Regulation of Autophagy Orchestrates Pyroptotic Cell Death in Molybdenum Disulfide Quantum Dot-Induced Microglial Toxicity.

Molybdenum disulfide quantum dots (MoS2 QDs) represent an emerging class of two-dimensional (2D) atomically layered transition metal dichalcogenide nanostructures with few nanometers in lateral size, which show attractive potential as versatile platforms for theranostic applications in various neurological disorders. However, the potential impacts of MoS2 QDs on microglia remain unclear. In this report, we showed that exposure of microglia to MoS2 QDs triggered NLRP3 inflammasome activation as revealed by the cleavage of the inactive precursor of caspase-1 to its active form and the increased release of downstream pro-inflammatory cytokines, resulting in microglia cell death that occurred through caspase-1-dependent pyroptosis. We also found that MoS2 QDs activated autophagy, and suppression of autophagy by specific inhibitors potentiated MoS2 QD-induced pyroptosis. Additionally, MoS2 QDs stimulated mitochondria-derived reactive oxygen species (mtROS) generation in BV-2 cells. However, ROS scavengers could diminish the MoS2 QD-mediated NLRP3 inflammasome activation and pyroptotic cell death in microglia. Overall, our findings identified pyroptosis as a cellular response to MoS2 QD exposure in microglial cells, affording novel insights into the neurotoxicity of MoS2 QDs and facilitating the rational design and application of functional MoS2 QDs in neuroscience.

[Construction of a mouse pDsRed2-N1-SDF-1alpha eukaryotic expression vector and its expression in mouse bone marrow mesenchymal stem cells].

OBJECTIVE: To construct the eukaryotic expression vector pDsRed2-N1-SDF-1alpha and observe its expression in the mouse bone marrow mesenchymal stem cells. METHOD: SDF-1alpha gene sequence with XhoI, EcoRI restriction enzyme cutting site was amplified from the total RNA of mouse smooth muscle cells by reverse transcription-polymerase chain reaction (RT-PCR) and inserted into the eukaryotic expression vector pDsRed2-N1 encoding red fluorescent protein gene, and the insertion was verified by endonuclease digestion and DNA sequencing. Mouse bone marrow mesenchymal stem cells identified with immunofluorescence assay for vimentin expression were transfected with the constructed plasmid pDsRed2-N1-SDF-1alpha, and the expression of sdf-1alpha was detected using immunofluorescence assay. RESULTS: The DNA fragment amplified by PCR from the total RNA was identical to SDF-1alpha from the gene library, and an identical DNA fragment was also amplified from the recombinants. Sequence analysis confirmed the successful insertion of SDF-1alpha into the pDsRed2-N1 vector and the eukaryotic expression vector pDsRed2-N1-SDF-1alpha was successfully constructed. The cultured mouse bone marrow mesenchymal stem cells positive for vimentin protein showed SDF-1alpha expression 24 h after transfection with the recombinant vector. CONCLUSION: The pDsRed2-N1-SDF-1alpha eukaryotic expression vector constructed is capable of expression of SDF-1alpha fusion protein in the mouse bone marrow mesenchymal stem cells.

Therapeutic DNA vaccination as a repair strategy following spinal cord injury.

Myelin-derived proteins, such as tenascin-R (TN-R), myelin associate glycoprotein (MAG), oligodendrocyte-myelin glycoprotein (OMgp), and Nogo-A, inhibit the central nervous system regeneration. In this study, the DNA vaccine encoding for oligodendrocyte and myelin-related antigens was employed to attenuate the axonal growth inhibitory properties of myelin in the setting of spinal cord injury. Using a rat spinal cord dorsal hemisection model, the vaccine directed against the inhibitory epitopes of Nogo-A, MAG, OMgp, and TN-R was administered intramuscularly once a week following spinal cord injury, supplemented with local application of specific anti-sera against the four antigens. Anterograde labeling of dorsal column fibers showed active axonal regeneration through the lesion site at the eighth week following the treatment in experimental group but not in control groups. Light microscopic and ultrastructural analysis revealed that vaccination with these myelin-related antigens did not lead to demyelinating disease. OMgp and TN-R levels were down-regulated at the lesion site together with a parallel increase in growth-associated protein 43 levels in the treatment groups. This study reveals the effective approach of a DNA vaccine strategy by attaining the special antibody to direct neutralization of the myelin inhibitors during spinal cord injury.

Adenoviral-mediated interleukin-18 expression in mesenchymal stem cells effectively suppresses the growth of glioma in rats.

Glioma is the most common primary intracranial malignant tumor. Despite advances in surgical techniques and adjuvant radio- and chemotherapies, the prognosis for patients with glioma remains poor. We have explored the effects of using genetically modified mesenchymal stem cells (MSCs) to treat malignant glioma in rats. Mesenchymal stem cells isolated from Sprague-Dawley rats can directly suppress the growth of C6 cells in vitro. MSCs transplanted intratumorally can also significantly inhibit the growth of glioma and prolong survival in C6 glioma-bearing models. MSCs producing Interleukin-18 infected by adenoviral vector inhibited glioma growth and prolonged the survival of glioma-bearing rats. Transplantation of IL-18 secreting MSCs was associated with enhanced T cell infiltration and long-term anti-tumor immunity. Thus, IL-18 may be an effective adoptive immunotherapy for malignant glioma. When used in conjunction with MSCs as targeting vehicles in vivo, IL-18 may offer a promising new treatment option for malignant glioma.