Improving HbF induction by inhibiting epigenetic target enzymes

描述(由申请人提供)： HBF的药理激活可以阻断镰状细胞病(SCD)病理生理学级联反应中的最近端事件，因此是治疗多器官疾病的首选方法。然而，它的临床潜力还没有发挥出来。我们假设，去除HBG基因座上的表观遗传激活标记是胎儿到成人珠蛋白“切换”的早期和必要的步骤，因此，抑制特定的染色质修饰酶去除这些激活的表观遗传标记(例如LSD1或DNMT1)将有效地防止HBG抑制。在SA1中，我们确定在成熟的珠蛋白转换过程中，HBG上的表观遗传标记的放置是否存在强制性序列。用芯片分析精确分期的红系祖细胞。表观遗传标记的相互依赖性是通过使用药物和针对负责催化这些修饰的酶的siRNA击倒来分析的。在SA2中，我们将探索最近发现的两种LSD1非细胞毒性抑制剂中的任何一种可能导致更有效的人类SCD药物。其中一种化合物三羟环丙胺(TC)已经获得FDA批准。另一种化合物是一种天然产物，属于色素-4-1类，是一种有效的非细胞毒性LSD1抑制剂，在进行体外和小鼠SCD模型评估之前，将通过进一步的SAR和药物化学进行改进，以产生关键的临床前体内原理证据。因此，我们已经有三种候选的表观遗传药物(两种LSD1抑制剂和DNMT1耗竭药物地西他滨)来评估和询问这些化合物的某种组合是否可以协同诱导HBF，使单个药物的剂量保持在很好地清除可能的毒性的水平。理想情况下，候选药物将针对红系隔室，以进一步提高治疗指数。在SA3中解决了这一需求，使用了一种高度创新的、通用的方法，通过金纳米簇中间体和化学方法将任何开发的药物与EPOR靶向多肽连接起来，这种方法不会阻碍两者的功能，并促进硫醇生物分子在靶细胞处原位释放药物。在SA4中，我们将在狒狒模型中探索单独和联合用药的有效性和安全性，为正式的毒理学和配方研究提供剂量和时间表指导，并最终取得临床试验的进展。虽然许多临床前动物模型不能充分预测临床实用性，但狒狒模型已经重复地促进了SCD新疗法的临床翻译。通过使用高度创新的方法和 合理的概念，开发新的药物组合和递送系统，可以最大限度地提高治疗指数，该项目努力实现HBF激活治疗的潜力。(末尾 摘要)

DESCRIPTION (provided by applicant): Pharmacologic activation of HbF can interrupt the most proximal events in the pathophysiological cascade of sickle cell disease (SCD), and is therefore a preferred approach to multi-organ disease modification. Its clinical potential, however, has not been fulfilled. We hypothesize that removal of epigenetic activation marks at the HBG locus is an early and necessary step in the fetal to adult globin "switch", and hence, inhibiting specific chromatin-modifying enzymes that remove these activating epigenetic marks (e.g. LSD1 or DNMT1) will efficiently prevent HBG repression. In SA1, we determine if there is an obligatory sequence in the placement of epigenetic marks at HBG during the maturational globin switch. Precisely staged erythroid progenitor cells are analyzed by ChIP. The interdependence of epigenetic marks is analyzed by use of drugs and siRNA knockdowns targeting the enzymes responsible for catalyzing these modifications. In SA2 we will explore the possibility that either of two recently discovered non-cytotoxic inhibitors of LSD1 could lead to more efficacious human SCD medications. One of these compounds, tranylcypromine (TC), is already FDA approved. The other compound, a natural product belonging to the chromen-4-one class and potent non-cytotoxic LSD1 inhibitor, will be improved with further SAR and medicinal chemistry prior to evaluation both in vitro and in murine models of SCD, to generate critical pre-clinical in vivo proof of principle. Thus we already have three candidate epigenetic drugs (the two LSD1 inhibitors and the DNMT1-depleting drug, decitabine) to evaluate and ask whether some combination of these compounds can synergistically induce HbF, enabling individual medication dosages to be kept at levels well clear of possible toxicity. Ideally, candidate drugs would be targeted to the erythroid compartment, to further enhance therapeutic index. This need is addressed in SA3, using a highly innovative, versatile method that connects any developed drug to an EPOR targeting peptide by way of gold nanocluster intermediaries and chemistry that does not impede the function of either, and which facilitates in situ release of drug by thiol biomolecules at target cells. In SA4 we will explore in the baboon model individual and combinatorial drug efficacy and safety, providing dose and schedule guidance for formal toxicology and formulation studies and definitive progress to clinical trials. While many pre-clinical animal models inadequately predict clinical utility, the baboon model has reproducibly facilitated clinical translation of novel therapies for SCD. By using highly innovative methods and rational concepts to develop novel drug combinations and delivery systems that can maximize therapeutic index, this project strives to fulfill the potential of HbF activation therapy. (End of Abstract)