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（由适用提供）：心力衰竭（HF）是一种毁灭性疾病，预后不良。病理心脏重塑的特征是进行性肥大，凋亡和纤维化。纤维化加剧了心脏重塑，心律不齐，心脏猝死和改善的心室依从性；新兴的证据表明，心脏成纤维细胞（CFS）在这些过程中起关键作用。迄今为止，还没有靶向纤维化的疗法。阐明CF在病理重塑中的作用可能具有巨大的治疗潜力。 CF研究受到体内缺乏遗传试剂的限制。我们正在协作表征两个新型的小鼠模型（perostinmercremer和TCF21Mercremer敲入小鼠），它们允许靶向和诱导CF功能/生存能力的操纵，以直接确定心脏纤维化的机械基础。 HF中的慢性G蛋白偶联受体（GPCR）刺激引起了募集到膜Gβγ亚基的GPCR激酶2（GRK2）的病理上调，以降低了激动剂摄取的GPCR。我们和其他人证明了抑制HF中Gβγ-GRK2相互作用的治疗潜力。我们的新型小分子Gβγ-GRK2抑制剂Gallein减弱了病理心脏重塑，使GPCR信号归一化并减少了HF中的间质心肌纤维化。为了探索GRK2在心肌纤维化中的成纤维细胞限制性作用，GRK2FL/FL小鼠已经与Nmercremer和TCF-21Mercremer一起繁殖。我们令人兴奋的初步数据表明，在心脏缺血/再灌注（I/R）损伤后，GRK2FL/FL-POSTNMERCREMCREMER小鼠受到了显着保护，而Gallein没有进一步的保护。有趣的是，GRK2FL/FL-POSTNMERCREMER小鼠似乎比GRK2FL/FL-αMHCMERCREMCREMER更受保护，这表明可以通过CF提供比以前想象的更大的心脏保护区。肾功能和纤维化的恶化通常涉及HF进展。它是晚期HF患者死亡率的有力预测指标（心脏 - 肾脏综合征2，CRS2），但知识渊博。在我们的研究中，TAC或I/R损伤导致大量的肾脏纤维化和功能障碍。急性肾脏I/R损伤后，全身性Gallein减弱了CRS2以及肾功能障碍和纤维化。我们的假设是，Gβγ-GRK2在HF进展和肾功能障碍中的病理CF激活中起着重要作用，并且其抑制作用对HF和CRS2具有热希望。为了解决我们的假设，我们提出以下目的：目标1：确定野生型HF模型中Gβγ-GRK2抑制或GRK2消融的治疗效率和特异性，并诱导的CF或CM GRK2 - / - 小鼠（+/-- gallein）。 AIM 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HF的治疗靶标。 AIM 3：确定Gβγ-GRK2信号传导在肾纤维化和CRS2中的作用。我们认为，在CF限制的GRK2 - / - 小鼠中验证的Gβγ-GRK2抑制化合物具有HF的热希望。该原理还可以扩展到CRS2和其他纤维化疾病。