178 research outputs found
Abnormal clock gene expression and locomotor activity rhythms in two month-old female APPSwe/PS1dE9 mice
In addition to cognitive decline, Alzheimer’s disease (AD) is also characterized by agitation and disruptions in activity and sleep. These symptoms typically occur in the evening or at night and have been referred to as ‘sundowning’. These symptoms are especially difficult for carers and there are no specific drug treatments. There is increasing evidence that these symptoms reflect an underlying pathology of circadian rhythm generation and transmission. We investigated whether a transgenic mouse model relevant to AD (APPswe/PS1dE9) exhibits circadian alterations in locomotor activity and expression of clock genes involved in the regulation of the circadian cycle. Female mice at 2 months of age were investigated in their home cage. Results show that the APPswe/PS1dE9 transgene alters levels and patterns in circadian rhythm of locomotor activity. Expression of the clock genes Per1, Per2, Cry1 and Cry2 was found to increase at night compared to day in wild-type control mice in the medulla/pons. This effect was blunted for Cry1 and Cry2 gene expression in APPswe/PS1dE9. In summary, this study suggests altered circadian regulation of locomotor activity is abnormal in female APPswe/PS1dE9 mice and that this alteration has biomolecular analogies in a widely available model of AD. Furthermore, the early age at which these effects are manifest suggests that these circadian effects may precede plaque development. The APPswe/PS1dE9 mouse genetic model may have potential to serve as a tool in understanding the neuropathology of circadian abnormalities in AD and as a model system to test novel therapeutic agents for these symptoms
PRAME Is a Golgi-Targeted Protein That Associates with the Elongin BC Complex and Is Upregulated by Interferon-Gamma and Bacterial PAMPs
Preferentially expressed antigen in melanoma (PRAME) has been described as a cancer-testis antigen and is associated with leukaemias and solid tumours. Here we show that PRAME gene transcription in leukaemic cell lines is rapidly induced by exposure of cells to bacterial PAMPs (pathogen associated molecular patterns) in combination with type 2 interferon (IFNγ). Treatment of HL60 cells with lipopolysaccharide or peptidoglycan in combination with IFNγ resulted in a rapid and transient induction of PRAME transcription, and increased association of PRAME transcripts with polysomes. Moreover, treatment with PAMPs/IFNγ also modulated the subcellular localisation of PRAME proteins in HL60 and U937 cells, resulting in targeting of cytoplasmic PRAME to the Golgi. Affinity purification studies revealed that PRAME associates with Elongin B and Elongin C, components of Cullin E3 ubiquitin ligase complexes. This occurs via direct interaction of PRAME with Elongin C, and PRAME colocalises with Elongins in the Golgi after PAMP/IFNγ treatment. PRAME was also found to co-immunoprecipitate core histones, consistent with its partial localisation to the nucleus, and was found to bind directly to histone H3 in vitro. Thus, PRAME is upregulated by signalling pathways that are activated in response to infection/inflammation, and its product may have dual functions as a histone-binding protein, and in directing ubiquitylation of target proteins for processing in the Golgi
Bioreducible cross-linked core polymer micelles enhance in vitro activity of methotrexate in breast cancer cells
Polymer micelles have emerged as promising carriers for controlled release applications, however, several limitations of micelle-based drug delivery have also been reported. To address these issues, we have synthesized a functional biodegradable and cytocompatible block copolymer based on methoxypoly(ethyleneglycol)-b-poly(?-caprolactone-co-?-azido-?-caprolactone) (mPEG-b-poly(?CL-co-?N3?CL)) as a precursor of reduction sensitive core-crosslinked micelles. The synthesized polymer was formulated as micelles using a dialysis method and loaded with the anti-inflammatory and anti-cancer drug methotrexate (MTX). The micellar cores were subsequently crosslinked at their pendant azides by a redox-responsive bis(alkyne). The size distributions and morphology of the polymer micelles were assessed using dynamic light scattering (DLS) and transmission electron microscopy, and drug release assays were performed under simplified (serum free) physiological and reductive conditions. Cellular uptake studies in human breast cancer cells were performed using Oregon-green loaded core-crosslinked micelles. The MTX-loaded core-crosslinked micelles were assessed for their effects on metabolic activity in human breast cancer (MCF-7) cells by evaluating the reduction of the dye MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The apoptosis inducing potential of MTX-loaded core-crosslinked micelles was analysed using Hoechst/propidium iodide (PI) and annexin-V/PI assays. The data from these experiments indicated that drug release from these cross-linked micelles can be controlled and that the redox-responsive micelles are more effective carriers for MTX than non-crosslinked analogues and the free drug in the cell-lines tested
Conofolidine, a Natural Plant Alkaloid Causes Apoptosis and Senescence in Cancer Cells
Natural products contribute substantially to anticancer therapy; the plant kingdom provides an important source of molecules. Conofolidine is a novel Aspidosperma-Aspidosperma bisindole alkaloid isolated from the Malayan plant Tabernaemontana corymbosa. Herein, we report conofolidine’s anticancer activity together with that of three other bisindoles - conophylline, leucophyllidine and bipleiophylline against human-derived carcinoma cell lines. Remarkably, conofolidine was able to induce apoptosis (as observed in MDA-MB-468 breast cancer cells) or senescence (as detected in HT-29 colorectal carcinoma cells). Annexin V-FITC/PI, caspase activation and PARP cleavage confirmed the former while positive β-gal staining corroborated the latter. Evident cell cycle perturbations were observed comprising S-phase depletion, accompanied by downregulated CDK2, and cyclins (A2, D1) with p21 upregulation. Confocal imaging of HCT-116 cells revealed induction of aberrant mitotic phenotypes - multi-nucleation, membrane blebbing and DNA-fragmentation. The DNA integrity assessment of HCT-116 and MDA-MB-468 showed irreparable damage identified by increased fluorescent γ-H2AX during the G1 cell cycle phase. Furthermore, γ-H2AX foci were visually validated in HCT-116 and MDA-MB-468 cells using confocal microscopy. Conofolidine increased oxidative stress, preceding apoptosis- and senescence-induction in most carcinoma cell lines as seen by enhanced ROS levels accompanied by NQO1 expression. Collectively, we present conofolidine as a potential anticancer candidate capable of inducing heterogeneous modes of cancer cell death in vitro, encouraging further preclinical evaluation of this natural product
Apoferritin-Encapsulated Jerantinine A for Transferrin Receptor Targeting and Enhanced Selectivity in Breast Cancer Therapy
he O-acetyl (or acetate) derivative of the Aspidosperma alkaloid Jerantinine A (JAa) elicits anti-tumor activity against cancer cell lines including mammary carcinoma cell lines irrespective of receptor status (0.14 < GI50 < 0.38 μM), targeting microtubule dynamics. By exploiting breast cancer cells’ upregulated transferrin receptor 1 (TfR1) expression and apoferritin (AFt) recognition, we sought to develop an AFt JAa-delivery vehicle to enhance tumor-targeting and reduce systemic toxicity. Optimizing pH-mediated reassembly, ∼120 JAa molecules were entrapped within AFt. Western blot and flow cytometry demonstrate TfR1 expression in cancer cells. Enhanced internalization of 5-carboxyfluorescein-conjugated human AFt in SKBR3 and MDA-MB-231 cancer cells is observed compared to MRC5 fibroblasts. Accordingly, AFt–JAa delivers significantly greater intracellular JAa levels to SKBR3 and MDA-MB-231 cells than naked JAa (0.2 μM) treatment alone. Compared to naked JAa (0.2 μM), AFt–JAa achieves enhanced growth inhibition (2.5–14-fold; <0.02 μM < GI50 < 0.15 μM) in breast cancer cells; AFt–JAa treatment results in significantly reduced clonal survival, more profound cell cycle perturbation including G2/M arrest, greater reduction in cell numbers, and increased apoptosis compared to the naked agent (p < 0.01). Decreased PLK1 and Mcl-1 expression, together with the appearance of cleaved poly (ADP-ribose)-polymerase, corroborate the augmented potency of AFt–JAa. Hence, we demonstrate that AFt represents a biocompatible vehicle for targeted delivery of JAa, offering potential to minimize toxicity and enhance JAa activity in TfR1-expressing tumors
Correction to “Apoferritin-Encapsulated Jerantinine A for Transferrin Receptor Targeting and Enhanced Selectivity in Breast Cancer Therapy”
Neil R. Thomas was added as an author. The change in authorship is reflected in the authorship of this Correction
A signature motif mediating selective interactions of BCL11A with the NR2E/F subfamily of orphan nuclear receptors
Despite their physiological importance, selective interactions between nuclear receptors (NRs) and their cofactors are poorly understood. Here, we describe a novel signature motif (F/YSXXLXXL/Y) in the developmental regulator BCL11A that facilitates its selective interaction with members of the NR2E/F subfamily. Two copies of this motif (named here as RID1 and RID2) permit BCL11A to bind COUP-TFs (NR2F1;NR2F2;NR2F6) and Tailless/TLX (NR2E1), whereas RID1, but not RID2, binds PNR (NR2E3). We confirmed the existence of endogenous BCL11A/TLX complexes in mouse cortex tissue. No interactions of RID1 and RID2 with 20 other ligand-binding domains from different NR subtypes were observed. We show that RID1 and RID2 are required for BCL11A-mediated repression of endogenous γ-globin gene and the regulatory non-coding transcript Bgl3, and we identify COUP-TFII binding sites within the Bgl3 locus. In addition to their importance for BCL11A function, we show that F/YSXXLXXL/Y motifs are conserved in other NR cofactors. A single FSXXLXXL motif in the NR-binding SET domain protein NSD1 facilitates its interactions with the NR2E/F subfamily. However, the NSD1 motif incorporates features of both LXXLL and FSXXLXXL motifs, giving it a distinct NR-binding pattern in contrast to other cofactors. In summary, our results provide new insights into the selectivity of NR/cofactor complex formation
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Parents' Experiences of Receiving the Initial Positive Newborn Screening (NBS) Result for Cystic Fibrosis and Sickle Cell Disease
The clinical advantages of the newborn screening programme (NBS) in the UK are well described in the literature. However, there has been little exploration of the psychosocial impact on the family. This study followed the principles of grounded theory to explore parents' experiences of receiving the initial positive NBS result for their child with cystic fibrosis (CF) or sickle cell disease (SCD). Semi-structured, qualitative interviews were conducted with 22 parents (12 mothers and 10 fathers) whose children had been diagnosed with CF or SCD via NBS and were under the age of 1 year at the time of interview. The main themes that arose from the data were; parents previous knowledge of the condition and the NBS programme, the method of delivery and parental reactions to the result, sharing the results with others, the impact on parental relationships and support strategies. Study conclusions indicate that most parents thought initial positive NBS results should be delivered by a health professional with condition specific knowledge, preferably with both parents present. Genetic counselling needs to include a focus on the impact of NBS results on parental relationships. Careful consideration needs to be given to strategies to support parents of babies who have positive NBS results both in terms of the psychological health and to assist them in sharing the diagnosis
A toolkit for incorporating genetics into mainstream medical services: Learning from service development pilots in England
Background:
As advances in genetics are becoming increasingly relevant to mainstream healthcare, a major challenge is to ensure that these are integrated appropriately into mainstream medical services. In 2003, the Department of Health for England announced the availability of start-up funding for ten 'Mainstreaming Genetics' pilot services to develop models to achieve this.
Methods:
Multiple methods were used to explore the pilots' experiences of incorporating genetics which might inform the development of new services in the future. A workshop with project staff, an email questionnaire, interviews and a thematic analysis of pilot final reports were carried out.
Results:
Seven themes relating to the integration of genetics into mainstream medical services were identified: planning services to incorporate genetics; the involvement of genetics departments; the establishment of roles incorporating genetic activities; identifying and involving stakeholders; the challenges of working across specialty boundaries; working with multiple healthcare organisations; and the importance of cultural awareness of genetic conditions.
Pilots found that the planning phase often included the need to raise awareness of genetic conditions and services and that early consideration of organisational issues such as clinic location was essential. The formal involvement of genetics departments was crucial to success; benefits included provision of clinical and educational support for staff in new roles. Recruitment and retention for new roles outside usual career pathways sometimes proved difficult. Differences in specialties' working practices and working with multiple healthcare organisations also brought challenges such as the 'genetic approach' of working with families, incompatible record systems and different approaches to health professionals' autonomous practice.
'Practice points' have been collated into a Toolkit which includes resources from the pilots, including job descriptions and clinical tools. These can be customised for reuse by other services.
Conclusions:
Healthcare services need to translate advances in genetics into benefits for patients. Consideration of the issues presented here when incorporating genetics into mainstream medical services will help ensure that new service developments build on the body of experience gained by the pilots, to provide high quality services for patients with or at risk of genetic conditions
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