Les oligonucléotides antisens : outils de génétique moléculaire et agents thérapeutiques

Toulmé, Jean Jacques; Verspieren, P.; Boiziau, Claudine; Loreau, Nadine; Cazenave, Christian; Thuong, Nguyen T.

doi:10.1051/parasite/1990651011

Cited by 11 publications

(10 citation statements)

References 18 publications

(20 reference statements)

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“…); malic enzyme (ME; E.C.1.1.1.40); phosphogluconate dehydrogenase (6PGD; E.C.1.1.1.44); glucose-6-phosphate dehydrogenase (G6PD; E.C.1.1.1.49); malate dehydrogenase (MDH; E.C.1.1.1.37); nucleoside phosphorylases 1 and 2 (NP1, NP2; E.C.2.4.2.1, E.C.4.2.1. *); mannose-phosphate isomerase (MPI; E.C.5.3.1.8); isocitrate dehydrogenase (ICD; E.C.1.1.1.42); diaphorase NADH (DIA; E.C.1.6.2.2); glutamate-dehydrogenase (GLUD; E.C.1.4.1.3); fumarate hydratase (FH; E.C.4.2.1.2) [ 49 ]. WHO reference strains of L .…”

Section: Methodsmentioning

confidence: 99%

“…Additional strains were selected as reference for zymodemes representative of the geographical species diversity within the subgenus Leishmania (from both the Old and New Worlds) and Viannia , from the New World. Results were analyzed for the association of single/multiple isoenzyme markers with geographical regions according to published literature [ 24 , 28 – 30 , 49 , 50 ], and unpublished information collected at our Centre.…”

Section: Methodsmentioning

confidence: 99%

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Epidemiology of Imported Leishmaniasis in Italy: Implications for a European Endemic Country

et al. 2015

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In the past decade, the number of imported leishmaniasis cases has increased in countries of Western Europe. The trend is associated with increasing travels, ecotourism activity, military operations and immigration. While in endemic countries leishmaniasis is usually well diagnosed, accurate patient history and parasite identification are necessary to distinguish between autochthonous and imported cases. This is particularly important, as new Leishmania species/genotypes may be introduced and transmitted by local phlebotomine vectors without appropriate surveillance, with unpredictable consequences. We report on the surveillance of imported leishmaniasis performed by the Leishmania Identification Reference Centre of Rome from 1986 through 2012, involving health care centres from 16/20 Italian regions. Suspected imported cases were analyzed and conclusions were based on clinical, epidemiological and diagnostic findings. Over the years, different parasite identification methods were employed, including MultiLocus Enzyme Electrophoresis and molecular techniques combining disease diagnosis (SSU rDNA nested-PCR) and Leishmania typing (nuclear repetitive sequence and ITS-1 PCR-RFLPs). A total of 105 imported cases were recorded (annual range: 0-20) of which 36 were visceral (VL) (16 HIV-coinfections) and 69 cutaneous (CL) cases; 85 cases (52 CL) were from the Old World and 20 (17 CL) from the New World. Eight Leishmania species were identified, of which 7 were exotic to Italy. VL importation until 1995 was associated with the spread of Mediterranean Leishmania-HIV co-infections in early 1990s. Following the introduction of HAART treatment, such cases became occasional in Italians but relatively frequent among immigrants. In contrast, a steady increase of CL cases was observed from different areas of the Old and New Worlds, that in recent years included mainly immigrants ‘visiting friends and relatives’ and Italian tourists. This positive trend likely depends on better diagnosis and reporting; however, we suspect that many CL cases remained unrecognized. Given the relatively low incidence of leishmaniasis importation, the risk of introduction of exotic parasites appears limited, although the detection of anthroponotic species requires attention.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Epidemiology of Imported Leishmaniasis in Italy: Implications for a European Endemic Country

et al. 2015

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“…This structure was superior to single-stranded asDNA, which may have been due to improved stability and possibly to secondary structures, which contributed to the antiviral effect (18,20). 3 Most asDNAs and ODNs activate RNases H, which cleave and degrade the RNA of DNA-RNA hybrids (15,20,52,53). AsDNA can also block translation by steric hindrance of the ribosomes (14,54,55), and miRs primarily inhibit translation of proteins (13,56).…”

Section: Discussionmentioning

confidence: 99%

A Short Hairpin DNA Analogous to miR-125b Inhibits C-Raf Expression, Proliferation, and Survival of Breast Cancer Cells

Hofmann

Heinrich

Radziwil

et al. 2009

Molecular Cancer Research

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The noncoding RNA miR-125b has been described to reduce ErbB2 protein expression as well as proliferation and migration of cancer cell lines. As additional target of miR-125b, we identified the c-raf-1 mRNA by sequence analysis. We designed a short hairpin-looped oligodeoxynucleotide (ODN) targeted to the same 3′ untranslated region of c-raf-1 mRNA as miR-125b. The fully complementary ODN antisense strand is linked to a second strand constituting a partially double-stranded structure of the ODN. Transfection of the c-raf-1-specific ODN (ODN-Raf) in a breast cancer cell line reduced the protein levels of C-Raf, ErbB2, and their downstream effector cyclin D1 similar to miR-125b. MiR-125b as well as ODN-Raf showed no effect on the c-raf-1 mRNA level in contrast to small interfering RNA. Unlike miR-125b, ODN-Raf induced a cytopathic effect. This may be explained by the structural properties of ODN-Raf, which can form G-tetrads. Thus, the short hairpin-looped ODN-Raf, targeting the same region of c-raf-1 as miR-125b, is a multifunctional molecule reducing the expression of oncoproteins and stimulating cell death. Both features may be useful to interfere with tumor growth. (Mol Cancer Res 2009;7(10):1635-44)

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“…Indeed, this allowed the demonstration of the general occurrence of trans-splicing in Leishmania and trypanosomes (4,5). Oligonucleotides complementary to the mini-exon sequence were shown to inhibit Trypanosoma brucei and Leishmania enriettii mRNA translation in cell-free assays, in a sequence-dependent manner (6)(7)(8). It was also shown that an anti-mini-exon 9-mer, covalently linked to an acridine derivative, was able to kill the procyclic forms of T. brucei in culture (9).…”

mentioning

confidence: 99%

Antisense phosphorothioate oligonucleotides: selective killing of the intracellular parasite Leishmania amazonensis.

Ramazeilles

Mishra

Moreau

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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We targeted the mini-exon sequence, present at the 5' end of every mRNA of the protozoan parasite Leishmania amazonensis, by phosphorothioate oligonucleotides. A complementary 16-mer (16PS) was able to kill amastigotes-the intracellular stage of the parasite-in murine macrophages in culture. After 24 hr of incubation with 10 pM 16PS, about 30% infected macrophages were cured. The oligomer 16PS acted through antisense hybridization in a sequence-dependent way; no effect on parasites was observed with noncomplementary phosphorothioate oligonucleotides. The antisense oligonucleotide 16PS was a selective killer of the protozoans without any detrimental effect to the host macrophage. Using 16PS linked to a palmitate chain, which enabled it to complex with low density lipoproteins, improved the leishmanicidal efficiency on intracellular amastigotes, probably due to increased endocytosis. Phosphorothioate oligonucleotides complementary to the intron part of the mini-exon pre-RNA were also effective, suggesting that antisense oligomers could prevent trans-splicing in these parasites.The life cycle of Leishmania involves two successive hosts: the sandfly, in which the parasite grows as a free promastigote, and the mammals, where the amastigote stage multiplies in a parasitophorous vacuole ofthe host's macrophages. These protozoan parasites display a particular process of RNA trans-splicing leading to the presence of a 39-nucleotide-long sequence, termed mini-exon, at the 5' end of all mRNAs (1). This sequence originates in an 89-nucleotidelong mini-exon derived pre-RNA (medRNA) (2).This mini-exon sequence offered an excellent target for antisense oligonucleotides (3). Indeed, this allowed the demonstration of the general occurrence of trans-splicing in Leishmania and trypanosomes (4, 5). Oligonucleotides complementary to the mini-exon sequence were shown to inhibit Trypanosoma brucei and Leishmania enriettii mRNA translation in cell-free assays, in a sequence-dependent manner (6-8). It was also shown that an anti-mini-exon 9-mer, covalently linked to an acridine derivative, was able to kill the procyclic forms of T. brucei in culture (9).For cellular or in vivo purposes, chemically modified oligonucleotides are of interest (10). In particular, modifications can be introduced in the molecules to make them resistant to nucleases (9, 11). Phosphorothioate (PS) analogues that are resistant to DNases and that mediate the degradation of the target RNA by RNase H are receiving particular attention for use in cultured cells and in vivo (12,13).We investigated the effect of PS antisense oligonucleotides on the development of the protozoan parasite Leishmania amazonensis, which is the causal agent of a cutaneous disease in South America. We targeted either the mini-exon sequence or the intron part of the medRNA of the parasite. We report the successful control of the development of L. amazonensis in culture by PS oligonucleotides. MATERIALS AND METHODSOligonucleotide Synthesis and Analysis. Unmodified oligodeoxynucleotides...

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Les oligonucléotides antisens : outils de génétique moléculaire et agents thérapeutiques

Cited by 11 publications

References 18 publications

Epidemiology of Imported Leishmaniasis in Italy: Implications for a European Endemic Country

Epidemiology of Imported Leishmaniasis in Italy: Implications for a European Endemic Country

A Short Hairpin DNA Analogous to miR-125b Inhibits C-Raf Expression, Proliferation, and Survival of Breast Cancer Cells

Antisense phosphorothioate oligonucleotides: selective killing of the intracellular parasite Leishmania amazonensis.

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