Biological and Medicinal Chemistry Approaches to Human Beta Cell Regeneration

1型和2型糖尿病（T1 D和T2 D）都是由正常功能的β细胞数量不足引起的。抑制激酶DYRK 1A的小分子药物，如去氢骆驼蓬碱等，可重复诱导成人β细胞复制，但速率较低（约2%/天）。最近，我们已经表明，将任何小分子DYRK 1A抑制剂添加到TGF-β超家族抑制剂（TGFβI）或GLP 1受体激动剂（如GLP 1或毒蜥外泌肽-4）中显著增强了这种复制诱导，平均速率为5-8%/天。这不仅通过体外和体内复制的“标记物”如Ki 67和BrdU来证明，而且通过增加β细胞的实际数量来证明。不幸的是，这些药物可能不仅影响β细胞，而且可能具有“脱靶”效应。因此，糖尿病研究人员有有效的再生药物递送到人类β细胞，但可能需要一种“靶向分子”将它们带到β细胞。因此，在过去的几年里，糖尿病研究人员已经确定了两类“原型β细胞靶向分子”：一种针对β细胞表面分子的单克隆抗体，称为“ENTPD 3”;以及GLP 1受体类分子。虽然这些分子对于β细胞靶向可能是完美的，也可能不是完美的，但它们无疑是在该领域试图鉴定更完美的β细胞靶向分子时使用的“原型”靶向分子。我们还合成了许多DYRK 1A抑制剂和TGF β抑制剂以及可裂解的化学接头，使其能够与任何潜在的β细胞靶向分子偶联。因此，本申请的目的是：1.合成具有化学接头的TGF-β抑制剂，以补充我们的新型DYRK 1A抑制剂接头化合物，用于缀合至原型靶向递送载体。2.骆驼蓬碱-接头和TGF-β-抑制剂-接头化合物与两种原型靶向分子的缀合：GLP 1受体激动剂和ENTPD 3单克隆抗体。3.骆驼蓬碱-接头和TGF-β抑制剂-接头偶联物在人胰岛移植模型中的体内长期功效、特异性和安全性的定义。这些目标都是可以实现的，并且直接响应了《国家残疾人权利公约》的目标。如果GLP 1受体激动剂和/或ENTPD 3单克隆抗体被证明是β细胞靶向的次优选择，则本文开发的方法和分子可以容易地扩展并适用于任何未来更特异的人β细胞靶向分子。

Both Type 1 and Type 2 diabetes (T1D and T2D) result from inadequate numbers of normally functioning beta cells. Small molecule drugs that inhibit the kinase, DYRK1A, such as harmine and others, are reproducibly able to induce adult human beta cells to replicate, but at low rates (~2%/day). More recently, we have shown that adding any small molecule DYRK1A inhibitor to either a TGF-beta superfamily inhibitor (TGFβI's) or to a GLP1 receptor agonist such as GLP1 or exendin-4 markedly enhances this replicative induction to rates averaging 5-8%/day. This has been documented not only by “markers” of replication such as Ki67 and BrdU, both in vitro and in vivo, but also by enhancing actual numbers of beta cells. Unfortunately, these drugs may not exclusively affect the beta cell, but instead may have “off target” effects as well. Thus, diabetes researchers have effective regenerative drugs to deliver to the human beta cell, but may require a “targeting molecule” to bring them to the beta cell. Accordingly, over the past few years, diabetes researchers have identified two classes of “prototype beta cell targeting molecules”: a monoclonal antibody raised against the beta cell surface molecule called “ENTPD3”; and, the GLP1-receptor class of molecules. While these molecules may or may not be perfect for beta cell targeting, they are unquestionably “prototype” targeting molecules with which to work while the field attempts to identify more perfect beta cell targeting molecules. We have also synthesized numerous DYRK1A inhibitors and TGFbeta inhibitors and cleavable chemical linkers that enable their conjugation to any potential beta cell targeting molecule. Thus, the Aims of this application are: 1. Synthesis of TGF-beta Inhibitors With Chemical Linkers, to Complement our Novel DYRK1A inhibitor Linker Compounds, For Conjugation To Prototype Targeted Delivery Vehicles. 2. Conjugation of Harmine-Linker and TGF-beta-Inhibitor-Linker Compounds to Two Prototype Targeting Molecules: GLP1 Receptor Agonists and ENTPD3 Monoclonal Antibodies. 3. Definition of Long Term Efficacy, Specificity and Safety of the Harmine-Linker and TGF-beta Inhibitor- Linker Conjugates in vivo in Human Islet Engraftment Models. These goals are both achievable and directly responsive to the goals of aims of the NIDDK. If GLP1 receptor agonists and/or ENTPD3 MAbs prove suboptimal for beta cell targeting, the approaches and molecules developed here can readily be extended and adapted to any future more specific human beta cell targeting molecule.