Key Regulatory Differentially Expressed Genes in the Blood of Atrial Septal Defect Children Treated With Occlusion Devices.

Atrial septal defects (ASDs) are the most common types of cardiac septal defects in congenital heart defects. In addition to traditional therapy, interventional closure has become the main treatment method. However, the molecular events and mechanisms underlying the repair progress by occlusion device remain unknown. In this study, we aimed to characterize differentially expressed genes (DEGs) in the blood of patients treated with occlusion devices (metal or poly-L-lactic acid devices) using RNA-sequencing, and further validated them by qRT-PCR analysis to finally determine the expression of key mediating genes after closure of ASD treatment. The result showed that total 1,045 genes and 1,523 genes were expressed differently with significance in metal and poly-L-lactic acid devices treatment, respectively. The 115 overlap genes from the different sub-analyses are illustrated. The similarities and differences in gene expression reflect that the body response process involved after interventional therapy for ASDs has both different parts that do not overlap and the same part that crosses. The same portion of body response regulatory genes are key regulatory genes expressed in the blood of patients with ASDs treated with closure devices. The gene ontology enrichment analysis showed that biological processes affected in metal device therapy are immune response with CXCR4 genes and poly-L-lactic acid device treatment, and the key pathways are nuclear-transcribed mRNA catabolic process and proteins targeting endoplasmic reticulum process with ribosomal proteins (such as RPS26). We confirmed that CXCR4, TOB1, and DDIT4 gene expression are significantly downregulated toward the pre-therapy level after the post-treatment in both therapy groups by qRT-PCR. Our study suggests that the potential role of CXCR4, DDIT4, and TOB1 may be key regulatory genes in the process of endothelialization in the repair progress of ASDs, providing molecular insights into this progress for future studies.

Tumor-suppressive microRNA-449a induces growth arrest and senescence by targeting E2F3 in human lung cancer cells.

MicroRNA-449a (miR-449a) was significantly downregulated in 156 lung cancer tissues (p<0.001). We found that the low expression of miR-449a was highly correlated with cancer recurrence and survival of lung cancer patients. The transient introduction of miR-449a caused cell cycle arrest and cell senescence in A549 and 95D cells. Further studies revealed that E2F3 was a direct target of miR-449a in lung cancer cells. miR-449a also suppressed tumor formation in vivo in nude mice. These results suggest that miR-449a plays an important role in lung cancer tumorigenesis and that miR-449a might predict cancer recurrence and survival of lung cancer patients.

RNA-based immunity terminates viral infection in adult Drosophila in the absence of viral suppression of RNA interference: characterization of viral small interfering RNA populations in wild-type and mutant flies.

Replication of viral RNA genomes in fruit flies and mosquitoes induces the production of virus-derived small interfering RNAs (siRNAs) to specifically reduce virus accumulation by RNA interference (RNAi). However, it is unknown whether the RNA-based antiviral immunity (RVI) is sufficiently potent to terminate infection in adult insects as occurs in cell culture. We show here that, in contrast to robust infection by Flock house virus (FHV), infection with an FHV mutant (FHVΔB2) unable to express its RNAi suppressor protein B2 was rapidly terminated in adult flies. FHVΔB2 replicated to high levels and induced high mortality rates in dicer-2 and argonaute-2 mutant flies that are RNAi defective, demonstrating that successful infection of adult Drosophila requires a virus-encoded activity to suppress RVI. Drosophila RVI may depend on the RNAi activity of viral siRNAs since efficient FHVΔB2 infection occurred in argonaute-2 and r2d2 mutant flies despite massive production of viral siRNAs. However, RVI appears to be insensitive to the relative abundance of viral siRNAs since FHVΔB2 infection was terminated in flies carrying a partial loss-of-function mutation in loquacious required for viral siRNA biogenesis. Deep sequencing revealed a low-abundance population of Dicer-2-dependent viral siRNAs accompanying FHVΔB2 infection arrest in RVI-competent flies that included an approximately equal ratio of positive and negative strands. Surprisingly, viral small RNAs became strongly biased for positive strands at later stages of infection in RVI-compromised flies due to genetic or viral suppression of RNAi. We propose that degradation of the asymmetrically produced viral positive-strand RNAs associated with abundant virus accumulation contributes to the positive-strand bias of viral small RNAs.