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Bricker-Anthony C, Herzog RW. Distortion of journal impact factors in the era of paper mills. Mol Ther 2023; 31:1503-1504. [PMID: 37236186 PMCID: PMC10277921 DOI: 10.1016/j.ymthe.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
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27
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Mulcrone PL, Lam AK, Frabutt D, Zhang J, Chrzanowski M, Herzog RW, Xiao W. Chemical modification of AAV9 capsid with N-ethyl maleimide alters vector tissue tropism. Sci Rep 2023; 13:8436. [PMID: 37231038 PMCID: PMC10212940 DOI: 10.1038/s41598-023-35547-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/19/2023] [Indexed: 05/27/2023] Open
Abstract
Although more adeno-associated virus AAV-based drugs enter the clinic, vector tissue tropism remains an unresolved challenge that limits its full potential despite that the tissue tropism of naturally occurring AAV serotypes can be altered by genetic engineering capsid vie DNA shuffling, or molecular evolution. To further expand the tropism and thus potential applications of AAV vectors, we utilized an alternative approach that employs chemical modifications to covalently link small molecules to reactive exposed Lysine residues of AAV capsids. We demonstrated that AAV9 capsid modified with N-ethyl Maleimide (NEM) increased its tropism more towards murine bone marrow (osteoblast lineage) while decreased transduction of liver tissue compared to the unmodified capsid. In the bone marrow, AAV9-NEM transduced Cd31, Cd34, and Cd90 expressing cells at a higher percentage than unmodified AAV9. Moreover, AAV9-NEM localized strongly in vivo to cells lining the calcified trabecular bone and transduced primary murine osteoblasts in culture, while WT AAV9 transduced undifferentiated bone marrow stromal cells as well as osteoblasts. Our approach could provide a promising platform for expanding clinical AAV development to treat bone pathologies such as cancer and osteoporosis. Thus, chemical engineering the AAV capsid holds great potential for development of future generations of AAV vectors.
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Kumar SR, Duan D, Herzog RW. Immune Responses to Muscle-Directed Adeno-Associated Viral Gene Transfer in Clinical Studies. Hum Gene Ther 2023; 34:365-371. [PMID: 37154743 PMCID: PMC10210217 DOI: 10.1089/hum.2023.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023] Open
Abstract
Muscle-directed gene therapy with adeno-associated viral (AAV) vectors is undergoing clinical development for treating neuromuscular disorders and for systemic delivery of therapeutic proteins. Although these approaches show considerable therapeutic benefits, they are also prone to induce potent immune responses against vector or transgene products owing to the immunogenic nature of the intramuscular delivery route, or the high doses required for systemic delivery to muscle. Major immunological concerns include antibody formation against viral capsid, complement activation, and cytotoxic T cell responses against capsid or transgene products. They can negate therapy and even lead to life-threatening immunotoxicities. Herein we review clinical observations and provide an outlook for how the field addresses these problems through a combination of vector engineering and immune modulation.
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Pierce GF, Herzog RW. Two gene therapies for hemophilia available: Now what? Mol Ther 2023; 31:919-920. [PMID: 36931266 PMCID: PMC10124068 DOI: 10.1016/j.ymthe.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/01/2023] [Accepted: 03/01/2023] [Indexed: 03/18/2023] Open
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30
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Herzog RW, Weiner HL, Biswas M. Innovation and clinical progress in oral tolerance. Cell Immunol 2023; 386:104695. [PMID: 36898277 DOI: 10.1016/j.cellimm.2023.104695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 02/27/2023]
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31
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Herzog RW, Suzuki M. Adenoviral gene therapy for bladder cancer. Cell 2023; 186:893. [PMID: 36868210 DOI: 10.1016/j.cell.2023.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Enhanced by polyamide surfactant Syn3, intravesical administration of rAd-IFNα2b results in transduction of the virus into the bladder epithelium, resulting in the synthesis and expression of local IFNα2b cytokine. Upon secretion, IFNα2b binds to the IFNα receptor on bladder cancer and other cells, resulting in signaling via the JAK-STAT pathway. A plethora of induced IFN-stimulated genes containing IFN-sensitive response elements that contribute to activation of pathways restrict cancer growth.
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32
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Bertolini TB, Herzog RW, Kumar SRP, Sherman A, Rana J, Kaczmarek R, Yamada K, Arisa S, Lillicrap D, Terhorst C, Daniell H, Biswas M. Suppression of anti-drug antibody formation against coagulation factor VIII by oral delivery of anti-CD3 monoclonal antibody in hemophilia A mice. Cell Immunol 2023; 385:104675. [PMID: 36746071 PMCID: PMC9993859 DOI: 10.1016/j.cellimm.2023.104675] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/26/2022] [Accepted: 01/27/2023] [Indexed: 01/31/2023]
Abstract
Active tolerance to ingested dietary antigens forms the basis for oral immunotherapy to food allergens or autoimmune self-antigens. Alternatively, oral administration of anti-CD3 monoclonal antibody can be effective in modulating systemic immune responses without T cell depletion. Here we assessed the efficacy of full length and the F(ab')2 fragment of oral anti-CD3 to prevent anti-drug antibody (ADA) formation to clotting factor VIII (FVIII) protein replacement therapy in hemophilia A mice. A short course of low dose oral anti-CD3 F(ab')2 reduced the production of neutralizing ADAs, and suppression was significantly enhanced when oral anti-CD3 was timed concurrently with FVIII administration. Tolerance was accompanied by the early induction of FoxP3+LAP-, FoxP3+LAP+, and FoxP3-LAP+ populations of CD4+ T cells in the spleen and mesenteric lymph nodes. FoxP3+LAP+ Tregs expressing CD69, CTLA-4, and PD1 persisted in spleens of treated mice, but did not produce IL-10. Finally, we attempted to combine the anti-CD3 approach with oral intake of FVIII antigen (using our previously established method of using lettuce plant cells transgenic for FVIII antigen fused to cholera toxin B (CTB) subunit, which suppresses ADAs in part through induction of IL-10 producing FoxP3-LAP+ Treg). However, combining these two approaches failed to improve suppression of ADAs. We conclude that oral anti-CD3 treatment is a promising approach to prevention of ADA formation in systemic protein replacement therapy, albeit via mechanisms distinct from and not synergistic with oral intake of bioencapsulated antigen.
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Herzog RW, VandenDriessche T, Ozelo MC. First hemophilia B gene therapy approved: More than two decades in the making. Mol Ther 2023; 31:1-2. [PMID: 36528029 PMCID: PMC9840138 DOI: 10.1016/j.ymthe.2022.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
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34
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Hakim CH, Kumar SRP, Pérez-López D, Teixeira J, Herzog RW, Duan D. Assessment of the Gene Therapy Immune Response in the Canine Muscular Dystrophy Model. Methods Mol Biol 2023; 2587:353-375. [PMID: 36401038 DOI: 10.1007/978-1-0716-2772-3_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The immune response is a primary hurdle in the development of gene therapy for neuromuscular diseases. Both innate and adaptive immune responses have been observed in human trials. The canine model is an excellent platform to understand immunological consequences of gene therapy. Over the last several decades, we have conducted gene replacement and gene repair therapies in the canine model of Duchenne muscular dystrophy (DMD) using adeno-associated virus (AAV)-mediated expression of the highly abbreviated micro-dystrophin gene, the larger mini-dystrophin gene, and the Cas9-based CRISPR genome editing machinery. We have evaluated the innate, humoral, and cellular immune responses to the AAV vector and the transgene product. In this chapter, we share our experience in collecting and processing of the dog blood samples for immunological assays, and our protocols for quantitative evaluation of cytokines and chemokines, antibodies, and T-cell responses.
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35
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Lam AK, Zhang J, Frabutt D, Mulcrone PL, Li L, Zeng L, Herzog RW, Xiao W. Fast and high-throughput LC-MS characterization, and peptide mapping of engineered AAV capsids using LC-MS/MS. Mol Ther Methods Clin Dev 2022; 27:185-194. [PMID: 36284765 PMCID: PMC9563341 DOI: 10.1016/j.omtm.2022.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/21/2022] [Indexed: 11/15/2022]
Abstract
Adeno-associated virus (AAV) has emerged as a leading platform for gene therapy. With the skyrocketing rate of AAV research and the prevalence of many new engineered capsids being investigated in preclinical and clinical trials, capsid characterization plays a vital role in serotype confirmation and quality control. Further, peptide mapping the capsid proteins might inevitably be a future requirement by regulatory agencies since it is a critical step in good manufacturing practice (GMP) for biotherapeutic characterization. To overcome many challenges that traditional methods like SDS-PAGE and western blots carry, liquid chromatography and mass spectrometry (LC-MS) allows high resolution and sensitivity with great accuracy in characterizing the AAV capsid proteins. Our optimized LC-MS method provides quick sample preparation, a fast and high-throughput 4-min run, and high sensitivity, which allows for very efficient characterization of wild-type and engineered capsids. This study also reports the usage of LC-MS/MS peptide mapping of AAV capsid proteins to determine the most accessible lysine residues targeted by chemical modifications. Our detailed protocols are anticipated to promote the development and discovery of AAV variants with high accuracy and efficiency.
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36
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Kapelanski-Lamoureux A, Chen Z, Gao ZH, Deng R, Lazaris A, Lebeaupin C, Giles L, Malhotra J, Yong J, Zou C, de Jong YP, Metrakos P, Herzog RW, Kaufman RJ. Ectopic clotting factor VIII expression and misfolding in hepatocytes as a cause for hepatocellular carcinoma. Mol Ther 2022; 30:3542-3551. [PMID: 36242517 PMCID: PMC9734080 DOI: 10.1016/j.ymthe.2022.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/12/2022] [Indexed: 11/07/2022] Open
Abstract
Hemophilia A gene therapy targets hepatocytes to express B domain deleted (BDD) clotting factor VIII (FVIII) to permit viral encapsidation. Since BDD is prone to misfolding in the endoplasmic reticulum (ER) and ER protein misfolding in hepatocytes followed by high-fat diet (HFD) can cause hepatocellular carcinoma (HCC), we studied how FVIII misfolding impacts HCC development using hepatocyte DNA delivery to express three proteins from the same parental vector: (1) well-folded cytosolic dihydrofolate reductase (DHFR); (2) BDD-FVIII, which is prone to misfolding in the ER; and (3) N6-FVIII, which folds more efficiently than BDD-FVIII. One week after DNA delivery, when FVIII expression was undetectable, mice were fed HFD for 65 weeks. Remarkably, all mice that received BDD-FVIII vector developed liver tumors, whereas only 58% of mice that received N6 and no mice that received DHFR vector developed liver tumors, suggesting that the degree of protein misfolding in the ER increases predisposition to HCC in the context of an HFD and in the absence of viral transduction. Our findings raise concerns of ectopic BDD-FVIII expression in hepatocytes in the clinic, which poses risks independent of viral vector integration. Limited expression per hepatocyte and/or use of proteins that avoid misfolding may enhance safety.
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Butterfield JSS, Yamada K, Bertolini TB, Syed F, Kumar SRP, Li X, Arisa S, Piñeros AR, Tapia A, Rogers CA, Li N, Rana J, Biswas M, Terhorst C, Kaufman RJ, de Jong YP, Herzog RW. IL-15 blockade and rapamycin rescue multifactorial loss of factor VIII from AAV-transduced hepatocytes in hemophilia A mice. Mol Ther 2022; 30:3552-3569. [PMID: 35821634 PMCID: PMC9734025 DOI: 10.1016/j.ymthe.2022.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/09/2022] [Accepted: 07/09/2022] [Indexed: 12/14/2022] Open
Abstract
Hepatic adeno-associated viral (AAV) gene transfer has the potential to cure the X-linked bleeding disorder hemophilia A. However, declining therapeutic coagulation factor VIII (FVIII) expression has plagued clinical trials. To assess the mechanistic underpinnings of this loss of FVIII expression, we developed a hemophilia A mouse model that shares key features observed in clinical trials. Following liver-directed AAV8 gene transfer in the presence of rapamycin, initial FVIII protein expression declines over time in the absence of antibody formation. Surprisingly, loss of FVIII protein production occurs despite persistence of transgene and mRNA, suggesting a translational shutdown rather than a loss of transduced hepatocytes. Some of the animals develop ER stress, which may be linked to hepatic inflammatory cytokine expression. FVIII protein expression is preserved by interleukin-15/interleukin-15 receptor blockade, which suppresses CD8+ T and natural killer cell responses. Interestingly, mice with initial FVIII levels >100% of normal had diminishing expression while still under immune suppression. Taken together, our findings of interanimal variability of the response, and the ability of the immune system to shut down transgene expression without utilizing cytolytic or antibody-mediated mechanisms, illustrate the challenges associated with FVIII gene transfer. Our protocols based upon cytokine blockade should help to maintain efficient FVIII expression.
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38
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Mulcrone PL, Herzog RW, Xiao W. Adding recombinant AAVs to the cancer therapeutics mix. Mol Ther Oncolytics 2022; 27:73-88. [PMID: 36321134 PMCID: PMC9588955 DOI: 10.1016/j.omto.2022.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gene therapy is a powerful biological tool that is reshaping therapeutic landscapes for several diseases. Researchers are using both non-viral and viral-based gene therapy methods with success in the lab and the clinic. In the cancer biology field, gene therapies are expanding treatment options and the possibility of favorable outcomes for patients. While cellular immunotherapies and oncolytic virotherapies have paved the way in cancer treatments based on genetic engineering, recombinant adeno-associated virus (rAAV), a viral-based module, is also emerging as a potential cancer therapeutic through its malleability, specificity, and broad application to common as well as rare tumor types, tumor microenvironments, and metastatic disease. A wide range of AAV serotypes, promoters, and transgenes have been successful at reducing tumor growth and burden in preclinical studies, suggesting more groundbreaking advances using rAAVs in cancer are on the horizon.
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Zhang J, Guo P, Yu X, Frabutt DA, Lam AK, Mulcrone PL, Chrzanowski M, Firrman J, Pouchnik D, Sang N, Diao Y, Herzog RW, Xiao W. Subgenomic particles in rAAV vectors result from DNA lesion/break and non-homologous end joining of vector genomes. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 29:852-861. [PMID: 36159586 PMCID: PMC9463555 DOI: 10.1016/j.omtn.2022.08.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 08/16/2022] [Indexed: 11/15/2022]
Abstract
Recombinant adeno-associated virus (rAAV) vectors have been developed for therapeutic treatment of genetic diseases. Current rAAV vectors administered to affected individuals often contain vector DNA-related contaminants. Here we present a thorough molecular analysis of the configuration of non-standard AAV genomes generated during rAAV production using single-molecule sequencing. In addition to the sub-vector genomic-size particles containing incomplete AAV genomes, our results showed that rAAV preparations were contaminated with multiple categories of subgenomic particles with a snapback genome (SBG) configuration or a vector genome with deletions. Through CRISPR and nuclease-based modeling in tissue culture cells, we identified that a potential mechanism leading to formation of non-canonical genome particles occurred through non-homologous end joining of fragmented vector genomes caused by genome lesions or DNA breaks present in the host cells. The results of this study advance our understanding of AAV vectors and provide new clues for improving vector efficiency and safety profiles for use in human gene therapy.
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Arruda VR, Lillicrap D, Herzog RW. Immune complications and their management in inherited and acquired bleeding disorders. Blood 2022; 140:1075-1085. [PMID: 35793465 PMCID: PMC9461471 DOI: 10.1182/blood.2022016530] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/23/2022] [Indexed: 02/06/2023] Open
Abstract
Disorders of coagulation, resulting in serious risks for bleeding, may be caused by autoantibody formation or by mutations in genes encoding coagulation factors. In the latter case, antidrug antibodies (ADAs) may form against the clotting factor protein drugs used in replacement therapy, as is well documented in the treatment of the X-linked disease hemophilia. Such neutralizing antibodies against factors VIII or IX substantially complicate treatment. Autoantibody formation against factor VIII leads to acquired hemophilia. Although rare, antibody formation may occur in the treatment of other clotting factor deficiencies (eg, against von Willebrand factor [VWF]). The main strategies that have emerged to address these immune responses include (1) clinical immune tolerance induction (ITI) protocols; (2) immune suppression therapies (ISTs); and (3) the development of drugs that can improve hemostasis while bypassing the antibodies against coagulation factors altogether (some of these nonfactor therapies/NFTs are antibody-based, but they are distinct from traditional immunotherapy as they do not target the immune system). Choice of immune or alternative therapy and criteria for selection of a specific regimen for inherited and autoimmune bleeding disorders are explained. ITI serves as an important proof of principle that antigen-specific immune tolerance can be achieved in humans through repeated antigen administration, even in the absence of immune suppression. Finally, novel immunotherapy approaches that are still in the preclinical phase, such as cellular (for instance, regulatory T cell [Treg]) immunotherapies, gene therapy, and oral antigen administration, are discussed.
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de Jong YP, Herzog RW. AAV and hepatitis: Cause or coincidence? Mol Ther 2022; 30:2875-2876. [PMID: 35981546 PMCID: PMC9482007 DOI: 10.1016/j.ymthe.2022.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
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42
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Herzog RW, Frederickson RM. Molecular Therapy's growing impact. Mol Ther 2022; 30:2641. [PMID: 35917816 PMCID: PMC9372313 DOI: 10.1016/j.ymthe.2022.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 07/10/2022] [Indexed: 10/16/2022] Open
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43
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Frederickson RM, Ritter T, Morris K, Kortylewski M, Nasr M, Herzog RW. Call for papers: Exploiting extracellular vesicles as therapeutic agents. Mol Ther 2022; 30:979. [PMID: 35182469 PMCID: PMC8899694 DOI: 10.1016/j.ymthe.2022.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 11/18/2022] Open
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44
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45
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Frederickson RM, Herzog RW. Second installment of Special Issue on expanding the scale and scope and of gene editing. Mol Ther 2022; 30:1. [PMID: 34921769 PMCID: PMC8753563 DOI: 10.1016/j.ymthe.2021.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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46
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Kumar SR, Xie J, Hu S, Ko J, Huang Q, Brown HC, Srivastava A, Markusic DM, Doering CB, Spencer HT, Srivastava A, Gao G, Herzog RW. Coagulation factor IX gene transfer to non-human primates using engineered AAV3 capsid and hepatic optimized expression cassette. Mol Ther Methods Clin Dev 2021; 23:98-107. [PMID: 34631930 PMCID: PMC8476648 DOI: 10.1016/j.omtm.2021.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/10/2021] [Indexed: 11/17/2022]
Abstract
Hepatic gene transfer with adeno-associated viral (AAV) vectors shows much promise for the treatment of the X-linked bleeding disorder hemophilia B in multiple clinical trials. In an effort to further innovate this approach and to introduce alternative vector designs with potentially superior features into clinical development, we recently built a vector platform based on AAV serotype 3 because of its superior tropism for human hepatocytes. A vector genome with serotype-matched inverted terminal repeats expressing hyperactive human coagulation factor IX (FIX)-Padua was designed for clinical use that is optimized for translation using hepatocyte-specific codon-usage bias and is depleted of immune stimulatory CpG motifs. Here, this vector genome was packaged into AAV3 (T492V + S663V) capsid for hepatic gene transfer in non-human primates. FIX activity within or near the normal range was obtained at a low vector dose of 5 × 1011 vector genomes/kg. Pre-existing neutralizing antibodies, however, completely or partially blocked hepatic gene transfer at that dose. No CD8+ T cell response against capsid was observed. Antibodies against the human FIX transgene product formed at a 10-fold higher vector dose, albeit hepatic gene transfer was remarkably consistent, and sustained FIX activity in the normal range was nonetheless achieved in two of three animals for the 3-month duration of the study. These results support the use of this vector at low vector doses for gene therapy of hemophilia B in humans.
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Srinivasan A, Herzog RW, Khan I, Sherman A, Bertolini T, Wynn T, Daniell H. Preclinical development of plant-based oral immune modulatory therapy for haemophilia B. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1952-1966. [PMID: 33949086 PMCID: PMC8486253 DOI: 10.1111/pbi.13608] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/02/2021] [Accepted: 04/14/2021] [Indexed: 05/03/2023]
Abstract
Anti-drug antibody (ADA) formation is a major complication in treatment of the X-linked bleeding disorder haemophilia B (deficiency in coagulation factor IX, FIX). Current clinical immune tolerance protocols are often not effective due to complications such as anaphylactic reactions against FIX. Plant-based oral tolerance induction may address this problem, as illustrated by the recent first regulatory approval of orally delivered plant cells to treat peanut allergy. Our previous studies showed that oral delivery of plant cells expressing FIX fused to the transmucosal carrier CTB (cholera toxin subunit B) in chloroplasts suppressed ADA in animals with haemophilia B. We report here creation of the first lettuce transplastomic lines expressing a coagulation factor, in the absence of antibiotic resistance gene. Stable integration of the CTB-FIX gene and homoplasmy (transformation of ˜10 000 copies in each cell) were maintained in both T1 and T2 generation marker-free plants. CTB-FIX expression in lyophilized leaves of T1 and T2 marker-free plants was 1.0-1.5 mg/g dry weight, confirming that the marker excision did not affect antigen levels. Oral administration of CTB-FIX to Sprague Dawley rats at 0.25, 1 or 2.5 mg/kg did not produce overt adverse effects or toxicity. The no-observed-adverse-effect level (NOAEL) is at least 2.5 mg/kg for a single oral administration in rats. Oral administration of CTB-FIX at 0.3 or 1.47 mg/kg either mixed in food or as an oral suspension to Beagle dogs did not produce any observable toxicity. These toxicology studies should facilitate filing of regulatory approval documents and evaluation in haemophilia B patients.
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Zhang J, Yu X, Herzog RW, Samulski RJ, Xiao W. Flies in the ointment: AAV vector preparations and tumor risk. Mol Ther 2021; 29:2637-2639. [PMID: 34450107 DOI: 10.1016/j.ymthe.2021.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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49
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Frederickson RM, Herzog RW. Call for papers: A special issue on tackling emerging infectious diseases. Mol Ther 2021; 29:2387. [PMID: 34297920 PMCID: PMC8299149 DOI: 10.1016/j.ymthe.2021.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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50
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Herzog RW, Frederickson R. ASGCT 2021: Time to celebrate and expand. Mol Ther 2021; 29:2183. [PMID: 34171304 DOI: 10.1016/j.ymthe.2021.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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