Immune and genetic controls of tissue regeneration in mice and humans

小鼠和人类组织再生的免疫和遗传控制

• 批准号: 10747506
• 负责人: Thomas H. Leung
• 金额: --
• 依托单位: PHILADELPHIA VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10747506
• 关键词: Architecture; Automobile Driving; Cell Surface Receptors; Cells; Cicatrix; Clinical; Clinical Trials; Data; Data Set; Diabetic Foot Ulcer; Ear; Excision; Exhibits; Foundations; Frequencies; Funding; Future; Genetic; Goals; Health; Human; Imiquimod; Immune; Infrastructure; Injury; Joints; Ligands; Mammals; Marketing; Mediating; Modeling; Molecular; Morbidity - disease rate; Mouse Strains; Mus; Natural regeneration; Neurons; Operative Surgical Procedures; Pathway interactions; Patients; Phenotype; Prevention; Research Personnel; Resources; Sampling; Signal Pathway; Site; Skin; Skin injury; Skin wound healing; Speed; Stromal Cell-Derived Factor 1; Testing; Time; Tissues; Translating; Trauma; Veterans; Work; aged; cell type; comparison control; decubitus ulcer; emotional distress; healing; improved; inhibitor; injured; mouse genetics; novel therapeutic intervention; pharmacologic; physically handicapped; pre-clinical; receptor; receptor-mediated signaling; recruit; single-cell RNA sequencing; skin regeneration; skin wound; skin xenograft; small molecule; synergism; tissue regeneration; tissue repair; transcriptomics; translational goal; wound; wound closure; wound healing

Humans generally heal skin injuries with a fibrous scar, which results in increased skin tightness, altered cosmesis, and morbidity when scars form over joints. Under specific and rare circumstances, humans and mammals exhibit spontaneous tissue regeneration, which heals tissue to their original architecture and function without a scar. Thus, the molecular machinery for tissue regeneration exists in mammals and understanding how to elicit regeneration will help us attain our long-term goal of regenerating injured human skin. Prior work from our group and others used ear hole closure to demonstrate that “regeneration-competent” mouse strains, including p21–/–, wildtype aged, and skin-specific CXCL12–/– mice, close ear holes to ~90% of the wounded size compared to control mice, which close holes to ~50%. Despite this improved healing, only 1% of regeneration-competent mice achieved complete ear hole closure. During the past funding cycle, we increased the frequency of complete hole closure, and most recently showed that topical imiquimod activates TRPA1+ neurons to drive complete ear hole closure in 20% of mice. This 20-fold improvement is substantial, and we continue to aim higher. In our preliminary data, we performed single-cell RNA-sequencing on wound- edge tissue from TRPA1+ activated and aged mice to identify signaling pathways driving tissue regeneration. Ligand-receptor interaction analysis identified a new receptor-mediated signaling pathway that promotes tissue regeneration. Unexpectedly, mice lacking this receptor exhibited the opposite phenotype; they demonstrated faster wound closure, decreased scar formation, and improved tissue regeneration in 3 different skin injury models. However, topical imiquimod treatment synergizes with receptor deficient mice to increase the frequency of complete ear hole closure to 90%. Taken together, we conclude that this newly identified receptor regulates both speed and quality of wound repair, which counters the current paradigm that the speed of wound closure and quality of wound healing are inversely related. Moreover, this pathway is independent from TRPA1+ neurons to promote regeneration. We hypothesize that this receptor pathway promotes scar formation and blocking this receptor permits tissue regeneration. In Aim 1, we elucidate the molecular mechanism of how this receptor promotes scar formation. We will use mouse genetics and our injury models to identify which cell types expressing this receptor are necessary and sufficient to drive scar formation. Next, we will use mouse genetics and pharmacologic inhibitors to identify the molecular mechanisms downstream of the receptor that promote scar formation. In Aim 2, a major gap in the wound healing field is the limited understanding of human wound healing due to sample availability. To fill this gap, we created the infrastructure to collect human skin in a dense time course after injury for single-cell RNA-sequencing. We expect increased recruitment of cells expressing our receptor to the injury site, and we will compare transcriptomic changes against our mouse dataset. Importantly, this dataset will be a resource for all wound healing researchers. Finally, we will translate our 90% complete ear hole closure finding into human skin. We hypothesize that combination small molecule mediated inhibition of our receptor and topical imiquimod will reduce scar formation in human skin. We will test this possibility by using human orthotopic skin xenografts on immune- deficient mice. If successful, this data may serve as the pre-clinical foundation for a future clinical trial. Taken together, we continue to improve our understanding of eliciting scarless wound healing and actively translate our findings into humans, which is applicable to all Veterans living with traumatic or surgically-created wounds.

人类通常用纤维性疤痕治愈皮肤损伤，这导致皮肤紧致度增加， 改变的外观和关节上形成疤痕时的发病率。在特殊和罕见的情况下，人类 和哺乳动物表现出自发的组织再生，其将组织愈合至其原始结构， 没有疤痕的功能。因此，组织再生的分子机制存在于哺乳动物中， 了解如何引发再生将有助于我们实现我们的长期目标， 皮肤我们小组和其他人先前的工作使用耳孔闭合来证明"再生能力" 小鼠品系，包括p21-/-、野生型老年小鼠和皮肤特异性CXCL12-/-小鼠， 与对照组小鼠相比，伤口尺寸缩小了约50%。尽管这种改善的愈合，只有 1%的再生能力小鼠实现了耳孔完全闭合。在过去的融资周期中，我们 增加了完全孔闭合的频率，最近显示局部咪喹莫特激活 TRPA1+神经元在20%的小鼠中驱动耳孔完全闭合。这20倍的改进是实质性的， 我们将继续追求更高的目标。在我们的初步数据中，我们对伤口进行了单细胞RNA测序， 来自TRPA1+激活和衰老小鼠的边缘组织，以鉴定驱动组织再生的信号通路。 配体-受体相互作用分析确定了一个新的受体介导的信号通路，促进组织 再生出乎意料的是，缺乏这种受体的小鼠表现出相反的表型;他们证明， 在3种不同的皮肤损伤中，伤口闭合更快，瘢痕形成减少，组织再生改善 模型然而，局部咪喹莫特治疗与受体缺陷小鼠协同作用，增加了受体的表达。 耳孔完全闭合的频率达到90%。综上所述，我们得出结论，这种新发现的受体 调节伤口修复的速度和质量，这与目前的范式相反， 伤口闭合和伤口愈合的质量成反比。此外，该途径独立于 TRPA 1+神经元促进再生。我们假设这种受体途径促进瘢痕形成 形成并阻断该受体允许组织再生。在目标1中，我们阐明了分子 这种受体如何促进疤痕形成的机制。我们将使用小鼠遗传学和我们的损伤模型， 确定哪些细胞类型表达这种受体是必要的，足以驱动疤痕形成。接下来我们 将使用小鼠遗传学和药理学抑制剂来确定下游的分子机制， 促进疤痕形成的受体。在目标2中，伤口愈合领域的主要差距是有限的 由于样品的可用性，对人类伤口愈合的理解。为了填补这一空白，我们建立了基础设施， 在损伤后的密集时间过程中收集人类皮肤用于单细胞RNA测序。我们预计， 募集表达我们的受体的细胞到损伤部位，我们将比较转录组学变化， 与我们的老鼠数据集进行对比。重要的是，该数据集将成为所有伤口愈合研究人员的资源。 最后，我们将把我们90%的耳孔闭合结果转化为人类皮肤。我们假设 小分子介导的OUR受体抑制和局部咪喹莫特的组合将减少瘢痕 在人体皮肤中形成。我们将通过使用人类原位异种皮肤移植来测试这种可能性， 缺陷小鼠如果成功的话，这些数据可以作为未来临床试验的临床前基础。采取 我们一起继续提高我们对无瘢痕伤口愈合的理解，并积极地将其转化为 我们对人类的研究结果，这适用于所有生活在创伤或创伤性伤口的退伍军人。

项目成果

Aging Suppresses Skin-Derived Circulating SDF1 to Promote Full-Thickness Tissue Regeneration.

• DOI: 10.1016/j.celrep.2018.08.054
• 发表时间: 2018-09-25
• 期刊: Cell reports
• 影响因子: 8.8
• 作者: Nishiguchi MA;Spencer CA;Leung DH;Leung TH
• 通讯作者: Leung TH