Safe, CRISPR/Cas-free B cell editing for therapeutic applications

用于治疗应用的安全、无 CRISPR/Cas 的 B 细胞编辑

• 批准号: 10725412
• 负责人: Michael R. Farzan
• 金额: $ 22.13万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-25 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10725412
• 关键词: Address; Affinity; Animals; Antibodies; Antigens; Apoptosis; Automobile Driving; B-Cell Antigen Receptor; B-Lymphocytes; Biological Assay; Biological Products; COVID-19 vaccine; Cell Survival; Cells; Chromosome Deletion; Chromosome abnormality; Clustered Regularly Interspaced Short Palindromic Repeats; Consumption; DNA; DNA cassette; Dangerousness; Deletion Mutagenesis; Dose; Elements; Engraftment; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Erythropoietin Receptor; Event; Exhibits; Gene Transduction Agent; Genes; Genetic; Genetic Diseases; Goals; HIV; HIV envelope protein; Hematocrit procedure; Human; Immunoglobulin Class Switching; Immunoglobulin Somatic Hypermutation; Infusion procedures; Insertional Mutagenesis; Intravenous infusion procedures; Introns; Inverted Terminal Repeat; Lesion; Measures; Membrane; Messenger RNA; Methods; Modeling; Monitor; Mus; Neoplastic Cell Transformation; Pathway interactions; Patients; Physiological; Privatization; Proliferating; Protocols documentation; Reagent; Recombinant Antibody; Recombinant adeno-associated virus (rAAV); Recombinants; Research Personnel; Retroviridae; Risk; Safety; Serotyping; Serum; Sorting; System; TP53 gene; Techniques; Terminal Repeat Sequences; Testing; Therapeutic; Therapeutic antibodies; Transcript; Transgenes; Vaccinated; Vaccination; adeno-associated viral vector; antibody test; arm; base editing; cellular engineering; cellular transduction; chimeric antigen receptor T cells; cost; cost effective; design; endonuclease; exome; experimental study; gene therapy; genetic element; improved; in vivo; infectious disease treatment; interest; neutralizing antibody; nuclease; repaired; response; retroviral transduction; therapeutic genome editing; transgene expression

ABSTRACT Both private entities and academic groups are pioneering B cell editing for therapeutic purposes, either to express therapeutic antibodies from their native Ig loci, or other transgenes from an ectopic locus. BCR editing is currently performed with CRISPR/Cas system and a homology- directed repair template. Non-BCR trasngenes are introduced by retroviral transduction or transposon-based random insertion. Both nuclease-based and insertion-based B cell engineering techniques carry risks associated with chromosomal deletion (CRISPR/Cas) or insertional mutagenesis (retroviruses/transposons). Furthermore, efficient editing is only possible by isolating and editing B cells ex vivo meaning that therapies based on these editing protocols will likely be very expensive. We have discovered a method of B cell editing that requires no exogenous nucleases and does not rely on random insertion. Our method relies on transducing class-switching B cells with a DNA template supplied by a recombinant adeno-associated virus (rAAV) vector. The inverted terminal repeat (ITR) sequences in the rAAV naturally integrate into double-strand breaks created by the B cell class-switch machinery. With the right expression cassette designs, we can replace the endogenous heavy chain variable (VH) segment or even express a non-antibody transgene from within the BCR locus. This nuclease-free technique has potential advantages in terms of safety and, because it requires only a single rAAV transduction event, it also promises a simple, cost effective means of editing B cells in vivo. Here we aim to develop our nuclease-free editing technique and provide proof-of-concept for therapeutic applications. In Aim 1, we will optimize the design of our rAAV-delivered repair template, and demonstrate the relative safety of our approach compared to CRISPR/Cas-based editing. In Aim 2, we test different expression cassette designs for antibody and non-antibody transgene expression and determine whether or not inclusion of cis-acting genetic elements that increase somatic hypermutation can enhance affinity maturation of our edited B cells. In Aim 3, we will address in vivo editing. We will determine whether or not in vivo nuclease-free editing efficiency can be enhanced by vaccinating mice prior to rAAV administration to drive B cell class switching and optimize our rAAV doses and timing relative to the pre-vaccination step. We will also demonstrate the ability of our edited B cell system to produce recombinant antibodies (BCR editing) and erythropoietin (non-antibody transgene expression) in mice.

抽象的 私人实体和学术团体都在开创用于治疗目的的 B 细胞编辑， 要么从其天然 Ig 位点表达治疗性抗体，要么从 Ig 基因座表达其他转基因 异位基因座。 BCR 编辑目前使用 CRISPR/Cas 系统和同源性进行 定向修复模板。非 BCR 转基因通过逆转录病毒转导或 基于转座子的随机插入。基于核酸酶和基于插入的 B 细胞工程 技术存在与染色体删除 (CRISPR/Cas) 或插入相关的风险 诱变（逆转录病毒/转座子）。此外，高效的编辑只能通过 离体分离和编辑 B 细胞意味着基于这些编辑方案的疗法将 可能非常昂贵。 我们发现了一种不需要外源核酸酶的 B 细胞编辑方法 不依赖于随机插入。我们的方法依赖于用 DNA 转导类别转换 B 细胞 模板由重组腺相关病毒（rAAV）载体提供。倒置端子 rAAV 中的重复 (ITR) 序列自然整合到由 rAAV 产生的双链断裂中。 B细胞类别转换机制。通过正确的表达盒设计，我们可以取代 内源重链可变 (VH) 片段或什至表达非抗体转基因 BCR 基因座内。这种无核酸酶技术在安全性方面具有潜在优势 而且，因为它只需要一个 rAAV 转导事件，所以它还承诺简单、成本低 体内编辑B细胞的有效手段。 在这里，我们的目标是开发我们的无核酸酶编辑技术并提供概念验证 治疗应用。在目标 1 中，我们将优化 rAAV 修复的设计 模板，并证明我们的方法与基于 CRISPR/Cas 的方法相比的相对安全性 编辑。在目标 2 中，我们测试了抗体和非抗体的不同表达盒设计 转基因表达并确定是否包含顺式作用遗传元件 增加体细胞超突变可以增强我们编辑的 B 细胞的亲和力成熟。在目标 3 中， 我们将讨论体内编辑。我们将确定是否进行体内无核酸酶编辑 在注射 rAAV 之前对小鼠进行疫苗接种可以提高效率，以驱动 B 细胞类别 相对于疫苗接种前步骤，切换并优化我们的 rAAV 剂量和时间。我们将 还证明了我们编辑的 B 细胞系统产生重组抗体 (BCR 编辑）和小鼠促红细胞生成素（非抗体转基因表达）。