Author
Hiromi Muramatsu
Other affiliations: Pennsylvania State University
Bio: Hiromi Muramatsu is an academic researcher from University of Pennsylvania. The author has contributed to research in topics: Medicine & Biology. The author has an hindex of 17, co-authored 27 publications receiving 3487 citations. Previous affiliations of Hiromi Muramatsu include Pennsylvania State University.
Topics: Medicine, Biology, Messenger RNA, Virology, Antibody
Papers
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TL;DR: It is found that mRNAs containing pseudouridines have a higher translational capacity than unmodified m RNAs when tested in mammalian cells and lysates or administered intravenously into mice at 0.015-0.15 mg/kg doses.
1,101 citations
TL;DR: It is identified that contaminants, including double-stranded RNA, in nucleoside-modified in vitro-transcribed RNA are responsible for innate immune activation and their removal by high performance liquid chromatography results in mRNA that does not induce IFNs and inflammatory cytokines and is translated at 10- to 1000-fold greater levels in primary cells.
Abstract: In vitro-transcribed mRNA has great therapeutic potential to transiently express the encoded protein without the adverse effects of viral and DNA-based constructs. Mammalian cells, however, contain RNA sensors of the innate immune system that must be considered in the generation of therapeutic RNA. Incorporation of modified nucleosides both reduces innate immune activation and increases translation of mRNA, but residual induction of type I interferons (IFNs) and proinflammatory cytokines remains. We identify that contaminants, including double-stranded RNA, in nucleoside-modified in vitro-transcribed RNA are responsible for innate immune activation and their removal by high performance liquid chromatography (HPLC) results in mRNA that does not induce IFNs and inflammatory cytokines and is translated at 10- to 1000-fold greater levels in primary cells. Although unmodified mRNAs were translated significantly better following purification, they still induced high levels of cytokine secretion. HPLC purified nucleoside-modified mRNA is a powerful vector for applications ranging from ex vivo stem cell generation to in vivo gene therapy.
649 citations
TL;DR: It is demonstrated that a single low-dose intradermal immunization with nucleoside-modified mRNA–LNP elicits rapid and durable protective immunity and therefore represents a new and promising vaccine candidate for the global fight against ZIKV.
Abstract: Zika virus (ZIKV) has recently emerged as a pandemic associated with severe neuropathology in newborns and adults. There are no ZIKV-specific treatments or preventatives. Therefore, the 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 proteins. 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 glycoproteins of a strain from the ZIKV outbreak in 2013 elicited potent and durable neutralizing antibody responses in mice and non-human primates. Immunization with 30 μg of nucleoside-modified ZIKV mRNA-LNP protected mice against ZIKV challenges at 2 weeks or 5 months after vaccination, and a single dose of 50 μg was sufficient to protect non-human primates against a challenge at 5 weeks after vaccination. These data demonstrate that nucleoside-modified mRNA-LNP elicits rapid and durable protective immunity and therefore represents a new and promising vaccine candidate for the global fight against ZIKV.
644 citations
TL;DR: It is demonstrated that LNPs are appropriate carriers for mRNA in vivo and have the potential to become valuable tools for delivering mRNA encoding therapeutic proteins.
554 citations
TL;DR: It is demonstrated 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.
Abstract: 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.
400 citations
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TL;DR: A two-dose regimen of BNT162b2 conferred 95% protection against Covid-19 in persons 16 years of age or older and safety over a median of 2 months was similar to that of other viral vaccines.
Abstract: Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (Covid-19) have afflicted tens of millions of people in a world...
10,274 citations
TL;DR: It is shown that this approach can reprogram multiple human cell types to pluripotency with efficiencies that greatly surpass established protocols and represents a safe, efficient strategy for somatic cell reprogramming and directing cell fate that has broad applicability for basic research, disease modeling, and regenerative medicine.
2,627 citations
TL;DR: The mRNA-1273 vaccine induced anti-SARS-CoV-2 immune responses in all participants, and no trial-limiting safety concerns were identified, which support further development of this vaccine.
Abstract: Background The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in late 2019 and spread globally, prompting an international effort to accelerate development of a vacci...
2,556 citations
TL;DR: The biological barriers to gene delivery in vivo are introduced and recent advances in material sciences, nanotechnology and nucleic acid chemistry that have yielded promising non-viral delivery systems are discussed, some of which are currently undergoing testing in clinical trials.
Abstract: Gene-based therapy is the intentional modulation of gene expression in specific cells to treat pathological conditions This modulation is accomplished by introducing exogenous nucleic acids such as DNA, mRNA, small interfering RNA (siRNA), microRNA (miRNA) or antisense oligonucleotides Given the large size and the negative charge of these macromolecules, their delivery is typically mediated by carriers or vectors In this Review, we introduce the biological barriers to gene delivery in vivo and discuss recent advances in material sciences, nanotechnology and nucleic acid chemistry that have yielded promising non-viral delivery systems, some of which are currently undergoing testing in clinical trials The diversity of these systems highlights the recent progress of gene-based therapy using non-viral approaches
2,460 citations
TL;DR: A detailed overview of mRNA vaccines is provided and future directions and challenges in advancing this promising vaccine platform to widespread therapeutic use are considered.
Abstract: mRNA vaccines represent a promising alternative to conventional vaccine approaches because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. However, their application has until recently been restricted by the instability and inefficient in vivo delivery of mRNA. Recent technological advances have now largely overcome these issues, and multiple mRNA vaccine platforms against infectious diseases and several types of cancer have demonstrated encouraging results in both animal models and humans. This Review provides a detailed overview of mRNA vaccines and considers future directions and challenges in advancing this promising vaccine platform to widespread therapeutic use.
2,274 citations