Sickle cell anemia is the most common heritable hematological disease, yet no curative treatment exists for this disorder. Moreover, the intricacies of globin gene expression have made the development of treatments for hemoglobinopathies based on gene therapy difficult. An alternative genetic approach to sickle cell therapy is based on RNA repair. A trans-splicing group I ribozyme was used to alter mutant β-globin transcripts in erythrocyte precursors derived from peripheral blood from individuals with sickle cell disease. Sickle β-globin transcripts were converted into messenger RNAs encoding the anti-sickling protein γ-globin. These results suggest that RNA repair may become a useful approach in the treatment of genetic disorders.

Severe acute respiratory syndrome coronavirus (SARS-CoV) is the etiological agent of a newly emerged disease SARS. The SARS-CoV nucleocapsid (N) protein is one of the most abundant structural proteins and serves as a diagnostic marker for accurate and sensitive detection of the virus. Using a SELEX (systematic evolution of ligand by exponential enrichment) procedure and recombinant N protein, we selected a high-affinity RNA aptamer capable of binding to N protein with a dissociation constant of 1.65 nM. Electrophoretic mobility shift assays and RNA competition experiments showed that the selected aptamer recognized selectively the C-terminal region of N protein with high specificity. Using a chemiluminescence immunosorbent assay and a nanoarray aptamer chip with the selected aptamer as an antigen-capturing agent, we could sensitively detect N protein at a concentration as low as 2 pg/ml. These aptamer–antibody hybrid immunoassays may be useful for rapid, sensitive detection ofSARS-CoV N protein.

Metastasis is a highly complicated and sequential process in which primary cancer spreads to secondary organic sites. Liver is a well-known metastatic organ from colorectal cancer. Carcinoembryonic antigen (CEA) is expressed in most gastrointestinal, breast, and lung cancer cells. Overexpression of CEA is closely associated with liver metastasis, which is the main cause of death from colorectal cancer. CEA is widely used as a diagnostic and prognostic tumor marker in cancer patients. It affects many steps of liver metastasis from colorectal cancer cells. CEA inhibits circulating cancer cell death. CEA also binds to heterogeneous nuclear RNA binding protein M4 (hnRNP M4), a Kupffer cell receptor protein, and activates Kupffer cells to secrete various cytokines that change the microenvironments for the survival of colorectal cancer cells in the liver. CEA also activates cell adhesion-related molecules. The close correlation between CEA and cancer has spurred the exploration of many CEA-targeted approaches as anticancer therapeutics. Understanding the detailed functions and mechanisms of CEA in liver metastasis will provide great opportunities for the improvement of anticancer approaches against colorectal cancers. In this report, the roles of CEA in liver metastasis and CEA-targeting anticancer modalities are reviewed.

Hepatitis C virus (HCV) is the major cause of progressive liver disease such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Previously, we reported that a 29 nucleotide-long 2’-F pyrimidine modified RNA aptamer against the HCV nonstructural protein 5B efficiently inhibited HCV replication and suppressed HCV infectious virus particle formation in a cell culture system. In this study, we modified this aptamer through conjugation of cholesterol for in vivo availability. This cholesterol-conjugated aptamer (chol-aptamer) efficiently entered the cell and inhibited HCV RNA replication, without any alteration in gene expression profiling including innate immune response-related genes. Moreover, systemic administration of the chol-aptamer was well tolerated without any abnormalities in mice. To evaluate the pharmacokinetics of the chol-aptamer in vivo, dose proportionality, bioavailability, and pharmacokinetic parameters were evaluated by noncompartmental analyses in normal BALB/c mice. Population analysis was performed using nonlinear mixed effects modeling. Moreover, the pharmacokinetics of two different routes (intravenous, IV, versus intraperitoneal, IP) were compared. Cholesterol conjugation showed dose proportionality, extended the time that the aptamer was in the plasma, and enhanced aptamer exposure to the body. Noticeably, the IV route was more suitable than the IP route due to the chol-aptamer remaining in the plasma for a longer period of time.

The mechanism by which hepatitis C virus (HCV) causes fibrosis and other chronic liver diseases remains poorly understood. Previously, we observed that HCV infection induces microRNA-192 (miR-192) expression, which in turn upregulates transforming growth factor β1 (TGF-β1) in hepatocytes. In this study, we aimed to determine the roles and mechanisms of HCV-induced miR-192 expression during chronic liver injury and fibrosis and to identify potential target of the liver disease. Noticeably, miR-192 is secreted and transmitted through exosomes from HCV-replicating hepatocytes into hepatic stellate cells (HSCs). Exosomal transferred miR-192 upregulated fibrogenic markers in HSCs through TGF-β1 upregulation, resulting in the activation and transdifferentiation of HSCs into myofibroblasts. Anti-miR-192 treatment of HCV-replicating hepatocytes efficiently reduced miR-192 levels in exosomes, downregulated miR-192 and fibrogenic marker levels in HSCs, and impeded transdifferentiation of the cells. In contrast, miR-192 mimic RNA treatment significantly increased miR-192 levels in exosomes from naive hepatocytes, increased miR-192 and fibrogenic marker expression in HSCs, and induced transdifferentiation of the cells. Notably, transdifferentiation of exosome-exposed HSCs was reversed following treatment with anti-miR-192 into the HSCs. This study revealed a novel mechanism of HCV-induced liver fibrosis and identified exosomal miR-192 as a major regulator and potential treatment target for HCV-mediated hepatic fibrosis.