Development Of Drugs Acting At Adenosine Receptors

作用于腺苷受体的药物的开发

• 批准号: 8349717
• 负责人: Kenneth Alan Jacobson
• 金额: $ 36.14万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8349717
• 关键词: Adenine; Adenosine; Adenosine A3 Receptor; Affect; Affinity; Agonist; Anti-Inflammatory Agents; Anti-inflammatory; Autoimmune Process; Binding; Binding Sites; Biochemical; Biological Assay; Brain; California; Cardiac Myocytes; Cardiovascular Diseases; Cell Surface Proteins; Cells; Chronic Obstructive Airway Disease; Clinical Treatment; Clinical Trials; Collaborations; Cooperative Research and Development Agreement; Dependence; Development; Diagnostic; Disease; Endocrine; Enhancers; Eye diseases; Family; Fluorescence Polarization; G-Protein-Coupled Receptors; Gerbils; Glaucoma; Goals; Heart; Hepatitis C virus; Homology Modeling; Human; Immune system; Inflammatory; Ischemia; Korea; Libraries; Ligands; Location; Malignant Neoplasms; Malignant neoplasm of liver; Methodology; Modeling; Modification; Molecular Conformation; Molecular Models; Molecular Structure; Movement; Mus; Muscle Cells; Mutagenesis; Myocardial Ischemia; Neuraxis; Neurodegenerative Disorders; Nucleosides; Nucleotides; Opsin; Patients; Pennsylvania; Peripheral; Pharmaceutical Preparations; Phase; Phase II Clinical Trials; Physiologic Intraocular Pressure; Physiological; Positioning Attribute; Process; Property; Psoriasis; Purinergic P1 Receptors; Radioactivity; Rattus; Receptor Activation; Relative (related person); Reporting; Research; Resolution; Rheumatoid Arthritis; Rhodopsin; Ribose; Role; Rotation; Sampling; San Francisco; Screening procedure; Sequence Analysis; Sequence Homology; Series; Signal Transduction; Skeletal Muscle; Structure; Structure-Activity Relationship; System; Therapeutic; Therapeutic Agents; Therapeutic Clinical Trial; Tissues; Viral Load result; Work; analog; base; clinical efficacy; design; drug discovery; extracellular; eye dryness; interest; molecular modeling; mouse model; novel; receptor; receptor binding; small molecule; Adenine; Adenosine; Adenosine A3 Receptor; Affect; Affinity; Agonist; Anti-Inflammatory Agents; Anti-inflammatory; Autoimmune Process; Binding; Binding Sites; Biochemical; Biological Assay; Brain; California; Cardiac Myocytes; Cardiovascular Diseases; Cell Surface Proteins; Cells; Chronic Obstructive Airway Disease; Clinical Treatment; Clinical Trials; Collaborations; Cooperative Research and Development Agreement; Dependence; Development; Diagnostic; Disease; Endocrine; Enhancers; Eye diseases; Family; Fluorescence Polarization; G-Protein-Coupled Receptors; Gerbils; Glaucoma; Goals; Heart; Hepatitis C virus; Homology Modeling; Human; Immune system; Inflammatory; Ischemia; Korea; Libraries; Ligands; Location; Malignant Neoplasms; Malignant neoplasm of liver; Methodology; Modeling; Modification; Molecular Conformation; Molecular Models; Molecular Structure; Movement; Mus; Muscle Cells; Mutagenesis; Myocardial Ischemia; Neuraxis; Neurodegenerative Disorders; Nucleosides; Nucleotides; Opsin; Patients; Pennsylvania; Peripheral; Pharmaceutical Preparations; Phase; Phase II Clinical Trials; Physiologic Intraocular Pressure; Physiological; Positioning Attribute; Process; Property; Psoriasis; Purinergic P1 Receptors; Radioactivity; Rattus; Receptor Activation; Relative (related person); Reporting; Research; Resolution; Rheumatoid Arthritis; Rhodopsin; Ribose; Role; Rotation; Sampling; San Francisco; Screening procedure; Sequence Analysis; Sequence Homology; Series; Signal Transduction; Skeletal Muscle; Structure; Structure-Activity Relationship; System; Therapeutic; Therapeutic Agents; Therapeutic Clinical Trial; Tissues; Viral Load result; Work; analog; base; clinical efficacy; design; drug discovery; extracellular; eye dryness; interest; molecular modeling; mouse model; novel; receptor; receptor binding; small molecule

The extracellular adenosine receptors have a modulatory role in the nervous, circulatory, endocrine and immunological systems. The prospect of harnessing these effects specifically for therapeutic purposes is attractive. We have recently synthesized highly selective A3 adenosine receptor agonists, antagonists, allosteric modulators. A3 agonists are under development for treating cancer, rheumatoid arthritis, and other diseases. Allosteric enhancers promise to be more specific in their action in an affected tissue, than a classical agonist, which can act at all locations of the receptor in the body. Imidazoquinoline and pyridinylisoquinoline derivatives were found to enhance the actions of agonists of the A3 receptor, and thus may prove to be suitable leads for the development of therapeutic agents based on this concept. We have identified two new classes of allosteric modulators of the A3 receptor and are currently exploring the structure activity relationship (SAR). The potential of A3 agonist therapy is of great interest. We are collaborating with Dr. Bruce Liang and Dr. Asher Shainberg on various aspects of the use of adenosine receptor agonists in protection of the heart. We have designed a mixed agonist of A1 and A3 subtypes, both of which are protective in the heart. A mixed A1/A3 agonist is protective in a model of ischemia in skeletal muscle. The adenosine A3 agonist IB-MECA is currently in clinical trials for use in autoimmune inflammatory diseases and cancer conducted by our CRADA partner Can-Fite Biopharma. This compound has already shown clinical efficacy in Phase 2 trials for treatment of rheumatoid arthritis, psoriasis, and dry eye disease. IB-MECA (CF-101) has just entered Phase 2/3 clinical trials for psoriasis. The 2-chloro analogue is currently in clinical trials for liver cancer, and it was shown to reduce viral load in several patients that are infected with hepatitis C virus. Other more selective A3 agonists from our lab, such as the conformationally constrained MRS3558, are of interest for their protective properties. One of the issues in the development of adenosine receptor ligands is the species dependence. Some compounds that are very potent at a given human adenosine receptor are weak in rat tissue. We have developed adenosine agonists and antagonists that work generally across species. The key to A3 receptor ligands that are potent and selective across species is the use of the nucleoside structure as the starting point in the design process. Nucleosides tend to bind to that receptor subtype with greater consistency across species than nonpurine heterocycles. Adenosine A3 antagonists may be useful for the treatment of glaucoma. Early efforts to identify antagonists of the A3 receptor in our library involved screening of chemically diverse libraries. One of the limitations of this approach is that the antagonists often bind well only at the human, but not murine A3 receptors. We are currently developing other novel A3 antagonists based on nucleotide structures, that have proven to be generally applicable across species. We are currently studying systematically the SAR of adenosine derivatives that affect efficacy as A3 adenosine receptor agonists. Surprisingly, a commonly used A1-selective agonist, cyclopentyladenosine, was found to act as a pure antagonist at the A3 subtype. Other nucleosides may be chemically modified, especially on the ribose moiety, to have reduced efficacy at the A3 receptor. Some of these analogues derived from highly potent A3 agonists, such as 5'-truncated nucleosides, were found to be A3 antagonists. Several novel nucleoside-based antagonists of the A3 receptor, including a rigid spirolactam derivative MRS1292 and a truncated 4'-thioadenosine derivative (collaboration with Prof. Lak Shin Jeong, EHWA Univ., Seoul Korea) were found to lower intraocular pressure a mouse model of glaucoma (demonstrated by Prof. Mort Civan, Univ. of Pennsylvania). We are using mutagenesis to study the determinants of recognition of adenosine within the binding site of the A2A and A3 receptors, and proposing conformational factors involved in receptor activation. Since the four subtypes of adenosine receptors have been cloned it has been possible to conduct molecular modeling of the receptor protein, based on sequence analyses and homology modeling using the high resolution rhodopsin structure as template. We intend to use such a modeling approach for the design of more selective adenosine receptor agonists and antagonists. Recently this project has also focused on the effects of adenosine agonists and antagonists in the central nervous system and in the heart and on the possibility of therapeutics for treating neurodegenerative and cardiovascular diseases. An A3 agonist, administered chronically, proved to be highly cerebroprotective in an ischemic model in gerbils. A3 agonists cause morphological and biochemical changes in astroglial cells. Adenosine is released in large amounts during myocardial ischemia and is capable of activating both A1 or A3 receptors that occur on cardiac myocytes to exert a potent cardioprotective effect. We have shown that synthetic adenosine agonists,selective for either the A1 or A3 subtype, protect ischemic cardiac myocytes in culture and in the isolated perfused heart and thus might be beneficial to the survival of the ischemic heart. We recently succeeded in identifying new chemotypes for antagonists of the A2A receptor using structure-based drug discovery (collaboration with B. Shoichet, Univ. of California, San Francisco). We also introduced a fluorescence polarization assay for affinity at the same receptor, that avoids the use fo radioactivity in the drug discovery/screening process. Adenosine receptor agonists, including those selective for the A2A subtype, are in clinical trials for therapeutic and diagnostic applications. Known A2A receptor agonists, most of which contain large substituents at various positions, display anti-inflammatory and vasodilatory properties. We have discovered a means of reducing the size of the ribose moiety of 4-thioadenosine agonists by truncation that preserves the ability to potently activate the A2A receptor. The same modification in nucleosides that are selective for the A3 receptor was shown previously to convert agonists into antagonists at that subtype, but the present series, modified with an A2A receptor-favoring group at the 2 position of the adenine moiety, maintained the ability to fully activate this subtype. Thus, there is a major difference in the mode of activation between the two subtypes. The coexistence of A2A receptor agonism and A3 receptor antagonism in this series of sterically small nucleosides might prove to be beneficial therapeutically in a synergistic manner. Activation of G protein-coupled receptors (GPCRs) upon agonist binding is a critical step in the signaling cascade for this family of cell surface proteins. In collaboration with the Stevens group, we recently reported the crystal structure of the A2A adenosine receptor bound to an agonist UK-432097 (formerly in clinical trials for COPD) at 2.7 angstrom resolution. Relative to inactive, antagonist-bound A2A receptor, the agonist-bound structure displays an outward tilt and rotation of the cytoplasmic half of helix VI, a movement of helix V and an axial shift of helix III, resembling the changes associated with the active-state opsin structure. Additionally, a seesaw movement of helix VII and a shift of extracellular loop 3 are likely specific to A2A receptor and its ligand. Our results define the UK-432097 as a conformationally selective agonist capable of receptor stabilization in a specific active state, in contrast to other GPCR agonists that sample multiple conformational states.

细胞外腺苷受体在神经，循环，内分泌和免疫系统中具有调节作用。专门用于治疗目的的这些效果的前景很有吸引力。我们最近合成了高度选择性的A3腺苷受体激动剂，拮抗剂，变构调节剂。 A3激动剂正在开发用于治疗癌症，类风湿关节炎和其他疾病。变构增强剂有望比经典的激动剂更具体地在受影响的组织中的作用，该组织可以在体内受体的所有位置起作用。发现咪达唑喹啉和吡啶基氨基喹啉衍生物可增强A3受体的激动剂的作用，因此可能被证明是根据此概念开发治疗剂的合适铅。我们已经确定了A3受体的两个新类变构调节剂，目前正在探索结构活动关系（SAR）。 A3激动剂疗法的潜力引起了极大的兴趣。 我们正在与Bruce Liang博士和Asher Shainberg博士合作，讨论使用腺苷受体激动剂在保护心脏方面的各个方面。 我们设计了A1和A3亚型的混合激动剂，它们在心脏中都具有保护性。 混合的A1/A3激动剂在骨骼肌缺血模型中具有保护性。 腺苷A3激动剂IB-MECA目前正在临床试验中，用于自身免疫性炎症性疾病和我们的Crada伴侣Can-Fite Biopharma进行的癌症。 该化合物已经显示出在2阶段试验中用于治疗类风湿关节炎，牛皮癣和干眼症的临床功效。 IB-MECA（CF-101）刚刚进入了牛皮癣的2/3期临床试验。 2-氯类似物目前正在接受肝癌的临床试验，并且证明可以减少几名感染丙型肝炎病毒的患者的病毒载量。来自我们实验室的其他更有选择性的A3激动剂，例如构象受限的MRS3558，对其保护性具有感兴趣。 腺苷受体配体发展的问题之一是物种依赖性。在给定的人腺苷受体中，一些非常有效的化合物在大鼠组织中较弱。我们已经开发了腺苷激动剂和拮抗剂，这些激动剂和拮抗剂通常在物种之间起作用。在物种之间具有有效和选择性的A3受体配体的关键是将核苷结构用作设计过程的起点。 核苷倾向于与该受体亚型结合，而在物种之间，核苷比非抑制杂环的核苷趋于结合。 腺苷A3拮抗剂可能有助于治疗青光眼。在我们的图书馆中鉴定A3受体的拮抗剂的早期努力涉及对化学多样的文库进行筛查。这种方法的局限性之一是，拮抗剂通常只能与人类的A3受体结合得很好。我们目前正在基于核苷酸结构开发其他新型A3拮抗剂，这些拮抗剂已被证明在各种物种之间通常适用。我们目前正在系统地研究腺苷衍生物的SAR，这些SAR衍生物会影响A3腺苷受体激动剂。令人惊讶的是，发现一种常用的A1选择性激动剂环戊酰腺苷，在A3亚型中充当纯拮抗剂。其他核苷可能是化学修饰的，尤其是在核糖部分上，以降低A3受体的功效。这些类似物中的某些类似物来自高度有效的A3激动剂，例如5'截断的核苷，是A3拮抗剂。 A3受体的几个新型基于核苷的拮抗剂，包括刚性螺旋藻衍生物MRS1292和截短的4'-硫代腺苷衍生物（与韩国Ehwa Univ教授的Lak Shin Jeong教授的合作发现，韩国ehwa Univ。 我们正在使用诱变来研究A2a和A3受体结合位点识别腺苷的决定因素，并提出参与受体激活的构象因子。由于已经克隆了腺苷受体的四个亚型，因此基于序列分析和使用高分辨率的视紫红质结构作为模板，可以基于序列分析和同源性建模进行分子建模。我们打算使用这种建模方法来设计更有选择性的腺苷受体激动剂和拮抗剂。 最近，该项目还集中在中枢神经系统，心脏以及治疗神经退行性和心血管疾病的治疗可能性上的腺苷激动剂和拮抗剂的影响。一种长期给药的A3激动剂被证明在沙鼠的缺血模型中被高度脑保护。 A3激动剂会导致星形胶质细胞的形态和生化变化。腺苷在心肌缺血期间大量释放，并且能够激活心肌细胞上发生的A1或A3受体以发挥有效的心脏保护作用。我们已经表明，对A1或A3亚型有选择性的合成腺苷激动剂保护培养和孤立的灌注心脏中缺血性心肌细胞，因此可能对缺血性心脏的存活有益。 最近，我们成功地使用了基于结构的药物发现（与加利福尼亚大学的B. Shoichet，旧金山的B. Shoichet合作），成功地识别了A2A受体拮抗剂的新化学型。我们还在同一受体下引入了对亲和力的荧光偏振分析，该测定避免了药物发现/筛查过程中的fo放射性。 腺苷受体激动剂，包括对A2A亚型的选择性的激动剂，正在接受治疗和诊断应用的临床试验。已知的A2A受体激动剂，其中大多数在各种位置都包含大型取代基，它们显示出抗炎和血管舒张特性。我们已经发现了一种通过截断来减少4-噻吩并腺苷激动剂的核糖部分的大小，从而保持有力激活A2A受体的能力。先前显示了对A3受体选择性选择性的核苷中相同的修饰，以将激动剂转化为该亚型的拮抗剂，但是在腺嘌呤部分的2个位置上以A2A受体培养的组进行了修饰，该系列维持了完全激活该亚型的A2A受体最受欢迎的组。因此，两个亚型之间的激活方式存在主要差异。在这一系列的一系列空间小核苷中，A2a受体激动剂和A3受体拮抗作用的共存可能被证明是有益的，以协同的方式在治疗上是有益的。 激动剂结合时G蛋白偶联受体（GPCR）的激活是该细胞表面蛋白家族的信号传导级联的关键步骤。 在与史蒂文斯集团（Stevens Group）合作的情况下，我们最近报道了与Angstrom分辨率为2.7的Agonist UK-432097（以前是COPD的临床试验）结合的A2A腺苷受体的晶体结构。相对于拮抗剂结合的A2A受体，激动剂结合的结构显示出螺旋VI的细胞质半旋转和旋转，螺旋VI的运动，螺旋V的运动以及螺旋III的轴向移动，类似于与活动状态OPSIN结构相关的变化。此外，螺旋VII的SEESAW运动和细胞外环3的转移可能是A2A受体及其配体的特异性。我们的结果将UK-432097定义为能够在特定活性状态下受体稳定的构象选择性激动剂，与其他采样多种构象状态的GPCR激动剂相比。