Pericellular Proteolysis and the Regulation of Bone/Tendon Stem Cell Fate

细胞周蛋白水解和骨/肌腱干细胞命运的调节

• 批准号: 10371563
• 负责人: STEPHEN J WEISS
• 金额: $ 43.5万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-05 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10371563
• 关键词: Anatomy; Animal Model; Bone Marrow; Caspase; Cell Lineage; Cell physiology; Cells; Chondrogenesis; Collagen; Collagen Type I; Data; Family; Genetic Transcription; Growth and Development function; In Vitro; Ligaments; Light; Link; MMP14 gene; Matrix Metalloproteinases; Membrane; Mesenchymal; Metalloproteases; Modeling; Molecular; Outcome; Pathologic; Pathway interactions; Periosteum; Phenotype; Physiologic Ossification; Physiological; Play; Population; Proteolysis; Regulation; Reporting; Role; Route; Series; Signal Pathway; Signal Transduction; Stromal Cells; Structure; Tendon structure; Tissues; Transforming Growth Factor beta; Transgenic Organisms; Trauma; Work; base; bone; carboxypeptidase C; cathepsin K; design; in vivo; intramembranous bone formation; mechanotransduction; novel; programs; proteinase In; receptor; skeletal stem cell; stem; stem cell differentiation; stem cell fate; stem cell function; stem cell population; stem cells; trafficking

ABSTRACT Bone as well as tendons each contain stem cell populations embedded in type I collagen-rich tissues. Bone marrow and endosteal-derived stem cells generate bone via endochondral ossification while periosteal stem cells form bone via the intramembranous route. In turn, tendon stem cells give rise to tenocytes that populate the mature tissues. Recent studies have identified the cysteine proteinase, cathepsin K (CTSK), as a unique marker of periosteal stem cells, a finding we have confirmed, but that also led to our identification of a heretofore uncharacterized second stem population associated with tendons. In bone marrow-derived MSCs, we have previously identified a novel requirement for the membrane-anchored metalloproteinase, MT1-MMP, in regulating a mechanosensitive, YAP/TAZ-dependent pathway that controls stem cell lineage commitment via the proteolytic remodeling of the pericellular collagen matrix. By contrast, the relative roles of MT1-MMP and CTSK in periosteal or tendon/ligament stem cells are unknown. Using a Ctsk-Cre transgenic line to target periosteal stem cells, we find that Mt1-mmp targeting alone elicits a profound osteopenic state in vivo that not only operates independently of Ctsk, but also redirects the stem cells to an aberrant hyperproliferative, chondrogenic state. Further, and unexpectedly, Ctsk-Cre–dependent targeting of MT1-MMP - but not Ctsk, disrupts tendon/ structure by altering a previously undescribed paratenon stem cell-tendon trafficking route. In vivo, MT1-MMP-null tendon stem cells commit to a hyperproliferative, chondrogenic phenotype similar to that observed following tendon/ligament trauma. Based on these new data, we propose that MT1-MMP controls each of these stem cell populations by regulating a mechanotransduction pathway that not only controls YAP/TAZ-linked co-transcriptional programs, but also canonical TFGβ signaling pathways via the proteolytic shedding of the accessory TGFβ receptor, TGFβRIII. Together, these findings outline a new model of MSC function wherein MT1-MMP-dependent collagenolysis and receptor shedding together play a required role in periosteal tissues and tendons. As such, we propose 3 aims; i) characterize the role of MT1-MMP in regulating periosteal stem cell differentiation and function in vitro and in vivo, ii) define a novel role for Ctsk+ tendon stem cells in controlling tendon function and its regulation by MT1-MMP and iii) delineate the impact of MT1-MMP on periosteal/paratenon stem cell YAP/TAZ mechanotransduction and TGFβ/TGFβRIII- dependent differentiation programs. Together, these aims should cast new light on a family of specialized stem cells that require MT1- MMP-dependent proteolysis to not only regulate intramembranous bone formation, but also tendon structure/function as well.

抽象的 骨骼和肌腱均含有嵌入富含 I 型胶原蛋白的组织中的干细胞群。 骨髓和骨内膜干细胞通过软骨内骨化生成骨，而骨膜干细胞 细胞通过膜内途径形成骨骼，肌腱干细胞又产生生长的肌腱细胞。 最近的研究发现半胱氨酸蛋白酶组织蛋白酶 K (CTSK) 是一种独特的酶。 骨膜干细胞的标记物，我们已经证实了这一发现，但这也导致我们迄今为止鉴定出 在骨髓来源的 MSC 中，我们有与肌腱相关的未表征的第二干细胞群。 先前确定了膜锚定金属蛋白酶 MT1-MMP 的新要求， 调节机械敏感、YAP/TAZ 依赖性途径，通过以下方式控制干细胞谱系定向： 相比之下，MT1-MMP 和细胞周围胶原基质的蛋白水解重塑。 使用 Ctsk-Cre 转基因系靶向骨膜或肌腱/韧带干细胞中的 CTSK 尚不清楚。 骨膜干细胞中，我们发现单独靶向 Mt1-mmp 会在体内引起严重的骨质减少状态，而 不仅独立于 Ctsk 运行，而且还将干细胞重定向到异常的过度增殖， 此外，出乎意料的是，Ctsk-Cre 依赖于 MT1-MMP 的靶向，但不是 Ctsk， 通过改变以前未描述的腱旁干细胞-肌腱运输途径来破坏肌腱/结构。 体内，MT1-MMP缺失的肌腱干细胞会形成与此类似的过度增殖、软骨形成表型 根据这些新数据，我们建议 MT1-MMP 进行控制。 这些干细胞群中的每一个都通过调节机械转导途径来控制，该途径不仅控制 YAP/TAZ 连接的共转录程序，以及通过蛋白水解的经典 TFGβ 信号传导途径 辅助 TGFβ 受体 TGFβRIII 的脱落，这些发现概述了 MSC 的新模型。 MT1-MMP 依赖性胶原溶解和受体脱落共同发挥着必要的作用 因此，我们提出 3 个目标；i) 描述 MT1-MMP 在调节中的作用。 骨膜干细胞在体外和体内的分化和功能，ii) 定义了 Ctsk+ 肌腱干的新作用 细胞控制肌腱功能及其通过 MT1-MMP 的调节，以及 iii) 描述了 MT1-MMP 对肌腱功能的影响 骨膜/腱旁干细胞 YAP/TAZ 机械转导和 TGFβ/TGFβRIII 依赖性分化 总之，这些目标将为需要 MT1 的特殊干细胞家族带来新的曙光。 MMP 依赖性蛋白水解不仅调节膜内骨形成，还调节肌腱 结构/功能也是如此。