Rational Development of Bioengineered Factor IX Variants for Hemophilia B Therapy

项目总结 K08职业发展奖详细介绍了一项为期四年的培训计划，以提升Samelson-Jones博士的 职业目标是成为一名独立的内科医生-科学家，专注于利用 将生物过程转化为治疗先天性血液疾病儿童的新疗法。在颁奖期间 期间，Samelson-Jones博士将继续发展他在凝血生物化学方面的专业知识，获得新的 科学技能，加深他的分子和细胞免疫学知识，并推进他的翻译 能力。在他的导师莫蒂默·庞兹博士和共同导师瓦尔德·阿鲁达博士的指导下，这些 培训目标将通过教学课程工作、参加系列研讨会、 研究经验，以及他的顾问委员会的指导。他的顾问委员会由世界各地的- 具有丰富指导经验和多样化和互补性科学专业知识的知名科学家 包括Sriram Krishnaswamy博士、Rodney Camire博士和Michael Milone博士。这项科学提案旨在 解决目前血友病B(HB)治疗方法的局限性。Hb是由遗传缺陷引起的 凝血因子IX(FIX)活性。发达国家目前对乙肝的护理标准是取代 缺失的修复方法是静脉输液，但也有几个正在进行的早期基因治疗试验。 最近，有研究表明，将高活性的FIX变异体R338L整合到一个基因中 治疗部分缓解了先前确定的疗效限制，而不存在额外的安全问题。这 结果强调了高度活跃的FIX变体作为基因、蛋白质或细胞疗法治疗乙肝的潜力。Dr。 Samelson-Jones的建议侧重于识别和仔细描述新的FIX变体 活动。他已经开发了一种Rational策略，通过专门测试来识别新的过度活跃的FIX变体 在1)进化上保守的位置上的替换；2)在Hb数据库中缺失的位置；以及3) 对蛋白水解酶功能具有重要的结构意义。这种方法已经确定了几个新的过度活跃的修复程序 变种。一种新的突变体FIX-LK的活性比FIX-R338L的活性高2倍以上。在目标1中， 其他FIX变异体将被识别，并用重组FIX蛋白进行生化特征分析。入内 表现最好的新变种的体内疗效将从蛋白质和基因两个方面进行综合评估 在目标2中，最有希望的新变种的安全性是 评估过了。将新的FIX变异体与野生型FIX进行免疫原性和血栓形成能力的比较 新的HB小鼠模型中的挑衅性挑战。

PROJECT SUMMARY This K08 Career Development Award details a four-year training program to advance Dr. Samelson-Jones’ career goal of becoming an independent physician-scientist focused on leveraging molecular insights of biological processes into new therapeutics for children with congenital blood disorders. During the award period, Dr. Samelson-Jones will continue developing his expertise in coagulation biochemistry, acquire new scientific skills, deepen his knowledge of molecular and cellular immunology, and advance his translational capabilities. Under the guidance of his mentor, Dr. Mortimer Ponz, and co-mentor, Dr. Valder Arruda, these training objectives will be met by a combination of didactic course work, participation in seminar series, research experience, and mentoring by his advisory committee. His advisory committee is composed of world- renowned scientists with extensive mentoring experience and diverse and complementary scientific expertise including Drs. Sriram Krishnaswamy, Rodney Camire, and Michael Milone. The scientific proposal is aimed at addressing the current limitations of therapies for hemophilia B (HB). HB is due to an inheritable deficiency in coagulation Factor IX (FIX) activity. The current standard-of-care in the developed world for HB is to replace the missing FIX with intravenous infusions, but there are also several ongoing early phase gene therapy trials. Recently, it was demonstrated that the incorporation of the hyperactive FIX variant, R338L into a gene therapeutic partially mitigates previously identified efficacy limitations without additional safety concerns. This result emphasizes the potential of hyperactive FIX variants as gene, protein, or cell therapeutics for HB. Dr. Samelson-Jones’ proposal focuses on identifying and carefully characterizing new FIX variants with increased activity. He has developed a rational strategy to identify new hyperactive FIX variants by specifically testing substitutions at positions that are 1) evolutionarily conserved; 2) absent from the HB database; and 3) structurally important for protease function. This approach has already identified several new hyperactive FIX variants. The activity of one new variant, FIX-LK, exceeds the activity of FIX-R338L by over 2 fold. In Aim 1, additional FIX variants will be identified and biochemically characterized with recombinant FIX protein. The in vivo efficacy of the best performing new variant will be comprehensively evaluated as protein and gene therapeutics in a HB mouse model in Aim 2. In Aim 3, the safety of the most promising new variants is assessed. The immunogenicity and thrombogenicity of new FIX variants is compared to wild-type FIX after provocative challenges in novel HB mouse models.