RNA therapeutics inhibit the expression of specific proteins/RNAs by targeting complementary sequences of corresponding genes or encode proteins for the synthesis desired genes to treat genetic diseases. RNA-based therapeutics are categorized as oligonucleotide drugs (antisense oligonucleotides, small interfering RNA, RNA aptamers), and mRNA drugs. The antisense oligonucleotides and small interfering RNA for treatment of genetic diseases have been approved by the FDA in the United States, while RNA aptamers and mRNA drugs are still in clinical trials. Chemical modifications can be applied to RNA drugs, such as pseudouridine modification of mRNA, to reduce immunogenicity and improve the efficacy. The secure and effective delivery systems such as lipid-based nanoparticles, extracellular vesicles, and virus-like particles are under development to address stability, specificity, and safety issues of RNA drugs. This article provides an overview of the specific molecular mechanisms of eleven RNA drugs currently used for treating genetic diseases, and discusses the research progress of chemical modifications and delivery systems of RNA drugs.
Aptamers, Nucleotide ; RNA, Small Interfering/therapeutic use* ; RNA, Messenger ; Oligonucleotides, Antisense/therapeutic use*

OBJECTIVE: MicroRNA-155 (miR-155) is significantly highly expressed in breast cancer, lung cancer, liver cancer and other malignant tumors. This study was to design and construct a radiolabeled probe targeting miR-155 for in vivo imaging in breast cancer. METHODS: Anti-miR-155 oligonucleotide (AMO-155) was chemically synthesized with 2' OMe modification. Its 5' end was linked with acetyl amine group. After chelated with a bifunctional chelator NHS-MAG3, AMO-155 was radiolabeled with ^99mTc using stannous chloride. The serum stability was evaluated at cellular level. In vivo imaging was performed in MCF-7 tumor bearing mice after the administration of ^99mTc radiolabeled AMO-155 and scramble control probes, respectively. Furthermore, the blocked imaging of tumor bearing mice was obtained after the injection of unlabeled AMO-155 2 hours ahead. MCF-7 and MDA-MB-231 tumor bearing mice with different expression level of miR-155 were imaged, respectively. Quantitative real-time PCR (qRT-PCR) was used to identify the expression level of miR-155 in the bearing tumors. RESULTS: ^99mTc-AMO-155 was prepared with high radiolabeled efficiency (97%), radiochemical purity (greater than 98%), and radioactive specific activity (3.75 GBq/μg). ^99mTc-AMO-155 was stable in fresh human serum for 12 hours. After the administration via tail vein, ^99mTc-AMO-155 displayed significant accumulation in MCF-7 bearing tumors with high expression level of miR-155, whereas ^99mTc-control showed little accumulation. After blocked with unlabeled AMO-155, the tumor could not be visualized clearly after the administration of ^99mTc-AMO-155. Furthermore, ^99mTc-AMO-155 could show the differential expression of miR-155 in vivo. MCF-7 tumor was shown with significantly higher radioactive accumulation than MDA-MB-231, based on its higher expression level of miR-155, which was verified by qRT-PCR. CONCLUSION ^99mTc-labeled AMO-155 with chemical modification showed good serum stability and in vivo tumor targeting ability. This study provides a potential probe for in vivo imaging of breast cancer.
Animals ; Breast Neoplasms/diagnostic imaging* ; Cell Line, Tumor ; Female ; Humans ; Mice ; MicroRNAs/analysis* ; Oligonucleotides, Antisense ; Oligopeptides ; Radiopharmaceuticals ; Succinimides ; Technetium ; Tissue Distribution

Echinostoma cinetorchis is an oriental intestinal fluke causing significant pathological damage to the small intestine. The aim of this study was to determine a full-length cDNA sequence of E. cinetorchis endoribonuclease (RNase H; EcRNH) and to elucidate its molecular biological characters. EcRNH consisted of 308 amino acids and showed low similarity to endoribonucleases of other parasites (<40%). EcRNH had an active site centered on a putative DDEED motif instead of DEDD conserved in other species. A recombinant EcRNH produced as a soluble form in Escherichia coli showed enzymatic activity to cleave the 3′-O-P bond of RNA in a DNA-RNA duplex, producing 3′-hydroxyl and 5′-phosphate. These findings may contribute to develop antisense oligonucleotides which could damage echinostomes and other flukes.
Amino Acids ; Catalytic Domain ; DNA, Complementary ; Echinostoma* ; Endoribonucleases ; Escherichia coli ; Intestine, Small ; Oligonucleotides, Antisense ; Parasites ; Ribonuclease H* ; Ribonucleases* ; RNA ; Trematoda

OBJECTIVE: To study the safety and efficiency of the transfection of antisense oligonucletide into kidney mediated by lipid microbubbles, and to evaluate its potential clinical application. METHODS: The potential and conditions regarding the transfection self-made lipid microbubbles (CY5)-labeled-oligonucleotide (ODN) or CY5-labeled-ODN connective tissue growth factor (CTGF) into the rat kidney were evaluated. Th e safety was evaluated by HE staining, liver and renal function tests. The transfection efficiency was evaluated by fluorescence microscopy. Th e expression of CTGF was detected by RT-PCR and Western blot. RESULTS: Self-made lipid microbubble and/or ultrasound significantly enhanced the efficiency of gene transfer and expression in the kidney. Especially, 85%-90% of total glomerular could be transfected. CY5-labeled-ODN expression could be observed in glomerular, tubular and interstitial area. Th ere was no significant change in blood tests aft er gene transfer. Levels of LDH in 7 days were decreased compared with that at the fi rst day aft er the transfection (P<0.05). CTGF expression was successfully suppressed by transfection of CTGF-antisense-ODN into kidney. CONCLUSION The ultrasound-mediated gene transfer by self-made lipid microbubble could enhance the efficiency of ODN and expression in the rat kidney. Th is self-made lipid microbubbles supplement may be use for transfection of target genes.
Animals ; Connective Tissue Growth Factor ; genetics ; metabolism ; Kidney ; metabolism ; Lipids ; chemistry ; Microbubbles ; Oligonucleotides, Antisense ; genetics ; RNA, Messenger ; Rats ; Transfection ; Ultrasonics

OBJECTIVEThe present study was undertaken to design antisense oligodeoxynucleotides (AS-ODNs) of glial glutamate transporter-la (GLT-1a) and to evaluate the effectiveness of the designed AS-ODNs on the expression of GLT-1a.

METHODSFive sequences of GLT-1a AS-ODNs were designed according to the C terminus specific sequences of GLT-1a mRNA using antisense design software of IDT Com- pany. Western blot analysis was used to evaluate the inhibition effects of the five GLT-1a AS-ODNs on the expression of GLT-la.

RESULTSThe sequence of GLT-1a AS-ODNs with sequence of 5'-GGTTCTTCCTCAACACTGCA-3' could specifically inhibit the expression of GLT-1a in the hippocampal CA1 subfield of rats, while it had no effect on the expression of GLT-1b. This sequence showed similar inhibition on the expression of GLT-la in sham and ceftriaxone (Cef)-treated rats. It could also significantly inhibit the cerebral ischemic preconditioning (CIP)-induced up-regulation in the expression of GLT-1a. The magnitude of the inhibition in sham, Cef- or CIP-treated rats was similar by more than 60%.

CONCLUSIONFrom the designed five sequences of GLT-1a AS-ODNs, we obtained an effective sequence which can specifically inhibit the expression of GLT-1a.

Animals ; CA1 Region, Hippocampal ; metabolism ; Excitatory Amino Acid Transporter 2 ; antagonists & inhibitors ; metabolism ; Ischemic Preconditioning ; Oligonucleotides, Antisense ; genetics ; RNA, Messenger ; Rats ; Up-Regulation

OBJECTIVETo test the efficiency of transfecting (99)Tc(m)-labeled anti-miR208b oligonucleotide into early hypertrophic cardiac myocytes in vitro.

METHODSThe anti-oligonucleotide targeting miR208b (AMO) was synthesized and modified with LNA followed by conjugation with N-hydroxysuccinimidyl S-acetyl-meraptoacetyl triglycine (NHS-MAG3) and radiolabeling with (99)Tc(m). NHS-MAG3-LNA-AMO and labeled AMO were purified with Sep-Pak C18 column chromatography, and the former was examined for UV absorption at the 260 nm using Gene Quant DNA/RNA calculator. The labeling efficiency, radiochemical purity, stability and molecular hybridization activity were analyzed. An angiotensin II-induced cell model of hypertrophic cardiac myocytes was transfected with (99)Tc(m)-NHS-MAG3-LNA-AMO via liposome, and the relative expression of miRNA208b and retention ratio of the labeled AMO in early hypertrophic cells were determined.

RESULTSThe labeling efficiency and radiochemical purity of the labeled AMO after purification exceeded 84% and 86%, respectively. The radio- chemical purities of the labeled AMO incubated in serum and normal saline for 12 h were both higher than 80%, and the labeled AMO showed a capacity to hybridize with the target gene. In the hypertrophic model of cardiac myocytes, the retention ratio of labeled AMO at 6 h was higher than 20%.

CONCLUSIONThe (99)Tc(m)-labeled antisense probe can be efficiently transfected into hypertrophic cardiac myocytes in vitro, which provides an experimental basis for subsequent radionuclide imaging studies.

Humans ; Isotope Labeling ; Liposomes ; MicroRNAs ; genetics ; Myocytes, Cardiac ; Oligonucleotides ; Oligonucleotides, Antisense ; Oligopeptides ; Radiopharmaceuticals ; Silicon Dioxide ; Succinimides ; Transfection

OBJECTIVETo observe the effects of miR-224 antisense oligonucleotide (ASO) on the proliferation and apoptosis of gastric cancer cells in vitro and vivo.

METHODSThe expression of miR-224 in the cancer tissues and their adjacent tissues in 120 gastric cancer patients were detected by real-time quantitative PCR. The biological effects of miR-224 ASO on human gastric cancer SGC7901 cells was assessed by MTT assay, clone formation assay, flow cytometry and in vivo experiment in nude mice.

RESULTSCompared with the control group (0.50 ± 0.07), miR-224 ASO significantly reduced the miR-224 mRNA expression in the cancer patients (0.09 ± 0.01, P < 0.05). MTT assay results showed that the survival rate of gastric cells at 24 h, 48 h and 72 h was 53.6%, 59.1% and 70.1% in the miR-224 ASO group, and 12.3%, 17.4% and 24.7%, respectively, in the control group (P < 0.05 for all). Clone formation assay revealed that clone formation rate in the miR-224 ASO group was (5.33 ± 0.74)%, significantly lower than the (33.33 ± 8.38)% in the control group (P < 0.05). Flow cytometry indicated that the apoptotic index was (15.68 ± 1.46)% in the miR-224 ASO group and (3.36 ± 0.88)% in the control group (P < 0.01). In addition, the expressions of Bcl2 mRNA and protein were 1.05 ± 0.04 and 0.21 ± 0.03 in the miR-224 ASO group, significantly lower than that in the control group (4.87 ± 0.96 and 0.88 ± 0.09, P < 0.01). The in vivo study further showed that the tumor volume in the experimental group is significantly smaller than that in the control group (P = 0.01).

CONCLUSIONSMiR-224 is overexpressed in human gastric cancer. Reducing the expression of miR-224 can effectively inhibit the growth and promote apoptosis of gastric cancer cells. miR-224 may become a new target for the regulation of gene expression in gastric cancer.

Adult ; Aged ; Animals ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Female ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; MicroRNAs ; genetics ; metabolism ; Middle Aged ; Neoplasm Transplantation ; Oligonucleotides, Antisense ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Tumor Burden

The effect of BHC80 (a component of BRAF-HDAC complex) on development was not well studied, because BHC80 gene knock-out mice died in one day after birth. Interestingly, zebrafish embryos can live, even if their important organs like cardiac system has severe dysfunction, as 25%-40% O2 are supplied through their skin. Therefore, a model of BHC80 gene knock-down zebrafish embryos was established to explore the effect of BHC80 on the early embryonic development. BHC80-morpholino antisense oligonucleotides 2 (BHC80-MO2) was designed and injected into zebrafish embryos to interrupt the correct translation of BHC80 mRNA at one or two cells stage, which was proved by RT-PCR analysis. Two control groups, including non-injection group and control-MO (con-MO) injection group, and four different doses of BHC80-MO2 injection groups, including 4 ng, 6 ng, 8 ng and 10 ng per embryo were set up. The embryonic heart phenotype and cardiac function were monitored, analyzed and compared between con-MO and BHC80-MO2 groups by fluorescence microscope in vmhc:gfp transgenic zebrafish which express green fluorescent protein in ventricle. The results showed that BHC80-MO2 microinjection effectively knocked down the BHC80 gene expression, because the BHC80-MO2 group emerged a new 249 bp band which reduced 51 bp compared to 300 bp band of con-MO group in RT-PCR analysis, and the 51 bp was the extron 10. The abnormal embryo rate rose with the increase of BHC80-MO2 dosage. The proper BHC80-MO2 injection dosage was 8 ng per embryo, as minor embryos had abnormal phenotype in 4 ng and 6 ng per embryo groups and most embryos died in 10 ng per embryo group. BHC80-MO2 embryos exhibited abnormal cardiac phenotype, including imbalance of the proportion of heart ventricle to atrium, incomplete D-loop, even tubular heart, slow heart rates and cardiac dysfunction. The results from a model of BHC80 gene knock-down zebrafish embryos show that the abnormal cardiac phenotype and cardiac dysfunction of BHC80-MO2 embryos may be one of the probable reasons for the BHC80 gene knock-out mice death, which would provide a good research model to clarify the mechanism of cardiac development.
Animals ; Embryonic Development ; genetics ; Gene Expression Regulation, Developmental ; Gene Knockdown Techniques ; Heart ; embryology ; Histone Deacetylases ; genetics ; Mice, Knockout ; Oligonucleotides, Antisense ; RNA, Messenger ; Zebrafish ; embryology ; Zebrafish Proteins ; genetics

OBJECTIVETo investigate the effect of functional blocking of endogenous miR-23a with a specific antisense oligonucleotide (ASO) on the proliferation and invasiveness of gastric adenocarcinoma cell line MGC803 in vitro.

METHODSA specific ASO targeting miR-23a, namely ASO-23a, was transfected into MGC803 cells to block endogenous miR-23a. The mRNA level of miR-23a in the transfected cells was detected with quantitative real-time PCR. The changes of cell proliferation following the transfection were detected with MTT assay and colony formation assay, and TUNEL assay and Transwell assay were employed to evaluate the changes in cell apoptosis and invasiveness, respectively.

RESULTSQuantitative real-time PCR demonstrated efficient functional blocking of endogenous miR-23a in MGC803 cells by ASO-23a. Suppression of miR-23a with ASO-23a obviously inhibited cell growth, colony formation and invasiveness of MGC803 cells and significantly enhanced the cell apoptosis.

CONCLUSIONASO-23a can efficiently block the function of endogenous miR-23a in MGC803 cells to inhibit cell proliferation and invasion and promote cell apoptosis.

Adenocarcinoma ; genetics ; pathology ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Humans ; MicroRNAs ; genetics ; Oligonucleotides, Antisense ; Stomach Neoplasms ; genetics ; pathology ; Transfection

DNA, Viral ; genetics ; Hep G2 Cells ; Hepatitis B virus ; drug effects ; Humans ; Oligonucleotides, Antisense ; pharmacology