Elucidating fibroblast heterogeneity as a pathway to target organ fibrosis

阐明成纤维细胞异质性作为靶器官纤维化的途径

• 批准号: 10272408
• 负责人: Sarika Saraswati
• 金额: $ 15.62万
• 依托单位: TENNESSEE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-03 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10272408
• 关键词: Elucidating; fibroblast; heterogeneity; pathway; target

PROJECT SUMMARY Following surgical or traumatic injury, organs and tissues can heal by regeneration but more often than not, the repair process is complicated by fibrosis, resulting in reduced function and eventually organ failure. Activated fibroblasts (FBs) are the central mediators of both repair and fibrosis making it difficult to target fibrosis without affecting repair. It is now well accepted that FBs represent a heterogeneous population of cells, yet we have a poor understanding of the molecular, cellular and functional basis of this heterogeneity. Our preliminary data have identified two major and distinct activated FB populations in mouse heart, skin and kidney following injury: Fibroblast specific protein 1 (FSP1)-expressing FBs and α-smooth muscle actin (αSMA)-expressing FBs, which appear at different time points after injury and remained as discrete populations during the healing process. Using mice which express GFP under FSP1 or α-SMA promoters we isolated these activated FB populations post cardiac injury and compared the gene expression profile of each population to those of FBs isolated from the uninjured heart. RNA sequencing indicated distinct molecular signatures. Particularly, pro-fibrotic genes such as type I collagen (Col I) and TGFβ signaling were significantly upregulated in αSMA-FBs, whereas genes involved in cellular homeostasis, tissue remodeling and cell-cell communication were upregulated in FSP1-FBs. Several studies, including from our group, have suggested that Secreted Frizzled-related protein 2 (sFRP2), a putative wnt pathway inhibitor, mediates wound repair by inhibiting fibrosis. We developed a novel mouse model in which we can induce expression of sFRP2 in activated FBs following injury. We found that early post-injury sFRP2 activation resulted in reduced fibrosis after myocardial, kidney and skin injuries without inhibiting tissue repair. Interestingly, our preliminary data showed that sFRP2 inhibited Col I synthesis and TGFβ signaling (but not Wnt signaling) only in αSMA-FBs but not in FSP-1 FBs in vitro. As such, sFRP2 represents an anti-fibrotic paracrine factor which may reduce tissue fibrosis by exerting distinct molecular effects on the post-injury (i.e. activated) FB subtypes. At the conclusion of this research proposal we will have characterized the cellular and functional heterogeneity of the major injury-activated FB populations and also have elucidated the mechanistic basis of the pro-reparative, antifibrotic effects of sFRP2 via its targeted and distinct effects on α-SMA-expressing FBs.

项目摘要 在手术或创伤性损伤后，器官和组织可以通过再生愈合，但更常见的是， 否则，修复过程会因纤维化而变得复杂，导致功能下降，最终导致器官衰竭。 活化的成纤维细胞（FB）是修复和纤维化的中心介质，使其难以靶向 纤维化而不影响修复。现在普遍认为，FB代表了一个异质性的群体， 细胞，但我们对这种异质性的分子，细胞和功能基础的理解很差。 我们的初步数据已经确定了两个主要的和不同的激活FB群体在小鼠心脏，皮肤和 损伤后肾脏：表达成纤维细胞特异性蛋白1（FSP 1）的FB和α-平滑肌肌动蛋白 （αSMA）表达的FB在损伤后的不同时间点出现，并且保持离散 在治疗过程中的人群。使用在FSP 1或α-SMA启动子下表达GFP的小鼠， 分离这些心脏损伤后激活的FB群体，并比较每个群体的基因表达谱。 与从未受伤的心脏分离的FB相比。RNA测序表明 签名.特别地，促纤维化基因如I型胶原（Col I）和TGFβ信号传导显著地被抑制。 在α SMA-FB中上调，而参与细胞稳态，组织重塑和细胞-细胞 在FSP 1-FB中上调。包括我们小组在内的几项研究表明， 分泌型卷曲相关蛋白2（sFRP 2），一种假定的wnt通路抑制剂，通过以下途径介导伤口修复： 抑制纤维化。我们开发了一种新的小鼠模型，在该模型中，我们可以诱导sFRP 2的表达， 损伤后激活FB。我们发现，损伤后早期sFRP 2激活导致纤维化减少， 在心肌、肾脏和皮肤损伤后不抑制组织修复。有趣的是，我们的初步数据 sFRP 2仅在α SMA-FB中抑制Col I合成和TGFβ信号传导（但不抑制Wnt信号传导）， 而不是在体外FSP-1 FB中。因此，sFRP 2代表抗纤维化旁分泌因子，其可以减少组织纤维化。 通过对损伤后（即活化的）FB亚型施加不同的分子效应来抑制纤维化。结束时 在这项研究计划中，我们将描述主要的细胞和功能异质性。 损伤激活的FB群体，也阐明了促修复的机制基础， sFRP 2通过其对表达α-SMA的FB的靶向和独特作用的抗纤维化作用。

项目成果

Molecular mediators of mesenchymal stem cell biology.

• DOI: 10.1016/b978-0-12-386015-6.00023-8
• 发表时间: 2011
• 期刊: Vitamins and hormones
• 作者: Alfaro MP;Saraswati S;Young PP
• 通讯作者: Young PP

Cell-based therapies for cardiac disease: a cellular therapist's perspective.

基于细胞的心脏病疗法：细胞治疗师的观点。

• DOI: 10.1111/trf.12826
• 发表时间: 2015-03
• 期刊: Transfusion
• 影响因子: 2.9
• 作者: Young PP;Schäfer R
• 通讯作者: Schäfer R

Temporary, Systemic Inhibition of the WNT/β-Catenin Pathway promotes Regenerative Cardiac Repair following Myocardial Infarct.

• DOI: 10.16966/2472-6990.111
• 发表时间: 2016-11
• 期刊: Cell, stem cells and regenerative medicine
• 作者: Bastakoty D;Saraswati S;Joshi P;Atkinson J;Feoktistov I;Liu J;Harris JL;Young PP
• 通讯作者: Young PP