Search tips
Search criteria

Results 1-10 (10)

Clipboard (0)

Select a Filter Below

Year of Publication
1.  Development of K562 cell clones expressing β-globin mRNA carrying the β039 thalassaemia mutation for the screening of correctors of stop-codon mutations 
Nonsense mutations, giving rise to UAA, UGA and UAG stop codons within the coding region of mRNAs, promote premature translational termination and are the leading cause of approx. 30 % of inherited diseases, including cystic fibrosis, Duchenne muscular dystrophy and thalassaemia. For instance, in β039-thalassaemia the CAG (glutamine) codon is mutated to the UAG stop codon, leading to premature translation termination and to mRNA destabilization through the well-described NMD (nonsense-mediated mRNA decay). In order to develop an approach facilitating translation and, therefore, protection from NMD, aminoglycoside antibiotics have been tested on mRNAs carrying premature stop codons. These drugs decrease the accuracy in the codon–anticodon base-pairing, inducing a ribosomal read-through of the premature termination codons. Interestingly, recent papers have described drugs designed and produced for suppressing premature translational termination, inducing a ribosomal read-through of premature but not normal termination codons. These findings have introduced new hopes for the development of a pharmacological approach to the therapy of β039-thalassaemia. In this context, we started the development of a cellular model of the β039-thalassaemia mutation that could be used for the screening of a high number of aminoglycosides and analogous molecules. To this aim, we produced a lentiviral construct containing the β039-thalassaemia globin gene under a minimal LCR (locus control region) control and used this construct for the transduction of K562 cells, subsequently subcloned, with the purpose to obtain several K562 clones with different integration copies of the construct. These clones were then treated with Geneticin (also known as G418) and other aminoglycosides and the production of β-globin was analysed by FACS analysis. The results obtained suggest that this experimental system is suitable for the characterization of correction of the β039-globin mutation causing β-thalassaemia.
PMCID: PMC3582994  PMID: 19216718
aminoglycoside antibiotics; K562 cell; locus control region; nonsense mutation; thalassaemia
2.  Production of β-globin and adult hemoglobin following G418 treatment of erythroid precursor cells from homozygous β039 thalassemia patients 
American journal of hematology  2009;84(11):720-728.
In several types of thalassemia (including β039-thalassemia), stop codon mutations lead to premature translation termination and to mRNA destabilization through nonsense-mediated decay. Drugs (for instance aminoglycosides) can be designed to suppress premature termination, inducing a ribosomal readthrough. These findings have introduced new hopes for the development of a pharmacologic approach to the cure of this disease. However, the effects of aminoglycosides on globin mRNA carrying β-thalassemia stop mutations have not yet been investigated. In this study, we have used a lentiviral construct containing the β039- thalassemia globin gene under control of the β-globin promoter and a LCR cassette. We demonstrated by fluorescence-activated cell sorting (FACS) analysis the production of β-globin by K562 cell clones expressing the β039-thalassemia globin gene and treated with G418. More importantly, after FACS and high-performance liquid chromatography (HPLC) analyses, erythroid precursor cells from β039-thalassemia patients were demonstrated to be able to produce β-globin and adult hemoglobin after treatment with G418. This study strongly suggests that ribosomal readthrough should be considered a strategy for developing experimental strategies for the treatment of β0-thalassemia caused by stop codon mutations.
PMCID: PMC3572903  PMID: 19810011
3.  Targeting pre-miRNA by Peptide Nucleic Acids 
Artificial DNA, PNA & XNA  2012;3(2):88-96.
PNAs conjugated to carrier peptides have been employed for the targeting of miRNA precursor, with the aim to develop molecules able to interfere in the pre-miRNA processing. The capability of the molecules to bind pre-miRNA has been tested in vitro by fluorescence assayes on Thiazole Orange labeled molecules and in vivo, in K562 cells, evaluating the amount of miRNA produced after treatment of cells with two amounts of PNAs.
PMCID: PMC3429535  PMID: 22699795
FACS; fluorescence; miR-210; PNA; pre-miR; thiazole orange
4.  A combined approach for β-thalassemia based on gene therapy-mediated adult hemoglobin (HbA) production and fetal hemoglobin (HbF) induction 
Annals of Hematology  2012;91(8):1201-1213.
Gene therapy might fall short in achieving a complete reversion of the β-thalassemic phenotype due to current limitations in vector design and myeloablative regimen. Following gene transfer, all or a large proportion of erythroid cells might express suboptimal levels of β-globin, impairing the therapeutic potential of the treatment. Our aim was to evaluate whether, in absence of complete reversion of the β-globin phenotype upon gene transfer, it is possible to use fetal hemoglobin induction to eliminate the residual α-globin aggregates and achieve normal levels of hemoglobin. Transgenic K562 cell lines and erythroid precursor cells from β039-thalassemia patients were employed. Gene therapy was performed with the lentiviral vector T9W. Induction of fetal hemoglobin was obtained using mithramycin. Levels of mRNA and hemoglobins were determined by qRT-PCR and HPLC. First, we analyzed the effect of mithramycin on K562 transgenic cell lines harboring different copies of a lentiviral vector carrying the human β-globin gene, showing that γ-globin mRNA expression and HbF production can be induced in the presence of high levels of β-globin gene expression and HbA accumulation. We then treated erythroid progenitor cells from β-thalassemic patients with T9W, which expresses the human β-globin gene and mithramycin separately or in combination. When transduction with our lentiviral vector is insufficient to completely eliminate the unpaired α-globin chains, combination of β-globin gene transfer therapy together with fetal hemoglobin induction might be very efficacious to remove the excess of α-globin proteins in thalassemic erythroid progenitor cells.
PMCID: PMC3389244  PMID: 22460946
β-thalassemia; Gene therapy; Lentiviral vectors; HbF induction; Erythroid progenitor cells
5.  Therapeutic Hemoglobin Levels after Gene Transfer in β-Thalassemia Mice and in Hematopoietic Cells of β-Thalassemia and Sickle Cells Disease Patients 
PLoS ONE  2012;7(3):e32345.
Preclinical and clinical studies demonstrate the feasibility of treating β-thalassemia and Sickle Cell Disease (SCD) by lentiviral-mediated transfer of the human β-globin gene. However, previous studies have not addressed whether the ability of lentiviral vectors to increase hemoglobin synthesis might vary in different patients.
We generated lentiviral vectors carrying the human β-globin gene with and without an ankyrin insulator and compared their ability to induce hemoglobin synthesis in vitro and in thalassemic mice. We found that insertion of an ankyrin insulator leads to higher, potentially therapeutic levels of human β-globin through a novel mechanism that links the rate of transcription of the transgenic β-globin mRNA during erythroid differentiation with polysomal binding and efficient translation, as reported here for the first time. We also established a preclinical assay to test the ability of this novel vector to synthesize adult hemoglobin in erythroid precursors and in CD34+ cells isolated from patients affected by β-thalassemia and SCD. Among the thalassemic patients, we identified a subset of specimens in which hemoglobin production can be achieved using fewer copies of the vector integrated than in others. In SCD specimens the treatment with AnkT9W ameliorates erythropoiesis by increasing adult hemoglobin (Hb A) and concurrently reducing the sickling tetramer (Hb S).
Our results suggest two major findings. First, we discovered that for the purpose of expressing the β-globin gene the ankyrin element is particularly suitable. Second, our analysis of a large group of specimens from β-thalassemic and SCD patients indicates that clinical trials could benefit from a simple test to predict the relationship between the number of vector copies integrated and the total amount of hemoglobin produced in the erythroid cells of prospective patients. This approach would provide vital information to select the best candidates for these clinical trials, before patients undergo myeloablation and bone marrow transplant.
PMCID: PMC3314006  PMID: 22479321
6.  Born at 27 weeks of gestation with classical PKU: challenges of dietetic management in a very preterm infant 
Pediatric Reports  2011;3(4):e26.
Few cases of premature infants with classical phenylketonuria (PKU) have been reported. Treatment of these patients is challenging due to the lack of a phenylalanine (Phe)-free amino acid (AA) solution for parenteral nutrition. A boy born at 27 weeks of gestation with a weight of 1000 g was diagnosed with classical PKU on day 7 because of highly elevated Phe level at newborn screening (2800 µmol/L). Phe intake was suspended for 5 days and during this time intravenous glucose and lipids as well as small amounts of Phe-free formula through nasogastric tube were given. Because of insufficient weight gain attributable to deficiency of essential AA, a Phe-reduced, BCAA-enriched parenteral nutrition was added to satisfy AA requirements without overloading in Phe. Under this regimen, the boy started to gain weight, Phe plasma levels progressively reduced and normalized on day 19. At the age of 40 months, the patient shows normal growth parameters (height 25th percentile, weight 25–50th percentile, head circumference 50th percentile) with a normal result for formally tested psychomotor development (WPPSI-III). The good outcome of the patient in spite of over 2 weeks of extremely high Phe concentrations suggests that the premature brain may still have enough plasticity to recover. Lacking a Phe-free intravenous AA solution, successful management of premature infants with PKU depends on the child's tolerance of enteral nutrition. Although the coincidence of PKU and prematurity is rare, there is strong need for the development of an appropriate Phe-free amino acid solution for parenteral nutrition especially in case of gastro-intestinal complications of prematurity.
PMCID: PMC3283194  PMID: 22355511
phenylketonuria; PAH deficiency; prematurity; dietetic management.
7.  Bergamot (Citrus bergamia Risso) fruit extracts and identified components alter expression of interleukin 8 gene in cystic fibrosis bronchial epithelial cell lines 
BMC Biochemistry  2011;12:15.
Cystic fibrosis (CF) airway pathology is a fatal, autosomal, recessive genetic disease characterized by extensive lung inflammation. After induction by TNF-α, elevated concentrations of several pro-inflammatory cytokines (i.e. IL-6, IL-1β) and chemokines (i.e. IL-8) are released from airway epithelial cells. In order to reduce the excessive inflammatory response in the airways of CF patients, new therapies have been developed and in this respect, medicinal plant extracts have been studied. In this article we have investigated the possible use of bergamot extracts (Citrus bergamia Risso) and their identified components to alter the expression of IL-8 associated with the cystic fibrosis airway pathology.
The extracts were chemically characterized by 1H-NMR (nuclear magnetic resonance), GC-FID (gas chromatography-flame ionization detector), GC-MS (gas chromatography-mass spectrometry) and HPLC (high pressure liquid chromatography). Both bergamot extracts and main detected chemical constituents were assayed for their biological activity measuring (a) cytokines and chemokines in culture supernatants released from cystic fibrosis IB3-1 cells treated with TNF-α by Bio-Plex cytokine assay; (b) accumulation of IL-8 mRNA by real-time PCR.
The extracts obtained from bergamot (Citrus bergamia Risso) epicarps contain components displaying an inhibitory activity on IL-8. Particularly, the most active molecules were bergapten and citropten. These effects have been confirmed by analyzing mRNA levels and protein release in the CF cellular models IB3-1 and CuFi-1 induced with TNF-α or exposed to heat-inactivated Pseudomonas aeruginosa.
These obtained results clearly indicate that bergapten and citropten are strong inhibitors of IL-8 expression and could be proposed for further studies to verify possible anti-inflammatory properties to reduce lung inflammation in CF patients.
PMCID: PMC3095539  PMID: 21496221
8.  Inhibitory Effects of Bangladeshi Medicinal Plant Extracts on Interactions between Transcription Factors and Target DNA Sequences 
Several transcription factors (TFs) play crucial roles in governing the expression of different genes involved in the immune response, embryo or cell lineage development, cell apoptosis, cell cycle progression, oncogenesis, repair and fibrosis processes and inflammation. As far as inflammation, TFs playing pivotal roles are nuclear factor kappa B (NF-kB), activator protein (AP-1), signal transducer and activator of transcription (STATs), cAMP response element binding protein (CREB) and GATA-1 factors. All these TFs regulate the expression of pro-inflammatory cytokines and are involved in the pathogenesis of a number of human disorders, particularly those with an inflammatory component. Since several medicinal plants can be employed to produce extracts exhibiting biological effects and because alteration of gene transcription represents a very interesting approach to control the expression of selected genes, this study sought to verify the ability of several extracts derived from Bangladeshi medicinal plants in interfering with molecular interactions between different TFs and specific DNA sequences. We first analyzed the antiproliferative activity of 19 medicinal plants on different human cell lines, including erythroleukemia K562, B lymphoid Raji and T lymphoid Jurkat cell lines. Secondly, we employed the electrophoretic mobility shift assay as a suitable technique for a fast screening of plant extracts altering the binding between NF-kB, AP-1, GATA-1, STAT-3, CREB and the relative target DNA elements.
PMCID: PMC2529391  PMID: 18830455
AP-1; CREB; GATA-1; gene expression; medicinal plants; NF-kB; STAT-3; transcription factors
9.  Fetal Hemoglobin Inducers from the Natural World: A Novel Approach for Identification of Drugs for the Treatment of β-Thalassemia and Sickle-Cell Anemia 
The objective of this review is to present examples of lead compounds identified from biological material (fungi, plant extracts and agro-industry material) and of possible interest in the field of a pharmacological approach to the therapy of β-thalassemia using molecules able to stimulate production of fetal hemoglobin (HbF) in adults. Concerning the employment of HbF inducers as potential drugs for pharmacological treatment of β-thalassemia, the following conclusions can be reached: (i) this therapeutic approach is reasonable, on the basis of the clinical parameters exhibited by hereditary persistence of fetal hemoglobin patients, (ii) clinical trials (even if still limited) employing HbF inducers were effective in ameliorating the symptoms of β-thalassemia patients, (iii) good correlation of in vivo and in vitro results of HbF synthesis and γ-globin mRNA accumulation indicates that in vitro testing might be predictive of in vivo responses and (iv) combined use of different inducers might be useful to maximize HbF, both in vitro and in vivo. In this review, we present three examples of HbF inducers from the natural world: (i) angelicin and linear psoralens, contained in plant extracts from Angelica arcangelica and Aegle marmelos, (ii) resveratrol, a polyphenol found in grapes and several plant extracts and (iii) rapamycin, isolated from Streptomyces hygroscopicus.
PMCID: PMC2686630  PMID: 18955291
fetal hemoglobin; β-thalassemia; rapamycin; medicinal plants; resveratrol; red wine; psoralens
10.  Cellular Uptakes, Biostabilities and Anti-miR-210 Activities of Chiral Arginine-PNAs in Leukaemic K562 Cells 
Chembiochem  2012;13(9):1327-1337.
A series of 18-mer peptide nucleic acids (PNAs) targeted against micro-RNA miR-210 was synthesised and tested in a cellular system. Unmodified PNAs, R8-conjugated PNAs and modified PNAs containing eight arginine residues on the backbone, either as C2-modified (R) or C5-modified (S) monomers, all with the same sequence, were compared. Two different models were used for the modified PNAs: one with alternated chiral and achiral monomers and one with a stretch of chiral monomers at the N terminus. The melting temperatures of these derivatives were found to be extremely high and 5 m urea was used to assess differences between the different structures. FACS analysis and qRT-PCR on K562 chronic myelogenous leukaemic cells indicated that arginine-conjugated and backbone-modified PNAs display good cellular uptake, with best performances for the C2-modified series. Resistance to enzymatic degradation was found to be higher for the backbone-modified PNAs, thus enhancing the advantage of using these derivatives rather than conjugated PNAs in the cells in serum, and this effect is magnified in the presence of peptidases such as trypsin. Inhibition of miR-210 activity led to changes in the erythroid differentiation pathway, which were more evident in mithramycin-treated cells. Interestingly, the anti-miR activities differed with use of different PNAs, thus suggesting a role of the substituents not only in the cellular uptake, but also in the mechanism of miR recognition and inactivation. This is the first report relating to the use of backbone-modified PNAs as anti-miR agents. The results clearly indicate that backbone-modified PNAs are good candidates for the development of very efficient drugs based on anti-miR activity, due to their enhanced bioavailabilities, and that overall anti-miR performance is a combination of cellular uptake and RNA binding.
PMCID: PMC3401907  PMID: 22639449
cell permeation; cellular differentiation; chiral PNA; microRNA; peptide nucleic acids; RNA

Results 1-10 (10)