spermatocytes and spermatids with a 4 C DNA content, suggesting that the first and possibly also the second meiotic division is abolished. Expression of Rec8-N in oocytes causes chromosome segregation to be asynchronous and delays its completion by 2-3 hours during anaphase I, probably due to inefficient proteolysis of Rec8-N by separase. Despite this effect, chromosome segregation must be quite accurate as Rec8-N does not greatly reduce female fertility. Our data is consistent with the notion that Rec8 cleavage is important and probably crucial for the resolution of chiasmata in males and females.
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http://dx.doi.org/10.1242/jcs.035287DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2909317PMC
August 2009

Obesity and metabolic syndrome in histone demethylase JHDM2a-deficient mice.

Genes Cells 2009 Aug 15;14(8):991-1001. Epub 2009 Jul 15.

Metabolism and Endocrinology Division, Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan.

Histone H3 lysine 9 (H3K9) methylation is a crucial epigenetic mark of heterochromatin formation and transcriptional silencing. Recent studies demonstrated that most covalent histone lysine modifications are reversible and the jumonji C (JmjC)-domain-containing proteins have been shown to possess such demethylase activities. However, there is little information available on the biological roles of histone lysine demethylation in intact animal model systems. JHDM2A (JmjC-domain-containing histone demethylase 2A, also known as JMJD1A) catalyses removal of H3K9 mono- and dimethylation through iron and alpha-ketoglutarate dependent oxidative reactions. Here, we demonstrate that JHDM2a also regulates metabolic genes related to energy homeostasis including anti-adipogenesis, regulation of fat storage, glucose transport and type 2 diabetes. Mice deficient in JHDM2a (JHDM2a-/-) develop adult onset obesity, hypertriglyceridemia, hypercholesterolemia, hyperinsulinemia and hyperleptinemia, which are hallmarks of metabolic syndrome. JHDM2a-/- mice furthermore exhibit fasted induced hypothermia indicating reduced energy expenditure and also have a higher respiratory quotient indicating less fat utilization for energy production. These observations may explain the obesity phenotype in these mice. Thus, H3K9 demethylase JHDM2a is a crucial regulator of genes involved in energy expenditure and fat storage, which suggests it is a previously unrecognized key regulator of obesity and metabolic syndrome.
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http://dx.doi.org/10.1111/j.1365-2443.2009.01326.xDOI Listing
August 2009

COUP-TFII acts downstream of Wnt/beta-catenin signal to silence PPARgamma gene expression and repress adipogenesis.

Proc Natl Acad Sci U S A 2009 Apr 23;106(14):5819-24. Epub 2009 Mar 23.

Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, Japan.

Wnt signaling through beta-catenin and TCF maintains preadipocytes in an un-differentiated proliferative state; however, the molecular pathway has not been completely defined. By integrating gene expression microarray, chromatin immunoprecipitation-chip, and cell-based experimental approaches, we show that Wnt/beta-catenin signaling activates the expression of COUP-TFII which recruits the SMRT corepressor complex to the first introns located downstream from the first exons of both PPARgamma1 and gamma2 mRNAs. This maintains the local chromatin in a hypoacetylated state and represses PPARgamma gene expression to inhibit adipogenesis. Our experiments define the COUP-TFII/SMRT complex as a previously unappreciated component of the linear pathway that directly links Wnt/beta-catenin signaling to repression of PPARgamma gene expression and the inhibition of adipogenesis.
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http://dx.doi.org/10.1073/pnas.0901676106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2667001PMC
April 2009

Hepatocyte nuclear factor 4alpha contributes to thyroid hormone homeostasis by cooperatively regulating the type 1 iodothyronine deiodinase gene with GATA4 and Kruppel-like transcription factor 9.

Mol Cell Biol 2008 Jun 21;28(12):3917-31. Epub 2008 Apr 21.

Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan.

Type 1 iodothyronine deiodinase (Dio1), a selenoenzyme catalyzing the bioactivation of thyroid hormone, is highly expressed in the liver. Dio1 mRNA and enzyme activity levels are markedly reduced in the livers of hepatocyte nuclear factor 4alpha (HNF4alpha)-null mice, thus accounting for its liver-specific expression. Consistent with this deficiency, serum T4 and rT3 concentrations are elevated in these mice compared with those in HNF4alpha-floxed control littermates; however, serum T3 levels are unchanged. Promoter analysis of the mouse Dio1 gene demonstrated that HNF4alpha plays a key role in the transactivation of the mouse Dio1 gene. Deletion and substitution mutation analyses demonstrated that a proximal HNF4alpha site (direct repeat 1 [TGGACAAAGGTGC]; HNF4alpha-RE) is crucial for transactivation of the mouse Dio1 gene by HNF4alpha. Mouse Dio1 is also stimulated by thyroid hormone signaling, but a direct role for thyroid hormone receptor action has not been reported. We also showed that thyroid hormone-inducible Krüppel-like factor 9 (KLF9) stimulates the mouse Dio1 promoter very efficiently through two CACCC sequences that are located on either side of HNF4alpha-RE. Furthermore, KLF9 functions together with HNF4alpha and GATA4 to synergistically activate the mouse Dio1 promoter, suggesting that Dio1 is regulated by thyroid hormone in the mouse through an indirect mechanism requiring prior KLF9 induction. In addition, we showed that physical interactions between the C-terminal zinc finger domain (Cf) of GATA4 and activation function 2 of HNF4alpha and between the basic domain adjacent to Cf of GATA4 and a C-terminal domain of KLF9 are both required for this synergistic response. Taken together, these results suggest that HNF4alpha regulates thyroid hormone homeostasis through transcriptional regulation of the mouse Dio1 gene with GATA4 and KLF9.
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http://dx.doi.org/10.1128/MCB.02154-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2423126PMC
June 2008

Cooperative interaction between hepatocyte nuclear factor 4 alpha and GATA transcription factors regulates ATP-binding cassette sterol transporters ABCG5 and ABCG8.

Mol Cell Biol 2007 Jun 2;27(12):4248-60. Epub 2007 Apr 2.

Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, Japan.

Cholesterol homeostasis is maintained by coordinate regulation of cholesterol synthesis and its conversion to bile acids in the liver. The excretion of cholesterol from liver and intestine is regulated by ATP-binding cassette half-transporters ABCG5 and ABCG8. The genes for these two proteins are closely linked and divergently transcribed from a common intergenic promoter region. Here, we identified a binding site for hepatocyte nuclear factor 4alpha (HNF4alpha) in the ABCG5/ABCG8 intergenic promoter, through which HNF4alpha strongly activated the expression of a reporter gene in both directions. The HNF4alpha-responsive element is flanked by two conserved GATA boxes that were also required for stimulation by HNF4alpha. GATA4 and GATA6 bind to the GATA boxes, coexpression of GATA4 and HNF4alpha leads to a striking synergistic activation of both the ABCG5 and the ABCG8 promoters, and binding sites for HNF4alpha and GATA were essential for maximal synergism. We also show that HNF4alpha, GATA4, and GATA6 colocalize in the nuclei of HepG2 cells and that a physical interaction between HNF4alpha and GATA4 is critical for the synergistic response. This is the first demonstration that HNF4alpha acts synergistically with GATA factors to activate gene expression in a bidirectional fashion.
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http://dx.doi.org/10.1128/MCB.01894-06DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1900057PMC
June 2007

Resolution of chiasmata in oocytes requires separase-mediated proteolysis.

Cell 2006 Jul;126(1):135-46

Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria.

In yeast, resolution of chiasmata in meiosis I requires proteolytic cleavage along chromosome arms of cohesin's Rec8 subunit by separase. Since activation of separase by the anaphase-promoting complex (APC/C) is supposedly not required for meiosis I in Xenopus oocytes, it has been suggested that animal cells might resolve chiasmata by a separase-independent mechanism related to the so-called "prophase pathway" that removes cohesin from chromosome arms during mitosis. By expressing Cre recombinase from a zona pellucida promoter, we have deleted a floxed allele of separase specifically in mouse oocytes. This prevents removal of Rec8 from chromosome arms and resolution of chiasmata. It also hinders extrusion of the first polar body (PBE) and causes female sterility. mRNA encoding wild-type but not catalytically inactive separase restores chiasma resolution. Both types of mRNA restore PBE. Proteolytic activity of separase is therefore essential for Rec8's removal from chromosome arms and for chiasma resolution but not for PBE.
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http://dx.doi.org/10.1016/j.cell.2006.05.033DOI Listing
July 2006