Notch signaling in diabetic wounds

项目概要/摘要 2型糖尿病（T2 D）患者的伤口不愈合是导致发病率增加的主要原因， mortality. T2 D患者的伤口愈合失败是美国截肢的最常见原因 五年死亡率接近50%因此，迫切需要了解伤口愈合 T2 D的缺陷，以开发靶向治疗。我们利用遗传（db/db）和饮食（饮食- 诱导的肥胖）T2 D的鼠模型以及从T2 D中收集的人伤口组织和血液样品 患者探索受损伤口愈合的机制。我们公布的和初步的数据表明， 伤口巨噬细胞（Mφs）和CD 4 +T细胞之间的相互作用，通过Notch信号传导，决定了CD 4 +T细胞 激活以最终调节伤口中的炎症和愈合。我们和其他人已经确认 CD 4 +Treg细胞表型对于正常组织修复至关重要，而TH 17表型促进过度的 炎症和损害愈合。我们的初步数据表明，创伤Mφs中的TLR 4信号上调了 Notch配体DLL 4然后与CD 4 +T细胞上的Notch 1和2受体相互作用，以促进TH 17， 与Treg分化相反。这些相互作用驱动糖尿病的过度炎症和病理愈合。 此外，DLL 4-Notch通路可能通过表观遗传机制在糖尿病伤口中进一步上调 涉及MLL 1，一种组蛋白甲基转移酶。MLL 1直接上调Mφ中的DLL 4， DLL 4通过TLR 4信号传导在Mφ中。此外，MLL 1可以直接增加Notch 1和2受体的表达。 CD 4 +T细胞，使它们更容易接受Notch激活并促进延长的TH 17反应。这些 然后，这些变化决定了糖尿病伤口中的病理性TH 17表型。这些结果导致我们 糖尿病伤口中DLL 4介导的Notch受体信号传导使伤口中的CD 4 +T细胞极化的假设 促进TH 17和慢性炎症和不愈合。此外，增加的下游IL 17 A 信号传导增加糖尿病组织中表皮和真皮细胞介导的炎症。我们的数据表明 创伤Mφ/CD 4 +T细胞创伤表型可通过Mφ靶向治疗（局部递送至 通过工程化纳米颗粒的伤口）用MLL 1抑制剂或用抗DLL 4抗体局部治疗。测试 我们的假设，我们将追求以下目标：目标1：检查直接（MLL 1）和间接 (TLR4/MyD 88）在正常和糖尿病条件期间对伤口巨噬细胞中DLL 4的调节。目标二： 确定Notch受体活化在正常和糖尿病患者Treg/TH 17分化中的作用， 伤口修复目的3：比较局部和Mφ靶向治疗以减少Notch信号传导，限制TH 17 本发明的目的是提供一种用于治疗创伤的方法，该方法包括以下步骤：在创伤中诱导IL 17 A分化、改善愈合并鉴定IL 17 A信号传导的细胞靶标。

PROJECT SUMMARY/ABSTRACT Non-healing wounds in patients with Type 2 Diabetes (T2D) are a major cause of increasing morbidity and mortality. Failure of wound healing in T2D patients represents the most common cause of amputation in the US with a 5-year mortality rate of nearly 50%. Thus, a critical need exists for understanding the wound healing defects in T2D in order to develop targeted therapies. We have utilized both genetic (db/db) and dietary (diet- induced obese) murine models of T2D as well as human wound tissue and blood samples collected from T2D patients to explore mechanisms of impaired wound healing. Our published and preliminary data demonstrate that interactions between wound macrophages (Mφs), and CD4+T cells, via Notch signaling, dictate CD4+T cell activation to ultimately regulate inflammation and healing in wounds. We and others have identified that a wound CD4+Treg cell phenotype is critical for normal tissue repair, while a TH17 phenotype promotes excess inflammation and impairs healing. Our preliminary data identify TLR4 signaling in wound Mφs upregulates the Notch ligand, DLL4, which then interacts with the Notch 1 and 2 receptors on CD4+T cells to promote TH17 as opposed to Treg differentiation. These interactions drive excess inflammation and pathologic healing in diabetes. Additionally, the DLL4-Notch pathway may be further upregulated in diabetic wounds via epigenetic mechanisms involving MLL1, a histone methyltransferase. MLL1 directly upregulates DLL4 in Mφs and can indirectly increase DLL4 via TLR4 signaling in Mφs. In addition, MLL1 can directly increase Notch 1 and 2 receptor expression in CD4+T cells, making them more receptive to Notch activation and promoting a prolonged TH17 response. These changes then dictate the pathologic TH17 phenotype in diabetic wounds. These results have led to our hypothesis that DLL4-mediated Notch receptor signaling in diabetic wounds polarizes CD4+T cells in the wound towards TH17 and promotes chronic inflammation and non-healing. Further, increased downstream IL17A signaling increases epidermal and dermal cell mediated inflammation in diabetic tissue. Our data suggest that wound Mφ/CD4+T cell wound phenotypes may be restored via Mφ-targeted treatment (delivered locally to the wound via engineered nanoparticles) with MLL1 inhibitor(s) or local treatment with anti-DLL4 antibodies. To test our hypotheses, we will pursue the following aims: Aim 1: To examine the direct (MLL1) and indirect (TLR4/MyD88) regulation of DLL4 in wound macrophages during normal and diabetic conditions. Aim 2: To identify the role of Notch receptor activation on Treg/TH17 differentiation during normal and diabetic wound repair. Aim 3: To compare local and Mφ-targeted therapies to reduce Notch signaling, limit TH17 differentiation, improve healing and identify the cellular targets for IL17A signaling in wounds.