Metal and its oxide nanoparticles show ideal pharmacological activity, especially in anti-tumor therapy. Our previous study demonstrated that cuprous oxide nanoparticles (CONPs) selectively induce apoptosis of tumor cells in vitro. To explore the anti-tumor properties of CONPs in vivo, we used the particles to treat mouse subcutaneous melanoma and metastatic lung tumors, based on B16-F10 mouse melanoma cells, by intratumoral and systemic injections, respectively. The results showed that CONPs significantly reduced the growth of melanoma, inhibited the metastasis of B16-F10 cells and increased the survival rate of tumor-bearing mice. Importantly, the results also indicated that CONPs were rapidly cleared from the organs and that these particles exhibited little systemic toxicity. Furthermore, we observed that CONPs targeted the mitochondria, which resulted in the release of cytochrome C from the mitochondria and the activation of caspase-3 and caspase-9 after the CONPs entered the cells. In conclusion, CONPs can induce the apoptosis of cancer cells through a mitochondrion-mediated apoptosis pathway, which raises the possibility that CONPs could be used to cure melanoma and other cancers.

Degeneration of retinal ganglion cells (RGCs) -an important cause of visual impairment -is often modeled by optic nerve transection, which leads to apoptotic death of these central nervous system neurons. With this model, we show that specific voltage-gated K þ channels (Kv1 family) contribute to the degeneration of rat RGCs and expression of apoptosis-related molecules in vivo. Retinal expression of Kv1.1, Kv1.2, Kv1.3 and Kv1.5 was examined by quantitative real-time reverse transcriptase-PCR and immunohistochemistry. Kv channel blockers and channel-specific short-interfering RNAs (siRNAs) were used to assess their roles in RGC degeneration. We found that (i) rat RGCs express Kv1.1, Kv1.2 and Kv1.3 (but not Kv1.5); (ii) intraocular injection of agitoxin-2 or margatoxin, potent blockers of Kv1.1, Kv1.2 and Kv1.3 channels, dose-dependently reduced the RGC degeneration; (iii) siRNAs applied to the cut optic nerve were rapidly transported throughout RGCs only, in which they reduced the expression of the cognate channel only. Our results show differential roles of the channels; siRNAs directed against Kv1.1 or Kv1.3 channels greatly reduced RGC death, whereas Kv1.2-targeted siRNAs had only a small effect, and siRNAs against Kv1.5 were without effect. (iv) Kv1.1 and Kv1.3 channels apparently contribute to cell-autonomous death of RGCs through different components of the apoptotic machinery. Kv1.1 depletion increased the antiapoptotic gene, Bcl-X L , whereas Kv1.3 depletion reduced the proapoptotic genes, caspase-3, caspase-9 and Bad.

Sustained endoplasmic reticulum (ER) stress has been linked to cell death and the pathogenesis of many liver diseases, including toxic liver, cholestasis, and infectious liver disease. The cellular pathways that attenuate hepatic ER stress have been the focus of many recent studies, but the role of microRNAs (miRNA) in this process remains unknown. Here, we report that one of the most abundant miRNAs in hepatocytes, miR-199a-5p, was elevated in both bile acid- and thapsigargin (TG)-stimulated cultured hepatocytes, as well as in the liver of bile duct-ligated mice. We identify the misfolded protein chaperone GRP78, as well as the unfolded protein response transducers endoplasmic reticulum to nucleus signaling 1 and activating transcription factor 6 as direct targets of miR-199a-5p, and show that endogenous miR-199a-5p represses the 3′ untranslated regions (UTRs) of their mRNAs. Through gain-of-function and loss of function approaches, we demonstrate that the elevated miR-199-5p disrupts sustained ER stress and prevents hepatocytes from undergoing bile acid- or TG-induced cell death. Furthermore, we reveal that the transcription factor AP-1 is a strong positive regulator of miR-199a-5p. In brief, our study demonstrates that AP-1/miR-199a-5p and ER stress mediators form a feedback loop, which shields hepatocytes from sustained ER stress and protects the liver from injury. On the basis of these findings, we also suggest that the miRNA miR-199a-5p is a potential target for clinical approaches aiming to protect hepatocytes in liver disease.

The demonstration that naked plasmid DNA can induce strong immune responses in mice has attracted considerable attention in the vaccine community. However, similar immunizations have been less/not effective in clinical trials during the past decade, and the underlying mechanisms remain unknown. In this study, we hypothesized that some DNA-binding proteins in human serum may serve as host barriers, responsible for the low efficiency of plasmids' transfection in vivo. Using proteomics, we showed that human serum amyloid P component (hSAP) is specifically present in human DNA-protein complexes. Further analysis indicated that hSAP effectively binds plasmid DNA, inhibits DNA transfection into somatic cells and facilitates the endocytosis of DNA by macrophages, whereas mouse SAP (mSAP) has similar, but much weaker, activities. In the presence of hSAP, the plasmid DNA expression in vivo and plasmid DNA-induced immune responses also significantly decreased. Therefore, our results suggest that hSAP contributes to extracellular DNA clearance and the inhibition of plasmid DNA transfection in vivo. This mechanism may be partly responsible for the insufficient immune responses to DNA vaccination in human beings; therefore, it may serve as a novel target for the improvement of DNA vaccines and DNA-based gene therapy.

Objective: To evaluate the role of corticotrophin-releasing hormone (CRH) in facilitating axon outgrowth. Background: Injured neural tissue is difficult to regenerate; the mechanism has not been fully understood.Methods: A rat model of spinal cord transection injury was developed. Levels of BDNF, CRH and oligodendrocyte glycoprotein (OMgp) in injured spinal cord were monitored dynamically after surgery. Cellular interaction among rat dorsal root ganglia (DRG) cells, oligocondrocytes and microglial cells was observed with a coculture model. The axon outgrowth from DRG cells was examined by confocal microscopy. Results: After spinal cord transection, levels of BDNF and CRH increased the next day and decreased afterward, whereas OMgp levels increased from day 3. Administration with BDNF suppressed the levels of OMgp in vitro. The results from a coculture model showed that CRH increased microglial cells to release BDNF; BDNF inhibited OMgp levels in oligodendrocytes and enhanced the axon outgrowth from DRG cells. Conclusions: This study shows that CRH has the ability to facilitate the outgrowth of axon in spinal neurons, which has therapeutic potential in the treatment of spinal cord injury.