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1.
Langmuir ; 40(27): 13844-13859, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38916256

ABSTRACT

Fullerene-based biosensors have received great attention due to their unique electronic properties that allow them to transduce electrical signals by accepting electrons from amino acids. Babies with MSUD (maple syrup urine disease) are unable to break down amino acids such as l-leucine, and excess levels of the l-leucine are harmful. Therefore, sensing of l-leucine is foremost required. We aim to investigate the interaction tendencies of size-variable fullerenes (CX; X = 24, 36, 50, and 70) toward l-leucine (LEU) using density functional theory (DFT-D3) and classical molecular dynamics (MD) simulation. The C24 fullerene shows the highest affinity of the LEU biomolecule in the gas phase. Smaller fullerenes (C24 and C36) show stronger interactions with leucine due to their higher curvature in water environments. Moreover, recovery times in the ranges of 1010 and 104 s make it a viable candidate for the isolation application of LEU from the biological system. Further, the interaction between LEU and fullerenes is in line with the natural bond order (NBO) analysis, Mulliken charge analysis, quantum theory atom in molecule (QTAIM) analysis, and reduced density gradient (RDG) analysis. At 310 K, employing the explicit water model in classical MD simulations, fullerenes C24 and C36 demonstrate notably elevated binding free energies (-24.946 kJ/mol) in relation to LEU, showcasing their potential as sensors for l-leucine. Here, we demonstrate that the smaller fullerene exhibits a higher potential for l-leucine sensors than the larger fullerene.


Subject(s)
Density Functional Theory , Fullerenes , Leucine , Molecular Dynamics Simulation , Fullerenes/chemistry , Leucine/chemistry , Particle Size
2.
Sci Rep ; 14(1): 4371, 2024 Feb 22.
Article in English | MEDLINE | ID: mdl-38388641

ABSTRACT

Transition metal oxides (TMO) are the preferred materials for metal ion battery cathodes because of their high redox potentials and good metal-ion intercalation capacity, which serve as an outstanding replacement for layered sulphide. In this work, using first-principles calculations based on Density functional theory approach, we explored the structural and electronic properties which comprise of adsorption and diffusion behaviour along with the analysis of voltage profile and storage capacity of Ru doped two-dimensional transition metal oxide [Formula: see text], [Formula: see text], and [Formula: see text] monolayers. The adsorption of alkali ions (Li, Na) to the surface of TMOs is strengthened by Ru-atom doping. Ru doping enhanced the adsorption energy of Li/Na-ion by 25%/11% for [Formula: see text], 8%/13% for [Formula: see text], and 10%/11% [Formula: see text] respectively. The open circuit voltage (OCV) also increases due to the high adsorption capacity of doped Monolayers. Ru doping makes the semiconducting TMOs conduct, which is suitable for battery application. As alkali ion moves closer to the dopant site, the adsorption energy increases. When alkali ions are close to the vicinity of doping site, their diffusion barrier decrease and rises as they go further away. Our current findings will be useful in finding ways to improve the storage performance of 2D oxide materials for application in energy harvesting and green energy architecture.

3.
Sci Rep ; 13(1): 21551, 2023 Dec 06.
Article in English | MEDLINE | ID: mdl-38057362

ABSTRACT

First-principles methods have been employed here to calculate structural, electronic and optical properties of CsPbI3 and CsPbBr3, in monolayer and heterostructure (HS) (PbI2-CsBr (HS1), CsI-CsBr (HS2), CsI-PbBr2 (HS3) and PbI2-PbBr2 (HS4)) configurations. Imaginary frequencies are absent in phonon dispersion curves of CsPbI3 and CsPbBr3 monolayers which depicts their dynamical stability. Values of interfacial binding energies signifies stability of our simulated heterostructures. The CsPbI3 monolayer, CsPbBr3 monolayer, HS1, HS2, HS3 and HS4 possess direct bandgap of 2.19 eV, 2.73 eV, 2.41 eV, 2.11 eV, 1.88 eV and 2.07 eV, respectively. In the HS3, interface interactions between its constituent monolayers causes substantial decrease in its resultant bandgap which suggests its solar cell applications. Static dielectric constants of all simulated heterostructures are higher when compared to those of pristine monolayers which demonstrates that these heterostructures possess low charge carrier recombination rate. In optical absorption plots of materials, the plot of HS3 displayed a red shift and depicted absorption of a substantial part of visible spectrum. Later on, via Shockley-Queisser limit we have calculated solar cell parameters of all the reported structures. The calculations showed that HS2, HS3 and HS4 showcased enhanced power conversion efficiency compared to CsPbI3 and CsPbBr3 monolayers when utilized as an absorber layer in solar cells.

4.
Int J Biol Macromol ; 253(Pt 7): 127444, 2023 Dec 31.
Article in English | MEDLINE | ID: mdl-37839595

ABSTRACT

In this work, nanostructures comprising silver nanoparticles supported on a wrinkled chitosan matrix (Ag@Ch) were successfully synthesized by a simple aging process at room temperature for four days through self-assembly. Chitosan, a natural polysaccharide was used as a support as well as a reducing agent for the formation of Ag nanostructures and the creation of hotspots for SERS activity. The fabricated Ag@Ch nanostructures were characterized by several spectroscopic techniques and were used as a surface-enhanced Raman scattering (SERS) substrate. The effect of wet, dry, and liquid samples on the SERS enhancement has been studied and was found to be effective for sensing Methylene blue, Crystal Violet, and p-Nitrophenol with detection limits of 3.8, 8.1, and 8.2 ppb respectively. The SERS enhancement of the Ag@Ch was attributed to the combination of both electromagnetic (EM) and chemical effects (CE). Density functional theory (DFT) calculations were used to explain the observed surface enhancement. Good agreement was observed between the experimental and simulated spectra.


Subject(s)
Chitosan , Metal Nanoparticles , Nanostructures , Spectrum Analysis, Raman/methods , Silver/chemistry , Metal Nanoparticles/chemistry , Density Functional Theory , Nanostructures/chemistry
5.
Org Biomol Chem ; 21(39): 7917-7923, 2023 Oct 11.
Article in English | MEDLINE | ID: mdl-37642260

ABSTRACT

An interesting molecular architecture, butterflyene, resembling the shape of a butterfly has been synthesized via a sequence of cyclocondensation, benzylic oxidation, McMurry coupling and Diels-Alder reaction (DAR), successively. The DAR of the tetrasubstituted double bond of a bicyclopentylidene moiety with various dienes has been performed to prepare the analogues of butterflyene. DFT calculations have also been used to analyze the structural optimization and reaction energies.

6.
Zhonghua Liu Xing Bing Xue Za Zhi ; 42(8): 1376-1379, 2021 Aug 10.
Article in Chinese | MEDLINE | ID: mdl-34814557

ABSTRACT

Injury is a threat to children globally and appears as the leading cause of death among children aged 1 to 17 years in China. Child injury prevention is a public health measure with a high cost-benefit ratio. Many years of research and practices have proved the effectiveness of specific child injury interventions. It is recommended that China should strengthen multi-sectoral cooperation and coordination mechanism on child injury prevention, including the clear clarification of responsibility and ensuring the necessary financial support. It is also essential to widely implement various effective interventions to ensure the healthy development of children.


Subject(s)
Family , Public Health , Child , China , Cost-Benefit Analysis , Humans
7.
Br Dent J ; 230(12): 789, 2021 06.
Article in English | MEDLINE | ID: mdl-34172841
8.
Acute Med ; 20(2): 110-115, 2021.
Article in English | MEDLINE | ID: mdl-34190737

ABSTRACT

AIM: To compare results of repeated surveys (2010, 2015 and 2017) regarding the knowledge of the medical workforce potentially involved in adrenaline administration for the emergency treatment of anaphylaxis in adults. METHODS: Convenience samples of medical (and advanced nursing) staff were surveyed on three separate occasions (2010, 2015 and 2017). Several educational methods were used to increase awareness of the specific administration of adrenaline. RESULTS: Overall, knowledge of the medical workforce regarding correct first dose adrenaline administration improved from 15% in 2010 to 49% in 2015 and finally 63% in 2017. CONCLUSION: This survey comparison shows knowledge of the medical workforce regarding adrenaline administration for treatment of anaphylaxis in adults can be significantly improved by employing a variety of educational methods.


Subject(s)
Anaphylaxis , Epinephrine , Adult , Anaphylaxis/drug therapy , Health Personnel , Humans , Surveys and Questionnaires , Workforce
9.
J Plast Reconstr Aesthet Surg ; 74(8): 1731-1742, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33422499

ABSTRACT

BACKGROUND: Electrosurgery makes dissection with simultaneous haemostasis possible. The produced heat can cause injury to the surrounding tissue. The PEAK PlasmaBlade™(PPB) is a new electrosurgery device which may overcome this by having the ability to operate on a lower temperature, therefore reducing collateral thermal damage. METHOD: A single-centre, double-blinded, randomised controlled trial (RCT) was conducted which included 108 abdominal-based free-flap breast reconstruction patients who had their flap raise performed using either the PPB (n = 56) or the conventional diathermy (n = 52). Data were collected during their in-patient stay and out-patient appointments. The primary outcome value was the number of days the abdominal drains were required. RESULTS: Baseline characteristics were similar between the groups, except a significantly lower flap weight in the PPB group. The median number of days the drains were required did not differ significantly (p = 0.48; 6.0 days for the diathermy and 5.0 days for the PPB). The total drain output (p = 0.68), the inflammatory cytokine in the drain fluid (p>0.054) and complications (p>0.24) did not differ significantly between the two groups. At the 2-week follow-up appointment, there was a trend towards less abdominal seromas on abdominal ultrasound (p = 0.09) in the PPB group which were significantly smaller (p = 0.04). CONCLUSION: The use of the PPB did not result in a significant reduction of drain requirement, total drain output or inflammatory cytokines but did reduce the size of seroma collections at the 2-week follow-up appointment. Therefore, the use of the PPB device could reduce early seroma formation after drain removal.


Subject(s)
Abdomen/surgery , Breast Neoplasms/surgery , Diathermy/methods , Free Tissue Flaps/transplantation , Mammaplasty/methods , Transplant Donor Site/surgery , Adult , Cytokines/metabolism , Double-Blind Method , Drainage , England , Female , Humans , Middle Aged , Postoperative Complications/prevention & control , Seroma/prevention & control
10.
Phys Chem Chem Phys ; 22(35): 19823-19836, 2020 Sep 21.
Article in English | MEDLINE | ID: mdl-32845260

ABSTRACT

The catalyst assisted water-splitting method as an eco-friendly and cleaner pathway for energy generation has gained much interest in recent times. In this regard, numerous two-dimensional electrocatalysts such as mono/binary compounds synthesized from group IV, III-V and V elements with compatible activity towards hydrogen evolution, oxygen evolution, oxygen reduction and CO2 reduction have been reported. Motivated by the novel approach of material design and the need for better and cheaper electrocatalytic materials, we have investigated the ground state properties of the GeSb monolayer using state-of-the-art density functional theory. The computed electronic properties reveal the metallic nature of the pristine GeSb monolayer, indicating its potential for utilization as an electrocatalyst. The site-dependent catalytic response of the GeSb monolayer indicates that the Sb-site is more sensitive towards hydrogen adsorption amongst the considered sites. The computed adsorption and Gibbs free energies follow the trend of E < E < E. Finally, we have investigated the role of arsenic (As) and bismuth (Bi) doping on the catalytic activity of the GeSb monolayer. We notice that the electron density modulation occurs at the Sb-site due to incorporation of substitutional doping which results in a 72% enhancement in the catalytic activity of the monolayer on As substitution. The present study envisages that the electron density modulation can be utilized as a pathway for tailoring the catalytic activity of a system for the hydrogen evolution reaction.

11.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117352, 2020 Jan 05.
Article in English | MEDLINE | ID: mdl-31344580

ABSTRACT

The detection and filtration of melamine in food products has become an emergence due to its harmful effect on humans. In present work, we have investigated the binding mechanism of melamine over carboxyl group edge-functionalized graphene quantum dots doped with oxygen and sulphur atoms (O-GQD and S-GQD). In order to monitor melamine, surface enhanced Raman scattering (SERS) is adopted which is an effective vibrational spectroscopic approach. Electronic and vibrational properties were analysed by means of well adapted density functional theory (DFT). The calculated adsorption energy of melamine over O-GQD and S-GQD is -1.18 and -0.15 eV respectively. The characteristic peak of melamine at 688 cm-1 is in good agreement with previously reported experimental work and enhances by 348.4% in SERS spectra of Mel-O-GQD and 48% in SERS spectra of Mel-S-GQD. We have calculated the chemical enhancement factor (EF) for melamine over O-GQD and S-GQD and found the enhancement of 4.51 and 1.48 which is greater than melamine­silver complexes. Our theoretical studies on SERS of melamine over O-GQD and S-GQD suggest that oxygen is a better candidate for SERS. Our work demonstrates that the graphene quantum dots are remarkable platforms for the detection of melamine.


Subject(s)
Graphite/chemistry , Quantum Dots/chemistry , Spectrum Analysis, Raman/methods , Triazines/analysis , Oxygen/chemistry , Triazines/chemistry
13.
Leukemia ; 31(4): 808-820, 2017 04.
Article in English | MEDLINE | ID: mdl-27740637

ABSTRACT

Enforced expression of microRNA-155 (miR-155) in myeloid cells has been shown to have both oncogenic or tumour-suppressor functions in acute myeloid leukaemia (AML). We sought to resolve these contrasting effects of miR-155 overexpression using murine models of AML and human paediatric AML data sets. We show that the highest miR-155 expression levels inhibited proliferation in murine AML models. Over time, enforced miR-155 expression in AML in vitro and in vivo, however, favours selection of intermediate miR-155 expression levels that results in increased tumour burden in mice, without accelerating the onset of disease. Strikingly, we show that intermediate and high miR-155 expression also regulate very different subsets of miR-155 targets and have contrasting downstream effects on the transcriptional environments of AML cells, including genes involved in haematopoiesis and leukaemia. Furthermore, we show that elevated miR-155 expression detected in paediatric AML correlates with intermediate and not high miR-155 expression identified in our experimental models. These findings collectively describe a novel dose-dependent role for miR-155 in the regulation of AML, which may have important therapeutic implications.


Subject(s)
Gene Expression Regulation, Leukemic , Leukemia, Myeloid, Acute/genetics , MicroRNAs/genetics , RNA Interference , Adolescent , Animals , Cell Line, Tumor , Cell Proliferation , Cell Transformation, Neoplastic/genetics , Child , Child, Preschool , Disease Models, Animal , Gene Expression , Hematopoiesis/genetics , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Humans , Infant , Infant, Newborn , Kaplan-Meier Estimate , Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/mortality , Leukemia, Myeloid, Acute/pathology , Mice , Prognosis , Tumor Stem Cell Assay
14.
J R Army Med Corps ; 162(5): 330-334, 2016 Oct.
Article in English | MEDLINE | ID: mdl-26908509

ABSTRACT

The suicide bombings in London on 7 July 2005 resulted in a mass casualty situation. Over 50% of casualties were treated at the Royal London Hospital where clinicians witnessed large numbers of severely injured patients. In some casualties human biological foreign material was found embedded in the soft tissue originating from the suicide bombers or other casualties. This had the potential of placing individuals at risk of transmission of blood-borne diseases. Advances in the fields of medicine and biology have led to increased survivorship in the context of trauma and mass casualty incidents. This has resulted in the emergence of ethical scenarios surrounding patient management. A systematic review of the literature of the 7/7 bombings, and suicide bombings reported globally, where biological implantation is noted, was performed to examine the medicolegal issues arising during such attack. Twelve casualties with human tissue implanted were recorded in the 7/7 bombings. While all patients at risk were given prophylaxis based on recommendations by the Health Protection Agency, several ethical considerations surfaced as a result. In this paper, we compare the sequence of events and the management process of the victims of the 7/7 bombings and the evidence-based research regarding blood-borne infection transmission. Furthermore, it explores the ethical dilemmas, experienced by the senior author on 7/7, surrounding prophylaxis for blood-borne diseases and protocols to avoid confusion over best practice in future bombing incidents.


Subject(s)
Antiviral Agents/therapeutic use , Chemoprevention/methods , HIV Infections/prevention & control , Hepatitis B/prevention & control , Hepatitis C/prevention & control , Mass Casualty Incidents , Occupational Exposure/prevention & control , Post-Exposure Prophylaxis/methods , Terrorism , Wounds and Injuries/therapy , Blood-Borne Pathogens , Bombs , Chemoprevention/ethics , HIV Infections/transmission , Hepatitis B/transmission , Hepatitis C/transmission , Humans , Informed Consent/ethics , London , Post-Exposure Prophylaxis/ethics , Wounds and Injuries/virology
15.
Acute Med ; 14(3): 125-31, 2015.
Article in English | MEDLINE | ID: mdl-26767202

ABSTRACT

Ambulatory Emergency Care is a key component of the service for many Acute Medical units across the United Kingdom. A well-functioning ambulatory care unit facilitiates early senior review by a consultant and may reduce the need for hospital admission by managing patients along alternative safe clinical pathways. In this article, we present 12 months of data (January 2014-January 2015) from our Ambulatory Unit at Wrightington, Wigan and Leigh NHS Foundation Trust (WWL NHSFT), which demonstrates how many different conditions can be safely managed along ambulatory care pathways and how this can significantly contribute to postive patient satisfaction survey results and meeting the A&E 4 hour target for a medium-sized Acute Trust such as WWL NHSFT. We also emphasise that the key factors of co-location of ambulatory care with the Emergency Department along with dedicated medical and nursing staff are essential to the success of this model of care.

16.
Cell Death Differ ; 21(11): 1815-24, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25012505

ABSTRACT

Loss of function mutations in the Prkar1a gene are the cause of most cases of Carney complex disorder. Defects in Prkar1a are thought to cause hyper-activation of PKA signalling, which drives neoplastic transformation, and Prkar1a is therefore considered to be a tumour suppressor. Here we show that loss of Prkar1a in genetically modified mice caused transcriptional activation of several proapoptotic Bcl-2 family members and thereby caused cell death. Interestingly, combined loss of Bim and Prkar1a increased colony formation of fibroblasts in culture and promoted their growth as tumours in immune-deficient mice. Apart from inducing apoptosis, systemic deletion of Prkar1a caused cachexia with muscle loss, macrophage activation and increased lipolysis as well as serum triglyceride levels. Loss of single allele of Prkar1a did not enhance tumour development in a skin cancer model, but surprisingly, when combined with the loss of Bim, caused a significant delay in tumorigenesis and this was associated with upregulation of other BH3-only proteins, PUMA and NOXA. These results show that loss of Prkar1a can only promote tumorigenesis when Prkar1a-mediated apoptosis is somehow countered.


Subject(s)
Apoptosis Regulatory Proteins/genetics , Apoptosis/physiology , Cachexia/genetics , Cyclic AMP-Dependent Protein Kinase RIalpha Subunit/genetics , Animals , Carcinogenesis , Cell Transformation, Neoplastic/genetics , Fibroblasts/metabolism , Gene Deletion , Genes, Tumor Suppressor , Mice , Proto-Oncogene Proteins c-bcl-2/genetics
18.
Ann R Coll Surg Engl ; 96(3): e3-4, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24780777

ABSTRACT

Cauterisation with silver nitrate is commonly used to treat overgranulation. Silver nitrate has a high density and a high mass attenuation coefficient, and it is therefore highly radio-opaque. We present a case in which its topical application to an area of overgranulation was interpreted as a bony fragment by the reporting radiologist in a patient with a supracondylar humeral fracture whose radiograph after removal of K-wires showed a large radio-opaque lesion. Although not a new phenomenon, it is one not widely known, and it can lead to confusion and unnecessary further imaging.


Subject(s)
Caustics , Granulation Tissue/diagnostic imaging , Humeral Fractures/diagnostic imaging , Silver Nitrate , Artifacts , Cautery/methods , Child, Preschool , Diagnostic Errors , Female , Fracture Healing , Humans , Radiography
19.
Public Health Action ; 4(3): 174-8, 2014 Sep 21.
Article in English | MEDLINE | ID: mdl-26400806

ABSTRACT

SETTING: The National Tuberculosis Programme (NTP) in Fiji. OBJECTIVE: To determine anti-tuberculosis treatment outcomes stratified by method of treatment supervision (i.e., self-administered treatment [SAT] vs. supervision by a family member). DESIGN: A retrospective descriptive study of all tuberculosis (TB) patients registered with the NTP in Fiji between January 2011 and June 2013. RESULTS: Of 563 TB patients registered, information on the type of treatment supervisor was available for 470 (83%). Of these, most (n = 401, 85%) had their treatment supervised by a family member, while 69 (15%) elected SAT. SAT patients had a treatment success rate of 79.4% compared to 88.5% in those supervised by a family member; the difference was statistically significant (P = 0.0374). CONCLUSION: Anti-tuberculosis treatment outcomes were more likely to be successful in patients who were supervised by a family member than in SAT patients. As this method of treatment supervision is not likely to be resource-intensive, we recommend that it continue in Fiji. Further prospective operational research could be carried out to determine patient preferences for anti-tuberculosis treatment supervision in Fiji, to promote a patient-centred approach.


Contexte: Le Programme National de lutte contre la Tuberculose (TB) (PNT) aux Fidji.Objectif: Déterminer les résultats du traitement anti-tuberculeux stratifiés par méthode de supervision de ce traitement (soit une auto supervision [SAT] par les patients euxmêmes, soit la supervision par un membre de la famille).Schéma: Etude rétrospective descriptive de tous les patients tuberculeux enregistrés par le PNT aux Fidji entre janvier 2011 et juin 2013.Résultats: Un total de 563 patients tuberculeux ont été enregistrés et pour 470 (83%) d'entre eux, on disposait d'informations sur le type de supervision. Parmi ces derniers, la majorité (n = 401 ; 85%) bénéficiait de la supervision de leur traitement par un membre de la famille ; 69 (15%) ont reçu SAT. Ces derniers ont eu un taux de succès du traitement anti tuberculeux de 79,4% comparé à 88,5% chez les patients supervisés par un membre de la famille ; ce résultat était statistiquement significatif (P = 0,0374).Conclusion: Les résultats du traitement anti-tuberculeux étaient plus souvent meilleurs chez les patients supervisés par un membre de la famille par rapport à ceux recevant SAT. Cette méthode de supervision du traitement n'exige pas beaucoup de ressources, c'est pourquoi nous recommandons qu'elle soit poursuivie aux Fidji. On pourrait réaliser une recherche opérationnelle prospective afin de déterminer les préférences des patients en matière de supervision de leur traitement anti-tuberculeux aux Fidji dans le cadre d'une approche centrée sur le patient.


Marco de Referencia: El Programa Nacional contra la Tuberculosis (PNT) en Fiji.Objetivo: Definir los desenlaces del tratamiento antituberculoso en función del método de supervisión (autosupervisado [SAT] o supervisado por un miembro de la familia).Método: Se llevó a cabo un estudio descriptivo retrospectivo de todos los pacientes registrados en el PNT de Fiji entre enero del 2011 y junio del 2013.Resultados: En el período estudiado se registraron 563 pacientes con diagnóstico de tuberculosis (TB); de estos, 470 contaban con información acerca del tipo de SAT (83%). En la mayoría de los casos un miembro de la familia supervisó el tratamiento (n = 401; 85%) y en 69 casos el tratamiento han recibido SAT (15%). La tasa de éxito terapéutico en los pacientes que recibieron SAT fue 79,4%, en comparación con 88,5% en los casos supervisados por un miembro de la familia; la diferencia fue estadísticamente significativa (P = 0,0374).Conclusión: Es más probable que el tratamiento antituberculoso sea eficaz cuando la supervisión está a cargo de algún miembro de la familia del paciente que cuando el paciente mismo lo supervisa. Esta estrategia de supervisión del tratamiento de la TB no exige grandes recursos y por ello se recomienda su continuación in Fiji. Se deben adelantar nuevos estudios de investigación operativa con el fin de terminar las preferencias de los pacientes con respecto a la supervisión del tratamiento en el país e impulsar una estrategia centrada en el paciente.

20.
Cell Death Differ ; 20(10): 1370-80, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23872792

ABSTRACT

Hoxb8 overexpression immortalises haematopoietic progenitor cells in a growth-factor-dependant manner and co-operates with interleukin-3 (IL-3) to cause acute myeloid leukaemia. To further understand how Hoxb8 contributes to myeloid cell immortalisation, we generated IL-3-dependant myeloid cells expressing Hoxb8 under the control of an inducible promoter. Downregulation of Hoxb8, in the presence of IL-3, caused cell-cycle arrest and apoptosis in the majority of cells. Apoptosis was dependant on Bax and Bak and, in part, on Bim, which was repressed by Hoxb8. Deletion of the miR-17∼92 seed sequences in the Bim 3'UTR abolished Hoxb8-dependant regulation of Bim reporter constructs. Expression of all six miRNAs from this cluster were elevated when Hoxb8 was overexpressed. The miR-17∼92 cluster was required for repression of Bim in Hoxb8-immortalised cells and deletion of the miR-17∼92 cluster substantially inhibited Hoxb8, but not Hoxa9, mediated survival and proliferation. Hoxb8 appears to promote miR-17∼92 expression through c-Myc, a known transcriptional regulator of the miR-17∼92 cluster. We have uncovered a previously unrecognised link between Hoxb8 expression and microRNAs that provides a new insight into the oncogenic functions of Hoxb8.


Subject(s)
Homeodomain Proteins/genetics , MicroRNAs/metabolism , 3' Untranslated Regions , Animals , Apoptosis/genetics , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Bcl-2-Like Protein 11 , Cell Death/genetics , Cell Differentiation/genetics , Cell Growth Processes/genetics , Gene Expression Regulation , Homeodomain Proteins/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Transgenic , MicroRNAs/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Transfection , bcl-2 Homologous Antagonist-Killer Protein/metabolism , bcl-2-Associated X Protein/metabolism
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