The Role of Macrophage Migration Inhibitory Factor (MIF) Family Proteins in Wound Repair and Obesity

巨噬细胞迁移抑制因子 (MIF) 家族蛋白在伤口修复和肥胖中的作用

• 批准号: 394654802
• 负责人: Professor Dr. Jürgen Bernhagen
• 金额: --
• 依托单位: Institut für Schlaganfall- und Demenzforschung (ISD)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/394654802?language=en
• 关键词: Role; Macrophage; Migration; Inhibitory; Factor

Obesity is a condition associated with chronic adipose tissue inflammation (CAI) and represents a risk factor for several diseases including type 2 diabetes mellitus (T2DM). Importantly, obese patients often show delayed wound repair and an increased risk of wound healing disorders which remains an unsolved issue, particularly in Plastic and Reconstructive Surgery. A strong body of evidence suggests that the chemokine-like inflammatory cytokine macrophage migration inhibitory factor (MIF) promotes obesity, T2DM, CAI, while inhibiting wound repair. In contrast, little is known about MIFs recently discovered homolog D-dopachrome tautomerase (DDT) in this context. Preliminary work by the applicants leading up to this proposal has provided evidence for a reciprocal regulation of MIF and DDT in adipose tissue of patients with acute wound healing disorders. Reciprocal MIF and DDT regulation in inflamed adipose tissue was observed in a murine LPS injection model and adipocytes were identified as the cellular source for differential MIF and DDT expression. Interestingly, the coincident up-regulation versus down-regulation of MIF and DDT, respectively, was seen to have a detrimental effect on wound repair in vitro. Furthermore, Only MIF regulated monocyte migration into LPS-injected adipose tissue via its receptors CXCR2 and CXCR4 while DDT did not appear to exhibit pro-migratory effects.Here we aim to comprehensively study the role of MIF and DDT in the context of CAI, insulin resistance and wound repair under obesity, applying murine in vivo models, patient tissue specimens, and mechanistic experiments. First, wildtype mice and mice with a global Ddt knockout will undergo a high fat diet (HFD) to investigate the hitherto unknown effect of DDT on obesity, insulin resistance and CAI. Next, mice with an adipose tissue-specific knockout of Mif and Ddt (or wildtype in the control) that are fed a HFD will undergo incisional and excisional wounding to characterize the precise role of adipose tissue-derived MIF and DDT on wound repair under obese conditions. We predict that the inverse role of MIF and DDT that was observed in our preliminary experiments also will apply to our in vivo models. To establish potential therapeutic strategies, the feasibility of administering recombinant MIF/DDT protein and/or MIF/DDT neutralizing antibodies will additionally be studied in the in vivo models. In a third part, the experimental in vivo studies will be complemented by evaluation of primary human adipose tissue samples of obese and lean individuals. To this end, MIF- and DDT-dependent wound healing processes will be examined using in vitro co-culture assays of the adipose tissue samples and human fibroblasts/keratinocytes. Lastly, to identify the receptors contributing to MIF and DDT interactions, mechanistic studies will be performed to address the role of CD74, CD44, CXCR2, and/or CXCR4 as well as the relevant signaling pathways.

肥胖是与慢性脂肪组织炎症（CAI）有关的疾病，代表了多种疾病的危险因素，包括2型糖尿病（T2DM）。重要的是，肥胖患者经常表现出延迟的伤口修复，并增加了伤口愈合障碍的风险，这仍然是一个未解决的问题，尤其是在塑料和重建手术中。大量证据表明，趋化因子样细胞因子巨噬细胞迁移抑制因子（MIF）促进肥胖，T2DM，CAI，同时抑制伤口修复。相比之下，在这种情况下，最近发现的MIF鲜为人知的同源性D-Dopachrome互变异酶（DDT）知之甚少。导致该提案的申请人的初步工作为急性伤口愈合障碍患者的脂肪组织中MIF和DDT的相互调节提供了证据。在鼠LPS注入模型中观察到发炎的脂肪组织中的相互MIF和DDT调节，并将脂肪细胞确定为差异MIF和DDT表达的细胞来源。有趣的是，分别认为MIF和DDT的同时上调与下调对体外伤口修复有不利影响。此外，只有MIF通过其受体CXCR2和CXCR4调节单核细胞迁移到注射LPS的脂肪组织中，而DDT似乎并未表现出促迁移效应。在肥胖症下的耐药性和伤口修复，在体内模型，患者组织标本和机械实验中应用鼠。首先，具有全球滴滴涕敲除的野生型小鼠和小鼠将接受高脂肪饮食（HFD），以研究迄今为止DDT对肥胖，胰岛素抵抗和CAI的未知作用。接下来，具有脂肪组织特异性敲除MIF和DDT（或对照中的野生型）的小鼠将喂HFD的小鼠会遭受切开和散布的伤口，以表征脂肪组织中的MIF和DDT在伤口修复下的精确作用状况。我们预测，在我们的初步实验中观察到的MIF和DDT的逆作用也将适用于我们的体内模型。为了建立潜在的治疗策略，将在体内模型中研究重组MIF/DDT蛋白和/或MIF/DDT中和抗体的可行性。在第三部分中，通过评估肥胖和瘦肉个体的原代人脂肪组织样品的评估，体内研究将得到补充。为此，将使用脂肪组织样品和人成纤维细胞/角质形成细胞的体外共培养测定法检查MIF和DDT依赖性伤口愈合过程。最后，为了确定有助于MIF和DDT相互作用的受体，将进行机械研究，以解决CD74，CD44，CXCR2和/或CXCR4的作用以及相关的信号通路。