Tumor Necrosis Factor Modulation of CPCs

本项目的总体目标是建立病理性 炎症和心脏祖细胞（CPC）介导组织修复。在心肌梗塞（MI）后， CPC数量增加，但不能产生足够的内源性愈合，这表明， 微环境损害了它们的修复能力。在LV重塑期间， 促炎细胞因子肿瘤坏死因子-a（TNF）的详细说明。肿瘤坏死因子在心肌梗死后的作用 心脏是异质性且依赖于其两种细胞表面受体（TNFR）-TNFR 1促进LV 核因子（NF）-κ B和p38 MAPK的重塑和激活，而TNFR 2对抗这些作用 并且是有益的。然而，不同的TNFR特异性作用是否延伸到CPC并调节它们的表达， 修复能力未知。在我们的初步研究中，我们发现了TNF 抑制CPC的心肌细胞分化，相反促进肾上腺素能表型， 增强重塑。这种反应依赖于TNFR 1并与NF-κ B相关，并且可以通过调节TNFR 1和NF-κ B的表达来调节。 因此，我们假设通过TNFR 1、TNFR 2和NF-κ B的不同TNF信号传导， plav在决定肾上腺素能与心肌源性的命运中起关键作用，因此， 根据MI的CPC容量。我们提出三个目标。在目标1中，我们将确定TNFR的影响- CPC能力和肾上腺素能与心源性分化的依赖性信号传导 GFP标记的lin-/c-kit+来自野生型（WT）、TNFR 1-/-、TNFR 2-/-、显性阴性（DN）-lKBa的CPC 转基因（Tg）和Tg-DN-p38 a MAPK小鼠心脏。我们还将建立神经肾上腺素能型 细胞来源于心脏祖细胞而不是常驻神经祖细胞。在目标2中，我们将描述 体内心脏修复过程中CPC定位的TNFR信号传导。在鼠再灌注Ml模型中，我们将递送 GFP标记的lin-/c-kit+ WT、TNFR 1-/-、TNFR 2-/-或Tg-DN-kBa CPC，并确定细胞命运及其 对LV重塑和组织肾上腺素能激活的影响。在目标3中，我们将确定TNF在 CPC介导的修复和肾上腺素能分化的组织微环境通过定义重塑 在WT和TNF-α中再灌注Ml后移植GFP标记的WT lin-/c-kit+ CPC后的反应 /-小鼠，或依那西普的限制性全身TNF抑制。总体而言，这些研究将：1） 揭示了TNF作为CPC功能抑制剂和CPC介导的通过TNFR 1和NF-κ B修复的新作用。 KB; 2）确定衰竭心脏中肾上腺素能细胞的迄今未知的CPC衍生来源;和3）靶向 与TNF信号相关的潜在治疗途径，以提高CPC移植的疗效 相关性（参见说明）： 这些研究将建立肿瘤坏死因子-a（TNF）深刻影响 心脏祖细胞（CPC）的行为通过其两种受体的不同作用，并通道这些 细胞朝向有益的（心脏细胞）或有害的（肾上腺素能细胞）组织修复的命运。结果 将揭示与TNF信号相关的潜在治疗途径， 外源性祖细胞移植和增强心脏的内在修复能力， 在没有祖细胞治疗的情况下的心肌梗死。

The overarching objective of this project is to establish the mechanistic relationships between pathological inflammation and cardiac progenitor cell (CPC)-mediated tissue repair. After myocardial infarction (Ml), CPCs are increased in number but fail to produce sufficient endogenous healing, suggesting that factors in the microenvironment compromise their reparative capacity. During LV remodeling, there is sustained elaboration of the pro-inflammatory cytokine tumor necrosis factor-a (TNF). The effects of TNF in the post-MI heart are heterogeneous and depend on its two cell-surface receptors (TNFRs) - TNFRl promotes LV remodeling and activation of nuclear factor (NF)-KB and p38 MAPK, whereas TNFR2 opposes these effects and is beneficial. However, whether divergent TNFR-specific effects extend to CPCs and modulate their reparative capacity is unknown. In our preliminary studies, we have uncovered the novel finding that TNF inhibits cardiomyocyte differentiation of CPCs and instead promotes an adrenergic phenotype that can potentiate remodeling. This response is dependent on TNFR1 and associated with NF-KB, and can be opposed by TNFR2, Hence, we hypothesize that differential TNF signaling via TNFR1, TNFR2, and NF-KB plavs a critical role in determining adrenergic versus cardiomyogenic fate and, conseguentiv, the reparative capacity of CPCs following Ml. We propose three Aims. In Aim 1, we will determine the effects of TNFR- dependent signaling on CPC competence and adrenergic versus cardiogenic differentiation in vitro using GFP-labeled lin-/c-kit+ CPCs from wild-type (WT), TNFRl-/-, TNFR2-/-, dominant-negative (DN)-lKBa transgenic (Tg), and Tg-DN-p38a MAPK mouse hearts. We will also establish that neuroadrenergic-type cells are derived from cardiac and not resident neural progenitors. In Aim 2, we will delineate the role of CPC-localized TNFR-signaling during cardiac repair in vivo. In a murine reperfused Ml model, we will deliver GFP-labeled lin-/c-kit+ WT, TNFR1-/-, TNFR2-/-, or Tg-DN-kBa CPCs and determine cell fate and their effects on LV remodeling and tissue adrenergic activation. In Aim 3, we will determine the effects of TNF in the tissue microenvironment on CPC-mediated repair and adrenergic differentiation by defining remodeling responses upon transplantation of GFP-labeled WT lin-/c-kit+ CPCs following reperfused Ml in WT and TNF- /- mice, or upon circumscribed systemic TNF inhibition with etanercept. Collectively, these studies will: 1) uncover a novel role for TNF as an inhibitor of CPC function and CPC-mediated repair via TNFR1 and NF- KB; 2) define a heretofore unknown CPC-derived origin for adrenergic cells in the failing heart; and 3) target potential therapeutic avenues related to TNF signaling to enhance the efficacy of CPC transplantation RELEVANCE (See instructions): These studies will establish the novel paradigm that tumor necrosis factor-a (TNF) profoundly influences cardiac progenitor cell (CPC) behavior through the divergent effects of its two receptors, and channels these cells toward either beneficial (cardiac cell) or detrimental (adrenergic cell) fates for tissue repair. The results will shed light on potential therapeutic avenues related to TNF signaling that can both enhance the efficacy of exogenous progenitor cell transplantation and augment the heart's intrinsic capacity to repair itself after myocardial infarction in the absence of progenitor cell therapy.