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Balestra D, Ferrarese M, Lombardi S, Ziliotto N, Branchini A, Petersen N, Bosma P, Pinotti M, van de Graaf SFJ. An Exon-Specific Small Nuclear U1 RNA (ExSpeU1) Improves Hepatic OTC Expression in a Splicing-Defective spf/ ash Mouse Model of Ornithine Transcarbamylase Deficiency. Int J Mol Sci 2020; 21:E8735. [PMID: 33228018 DOI: 10.3390/ijms21228735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 11/22/2022] Open
Abstract
OTC splicing mutations are generally associated with the severest and early disease onset of ornithine transcarbamylase deficiency (OTCD), the most common urea cycle disorder. Noticeably, splicing defects can be rescued by spliceosomal U1snRNA variants, which showed their efficacy in cellular and animal models. Here, we challenged an U1snRNA variant in the OTCD mouse model (spf/ash) carrying the mutation c.386G > A (p.R129H), also reported in OTCD patients. It is known that the R129H change does not impair protein function but affects pre-mRNA splicing since it is located within the 5′ splice site. Through in vitro studies, we identified an Exon Specific U1snRNA (ExSpeU1O3) that targets an intronic region downstream of the defective exon 4 and rescues exon inclusion. The adeno-associated virus (AAV8)-mediated delivery of the ExSpeU1O3 to mouse hepatocytes, although in the presence of a modest transduction efficiency, led to increased levels of correct OTC transcripts (from 6.1 ± 1.4% to 17.2 ± 4.5%, p = 0.0033). Consistently, this resulted in increased liver expression of OTC protein, as demonstrated by Western blotting (~3 fold increase) and immunostaining. Altogether data provide the early proof-of-principle of the efficacy of ExSpeU1 in the spf/ash mouse model and encourage further studies to assess the potential of RNA therapeutics for OTCD caused by aberrant splicing.
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Somanathan S, Calcedo R, Wilson JM. Adenovirus-Antibody Complexes Contributed to Lethal Systemic Inflammation in a Gene Therapy Trial. Mol Ther 2020; 28:784-93. [PMID: 32035027 DOI: 10.1016/j.ymthe.2020.01.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 12/21/2022] Open
Abstract
Intra-arterial administration of an adenovirus serotype 5 (Ad5) vector in a gene therapy trial caused lethal, systemic inflammation in subject 019 with ornithine transcarbamylase deficiency. This unanticipated inflammatory response was absent in another subject receiving the same vector dose and in 16 subjects receiving lower vector doses. We hypothesized that an immune memory to a previous natural adenovirus infection enhanced the immune response to high-dose systemic Ad5 vector, causing the exaggerated immune response in subject 019. To investigate this, we found that rabbit polyclonal sera to Ad5 and pooled human immunoglobulin (Ig) inhibited Ad5 vector transduction of non-immune cells in vitro, but enhanced transduction and activation of human dendritic cells (DCs). Sera from approximately 7% of normal human subjects and 50% of patients treated topically with Ad5 vectors enhanced Ad5 transduction and activation of DCs, apparently from formation of Ig-Ad5 immune complexes and binding to DCs through FcγR. Subject 019's blood substantially increased Ad5-vector activation of human DC primary cultures at levels exceeding those from normal subjects. Although this study is based on one event in a single subject, the results implicate a pre-existing humoral immune response to Ad5 in the lethal systemic inflammatory response that occurred in subject 019.
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Prieve MG, Harvie P, Monahan SD, Roy D, Li AG, Blevins TL, Paschal AE, Waldheim M, Bell EC, Galperin A, Ella-Menye JR, Houston ME. Targeted mRNA Therapy for Ornithine Transcarbamylase Deficiency. Mol Ther 2018; 26:801-813. [PMID: 29433939 PMCID: PMC5910669 DOI: 10.1016/j.ymthe.2017.12.024] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 11/18/2022] Open
Abstract
We describe a novel, two-nanoparticle mRNA delivery system and show that it is highly effective as a means of intracellular enzyme replacement therapy (i-ERT) using a murine model of ornithine transcarbamylase deficiency (OTCD). Our Hybrid mRNA Technology delivery system (HMT) comprises an inert lipid nanoparticle that protects the mRNA from nucleases in the blood as it distributes to the liver and a polymer micelle that targets hepatocytes and triggers endosomal release of mRNA. This results in high-level synthesis of the desired protein specifically in the liver. HMT delivery of human OTC mRNA normalizes plasma ammonia and urinary orotic acid levels, and leads to a prolonged survival benefit in the murine OTCD model. HMT represents a unique, non-viral mRNA delivery method that allows multi-dose, systemic administration for treatment of single-gene inherited metabolic diseases.
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Affiliation(s)
- Mary G Prieve
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA.
| | - Pierrot Harvie
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Sean D Monahan
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Debashish Roy
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Allen G Li
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Teri L Blevins
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Amber E Paschal
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Matt Waldheim
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Eric C Bell
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Anna Galperin
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | | | - Michael E Houston
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
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Magesh R, George Priya Doss C. Computational pipeline to identify and characterize functional mutations in ornithine transcarbamylase deficiency. 3 Biotech 2014; 4:621-634. [PMID: 28324312 PMCID: PMC4235886 DOI: 10.1007/s13205-014-0216-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/01/2014] [Indexed: 11/28/2022] Open
Abstract
Ornithine transcarbamylase (OTC) (E.C. 2.1.3.3) is one of the enzymes in the urea cycle, which involves in a sequence of reactions in the liver cells. During protein assimilation in our body surplus nitrogen is made, this open nitrogen is altered into urea and expelled out of the body by kidneys, in this cycle OTC helps in the conversion of free toxic nitrogen into urea. Ornithine transcarbamylase deficiency (OTCD: OMIM#311250) is triggered by mutation in this OTC gene. To date more than 200 mutations have been noted. Mutation in OTC gene indicates alteration in enzyme production, which upsets the ability to carry out the chemical reaction. The computational analysis was initiated to identify the deleterious nsSNPs in OTC gene in causing OTCD using five different computational tools such as SIFT, PolyPhen 2, I-Mutant 3, SNPs&Go, and PhD-SNP. Studies on the molecular basis of OTC gene and OTCD have been done partially till date. Hence, in silico categorization of functional SNPs in OTC gene can provide valuable insight in near future in the diagnosis and treatment of OTCD.
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Affiliation(s)
- R Magesh
- Department of Biotechnology, Faculty of Biomedical Sciences, Technology and Research, Sri Ramachandra University, Chennai, 600116, India
| | - C George Priya Doss
- Medical Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, India.
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