Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 20
Filter
1.
Nat Med ; 29(12): 3127-3136, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37957373

ABSTRACT

Toll-like receptor-driven and interleukin-1 (IL-1) receptor-driven inflammation mediated by IL-1 receptor-associated kinase 4 (IRAK4) is involved in the pathophysiology of hidradenitis suppurativa (HS) and atopic dermatitis (AD). KT-474 (SAR444656), an IRAK4 degrader, was studied in a randomized, double-blind, placebo-controlled phase 1 trial where the primary objective was safety and tolerability. Secondary objectives included pharmacokinetics, pharmacodynamics and clinical activity in patients with moderate to severe HS and in patients with moderate to severe AD. KT-474 was administered as a single dose and then daily for 14 d in 105 healthy volunteers (HVs), followed by dosing for 28 d in an open-label cohort of 21 patients. Degradation of IRAK4 was observed in HV blood, with mean reductions after a single dose of ≥93% at 600-1,600 mg and after 14 daily doses of ≥95% at 50-200 mg. In patients, similar IRAK4 degradation was achieved in blood, and IRAK4 was normalized in skin lesions where it was overexpressed relative to HVs. Reduction of disease-relevant inflammatory biomarkers was demonstrated in the blood and skin of patients with HS and patients with AD and was associated with improvement in skin lesions and symptoms. There were no drug-related infections. These results, from what, to our knowledge, is the first published clinical trial using a heterobifunctional degrader, provide initial proof of concept for KT-474 in HS and AD to be further confirmed in larger trials. ClinicalTrials.gov identifier: NCT04772885 .


Subject(s)
Dermatitis, Atopic , Hidradenitis Suppurativa , Humans , Hidradenitis Suppurativa/drug therapy , Dermatitis, Atopic/drug therapy , Interleukin-1 Receptor-Associated Kinases , Treatment Outcome , Skin/pathology , Double-Blind Method , Severity of Illness Index
2.
Waste Manag Res ; 40(11): 1618-1628, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35380070

ABSTRACT

Trees have morphological adaptations that allow methane (CH4) generated below ground to bypass oxidation in aerobic surface soils. This natural phenomenon however has not been measured in a landfill context where planted trees may alter the composition and magnitude of CH4 fluxes from the surface. To address this research gap, we measured tree stem and soil greenhouse gas (GHG) emissions (CH4 and CO2) from a closed UK landfill and comparable natural site, using an off-axis integrated cavity output spectroscopy analyser and flux chambers. Analyses showed average CH4 stem fluxes from the landfill and non-landfill sites were 31.8 ± 24.4 µg m-2 h-1 and -0.3 ± 0.2 µg m-2 h-1, respectively. The landfill site showed seasonal patterns in CH4 and CO2 stem emissions, but no significant patterns were observed in CH4 and CO2 fluxes at different stem heights or between tree species. Tree stem emissions accounted for 39% of the total CH4 surface flux (7% of the CO2); a previously unknown contribution that should be included in future carbon assessments.


Subject(s)
Greenhouse Gases , Methane , Carbon , Carbon Dioxide/analysis , Methane/analysis , Soil , Trees
3.
Ambio ; 50(1): 242-259, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32885401

ABSTRACT

Resource allocation is a fundamental and challenging component of common pool resource governance, particularly transboundary fisheries. We highlight the growing importance of allocation in fisheries governance, comparing approaches of the five tuna Regional Fisheries Management Organizations (tRFMOs). We find all tRFMOs except one have defined resources for allocation and outlined principles to guide allocation based on equity, citizenship, and legitimacy. However, all fall short of applying these principles in assigning fish resources. Most tRFMOs rely on historical catch or effort, while equity principles rarely determine dedicated rights. Further, the current system of annual negotiations reduces certainty, trust, and transparency, counteracting many benefits asserted by rights-based management proponents. We suggest one means of gaining traction may be to shift conversations from allocative rights toward weighting of principles already identified by most tRFMOs. Incorporating principles into resource allocation remains a major opportunity, with important implications for current and future access to fish.


Subject(s)
Fisheries , Tuna , Animals , Conservation of Natural Resources , Fishes , Resource Allocation
5.
Lancet Oncol ; 19(5): 649-659, 2018 05.
Article in English | MEDLINE | ID: mdl-29650362

ABSTRACT

BACKGROUND: Activating enhancer of zeste homolog 2 (EZH2) mutations or aberrations of the switch/sucrose non-fermentable (SWI/SNF) complex (eg, mutations or deletions of the subunits INI1 or SMARCA4) can lead to aberrant histone methylation, oncogenic transformation, and a proliferative dependency on EZH2 activity. In this first-in-human study, we aimed to investigate the safety, clinical activity, pharmacokinetics, and pharmacodynamics of tazemetostat, a first-in-class selective inhibitor of EZH2. METHODS: We did an open-label, multicentre, dose-escalation, phase 1 study using a 3 + 3 design with planned cohort expansion at the two highest doses below the maximally tolerated dose. The study was done at two centres in France: Institut Gustave Roussy (Villejuif, Val de Marne) and Institut Bergonié (Bordeaux, Gironde). Eligible patients had relapsed or refractory B-cell non-Hodgkin lymphoma or an advanced solid tumour and were older than 18 years, with Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate end-organ function. Tazemetostat was administered orally from 100 mg twice daily to 1600 mg twice daily in 28-day cycles. The primary endpoint was to establish the maximum tolerated dose or recommended phase 2 dose of tazemetostat, as determined by dose-limiting toxicities, laboratory values, and other safety or pharmacokinetic measures in cycle one according to local investigator assessment. Safety was assessed in patients who received at least one dose of tazemetostat; antitumour activity was assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT01897571. The phase 1 part of the study is complete, and phase 2 is ongoing. FINDINGS: Between June 13, 2013, and Sept 21, 2016, 64 patients (21 with B-cell non-Hodgkin lymphoma, and 43 with advanced solid tumours) received doses of tazemetostat. The most common treatment-related adverse events, regardless of attribution, were asthenia (21 [33%] of 64 treatment-related events), anaemia (nine [14%]), anorexia (four [6%]), muscle spasms (nine [14%]), nausea (13 [20%]), and vomiting (six [9%]), usually grade 1 or 2 in severity. A single dose-limiting toxicity of grade 4 thrombocytopenia was identified at the highest dose of 1600 mg twice daily. No treatment-related deaths occurred; seven (11%) patients had non-treatment-related deaths (one at 200 mg twice daily, four at 400 mg twice daily, and two at 1600 mg twice daily). The recommended phase 2 dose was determined to be 800 mg twice daily. Durable objective responses, including complete responses, were observed in eight (38%) of 21 patients with B-cell non-Hodgkin lymphoma and two (5%) of 43 patients with solid tumours. INTERPRETATION: Tazemetostat showed a favourable safety profile and antitumour activity in patients with refractory B-cell non-Hodgkin lymphoma and advanced solid tumours, including epithelioid sarcoma. Further clinical investigation of tazemetostat monotherapy is ongoing in phase 2 studies in adults and a phase 1 study for children, which are currently enrolling patients who have B-cell non-Hodgkin lymphoma and INI1-negative or SMARCA4-negative tumours. FUNDING: Epizyme and Eisai.


Subject(s)
Antineoplastic Agents/administration & dosage , Benzamides/administration & dosage , Enhancer of Zeste Homolog 2 Protein/antagonists & inhibitors , Enzyme Inhibitors/administration & dosage , Lymphoma, B-Cell/drug therapy , Pyridones/administration & dosage , Aged , Antineoplastic Agents/adverse effects , Antineoplastic Agents/pharmacokinetics , Benzamides/adverse effects , Benzamides/pharmacokinetics , Biphenyl Compounds , Dose-Response Relationship, Drug , Enhancer of Zeste Homolog 2 Protein/metabolism , Enzyme Inhibitors/adverse effects , Enzyme Inhibitors/pharmacokinetics , Female , France , Humans , Lymphoma, B-Cell/enzymology , Lymphoma, B-Cell/pathology , Male , Maximum Tolerated Dose , Middle Aged , Morpholines , Pyridones/adverse effects , Pyridones/pharmacokinetics , Time Factors , Treatment Outcome
6.
Crit Pathw Cardiol ; 16(1): 1-6, 2017 03.
Article in English | MEDLINE | ID: mdl-28195936

ABSTRACT

BACKGROUND: Exercise stress testing (EST) is a noninvasive procedure that aids the diagnosis and prognosis of a range of cardiac pathologies. Reduced access is recognized as a limiting factor in enabling early access to treatment or safe and appropriate discharge. Increased accessibility can be achieved by utilizing nonphysician health practitioners to supervise tests. To implement nonphysician-led EST in clinical environments, there is a need for the development and administration of feasible and effective models. OBJECTIVE: Via inpatient and outpatient referral, this article aims to present 2 standardized models of care for patients requiring EST for diagnostic and prognostic evaluation of numerous pathologies. METHOD: An inpatient and outpatient model was implemented at the Royal Brisbane and Women's Hospital and Logan Hospital in Queensland, Australia between July 2013 and December 2015. Tests were performed by 2 cardiac scientists employed by each hospital. All tests were immediately reported by a cardiology advanced trainee registrar or consultant cardiologist. RESULTS: A total of 2095 tests were performed via the 2 models. Overall, 73 had a positive result (3.5%), 120 equivocal (5.7%), 129 inconclusive/submaximal (6.2%), and 1773 negative (85.2%). After further testing, 38 of the patients with positive and equivocal results were diagnosed with flow-limiting coronary artery disease. The remaining patients were resolved as negative through further diagnostic testing or lost to follow up. CONCLUSIONS: After implementation of the 2 models, patient flow was improved for earlier discharge, reduced waiting times, or timely identification of possible cardiac pathologies, thereby optimizing patient care.


Subject(s)
Coronary Artery Disease/diagnosis , Exercise Test/methods , Health Personnel , Inpatients , Outpatients , Risk Assessment/methods , Coronary Artery Disease/epidemiology , Coronary Artery Disease/physiopathology , Female , Follow-Up Studies , Humans , Incidence , Male , Middle Aged , Predictive Value of Tests , Prognosis , Queensland/epidemiology , Referral and Consultation , Retrospective Studies , Risk Factors , Time Factors
7.
Invest New Drugs ; 35(1): 11-25, 2017 02.
Article in English | MEDLINE | ID: mdl-27783255

ABSTRACT

Background The neddylation pathway conjugates NEDD8 to cullin-RING ligases and controls the proteasomal degradation of specific proteins involved in essential cell processes. Pevonedistat (MLN4924) is a selective small molecule targeting the NEDD8-activating enzyme (NAE) and inhibits an early step in neddylation, resulting in DNA re-replication, cell cycle arrest and death. We investigated the anti-tumor potential of pevonedistat in preclinical models of melanoma. Methods Melanoma cell lines and patient-derived tumor xenografts (PDTX) treated with pevonedistat were assessed for viability/apoptosis and tumor growth, respectively, to identify sensitive/resistant models. Gene expression microarray and gene set enrichment analyses were performed in cell lines to determine the expression profiles and pathways of sensitivity/resistance. Pharmacodynamic changes in treated-PDTX were also characterized. Results Pevonedistat effectively inhibited cell viability (IC50 < 0.3 µM) and induced apoptosis in a subset of melanoma cell lines. Sensitive and resistant cell lines exhibited distinct gene expression profiles; sensitive models were enriched for genes involved in DNA repair, replication and cell cycle regulation, while immune response and cell adhesion pathways were upregulated in resistant models. Pevonedistat also reduced tumor growth in melanoma cell line xenografts and PDTX with variable responses. An accumulation of pevonedistat-NEDD8 adduct and CDT1 was observed in sensitive tumors consistent with its mechanism of action. Conclusions This study provided preclinical evidence that NAE inhibition by pevonedistat has anti-tumor activity in melanoma and supports the clinical benefits observed in recent Phase 1 trials of this drug in melanoma patients. Further investigations are warranted to develop rational combinations and determine predictive biomarkers of pevonedistat.


Subject(s)
Antineoplastic Agents/pharmacology , Cyclopentanes/pharmacology , Melanoma/drug therapy , Pyrimidines/pharmacology , Ubiquitin-Activating Enzymes/antagonists & inhibitors , Apoptosis/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Humans , Melanoma/genetics , Melanoma/metabolism , Ubiquitin-Activating Enzymes/metabolism , Ubiquitination/drug effects
8.
Iperception ; 4(2): 101-10, 2013.
Article in English | MEDLINE | ID: mdl-23755355

ABSTRACT

We compared performance on three manual-dexterity tasks under monocular and binocular viewing. The tasks were the standard Morrisby Fine Dexterity Test, using forceps to manipulate the items, a modified version of the Morrisby test using fingers, and a "buzz-wire" task in which subjects had to guide a wire hoop around a 3D track without bringing the hoop into contact with the track. In all three tasks, performance was better for binocular viewing. The extent of the binocular advantage in individuals did not correlate significantly with their stereoacuity measured on the Randot test. However, the extent of the binocular advantage depended strongly on the task. It was weak when fingers were used on the Morrisby task, stronger with forceps, and extremely strong on the buzz-wire task (fivefold increase in error rate with monocular viewing). We suggest that the 3D buzz-wire game is particularly suitable for assessing binocularly based dexterity.

10.
Cancer Cell ; 21(3): 388-401, 2012 Mar 20.
Article in English | MEDLINE | ID: mdl-22439935

ABSTRACT

MLN4924 is an investigational small-molecule inhibitor of NEDD8-activating enzyme (NAE) in clinical trials for the treatment of cancer. MLN4924 is a mechanism-based inhibitor, with enzyme inhibition occurring through the formation of a tight-binding NEDD8-MLN4924 adduct. In cell and xenograft models of cancer, we identified treatment-emergent heterozygous mutations in the adenosine triphosphate binding pocket and NEDD8-binding cleft of NAEß as the primary mechanism of resistance to MLN4924. Biochemical analyses of NAEß mutants revealed slower rates of adduct formation and reduced adduct affinity for the mutant enzymes. A compound with tighter binding properties was able to potently inhibit mutant enzymes in cells. These data provide rationales for patient selection and the development of next-generation NAE inhibitors designed to overcome treatment-emergent NAEß mutations.


Subject(s)
Cyclopentanes/pharmacology , Enzyme Inhibitors/pharmacology , Mutation , Pyrimidines/pharmacology , Ubiquitin-Activating Enzymes/genetics , Animals , Binding Sites , Cell Line, Tumor , Clinical Trials as Topic , Drug Resistance, Neoplasm/genetics , Female , Humans , Mice , Mice, Nude , Rats , Rats, Nude , Tumor Cells, Cultured , Ubiquitin-Activating Enzymes/chemistry , Ubiquitin-Activating Enzymes/physiology , Xenograft Model Antitumor Assays
11.
Leuk Lymphoma ; 51(7): 1269-77, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20572799

ABSTRACT

Immunohistochemical analyses of archival tumor specimens were used for pre-planned exploratory analyses of protocol-specified candidate biomarkers of bortezomib activity in 73 patients with relapsed/refractory mantle cell lymphoma in the phase 2 PINNACLE study. Consistent with other studies, elevated Ki-67 was a marker of poor prognosis, demonstrating significant associations with shorter time to progression and overall survival. Elevated NF-kappaB p65 and low PSMA5 expression demonstrated a trend for better response and were significantly associated with longer time to progression; elevated NF-kappaB p65 demonstrated a trend toward longer overall survival. This is consistent with myeloma clinical genomics research, suggesting biomarker relevance across tumor types. Elevated p27 was significantly associated with longer overall survival. Overall survival analyses by International Prognostic Index and Mantle Cell Lymphoma International Prognostic Index confirmed differential prognosis by both scores. These biomarkers data begin to illuminate bortezomib's mechanism of action in lymphoma.


Subject(s)
Antineoplastic Agents/therapeutic use , Biomarkers, Tumor/metabolism , Boronic Acids/therapeutic use , Lymphoma, Mantle-Cell/drug therapy , Lymphoma, Mantle-Cell/metabolism , Pyrazines/therapeutic use , Adult , Aged , Aged, 80 and over , Bortezomib , Cyclin-Dependent Kinase Inhibitor p27 , Female , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Male , Middle Aged , NF-kappa B/metabolism , Proteasome Endopeptidase Complex/metabolism , Retrospective Studies , Survival Rate , Treatment Outcome
12.
Mol Cancer Res ; 8(3): 373-84, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20197380

ABSTRACT

Aurora A kinase is a serine/threonine protein kinase responsible for regulating several mitotic processes including centrosome separation, spindle assembly, and chromosome segregation. Small molecule inhibitors of Aurora A kinase are being pursued as novel anticancer agents, some of which have entered clinical trials. Despite the progress in developing these agents, terminal outcomes associated with Aurora A inhibition are not fully understood. Although evidence exists that Aurora A inhibition leads to apoptosis, other therapeutically relevant cell fates have not been reported. Here, we used the small molecule inhibitor MLN8054 to show that inhibition of Aurora A induces tumor cell senescence both in vitro and in vivo. Treatment of human tumor cells grown in culture with MLN8054 showed a number of morphologic and biochemical changes associated with senescence. These include increased staining of senescence-associated beta-galactosidase, increased nuclear and cell body size, vacuolated cellular morphology, upregulation/stabilization of p53, p21, and hypophosphorylated pRb. To determine if Aurora A inhibition induces senescence in vivo, HCT-116 xenograft-bearing animals were dosed orally with MLN8054 for 3 weeks. In the MLN8054-treated animals, increased senescence-associated beta-galactosidase activity was detected in tissue sections starting on day 15. In addition, DNA and tubulin staining of tumor tissue showed a significant increase in nuclear and cell body area, consistent with a senescent phenotype. Taken together, this data shows that senescence is a terminal outcome of Aurora A inhibition and supports the evaluation of senescence biomarkers in clinic samples.


Subject(s)
Antineoplastic Agents/pharmacology , Benzazepines/pharmacology , Cellular Senescence/drug effects , Enzyme Inhibitors/pharmacology , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/enzymology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Administration, Oral , Animals , Antineoplastic Agents/therapeutic use , Aurora Kinase A , Aurora Kinases , Benzazepines/therapeutic use , Biomarkers, Tumor/analysis , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Cell Size/drug effects , Cellular Senescence/physiology , Cyclin-Dependent Kinase Inhibitor p21/drug effects , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Drug Administration Schedule , Enzyme Inhibitors/therapeutic use , Female , Humans , Mice , Mice, Nude , Neoplasms, Experimental/physiopathology , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Retinoblastoma Protein/drug effects , Retinoblastoma Protein/metabolism , Transplantation, Heterologous , Tumor Suppressor Protein p53/drug effects , Tumor Suppressor Protein p53/metabolism , beta-Galactosidase/drug effects , beta-Galactosidase/metabolism
13.
Nature ; 458(7239): 732-6, 2009 Apr 09.
Article in English | MEDLINE | ID: mdl-19360080

ABSTRACT

The clinical development of an inhibitor of cellular proteasome function suggests that compounds targeting other components of the ubiquitin-proteasome system might prove useful for the treatment of human malignancies. NEDD8-activating enzyme (NAE) is an essential component of the NEDD8 conjugation pathway that controls the activity of the cullin-RING subtype of ubiquitin ligases, thereby regulating the turnover of a subset of proteins upstream of the proteasome. Substrates of cullin-RING ligases have important roles in cellular processes associated with cancer cell growth and survival pathways. Here we describe MLN4924, a potent and selective inhibitor of NAE. MLN4924 disrupts cullin-RING ligase-mediated protein turnover leading to apoptotic death in human tumour cells by a new mechanism of action, the deregulation of S-phase DNA synthesis. MLN4924 suppressed the growth of human tumour xenografts in mice at compound exposures that were well tolerated. Our data suggest that NAE inhibitors may hold promise for the treatment of cancer.


Subject(s)
Antineoplastic Agents/pharmacology , Cyclopentanes/pharmacology , Enzyme Inhibitors/pharmacology , Neoplasms/drug therapy , Pyrimidines/pharmacology , Ubiquitin-Activating Enzymes/metabolism , Animals , Cell Line, Tumor , Cells, Cultured , Cullin Proteins/metabolism , Female , Humans , Mice , NEDD8 Protein , Proteasome Inhibitors , Transplantation, Heterologous , Ubiquitins/metabolism
14.
J Immunol ; 177(10): 6940-51, 2006 Nov 15.
Article in English | MEDLINE | ID: mdl-17082609

ABSTRACT

CD4+ Th2 cells are important regulators of allergic inflammation. CCR8 is thought to play a role in Th2-mediated responses, however, expression of CCR8 in peripheral blood has not been fully characterized. Using a fluorescent form of the ligand selective for CCR8 (F-CCL1), we identified the leukocytes expressing CCR8 in human, monkey, and mouse peripheral blood. CCR8 expression is primarily restricted to a subset of human CD4 memory T lymphocytes (15%). Approximately 40% of CCR8+CD4+ T cells express Th2 cytokines IL-4 or IL-13 while 13% express the Th1 cytokine IFN-gamma. In fact, 50% of all Th2, but only 5% of Th1, cells express CCR8. Upon anti-CD3/anti-CD28 mAb-mediated activation, CCR8+CD4+ T cells secrete 3- to 7-fold higher levels of IL-4, IL-5, IL-9, and IL-13 and 10- to 20-fold lower levels of IFN-gamma or IL-17, compared with CCR8-CD4+ memory T cells. Two-thirds of CCR8+CD4 T cells express cutaneous lymphocyte-associated Ag while the majority lack gut-homing receptors. CCR8+CD4+ cells express CCR7 and CD62L and are present in spleen and lymph nodes of mice. Approximately 25% of CCR8+CD4 T cells express CD25high while 20% of CCR8+CD4+ express the T regulatory cell transcription factor FOXP3 accounting for 60% of all FOXP3-expressing CD4+ T cells. In conclusion, CCR8 marks a diverse subset of CD4 memory T cells enriched for T regulatory and Th2 cells which have the potential for recruitment into sites of allergic inflammation where they could participate in the induction and regulation of the allergic response.


Subject(s)
Forkhead Transcription Factors/biosynthesis , Immunologic Memory , Receptors, Chemokine/biosynthesis , T-Lymphocytes, Regulatory/metabolism , Th2 Cells/immunology , Animals , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , Chemokine CCL1 , Chemokines, CC/physiology , Chemotaxis, Leukocyte/genetics , Chemotaxis, Leukocyte/immunology , Humans , Immunologic Memory/genetics , Immunophenotyping , Lymphocyte Activation/genetics , Lymphocyte Activation/immunology , Macaca fascicularis , Mice , Mice, Inbred C57BL , Mice, Knockout , Receptors, CCR8 , Receptors, Chemokine/blood , Receptors, Chemokine/deficiency , Receptors, Chemokine/physiology , T-Lymphocytes, Regulatory/cytology , T-Lymphocytes, Regulatory/immunology , Th2 Cells/cytology , Th2 Cells/metabolism
15.
Blood ; 108(4): 1388-94, 2006 Aug 15.
Article in English | MEDLINE | ID: mdl-16609065

ABSTRACT

Iron and copper are essential for all organisms, assuming critical roles as cofactors in many enzymes. In eukaryotes, the transmembrane transport of these elements is a highly regulated process facilitated by the single electron reduction of each metal. Previously, we identified a mammalian ferrireductase, Steap3, critical for erythroid iron homeostasis. Now, through homology, expression, and functional studies, we characterize all 4 members of this protein family and demonstrate that 3 of them, Steap2, Steap3, and Steap4, are not only ferrireductases but also cupric reductases that stimulate cellular uptake of both iron and copper in vitro. Finally, the pattern of tissue expression and subcellular localization of these proteins suggest they are physiologically relevant cupric reductases and ferrireductases in vivo.


Subject(s)
Antigens, Neoplasm/metabolism , Coenzymes/metabolism , Copper/metabolism , Gene Expression Regulation, Enzymologic/physiology , Iron/metabolism , Oxidoreductases/metabolism , Animals , Antigens, Neoplasm/genetics , Cell Line , Humans , Ion Transport/physiology , Mice , Oxidation-Reduction , Oxidoreductases/genetics , RNA, Messenger/metabolism
16.
Nature ; 440(7083): 520-3, 2006 Mar 23.
Article in English | MEDLINE | ID: mdl-16554817

ABSTRACT

Expansion of the cattle and soy industries in the Amazon basin has increased deforestation rates and will soon push all-weather highways into the region's core. In the face of this growing pressure, a comprehensive conservation strategy for the Amazon basin should protect its watersheds, the full range of species and ecosystem diversity, and the stability of regional climates. Here we report that protected areas in the Amazon basin--the central feature of prevailing conservation approaches--are an important but insufficient component of this strategy, based on policy-sensitive simulations of future deforestation. By 2050, current trends in agricultural expansion will eliminate a total of 40% of Amazon forests, including at least two-thirds of the forest cover of six major watersheds and 12 ecoregions, releasing 32 +/- 8 Pg of carbon to the atmosphere. One-quarter of the 382 mammalian species examined will lose more than 40% of the forest within their Amazon ranges. Although an expanded and enforced network of protected areas could avoid as much as one-third of this projected forest loss, conservation on private lands is also essential. Expanding market pressures for sound land management and prevention of forest clearing on lands unsuitable for agriculture are critical ingredients of a strategy for comprehensive conservation.


Subject(s)
Conservation of Natural Resources , Models, Biological , Agriculture , Animals , Biodiversity , Brazil , Cattle , Ecosystem , Humans , Rivers , Socioeconomic Factors , Glycine max , Trees
17.
Hum Mol Genet ; 15(6): 953-64, 2006 Mar 15.
Article in English | MEDLINE | ID: mdl-16467350

ABSTRACT

Proteins with iron-sulfur (Fe-S) clusters participate in multiple metabolic pathways throughout the cell. The mitochondrial ABC half-transporter Abcb7, which is mutated in X-linked sideroblastic anemia with ataxia in humans, is a functional ortholog of yeast Atm1p and is predicted to export a mitochondrially derived metabolite required for cytosolic Fe-S cluster assembly. Using an inducible Cre/loxP system to delete exons 9 and 10 of the Abcb7 gene, we examined the phenotype of mice deficient in Abcb7. We found that Abcb7 was essential in extra-embryonic tissues early in gestation and that the mutant allele exhibits an X-linked parent-of-origin lethality effect. Furthermore, using X-chromosome inactivation assays and tissue-specific deletions, Abcb7 was found to be essential for the development and function of numerous other cell types and tissues. A notable exception to this was liver, where loss of Abcb7 impaired cytosolic Fe-S cluster assembly but was not lethal. In this situation, control of iron regulatory protein 1, a key cytosolic modulator of iron metabolism, which is responsive to the availability of cytosolic Fe-S clusters, was impaired and contributed to the dysregulation of hepatocyte iron metabolism. Altogether, these studies demonstrate the essential nature of Abcb7 in mammals and further substantiate a central role for mitochondria in the biogenesis of cytosolic Fe-S proteins.


Subject(s)
ATP-Binding Cassette Transporters/physiology , Cytosol/metabolism , Iron-Sulfur Proteins/biosynthesis , Mitochondrial Proteins/physiology , ATP-Binding Cassette Transporters/genetics , Animals , Cell Line , Cell Lineage/genetics , Genes, Lethal , Hepatocytes/metabolism , Hepatocytes/ultrastructure , Iron/metabolism , Iron Regulatory Protein 1/metabolism , Iron Regulatory Protein 2/metabolism , Male , Mice , Mitochondrial Proteins/deficiency , Mitochondrial Proteins/genetics , X Chromosome/genetics
18.
Nat Genet ; 37(11): 1264-9, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16227996

ABSTRACT

The reduction of iron is an essential step in the transferrin (Tf) cycle, which is the dominant pathway for iron uptake by red blood cell precursors. A deficiency in iron acquisition by red blood cells leads to hypochromic, microcytic anemia. Using a positional cloning strategy, we identified a gene, six-transmembrane epithelial antigen of the prostate 3 (Steap3), responsible for the iron deficiency anemia in the mouse mutant nm1054. Steap3 is expressed highly in hematopoietic tissues, colocalizes with the Tf cycle endosome and facilitates Tf-bound iron uptake. Steap3 shares homology with F(420)H(2):NADP(+) oxidoreductases found in archaea and bacteria, as well as with the yeast FRE family of metalloreductases. Overexpression of Steap3 stimulates the reduction of iron, and mice lacking Steap3 are deficient in erythroid ferrireductase activity. Taken together, these findings indicate that Steap3 is an endosomal ferrireductase required for efficient Tf-dependent iron uptake in erythroid cells.


Subject(s)
Anemia, Iron-Deficiency/metabolism , Antigens, Neoplasm/metabolism , Erythrocytes/enzymology , FMN Reductase/metabolism , Iron/metabolism , Transferrin/metabolism , Amino Acid Sequence , Animals , Antigens, Neoplasm/genetics , Blotting, Western , Cells, Cultured , Endosomes , FMN Reductase/genetics , Female , Gene Targeting , Kidney/metabolism , Male , Mice , Mice, Mutant Strains , Molecular Sequence Data , Oxidoreductases , Retroviridae/genetics , Sequence Homology, Amino Acid , Subcellular Fractions
19.
Estud. av ; 19(54): 137-152, ago. 2005.
Article in Portuguese | LILACS | ID: lil-430404

ABSTRACT

A AMAZÕNIA está entrando em uma era de rápidas mudanças impulsionadas pela previsão de asfaltamento de rodovias que estimularão a expansão da fronteira agrícola e de exploração madeireira. O declínio do custo de transporte tem importantes implicações para a biodiversidade, emissão de gases que contribuem para o efeito estufa e prosperidade da sociedade da Amazônia a longo prazo. Para analisar esse contexto, foi desenvolvido um modelo de simulação de desmatamento na bacia Amazônica, sensível a diferentes cenários de políticas públicas frente à expansão da infra-estrutura de transporte pela região. Resultados do modelo indicam que, dentro de um cenário pessimista, o desmatamento projetado pode eliminar, até meados deste século, 40 por cento dos atuais 5,4 milhões de km² de florestas da Amazônia, liberando o equivalente a 32 Pg (10(9) toneladas) de carbono para atmosfera. A modelagem de cenários alternativos aponta que a expansão de uma rede de áreas protegidas, efetivamente implementadas, poderia reduzir em até 1/3 as perdas florestais projetadas. Contudo, outras medidas de conservação são ainda necessárias para se manter a integridade funcional das paisagens e bacias hidrográficas amazônicas. Atuais experimentos em conservação florestal em propriedades privadas, mercados de serviços ambientais e zoneamento agro-ecológico devem ser refinados e multiplicados a fim de se buscar uma conservação extensiva.


Subject(s)
Amazonian Ecosystem , Conservation of Natural Resources
20.
Mol Cell Biol ; 22(12): 4433-8, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12024052

ABSTRACT

The WT1 tumor suppressor gene is a zinc finger-containing transcription factor which is required for development of the kidney and gonads. A mammal-specific alternative splicing event within this gene results in the presence or absence of a 17-amino-acid sequence within the WT1 protein. To determine the function of this sequence in vivo, gene targeting was utilized to specifically eliminate the exon encoding this sequence in mice. Mice lacking WT1 exon 5 develop normally. Adult mice lacking this exon are viable and fertile, and females are capable of lactation.


Subject(s)
Exons , Fertility/genetics , WT1 Proteins/genetics , Alternative Splicing , Animals , Female , Male , Mammals/genetics , Mice , Mice, Inbred C57BL , Mice, Mutant Strains , Sperm Count
SELECTION OF CITATIONS
SEARCH DETAIL
...