Current Status and Challenges of Aptamers Screening and Optimization.

BACKGROUND: Aptamers, consisting of single-stranded DNA or RNA, have secondary and tertiary structures which could bind specifically to target molecules. They are characterized by strong specificity, high affinity, low molecular weight, and low immunogenicity; therefore, the current research focuses on their potential as a targeted drug carrier, a diagnostic probe for diseases, or as a direct therapeutic drug. OBJECTIVE: In this review, how to improve the success rate of adaptor screening and the optimization after screening is described. RESULTS: For aptamer screening, an efficient selection strategy is needed. In this article, by analyzing key aspects of SELEX such as initial library design, screening procedures, truncation and modification after screening, a comprehensive analysis of each step that might meet obstacles in SELEX is provided. CONCLUSION: Aptamers, which possess the specificity and affinity with the target, can serve as targeted drug carriers or biosensors for diagnosing a disease. If the problems in the screening process in cell-SELEX technology, truncation, and modification after screening are solved, it will have a broader range of applications.

The miR-23b/27b/24-1 Cluster Inhibits Hepatic Fibrosis by Inactivating Hepatic Stellate Cells.

BACKGROUND & AIMS: Hepatic fibrosis is characterized by hepatic stellate cell (HSC) activation and transdifferentiation-mediated extracellular matrix (ECM) deposition, which both contribute to cirrhosis. However, no antifibrotic regimen is available in the clinic. microRNA-23b/27b/24-1 cluster inhibition of transforming growth factor-ß (TGF-ß) signaling during hepatic development prompted us to explore whether this cluster inhibits HSC activation and hepatic fibrosis. METHODS: Experimental fibrosis was studied in carbon tetrachloride (CCl4)-treated C57BL/6 mice. After administration of miR-23b/27b/24-1 lentivirus or vehicle, animals were euthanized for liver histology. In primary rat HSC and HSC-T6, the anti-fibrotic effect of miR-23b/27b/24-1 cluster was furtherly investigated by RNA-sequencing, luciferase reporter assay, western blotting and bioinformatic means. RESULTS: In this study, we showed that increasing the miR-23b/27b/24-1 level through intravenous delivery of miR-23b/27b/24-1 lentivirus ameliorated mouse hepatic fibrosis. Mechanistically, the miR-23b/27b/24-1 cluster directly targeted messenger RNAs, which reduced the protein expression of 5 secretory profibrotic genes (TGF-ß2, Gremlin1, LOX, Itgα2, and Itgα5) in HSCs. Suppression of the TGF-ß signaling pathway by down-regulation of TGF-ß2, Itgα2, and Itgα5, and activation of the bone morphogenetic protein signaling pathway by inhibition of Gremlin1, decreased extracellular matrix secretion of HSCs. Furthermore, down-regulation of LOX expression softened the ECM. Moreover, a reduction in tissue inhibitors of metalloproteinase 1 expression owing to weakened TGF-ß signaling increased ECM degradation. CONCLUSIONS: Hepatic overexpression of the miR-23b/27b/24-1 cluster blocked hepatic fibrosis and may be a novel therapeutic regimen for patients with hepatic fibrosis.

Analysis of key genes and related transcription factors in liver fibrosis based on bioinformatic technology.

OBJECTIVE: To analyze differentially expressed genes (DEGs) related to liver fibrosis, and clarify the key genes and the possible targets in the progression of liver fibrosis. METHODS: Using microarray datasets, GSE38199 was extracted from Gene Expression Omnibus (GEO), and a bioinformatics method was performed to find DEGs and transcription factors related to liver fibrosis. RESULTS: A total of 58 DEGs were screened out according to GEO2R online analysis tool, which included 49 up-regulated and 9 down-regulated genes. These DEGs were mainly involved in formation with the extracellular region and extracellular exosome through gene ontology (GO) enrichment analysis. Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analysis showed that DEGs mainly participated in the PI3K-Akt signaling pathway, focal adhesion, ECM-receptor interaction, and metabolic pathways. Based on the results of the Protein-Protein Interaction (PPI) network and Molecular Complex Detection (MCODE) analysis, 9 key genes (COL1A1, FBN1, BGN, COL6A3, MMP2, FBLN5, LUM, PDGFRB, LOXL1) were screened out. A total of 30 transcription factors were found according to these 9 key genes, of which 4 transcription factors (Stat3, Trp53, NF-κB1, Sp1) were enriched. CONCLUSION: Stat3, Trp53, NF-κB1, and Sp1 were all related to the development of liver fibrosis, and FBLN5 might be a target for liver fibrosis.

Interaction of non­parenchymal hepatocytes in the process of hepatic fibrosis (Review).

Hepatic fibrosis (HF) is the process of fibrous scar formation caused by chronic liver injury of different etiologies. Previous studies have hypothesized that the activation of hepatic stellate cells (HSCs) is the central process in HF. The interaction between HSCs and surrounding cells is also crucial. Additionally, hepatic sinusoids capillarization, inflammation, angiogenesis and fibrosis develop during HF. The process involves multiple cell types that are highly connected and work in unison to maintain the homeostasis of the hepatic microenvironment, which serves a key role in the initiation and progression of HF. The current review provides novel insight into the intercellular interaction among liver sinusoidal endothelial cells, HSCs and Kupffer cells, as well as the hepatic microenvironment in the development of HF.