Bone marrow-derived fibroblasts in skin wound healing

描述（由申请人提供）：皮肤伤口愈合中的骨髓源性成纤维细胞。近25%患有足部溃疡的糖尿病患者将不可避免地发展为主要肢体截肢。糖尿病伤口愈合缺陷与组织水平新生血管受损、角化细胞功能受损、抗张强度降低和感染率升高有关。虽然糖尿病患者的这些广泛性伤口愈合不良缺陷已经得到了很好的证实，但导致这些伤口愈合缺陷的具体组织水平机制仍然知之甚少。复杂的细胞级联介导正常皮肤伤口愈合，所有皮肤细胞合作修复和重建真皮层和表皮。但在慢性伤口患者中，这些用于细胞募集、增殖和分化的信号在伤口床中被破坏。总的来说，我们的目标是通过主要识别特定分子来开发治疗慢性腿部伤口的新策略，这些分子在伤口本身的细胞表达时，将促进慢性伤口的愈合，并完全恢复皮肤的结构和功能。由于成纤维细胞是早期和晚期伤口愈合的关键细胞类型，我们假设，在正常的伤口愈合过程中，成纤维细胞前体细胞从皮肤和骨髓来源的干细胞群体中招募，然后迁移到伤口床并分化成成熟的成纤维细胞。为了区分这两种细胞群，我们开发了体内骨髓移植模型，使用正常和糖尿病小鼠，以及新的体外三维重建人类真皮，血管化真皮和皮肤，其中成纤维细胞可以与其他关键细胞类型相互作用，参与伤口愈合。在这些体内伤口愈合模型和体外重建中，我们将确定骨髓来源的成纤维细胞对伤口愈合过程的影响程度，包括胶原收缩、刺激血管形成、再上皮化和角化细胞生长和分化。通过使用激动剂和抑制剂的病毒载体，我们将验证生长因子，特别是PDGF-B（血小板来源的生长因子）对于骨髓来源的成纤维细胞的激活至关重要，从而侵入胶原蛋白，增殖，迁移到伤口，存活并分化为愈合皮肤伤口的长期细胞成分。

DESCRIPTION (provided by applicant): Bone marrow-derived fibroblasts in skin wound healing. Nearly 25% of all diabetic patients, with foot ulcers, will inevitably progress to major limb amputation. Diabetic wound healing deficiencies are associated with impaired tissue level neovascularization, impaired keratinocyte function, reduced tensile strength, and higher infection rates. While these generalized poor wound healing defects of patients with diabetes mellitus are well established, the specific tissue level mechanisms responsible for these wound-healing deficiencies remain poorly understood. A complex cellular cascade mediates normal cutaneous wound healing, where all skin cells cooperate to repair and rebuild the dermis and epidermis. But in patients with chronic wounds, these signals for cell recruitment, proliferation, and differentiation in the wound bed are disrupted. Overall, we aim to develop new strategies for treating chronic leg wounds by primarily identifying specific molecules, that when expressed by cells within the wound itself, will promote healing of chronic wounds as well as fully restore skin architecture and function. Because fibroblasts are the critical cell type for early and late wound healing, we hypothesize that, during normal wound healing, fibroblast precursor cells are recruited from both, the resident resting pool in the skin and the bone marrow-derived stem cell populations, which then subsequently migrate into the wound bed and differentiate into mature fibroblasts. To distinguish between these two cellular populations we have developed in vivo bone marrow transplantation models, using normal and diabetic mice, and novel in vitro three-dimensional reconstructions of human dermis, vascularized dermis, and skin, in which fibroblasts can interact with other key cell types involved in wound healing. In these in vivo wound-healing models and in vitro reconstructions we will determine the extent to which bone marrow-derived fibroblasts influence wound- healing processes including contraction of collagen, stimulation of vessel formation, re-epithelialization and keratinocyte growth and differentiation. With the use of viral vector delivery of agonists and inhibitors, we will test the hypothesis that growth factors, specifically PDGF-B (platelet-derived growth factor) are critical for the activation of bone marrow-derived fibroblasts to invade into collagen, proliferate, migrate to the wound, survive, and differentiate into long-term cellular components of the healed skin wound.