Lipofectin-aided cell delivery of ribozyme targeted to human urokinase receptor mRNA

AbstractA 37-mer hammerhead ribozyme has been designed to efficiently cleave the 1.4 kb mRNA of the urokinase plasminogen activator receptor (uPAR). Under in vitro conditions, the chemically synthesized ribozyme cleaved uPAR mRNA and inhibited its translation in a concentration-dependent fashion. The ribozymes were 5′-[35S]thiophosphorylated and used as a model to analyze conditions for RNA delivery in a cultured human osteosarcoma cell system. Ribozymes degraded immediately in cell-conditioned medium but ribozymes complexed with lipofectin were protected from RNases for up to 22 h. Lipofectin rapidly transported ribozyme into the cell, where it accumulated almost exclusively in the cytoplasm. Thus, lipofectin dramatically enhances stability and cytoplasmic delivery of ribozymes, potentially enabling targeting of mRNA in vivo

Increased Erythropoiesis in Mice Injected With Submicrogram Quantities of Pseudouridine-containing mRNA Encoding Erythropoietin

Advances in the optimization of in vitro-transcribed mRNA are bringing mRNA-mediated therapy closer to reality. In cultured cells, we recently achieved high levels of translation with high-performance liquid chromatography (HPLC)-purified, in vitro-transcribed mRNAs containing the modified nucleoside pseudouridine. Importantly, pseudouridine rendered the mRNA non-immunogenic. Here, using erythropoietin (EPO)-encoding mRNA complexed with TransIT-mRNA, we evaluated this new generation of mRNA in vivo. A single injection of 100 ng (0.005 mg/kg) mRNA elevated serum EPO levels in mice significantly by 6 hours and levels were maintained for 4 days. In comparison, mRNA containing uridine produced 10–100-fold lower levels of EPO lasting only 1 day. EPO translated from pseudouridine-mRNA was functional and caused a significant increase of both reticulocyte counts and hematocrits. As little as 10 ng mRNA doubled reticulocyte numbers. Weekly injection of 100 ng of EPO mRNA was sufficient to increase the hematocrit from 43 to 57%, which was maintained with continued treatment. Even when a large amount of pseudouridine-mRNA was injected, no inflammatory cytokines were detectable in plasma. Using macaques, we could also detect significantly-increased serum EPO levels following intraperitoneal injection of rhesus EPO mRNA. These results demonstrate that HPLC-purified, pseudouridine-containing mRNAs encoding therapeutic proteins have great potential for clinical applications

神戸大学大学院人文学研究科地域連携センター 福崎町連携事業平成23年度活動報告書 : 共同研究「福崎町の地域歴史遺産掘り起こし及び大庄屋三木家住宅活用案の作成等」

Major biological effects of UVB are attributed to cyclobutane pyrimidine dimers (CPDs), the most common photolesions formed on DNA. To investigate the contribution of CPDs to UVB-induced changes of gene expression, a model system was established by transfecting keratinocytes with pseudouridine-modified mRNA (Ψ-mRNA) encoding CPD-photolyase. Microarray analyses of this model system demonstrated that more than 50% of the gene expression altered by UVB was mediated by CPD photolesions. Functional classification of the gene targets revealed strong effects of CPDs on the regulation of the cell cycle and transcriptional machineries. To confirm the microarray data, cell cycle-regulatory genes, CCNE1 and CDKN2B that were induced exclusively by CPDs were selected for further investigation. Following UVB irradiation, expression of these genes increased significantly at both mRNA and protein levels, but not in cells transfected with CPD-photolyase Ψ-mRNA and exposed to photoreactivating light. Treatment of cells with inhibitors of c-Jun N-terminal kinase (JNK) blocked the UVB-dependent upregulation of both genes suggesting a role for JNK in relaying the signal of UVB-induced CPDs into transcriptional responses. Thus, photolyase mRNA-based experimental platform demonstrates CPD-dependent and -independent events of UVB-induced cellular responses, and, as such, has the potential to identify novel molecular targets for treatment of UVB-mediated skin diseases

Incorporation of pseudouridine into mRNA enhances translation by diminishing PKR activation

Previous studies have shown that the translation level of in vitro transcribed messenger RNA (mRNA) is enhanced when its uridines are replaced with pseudouridines; however, the reason for this enhancement has not been identified. Here, we demonstrate that in vitro transcripts containing uridine activate RNA-dependent protein kinase (PKR), which then phosphorylates translation initiation factor 2-alpha (eIF-2α), and inhibits translation. In contrast, in vitro transcribed mRNAs containing pseudouridine activate PKR to a lesser degree, and translation of pseudouridine-containing mRNAs is not repressed. RNA pull-down assays demonstrate that mRNA containing uridine is bound by PKR more efficiently than mRNA with pseudouridine. Finally, the role of PKR is validated by showing that pseudouridine- and uridine-containing RNAs were translated equally in PKR knockout cells. These results indicate that the enhanced translation of mRNAs containing pseudouridine, compared to those containing uridine, is mediated by decreased activation of PKR

Sequence- and target-independent angiogenesis suppression by siRNA via TLR3

Clinical trials of small interfering RNA (siRNA) targeting vascular endothelial growth factor-A (VEGFA) or its receptor VEGFR1 (also called FLT1), in patients with blinding choroidal neovascularization (CNV) from age-related macular degeneration, are premised on gene silencing by means of intracellular RNA interference (RNAi). We show instead that CNV inhibition is a siRNA-class effect: 21-nucleotide or longer siRNAs targeting non-mammalian genes, non-expressed genes, non-genomic sequences, pro- and anti-angiogenic genes, and RNAi-incompetent siRNAs all suppressed CNV in mice comparably to siRNAs targeting Vegfa or Vegfr1 without off-target RNAi or interferon-α/β activation. Non-targeted (against non-mammalian genes) and targeted (against Vegfa or Vegfr1) siRNA suppressed CNV via cell-surface toll-like receptor 3 (TLR3), its adaptor TRIF, and induction of interferon-γ and interleukin-12. Non-targeted siRNA suppressed dermal neovascularization in mice as effectively as Vegfa siRNA. siRNA-induced inhibition of neovascularization required a minimum length of 21 nucleotides, a bridging necessity in a modelled 2:1 TLR3–RNA complex. Choroidal endothelial cells from people expressing the TLR3 coding variant 412FF were refractory to extracellular siRNA-induced cytotoxicity, facilitating individualized pharmacogenetic therapy. Multiple human endothelial cell types expressed surface TLR3, indicating that generic siRNAs might treat angiogenic disorders that affect 8% of the world’s population, and that siRNAs might induce unanticipated vascular or immune effects

Zika virus protection by a single low dose nucleoside modified mRNA vaccination

Zika virus (ZIKV) has recently emerged as an explosive pandemic associated with severe neuropathology in newborns and adults1. There are no ZIKV-specific treatments or preventatives; thus, development of a safe and effective vaccine is a high priority. Messenger RNA (mRNA) has emerged as a versatile and highly effective platform to deliver vaccine antigens and therapeutic proteins2,3. Here, we demonstrate that a single low-dose intradermal immunization with lipid nanoparticle-encapsulated nucleoside-modified mRNA (mRNA-LNP) encoding the pre-membrane and envelope (prM-E) glycoproteins of a 2013 ZIKV outbreak strain elicited potent and durable neutralizing antibody responses in mice and non-human primates. Immunization with 30 μg of nucleoside-modified ZIKV mRNA-LNPs protected mice from ZIKV challenges at 2 weeks or 5 months post-vaccination, and a single dose of 50 μg was sufficient to protect non-human primates from a challenge at 5 weeks post-vaccination. These data demonstrate that nucleoside-modified mRNA-LNPs elicit rapid and durable protective immunity and thus represent a new and promising vaccine candidate for the global fight against ZIKV