Targeting Gbg-GRK2 signaling in fibrotic remodeling

纤维化重塑中靶向 Gbg-GRK2 信号传导

• 批准号: 9125578
• 负责人: Burns C Blaxall
• 金额: $ 39万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9125578
• 关键词: Ablation; Acute; Address; Adrenergic Agents; Agonist; Apoptosis; Arrhythmia; Attenuated; Biological Assay; Breeding; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cardiovascular Pathology; Cells; Characteristics; Chronic; Cicatrix; Data; Disease; Environment; Extracellular Matrix; Fibroblasts; Fibrosis; Functional disorder; G Protein-Coupled Receptor Signaling; G protein coupled receptor kinase; G-Protein-Coupled Receptors; Genetic; Heart failure; Human; Hypertrophy; Kidney; Knock-in Mouse; Knockout Mice; Lead; Mechanics; Mediator of activation protein; Membrane; Modeling; Molecular; Mus; Muscle Cells; Myocardial Ischemia; Myofibroblast; Pathologic; Patients; Phosphotransferases; Play; Process; Reagent; Recruitment Activity; Renal function; Reperfusion Injury; Reporting; Rodent; Role; Signal Transduction; Specificity; Syndrome; Testing; Therapeutic; Tissues; Treatment Efficacy; United States; Up-Regulation; Ventricular; base; cell type; clinically relevant; constriction; coronary fibrosis; desensitization; extracellular; gallein; in vivo; inhibitor/antagonist; interstitial; mortality; mouse model; new therapeutic target; novel; outcome forecast; public health relevance; renal ischemia; response; small molecule; sudden cardiac death; targeted treatment; therapeutic target

 DESCRIPTION (provided by applicant): Heart failure (HF) is a devastating disease with poor prognosis. Pathologic cardiac remodeling is characterized by progressive hypertrophy, apoptosis and fibrosis. Fibrosis exacerbates cardiac remodeling, arrhythmias, sudden cardiac death, and decreased ventricular compliance; emerging evidence suggests that cardiac fibroblasts (CFs) play a key role in these processes. To date, there are no therapies that target fibrosis. Elucidating the role(s) of CF in pathologic remodeling may hold substantial therapeutic potential. CF studies have been limited by the lack of genetic reagents in vivo. We are collaboratively characterizing two novel mouse models (PeriostinMerCreMer and Tcf21MerCreMer knock-in mice) that permit targeted and inducible manipulation of CF function/viability to directly determine the mechanistic basis of cardiac fibrosis. Chronic G- protein coupled receptor (GPCR) stimulation in HF elicits pathologic upregulation of GPCR kinase 2 (GRK2) that is recruited to membrane Gβγ subunits to desensitize agonist-occupied GPCRs. We and others have demonstrated therapeutic potential for inhibiting Gβγ-GRK2 interaction in HF. Our novel, small molecule Gβγ- GRK2 inhibitor, gallein, attenuates pathologic cardiac remodeling, normalizes GPCR signaling and reduces interstitial myocardial fibrosis in HF. To explore a fibroblast-restricted role for GRK2 in myocardial fibrosis, GRK2fl/fl mice have been bred with POSTNMerCreMer and Tcf-21MerCreMer. Our exciting preliminary data suggest that the GRK2fl/fl-POSTNMerCreMer mice are significantly protected following cardiac ischemia/reperfusion (I/R) injury, with no further protection conferred by gallein. Interestingly, GRK2fl/fl-POSTNMerCreMer mice appeared to be more protective than GRK2fl/fl-αMHCMerCreMer, suggesting that greater cardioprotection may be provided via the CF than previously thought. Worsening renal function and fibrosis often accompanies HF progression; it is a strong predictor of mortality in advanced HF patients (cardio-renal syndrome 2, CRS2) but remains poorly understood. TAC or I/R injury resulted in substantial kidney fibrosis and dysfunction in our studies; systemic gallein attenuated CRS2 as well as renal dysfunction and fibrosis following acute renal I/R injury. Our hypothesis is that Gβγ-GRK2 plays an important role in pathologic CF activation in HF progression and kidney dysfunction and that its inhibition holds therapeutic promise for HF and CRS2. To address our hypothesis, we propose the following Aims: Aim 1: Determine the therapeutic efficacy and specificity of Gβγ-GRK2 inhibition or GRK2 ablation in a clinically-relevant HF model in wild type and inducible CF or CM GRK2-/- mice (+/- Gallein). Aim 2: Elucidate the cellular mechanisms underlying Gβγ-GRK2 inhibition in fibroblasts and validate Gβγ-GRK2 inhibition as a therapeutic target in both mouse and human cardiac fibrosis and HF. Aim 3: Determine the role of Gβγ-GRK2 signaling in renal fibrosis and CRS2. We believe this proposal, with Gβγ-GRK2 inhibitory compounds, validated in CF-restricted GRK2-/- mice, holds therapeutic promise for HF. The principle may also extend to CRS2 and other fibrotic diseases.

 描述（由申请人提供）：心力衰竭（HF）是一种预后不良的毁灭性疾病，其特征是进行性肥厚、细胞凋亡和纤维化，导致心脏重塑恶化、心律失常、心源性猝死和心室顺应性降低。有证据表明，心脏成纤维细胞（CF）在这些过程中发挥着关键作用，迄今为止，还没有针对纤维化的疗法阐明其作用。由于缺乏体内遗传试剂，CF 的病理重塑可能具有巨大的治疗潜力。我们正在合作表征两种新型小鼠模型（PeriostinMerCreMer 和 Tcf21MerCreMer 敲入小鼠），它们允许对 CF 进行靶向和诱导操作。功能/活力直接确定心力衰竭中慢性 G 蛋白偶联受体 (GPCR) 刺激引起的病理学基础。 GPCR 激酶 2 (GRK2) 被募集至膜 Gβγ 亚基以使激动剂占据的 GPCR 脱敏。我们和其他人已经证明了我们的新型小分子 Gβγ-GRK2 抑制剂 Gallein 具有抑制 HF 中 Gβγ-GRK2 相互作用的治疗潜力。减弱病理性心脏重塑，使 GPCR 信号正常化并减少心力衰竭时的间质性心肌纤维化。由于 GRK2 在心肌纤维化中的成纤维细胞限制作用，GRK2fl/fl 小鼠已与 POSTNMerCreMer 和 Tcf-21MerCreMer 一起饲养，我们令人兴奋的初步数据表明，GRK2fl/fl-POSTNMerCreMer 小鼠在心脏缺血/再灌注 (I/R) 后受到显着保护。伤害，而加莱因没有提供进一步的保护。 GRK2fl/fl-POSTNMerCreMer 小鼠似乎比 GRK2fl/fl-αMHCMerCreMer 具有更强的保护作用，这表明 CF 可能比以前认为的提供更强的心脏保护作用。晚期 HF 患者（心肾综合征 2，CRS2）但仍知之甚少，TAC 或 I/R 损伤会导致大量肾脏损伤。我们的研究中的纤维化和功能障碍；全身性没食子素减弱了 CRS2 以及急性肾 I/R 损伤后的肾功能障碍和纤维化。抑制对 HF 和 CRS2 具有治疗前景 为了解决我们的假设，我们提出以下目标： 目标 1：确定 Gβγ-GRK2 抑制或的治疗功效和特异性。在野生型和诱导型 CF 或 CM GRK2-/- 小鼠 (+/- Gallein) 的临床相关 HF 模型中进行 GRK2 消除 目标 2：阐明成纤维细胞中 Gβγ-GRK2 抑制的细胞机制，并验证 Gβγ-GRK2 抑制为小鼠和人类心脏纤维化和心力衰竭的治疗靶标目标 3：确定 Gβγ-GRK2 信号传导的作用。我们相信，这一利用 Gβγ-GRK2 抑制化合物在 CF 限制性 GRK2-/- 小鼠中得到验证的建议，也可为 HF 带来治疗希望。