Role of Bone Marrow-Derived Fibroblast Precursors in Cardiac Fibrosis

描述(由申请人提供)：本提案描述了一项为期五年的培训计划，旨在发展学术医学的独立研究生涯。首席调查员拥有内科委员会证书和药理学博士学位。PI的长期目标是成为生物医学研究领域的独立内科医生兼科学家。心力衰竭(HF)是慢性肾脏病(CKD)患者的一个非常严重的问题。PI的研究计划旨在确定在CKD小鼠模型中导致心脏纤维化和心力衰竭的细胞和分子机制。炎症和心脏重塑方面的权威医学博士Mark Entman将指导PI的科学发展，而CKD及其后果方面的专家William Mitch将担任共同导师。这两家公司在培训年轻调查人员方面都有出色的记录。为了扩大独立调查团的培训范围，成立了一个由常设调查员组成的咨询委员会。此外，贝勒和医学部拥有广泛的资源，为初级内科科学家提供了理想的培训环境。从流行病学来看，CKD患者有明显的心脏纤维化和心力衰竭的易感性。然而，导致心脏纤维化的机制尚不清楚，也没有有效的治疗方法。我们的初步结果表明，高水平的血管紧张素II(Ang II)(如在CKD/HF中发现的)导致骨髓来源的成纤维细胞在心脏中积聚，这对心脏纤维化源于心脏成纤维细胞的范式提出了挑战，并导致我们假设骨髓来源的成纤维细胞前体细胞迁移到心脏内，从而产生心脏纤维化。为了验证这一假设，我们将追求以下具体目标。具体目的1是确定尿毒症是否刺激趋化因子的产生，继而在心脏中积累成纤维细胞前体。具体目的2是检查骨髓来源的成纤维细胞前体是否通过趋化因子(如MCP-1)被招募到心脏，这些趋化因子在慢性肾脏病中也很高。由于ACEI和ARB在CKD患者中广泛使用，而且Ang II在CKD患者中含量很高，因此特定的目标3是评估抑制Ang II是否会阻止尿毒症患者心脏中成纤维细胞前体的募集。相关性(见说明书)：拟议的研究可能导致一种新的范式，即骨髓来源的成纤维细胞前体有助于心脏纤维化的发病机制。了解导致骨髓源性成纤维细胞前体细胞重新进入心脏的触发事件可以揭示为什么慢性肾脏病与心脏纤维化和心力衰竭有关，并可能导致治疗心力衰竭的新疗法。

DESCRIPTION (provided by applicant): This proposal describes a five year training program for development of an independent research career in academic medicine. The principle investigator is board certified in Internal Medicine with a PhD degree in Pharmacology. The Pi's long term goal is to become an independent physician-scientist in biomedical research. Heart failure (HF) is a very serious problem of chronic kidney disease (CKD) patients. The PI's research plan is directed at identifying cellular and molecular mechanisms causing cardiac fibrosis and HF in a murine model of CKD. Mark Entman, MD, an authority on inflammation and cardiac remodeling will mentor the Pi's scientific development while William Mitch, MD, an expert on CKD and its consequences will serve as a co-mentor. Both have outstanding records of training young investigators. To broaden the PI's training, an Advisory Committee of established investigators has been organized. Furthermore, Baylor and the Department of Medicine have extensive resources providing an ideal training environment for junior physician-scientists. Epidemiologically, CKD patients have marked susceptibility for developing cardiac fibrosis and HF. However, the mechanisms causing cardiac fibrosis are unknown and there is no effective therapy. Our Preliminary Results demonstrate that high angiotensin II (Ang II) level (as found in CKD/HF) leads to accumulation of bone marrow-derived fibroblasts in the heart, which challenge the paradigm that cardiac fibrosis arises from fibroblasts residing in the heart and lead us to hypothesize that bone marrow- derived fibroblast precursor cells migrate into the heart to produce cardiac fibrosis. To test this hypothesis, the following specific aims will be pursued. Specific Aim 1 is to determine whether uremia stimulates chemokine production followed by accumulation of fibroblast precursors in the heart. Specific Aim 2 is to examine whether bone marrow-derived fibroblast precursors are recruited into the heart via chemokines (e.g. MCP-1) which are also high in CKD. Since ACEi & ARB's are widely used in CKD patients and since Ang II is high in CKD, Specific Aim 3 is to evaluate whether inhibition of Ang II will block the recruitment of fibroblast precursors into the heart in response to uremia. RELEVANCE (See instructions): The proposed studies could lead to a new paradigm that bone marrow-derived fibroblast precursors contribute to the pathogenesis of cardiac fibrosis. Understanding the triggering events that lead to the recruitement of bone marrow-derived fibroblast precursors into the heart could reveal why CKD is linked to cardiac fibrosis and heart failure and may lead to novel therapy for the treatment of heart failure.