comprehensive-evaluation-effectiveness-safety-placenta-targeted-drug

Comprehensive Evaluation of the Effectiveness and Safety of Placenta-Targeted Drug Delivery Using Three Complementary Methods

No effective treatments currently exist for placenta-associated pregnancy complications, and developing strategies for the targeted delivery of drugs to ...

Chinese Academy of Sciences

Hunan Agricultural University

Riboflavin, suggested to be a radiosensitizer, was studied in murine thymocytes and human hepatoma L02 cell line in vitro with MTT method and fluorescence microscopy. When the murine thymocytes treated with 5-400 mumol/L riboflavin were irradiated by 5 Gy (60)Co gamma ionizing radiation, the low concentration groups, i.e. treated with 5-50 mumol/L riboflavin, showed a different surviving fractions-time relating correlation compared with the high concentration groups, i.e. treated with 100-400 mumol/L riboflavin. The former had a high survival level at the end of irradiation, but which, after 4-h incubation, decreased rapidly to a low level. On the contrary, the high concentration groups showed a low survival level at the end of irradiation, and a poor correlation was found between the surviving fraction and the incubation time, after 4 h a little difference was observed. The results of fluorescence microscopy indicated that under low concentration conditions, the riboflavin localized mainly in nucleus (both perinuclear area and inside of nuclear membrane), while under high concentration conditions, intensive riboflavin also localized around cytoplasmic membranes. Thus we can conclude: the riboflavin had radiosensitivity effect on DNA under low concentration conditions, and enhanced the damage to cytoplasmic membrane under high concentration conditions. Also the most effective concentration of riboflavin can be evaluated to be approximate 100 mumol/L.

Radiosensitization mechanism of riboflavin in vitro.

Dysregulation of non-coding RNA H19 has been observed in various tumors. However, it remains unknown whether H19 is involved in Bcr-Abl-induced leukemia. Here, we demonstrate a critical requirement for H19 in Bcr-Abl-mediated tumorigenesis. H19 was highly expressed in Bcr-Abl-transformed cell lines and primary cells derived from patients in a Bcr-Abl kinase-dependent manner. Silencing H19 expression sensitized leukemic cells to undergo imatinib-induced apoptosis and inhibited Bcr-Abl-induced tumor growth. Furthermore, H19 was shown to be regulated by c-Myc in Bcr-Abl-expressing cells. These results reveal an important role H19 plays in Bcr-Abl-mediated transformation and provide novel insights into complex mechanisms underlying Bcr-Abl-induced cancers. 

High expression of long non-coding RNA H19 is required for efficient tumorigenesis induced by Bcr-Abl oncogene.

Although alteration in host cellular translation machinery occurs in virus-infected cells, the role of such alteration and the precise pathogenic processes are not well understood. Influenza A virus (IAV) infection shuts off host cell gene expression at transcriptional and translational levels. Here, we found that the protein level of eukaryotic translation initiation factor 4B (eIF4B), an integral component of the translation initiation apparatus, was dramatically reduced in A549 cells as well as in the lung, spleen, and thymus of mice infected with IAV. The decrease in eIF4B level was attributed to lysosomal degradation of eIF4B, which was induced by viral NS1 protein. Silencing eIF4B expression in A549 cells significantly promoted IAV replication, and conversely, overexpression of eIF4B markedly inhibited the viral replication. Importantly, we observed that eIF4B knockdown transgenic mice were more susceptible to IAV infection, exhibiting faster weight loss, shorter survival time, and more-severe organ damage. Furthermore, we demonstrated that eIF4B regulated the expression of interferon-induced transmembrane protein 3 (IFITM3), a critical protein involved in immune defense against a variety of RNA viruses, including influenza virus. Taken together, our findings reveal that eIF4B plays an important role in host defense against IAV infection at least by regulating the expression of IFITM3, which restricts viral entry and thereby blocks early stages of viral production. These data also indicate that influenza virus has evolved a strategy to overcome host innate immunity by downregulating eIF4B protein.

Influenza A virus-induced degradation of eukaryotic translation initiation factor 4B contributes to viral replication by suppressing IFITM3 protein expression.

Muscovy duck reovirus (MDRV) is a highly pathogenic virus in waterfowl and causes significant economic loss in the poultry industry worldwide. Because the host innate immunity plays a key role in defending against virus invasion, more and more attentions have been paid to the immune response triggered by viral infection. Here we found that the genomic RNA of MDRV was able to rapidly induce the production of interferons (IFNs) in host. Mechanistically, MDRV infection induced robust expression of IFNs in host mainly through RIG-I, MDA5 and TLR3-dependent signaling pathways. In addition, we observed that silencing VISA expression in 293T cells could significantly inhibit the secretion of IFNs. Remarkably, the production of IFNs was reduced by inhibiting the activation of NF-κB or knocking down the expression of IRF-7. Furthermore, our study showed that treatment of 293T cells and Muscovy duck embryo fibroblasts with IFNs markedly impaired MDRV replication, suggesting that these IFNs play an important role in antiviral response during the MDRV infection. Importantly, we also detected the induced expression of RIG-I, MDA5, TLR3 and type I IFN in Muscovy ducks infected with MDRV at different time points post infection. The results from in vivo studies were consistent with those in 293T cells infected with MDRV. Taken together, our findings reveal that the host can resist MDRV invasion by activating innate immune response involving RIG-I, MDA5 and TLR3-dependent signaling pathways that govern IFN production. 

Muscovy duck reovirus infection rapidly activates host innate immune signaling and induces an effective antiviral immune response involving critical interferons.

 The availability of therapeutics to treat pregnancy complications is severely lacking, mainly due to the risk of harm to the fetus. In placental malaria, infected erythrocytes (IEs) accumulate in the placenta by adhering to chondroitin sulfate A (CSA) on the surfaces of trophoblasts. Based on this principle, we have developed a method for targeted delivery of payloads to the placenta using a synthetic placental CSA-binding peptide (plCSA-BP) derived from VAR2CSA, a CSA-binding protein expressed on IEs.  A biotinylated plCSA-BP was used to examine the specificity of plCSA-BP binding to mouse and human placental tissue in tissue sections . Different nanoparticles, including plCSA-BP-conjugated nanoparticles loaded with indocyanine green (plCSA-INPs) or methotrexate (plCSA-MNPs), were administered intravenously to pregnant mice to test their efficiency at drug delivery to the placenta . The tissue distribution and localization of the plCSA-INPs were monitored in live animals using an IVIS imaging system. The effect of plCSA-MNPs on fetal and placental development and pregnancy outcome were examined using a small-animal high-frequency ultrasound (HFUS) imaging system, and the concentrations of methotrexate in fetal and placental tissues were measured using high-performance liquid chromatography (HPLC).  plCSA-BP binds specifically to trophoblasts and not to other cell types in the placenta or to CSA-expressing cells in other tissues. Moreover, we found that intravenously administered plCSA-INPs accumulate in the mouse placenta, and  analysis of the fetuses and placentas confirmed placenta-specific delivery of these nanoparticles. We also demonstrate successful delivery of methotrexate specifically to placental cells by plCSA-BP-conjugated nanoparticles, resulting in dramatic impairment of placental and fetal development. Importantly, plCSA-MNPs treatment had no apparent adverse effects on maternal tissues.  These results demonstrate that plCSA-BP-guided nanoparticles could be used for the targeted delivery of payloads to the placenta and serve as a novel placenta-specific drug delivery option.

Zhilong Chen

Laboratory for Reproductive Health,
Institute of Biomedicine and Biotechnology,
Shenzhen Institutes of Advanced Technology,
Laboratory for Reproductive Health, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology

Chinese Academy of Sciences

Comprehensive Evaluation of the Effectiveness and Safety of Placenta-Targeted Drug Delivery Using Three Complementary Methods