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BACKGROUND: Anti-TNF are usually maintained during pregnancy in patients with inflammatory bowel disease (IBD) but safety is still a concern for them. AIMS: To provide data on management of anti-TNF agents during pregnancy, safety of live vaccines (BCG-MMR-rotavirus) and breastfeeding in newborns and dedicated information delivered to IBD women. METHODS: We performed an observational study in 25 centers from 2016 to 2018. We administered questionnaires to women with IBD receiving anti-TNF during pregnancy with newborn follow-up ≥ one year. RESULTS: Of 153 patients, 52 % maintained anti-TNF during the third trimester. Anti-TNF was shortly resumed in 79 % (58/73) after delivery. The rate of breastfeeding was 44 % (68/153) without any complication; 38 % of the mothers denied to breastfeed based on physician's advice. 26 % (34/129) of the newborns received live vaccines before 6 months-old (BCG:30 %; MMR:63 %; Rotavirus:8 %) and only 3 complications occurred (local BCGitis=1, fever=2). Information concerning anti-TNF during pregnancy/post-partum was delivered to 92 % of the patients, mainly by a gastroenterologist (97 %) who discussed with the obstetrician or the paediatrician in only 48 % and 25 %. CONCLUSION: In IBD patients, maintaining anti-TNF during pregnancy and breastfeeding is safe. Accidental live vaccines before 6 months did not lead to significant adverse events. The communication about these questions remains to improve.
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BACKGROUND: Data on infliximab efficacy in bio-exposed patients with ulcerative colitis (UC) are limited. AIMS: To evaluate infliximab effectiveness and its predictors in UC patients with prior exposure to subcutaneous (SC) anti-TNF agent. METHODS: In this multicenter retrospective study (8 centers), we included all consecutive UC patients with prior exposure to subcutaneous anti-TNF, starting infliximab for symptomatic UC, excluding acute severe colitis. Corticosteroid-free clinical remission (CFREM) was assessed at week 14 (W14) and W52 while endoscopic improvement (CFREM + endoscopic Mayo score≤1) was evaluated at W14. RESULTS: Overall, 104 patients were included (pancolitis=54.8%, primary failure to subcutaneous anti-TNF=57.4%, concomitant immunosuppressant=53.8%, median partial Mayo score at baseline=7[5-8]). The rate of CFREM was 33.6% (35/104) at W14 and 40.4% (42/104) at W52. At W14, endoscopic improvement was achieved in 29.8%(31/104). In multivariable analysis, concomitant immunosuppressant was associated with higher rate of CFREM at W14(OR=2.83[1.06-7.54], p = 0.037) and W52(OR=2.68[1.16-6.22];p = 0.021), while primary failure to a previous subcutaneous anti-TNF agent led to lower rate of CFREM at W14 (OR=0.37[0.14-0.98], p = 0.046). After a median follow-up of 20.9 months[11.7-33.7]), 50.0%(52/104) patients had discontinued infliximab. CONCLUSION: Infliximab is an effective option in UC patients previously exposed to prior subcutaneous anti-TNF agent and should be used with concomitant immunosuppressant.
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Colite Ulcerativa , Fármacos Gastrointestinais , Infliximab , Humanos , Colite Ulcerativa/tratamento farmacológico , Infliximab/administração & dosagem , Infliximab/uso terapêutico , Masculino , Feminino , Estudos Retrospectivos , Adulto , Pessoa de Meia-Idade , Injeções Subcutâneas , Fármacos Gastrointestinais/administração & dosagem , Fármacos Gastrointestinais/uso terapêutico , Resultado do Tratamento , Indução de Remissão , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Análise Multivariada , Imunossupressores/administração & dosagem , Imunossupressores/uso terapêuticoRESUMO
BACKGROUND: The long-term risk of relapse after switching from intravenous (IV) to subcutaneous (SC) infliximab remains unknown in inflammatory bowel disease (IBD). AIMS: To assess the long-term effectiveness and acceptability of switching from IV to SC infliximab in patients with IBD treated with or without an intensified IV regimen. METHODS: We extended the follow-up of the REMSWITCH study including patients with IBD in clinical remission who were switched from IV to SC infliximab (120 mg/2 weeks). Relapse was defined as clinical relapse or faecal calprotectin increase ≥150 µg/g compared to baseline. RESULTS: After median follow-up of 18 [15-20] months, among 128 patients, rates of relapse were 13.8% (8/58), 18.4% (7/38), 35.3% (6/17) and 86.7% (13/15) at last follow-up (p < 0.001), in those receiving 5 mg/kg/8 weeks, 10 mg/kg/8 weeks, 10 mg/kg/6 weeks and 10 mg/kg/4 weeks at baseline, respectively. Among relapsing patients, dose escalation led to clinical remission in 82.1% (23/28). In multivariable analyses, factors associated with higher risk of relapse were IV infliximab 10 mg/kg/4 weeks (OR = 61.0 [6.1-607.0], p < 0.001) or 10 mg/kg/6 weeks (OR = 4.7 [1.1-20.2], p = 0.017), and decreased (OR = 5.6 [1.5-20.3], p = 0.004) or stable (OR = 5.0 [1.6-15.0], p = 0.009) serum levels of infliximab between baseline and first post-switch visit. Acceptability was improved at 6 months and did not decrease over time (6.9 ± 1.6 before the switch vs. 8.8 ± 1.3 at 6 months and 8.8 ± 1.3 at last follow-up; p < 0.001). No severe adverse events were reported. CONCLUSIONS: Switching from IV to SC infliximab 120 mg every other week is safe and well accepted leading to low long-term risk of relapse. Tight monitoring and dose escalation should be recommended for patients receiving 10 mg/kg/6 weeks and 4 weeks, respectively.
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Medicamentos Biossimilares , Doenças Inflamatórias Intestinais , Humanos , Medicamentos Biossimilares/uso terapêutico , Fármacos Gastrointestinais , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/induzido quimicamente , Infliximab/efeitos adversos , Recidiva , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Long-term outcome of ustekinumab in Crohn's disease (CD) has not been evaluated. AIM: To evaluate the long-term efficacy and safety of ustekinumab and identify the predictive factors of ustekinumab failure-free persistence in a cohort of anti-TNF refractory CD patients. METHODS: We performed a retrospective multicentre cohort study including all consecutive CD patients who began subcutaneous ustekinumab and presented a clinical response (defined as a significant improvement of CD-related clinical symptoms assessed by the patient's physician leading to continued ustekinumab) during the first year of treatment. Primary outcome was treatment failure defined as withdrawal of treatment due to loss of response, intolerance or need for surgery. RESULTS: Eighty-eight of the 122 (72%) CD patients beginning ustekinumab from March 2011 to December 2014, responded to ustekinumab and were followed up until November 2016. Median time on ustekinumab was 26.6 (13.4-34.4) months. Forty-seven patients (54%) continued ustekinumab with a clinical response and 38 (43%) stopped treatment (32 for failure, five for remission and one for pregnancy). Endoscopic response was observed in 82% of patients with endoscopic evaluation and mucosal healing in 39%. Ustekinumab failure-free persistence rates were 78% at 12 months, 66% at 24 months and 55% at 36 months. No predictive factor of ustekinumab failure-free persistence was identified. One severe adverse event was observed (anal adenocarcinoma). CONCLUSION: In this cohort of refractory CD patients receiving long-term ustekinumab therapy, more than 50% of patients continued ustekinumab treatment with no loss of response, intolerance or surgery and with a good safety profile.
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Doença de Crohn/tratamento farmacológico , Ustekinumab/administração & dosagem , Ustekinumab/efeitos adversos , Adulto , Estudos de Coortes , Doença de Crohn/epidemiologia , Resistência a Medicamentos/efeitos dos fármacos , Endoscopia , Feminino , Seguimentos , Humanos , Masculino , Gravidez , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento , Fator de Necrose Tumoral alfa/uso terapêuticoRESUMO
BACKGROUND: Anti-tumour necrosis factor (TNF) agents have improved the care of Crohn's disease (CD). After the first anti-TNF discontinuation, it is possible to switch to another anti-TNF. Three anti-TNF agents are available for ulcerative colitis (infliximab, adalimumab and golimumab), but only the first 2 have been approved for CD because golimumab has not been studied for this indication. AIM: To report the efficacy and safety of golimumab in CD. METHODS: Crohn's disease patients who received golimumab were identified in 12 French tertiary centres and were retrospectively analysed. The primary endpoint was the duration of golimumab treatment before escalation or discontinuation. The clinical response was defined as a decrease of more than 3 points in the Harvey-Bradshaw index or by global physician assessment. RESULTS: One hundred and fifteen patients were included. The golimumab treatment duration was 9.8 months (0.55-44), and 48.7% of the patients were still under treatment at the end of follow-up. Clinical response was observed in 55.8% of the patients after a mean duration of 3.8 months. The probability of remaining under treatment without escalation at 6, 12 and 24 months was 54.6%, 34.9% and 19.3% respectively. In multivariate analysis, discontinuation of the first anti-TNF agent due to intolerance (odds ratio, OR = 2.16; 95% CI, confidence interval [1.25-3.86]; P = .005) and co-immunosuppression for more than 6 months (OR = 3.98; 95% CI [2.3-7.1]; P < .0001) were predictive factors of efficacy. Six per cent of the patients discontinued treatment due to intolerance. CONCLUSION: After failure of infliximab or adalimumab for Crohn's disease, golimumab was safe and seemed beneficial in half of the patients.
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Anticorpos Monoclonais/uso terapêutico , Doença de Crohn/tratamento farmacológico , Fármacos Gastrointestinais/uso terapêutico , Adolescente , Adulto , Idoso , Anticorpos Monoclonais/administração & dosagem , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Feminino , Fármacos Gastrointestinais/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Recently, a new enteropathy has been described: olmesartan-associated enteropathy. However, the association has been questioned: a phase 3 trial and a cohort study found no association between gastrointestinal events and olmesartan. AIM: To collect French cases of sartan-associated enteropathy to describe further this entity, confirm or refute causality, and determine if the association exists with other sartans. METHODS: French gastroenterologists were invited to report cases of sartan-associated enteropathy and collect clinical, biological and histological data. Patients with diarrhoea and histological duodenal abnormalities were included. RESULTS: Thirty-six patients with olmesartan-associated enteropathy were reported, including 32 with villous atrophy and four without. There was only one patient with irbesartan-associated enteropathy. None of the patients died. Patients with villous atrophy had diarrhoea, vomiting, renal failure, hypokalaemia, body weight loss and hypoalbuminaemia. Thirty-one patients were hospitalised; four required intensive care. Anti-transglutaminase and anti-enterocyte antibodies were negative; anti-nuclear antibodies were positive (9/11). Endoscopic duodenal biopsies showed villous atrophy (32/32) and polyclonal intra-epithelial CD3+CD8+ lymphocytosis (11/11). Exactly, 14/15 patients responded to steroids and/or immunosuppressants, prescribed because of suspected autoimmune enteropathy. Ten olmesartan interruptions were followed by reintroductions before steroids or immunosuppressants. Interruptions were followed by remissions (9/10), but reintroductions were followed by relapses (9/9). Twenty-nine patients were in remission since olmesartan interruption, including 26 without immunosuppressants. Patients with normal villi had similar clinical characteristics, but mild histological abnormalities (intra-epithelial lymphocytosis and lamina propria lymphocytic infiltration). CONCLUSIONS: Olmesartan causes a severe and immune-mediated enteropathy, with or without villous atrophy. Enteropathy associated with other sartans seems to be very rare.
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Bloqueadores do Receptor Tipo 1 de Angiotensina II/efeitos adversos , Coleta de Dados , Gastroenteropatias/induzido quimicamente , Gastroenteropatias/epidemiologia , Imidazóis/efeitos adversos , Tetrazóis/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Coleta de Dados/métodos , Diarreia/induzido quimicamente , Diarreia/diagnóstico , Diarreia/epidemiologia , Feminino , França/epidemiologia , Gastroenteropatias/diagnóstico , Humanos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Masculino , Pessoa de Meia-IdadeRESUMO
A folate-targeted, cationic lipid based transfection complex was developed and found to specifically transfect folate receptor-expressing cells and tumors. These liposomal vectors were comprised of protamine-condensed plasmid DNA, a mixture of cationic and neutral lipids, and a folic acid-cysteine-polyethyleneglycol-phosphatidylethanolamine (FA-Cys-PEG-PE) conjugate. Pre-optimization studies revealed that inclusion of low amounts (0.01 to 0.03%) of FA-Cys-PEG-PE yielded the highest binding activity of dioleoylphosphatidylcholine/cholesterol liposomes to folate receptor-bearing cells. In contrast, higher amounts (>0.5%) of FA-Cys-PEG-PE progressively decreased cellular binding of the liposomes. In vitro studies with cationic lipid/dioleoylphosphatidylethanolamine formulations indicated that as little as 0.01 to 0.3% of FA-Cys-PEG-PE was needed to produce optimal targeted expression of plasmid DNA. Similarly, using a disseminated intraperitoneal L1210A tumor model, maximum in vivo transfection activity occurred with intraperitoneally administered formulations that contained low amounts (0.01 mol%) of the FA-Cys-PEG-PE targeting lipid. Overall, folate-labeled formulations produced an eight- to 10-fold increase in tumor-associated luciferase expression, as compared with the corresponding non-targeted cationic lipid/DNA formulations. These results collectively indicate that transfection of widespread intraperitoneal cancers can be significantly enhanced using folate-targeted techniques.
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Proteínas de Transporte/metabolismo , Ácido Fólico/genética , Marcação de Genes/métodos , Terapia Genética/métodos , Neoplasias Peritoneais/terapia , Receptores de Superfície Celular , Animais , Linhagem Celular , Feminino , Receptores de Folato com Âncoras de GPI , Ácido Fólico/metabolismo , Lipossomos , Luciferases/genética , Camundongos , Camundongos Endogâmicos DBA , Neoplasias Peritoneais/metabolismo , Ligação Proteica , Transfecção/métodosRESUMO
BACKGROUND: Cationic lipid-mediated gene transfer is a promising approach for gene therapy. However, despite the significant amount of lipoplexes internalized by target cells, transgene expression remains too low. Obstacles to nuclear accumulation of plasmid DNA include: the passage of DNA across the cellular membrane, the dismantling of nucleolipidic particles in the cytoplasm and the nuclear import of plasmid DNA. The purpose of the present study was to evaluate the impact of cell status on cationic lipid-mediated transfer. METHODS: Cells were either growth-arrested (by aphidicolin) or synchronized (by a classical double-thymidine block protocol) and cationic lipid-mediated transfection of these cells was evaluated. For the study of the nuclear import of plasmid DNA, two techniques were developed: microinjection of plasmid DNA into intact cells, and the use of cells permeabilized with digitonin. RESULTS: When CV-1 cells were growth-arrested by aphidicolin, cationic lipid-mediated gene transfer was inhibited. Hela cells were synchronized and incubated with lipoplexes at different times after release of the block. Gene expression was greatly enhanced when cells underwent mitosis. When transfection was performed during the early period after block release, when fewer than 5% of the cells had divided, gene expression was carefully quantified and could be attributed to cells that escaped cell cycle block. However, by direct analysis of nuclear import of GFP-coding plasmid using cytoplasmic microinjection, GFP expression could be detected in a few cells that had not divided. CONCLUSIONS: Cationic lipid-mediated gene transfer efficiency increased when cells underwent mitosis. However, when cells did not divide, gene transfer was not completely abolished. Nuclear import of plasmid was greatly facilitated by a mitotic event. In non-mitotic cells, nuclear envelope crossing by plasmid DNA could be detected but was a very rare event.
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Núcleo Celular/metabolismo , Lipídeos/farmacologia , Plasmídeos/metabolismo , Transfecção , Animais , Afidicolina/farmacologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Chlorocebus aethiops , Proteínas de Fluorescência Verde , Células HeLa , Humanos , Proteínas Luminescentes/genética , MicroinjeçõesRESUMO
Vaccination by intramuscular injection of naked DNA is very efficient in the mouse, but immunogenicity of DNA vaccines needs to be improved in man. The aim of our study was to determine in BALB/c mice if suitable electric pulses delivered to the muscle after DNA injection--a procedure called electrotransfer--could improve the immunogenicity of suboptimal doses of a DNA vaccine expressing the influenza hemagglutinin protein. The results show a significant enhancement of the cellular and antibody responses following electrotransfer for the 1- and 10-microg DNA doses, respectively, but no effect on a lower dose. At the 10-microg dose, the IgG and hemagglutination inhibition mean titres were increased 25-fold and the inter-individual variability was markedly reduced.
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Estimulação Elétrica/métodos , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Orthomyxoviridae/imunologia , Vacinas de DNA/administração & dosagem , Vacinas de DNA/imunologia , Animais , Anticorpos Antivirais/imunologia , Testes Imunológicos de Citotoxicidade , Relação Dose-Resposta Imunológica , Ensaio de Imunoadsorção Enzimática , Feminino , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/administração & dosagem , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Imunoglobulina G/imunologia , Injeções Intramusculares , Interferon gama/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T Citotóxicos/imunologiaRESUMO
This chapter focuses on a methodology for covalently associating nuclear localization signal (NLS) peptides to DNA, in which cationic NLS peptides are covalently bound to plasmid DNA by photoactivation. Described here are the synthesis and characterization of these conjugates.
RESUMO
We have developed a chemical strategy for covalent coupling of fluorophores to plasmid DNA. A p-azido-tetrafluoro-benzyl-lissamine conjugate was synthesized and purified. This conjugate was used to covalently associate fluorescent molecules to plasmid DNA by photoactivation. In contrast to nick-translated plasmid DNA, plasmid-lissamine conjugates appeared on gel as supercoiled DNA. Reporter gene was expressed after transfection of the plasmid-lissamine conjugates in NIH 3T3 cells, although gene transfer efficiency was decreased by 60% as compared with unlabeled DNA. Intracellular traffic of plasmid-lissamine conjugates was studied in transfected cells. After cytoplasmic microinjection, fluorescent plasmid did not diffuse from the site of injection and appeared to be progressively degraded in the cytoplasm.
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DNA/química , Corantes Fluorescentes/química , Naftalenossulfonatos/química , Naftoquinonas/química , Plasmídeos/química , Células 3T3 , Animais , Linhagem Celular , Chlorocebus aethiops , DNA/genética , Corantes Fluorescentes/síntese química , Expressão Gênica , Corantes Verde de Lissamina/síntese química , Corantes Verde de Lissamina/química , Camundongos , Microinjeções , Naftalenossulfonatos/síntese química , Naftoquinonas/síntese química , Fotoquímica , Plasmídeos/genética , Plasmídeos/metabolismo , Transfecção , TransgenesRESUMO
One of the major steps limiting nonviral gene transfer efficiency is the entry of plasmid DNA from the cytoplasm into the nucleus of the transfected cells. The nuclear localization signal (NLS) of the SV40 large T antigen is known to efficiently induce nuclear targeting of proteins. We have developed two chemical strategies for covalent coupling of NLS peptides to plasmid DNA. One method involves a site-specific labeling of plasmid DNA by formation of a triple helix with an oligonucleotide NLS peptide conjugate. After such modification with one NLS peptide per plasmid molecule, plasmid DNA remained fully active in cationic lipid-mediated transfection. In the other method, we randomly coupled 5-115 p-azidotetrafluorobenzyllissamine-NLS peptide molecules per plasmid DNA by photoactivation. Oligonucleotide-NLS and plasmid lissamine-NLS conjugates interacted specifically with the NLS-receptor importin alpha. Plasmid-lissamine-NLS conjugates were not detected in the nucleus, after cytoplasmic microinjection. Plasmids did not diffuse from the site of injection and plasmid-lissamine-NLS conjugates appeared to be progressively degraded in the cytoplasm. The process of plasmid DNA sequestration/degradation stressed in this study might be as important in limiting the efficiency of nonviral gene transfer as the generally recognized entry step of plasmid DNA from the cytoplasm into the nucleus.
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DNA/genética , DNA/metabolismo , Sinais de Localização Nuclear/genética , Peptídeos/metabolismo , Plasmídeos/genética , Células 3T3 , Animais , Sítios de Ligação , Núcleo Celular/metabolismo , Citomegalovirus/genética , DNA/química , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Técnicas de Transferência de Genes , Corantes Verde de Lissamina/química , Corantes Verde de Lissamina/metabolismo , Camundongos , Microinjeções , Proteínas Nucleares/metabolismo , Peptídeos/química , Fotoquímica , Transfecção , alfa CarioferinasRESUMO
Cationic lipids can deliver genes efficiently in vitro, but are generally inhibited by the presence of serum, and their efficiency in vivo is much lower than in vitro. An attractive strategy is to induce strong DNA compaction by its association with proteins, before addition of lipids. However the use of whole proteins might present both production and immunological limitations. We have devised a system in which DNA is associated with short peptides derived from human histone or protamine, before the addition of a cationic lipid or polymer. Peptides strongly associating with DNA confer to such peptide-DNA-lipid particles an enhanced in vitro transfection efficiency over that observed with classical DNA/lipid lipoplexes, and particularly confer the capacity to transfect in the presence of serum. This acquisition of serum resistance is cell type-independent, and observed with all four lipopolyamines tested and polyethylenimine. Precompacting DNA with a histone H1-derived peptide enhances cationic lipid RPR 115335-mediated gene transfer in an in vivo model of Lewis lung carcinoma. Apart from their use in peptide-DNA-lipid association, such peptides could be useful as part of chimeric gene delivery vectors presenting a DNA-binding moiety that can be easily associated with other functional domains.
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Vetores Genéticos , Transfecção/métodos , Células 3T3 , Animais , Cátions , Engenharia Genética , Histonas/genética , Humanos , Lipídeos , Neoplasias Pulmonares/terapia , CamundongosRESUMO
The nuclear localization signal (NLS) of the SV40 large T antigen efficiently induces nuclear entry of proteins. We have developed a strategy for covalent coupling of one or a controlled number of NLS peptides to plasmid DNA at a specific site by triple helix formation. A psoralen-oligonucleotide-NLS peptide conjugate was synthesized and characterized by proteolysis with trypsin. This conjugate was used to covalently associate one NLS peptide to plasmid DNA by triple helix formation and photoactivation. The oligonucleotide-NLS peptide conjugate interacted with the NLS-receptor importin alpha. The reporter gene was expressed after transfection of the modified plasmid in NIH 3T3 cells, indicating no loss of the gene expression functionality of the plasmid. On the other hand, no increase in expression was observed as a result of the NLS peptide. This site-specific coupling technology can be used to couple to a plasmid other ligands targeting to a specific receptor.
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Técnicas de Transferência de Genes , Vetores Genéticos , Sinais de Localização Nuclear , Plasmídeos , Antígenos Virais de Tumores , Ficusina/química , Vetores Genéticos/química , Conformação de Ácido Nucleico , Oligonucleotídeos/química , Peptídeos/química , Plasmídeos/química , Vírus 40 dos Símios/imunologiaRESUMO
Several cationic lipids which are highly efficient for delivering genes in vitro do not increase gene delivery in vivo after an intramuscular injection. In order to elucidate the origin of this phenomenon, we have studied the cellular uptake and intracellular fate of cationic lipid/DNA complexes in vitro on myogenic mouse cells (myoblasts and myotubes) of the C2 cell line and of primary cultures. We used a cationic lipid with a spermine head group and its fluorescent analog, and a fluorescent plasmid obtained by nick-translation. In myoblasts, transgene expression was obtained and lipoplexes were internalized in cytoplasmic vesicles. In myotubes, no transgene expression could be detected and we observed an absence of lipoplex internalization. The in vitro uptake of cationic lipid was inversely correlated with the degree of fusion of C2 cell myotubes cultures.
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DNA/farmacologia , Lipídeos/farmacologia , Músculo Esquelético/química , Transfecção/métodos , Animais , Diferenciação Celular , Fusão Celular , Linhagem Celular , Células Cultivadas , DNA/química , Lipídeos/química , Camundongos , Microinjeções , Microscopia de Fluorescência , Plasmídeos , beta-Galactosidase/análiseRESUMO
The nuclear localization signal (NLS) of the SV40 large T antigen efficiently induces nuclear targeting of proteins. We have developed a chemical strategy for covalent coupling of NLS peptides to plasmid DNA. A p-azido-tetrafluoro-benzyl-NLS peptide conjugate was synthesized. This conjugate was used to covalently associate NLS peptides to plasmid DNA by photoactivation. Reporter gene was expressed after transfection of the plasmid-NLS conjugates in NIH 3T3 cells. The conjugates interacted specifically with the NLS-receptor importin alpha, but plasmid-NLS conjugates were not detected in the nucleus, by fluorescence microscopy, after cytoplasmic microinjection.
Assuntos
Sinais de Localização Nuclear , Proteínas Nucleares/química , Plasmídeos/química , Células 3T3 , Animais , Cromatografia Líquida de Alta Pressão , Genes Reporter , Glutationa Transferase/genética , Camundongos , Microinjeções , Microscopia de Fluorescência , Sinais de Localização Nuclear/genética , Sinais de Localização Nuclear/efeitos da radiação , Proteínas Nucleares/genética , Peptídeos/química , Peptídeos/efeitos da radiação , Plasmídeos/genética , Plasmídeos/efeitos da radiação , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacologia , Transfecção , Raios Ultravioleta , alfa CarioferinasRESUMO
Cationic lipids are widely used for in vitro gene transfer due to their efficiency. The major challenges for the improvement of in vivo cationic lipid-mediated gene delivery reside in the design of more biocompatible lipoplexes mimicking viral-mediated gene delivery and in understanding the fate of the lipoplexes within the cells.
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Técnicas de Transferência de Genes , Lipídeos/química , Plasmídeos/genética , Animais , Biotecnologia , Cátions , Fenômenos Químicos , Físico-Química , Desenho de Fármacos , Vetores Genéticos , HumanosRESUMO
Cationic lipids are widely used for gene transfer in vitro and show promise as vectors for in vivo gene therapy applications. However, there is limited understanding of the cellular mechanisms involved in nonviral gene transfer. We investigated two major steps that could be limiting barriers to cationic lipid-mediated gene transfer in vitro. We used a fluorescent plasmid to study the cellular uptake and the intracellular fate of lipoplexes during in vitro transfection of fibroblast cells and found that 100% of the cells take up lipoplexes. The intracellular staining observed with lipoplexes was clearly different from that obtained with endocytosed fluorescent dextran. This suggests that cells readily take up lipoplexes by a mechanism that could be different from endocytosis in our conditions. However, the escape of DNA from intracellular vesicles could be a major limiting barrier to gene transfer. Direct injection of plasmid DNA into the nucleus and cytoplasm of cells indicated that DNA traffic from the cytoplasm to the nucleus might be also an important limiting step.
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Fibroblastos/metabolismo , Técnicas de Transferência de Genes , Vetores Genéticos/metabolismo , Metabolismo dos Lipídeos , Animais , Biotinilação , Cátions/química , Linhagem Celular , Núcleo Celular/metabolismo , Citoplasma/metabolismo , DNA/metabolismo , Terapia Genética , Lipídeos/química , Microscopia de Fluorescência , Cifozoários , Transfecção/métodosRESUMO
We have designed and synthesized original cationic lipids for gene delivery. A synthetic method on solid support allowed easy access to unsymmetrically monofunctionalized polyamine building blocks of variable geometries. These polyamine building blocks were introduced into cationic lipids. To optimize the transfection efficiency in the novel series, we have carried out structure-activity relationship studies by introduction of variable-length lipids, of variable-length linkers between lipid and cationic moiety, and of substituted linkers. We introduce the concept of using the linkers within cationic lipids molecules as carriers of side groups harboring various functionalities (side chain entity), as assessed by the introduction of a library composed of cationic entities, additional lipid chains, targeting groups, and finally the molecular probes rhodamine and biotin for cellular traffic studies. The transfection activity of the products was assayed in vitro on Hela carcinoma, on NIH3T3, and on CV1 fibroblasts and in vivo on the Lewis Lung carcinoma model. Products from the series displayed high transfection activities. Results indicated that the introduction of a targeting side chain moiety into the cationic lipid is permitted. A primary physicochemical characterization of the DNA/lipid complexes was demonstrated with this leading compound. Selected products from the series are currently being developed for preclinical studies, and the labeled lipopolyamines can be used to study the intracellular traffic of DNA/cationic lipid complexes.
Assuntos
Cátions/síntese química , DNA/administração & dosagem , Lipídeos/síntese química , Compostos de Amônio Quaternário/síntese química , Transfecção/métodos , Células 3T3 , Animais , Carcinoma Pulmonar de Lewis/genética , Cátions/administração & dosagem , DNA/metabolismo , Eletroforese em Gel de Ágar , Metabolismo dos Lipídeos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Químicos , Transplante de Neoplasias , Poliaminas/química , Compostos de Amônio Quaternário/metabolismo , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Most of the cationic lipids used for gene transfer experiments drastically lose their efficiency in the presence of serum. We used a cationic lipid with a spermine head group and its fluorescent analog to study the cellular uptake and the intracellular fate of lipoplexes in the presence and absence of serum. We found that the amount of DNA and lipid taken up by the cells was not related to the efficacy of the gene transfer. When the lipofection was performed in the presence of serum, lipoplexes were contained within small intracellular vesicles. In the absence of serum, the vesicles were larger and heterogeneous in size and shape. By analysis of their size distribution, we showed that lipoplexes preformed in the absence of serum tended to aggregate. This aggregation was inhibited in the presence of serum. We used a carbonate formulation that led to the preformation of large particles: those large particles gave a high lipofection efficiency in the presence of serum and their intracellular distribution was identical to that observed in the absence of serum.