Altered gamma delta T cell-keratinocyte interplay in the skin of diabetic mice

描述(申请人提供)：糖尿病足溃疡是一种常见于1型和2型糖尿病的衰弱并发症。迫切需要进行研究，确定糖尿病如何影响皮肤等非常容易受到损害的上皮组织中的细胞与细胞之间的相互作用。小鼠皮肤34T细胞，又称树突状表皮T细胞(DETC)，在皮肤动态平衡和创面修复中发挥作用。激活的角质形成细胞和应答的DETC之间的复杂串扰是由受体表达和生长因子产生介导的。我们的长期目标是确定糖尿病如何对免疫系统产生负面影响，并特别关注上皮T细胞群。这项应用将研究2型糖尿病如何改变DETC的存活率和功能，以及这种改变是否可以在治疗上逆转。工作假设是，DETC被胰岛素抵抗的角质形成细胞慢性刺激，导致DETC凋亡，最终无能。这一假设是基于初步结果，初步结果表明，在糖尿病皮肤中，DETC和角质形成细胞之间的正常串扰发生了改变。提出了以下具体目标：(1)确定2型糖尿病小鼠皮肤中DETC减少的原因，(2)确定角质形成细胞-DETC相互作用对糖尿病小鼠DETC功能障碍的贡献，以及(3)恢复糖尿病小鼠的DETC数量和功能。一旦我们确定DETC在糖尿病小鼠皮肤中是如何被抑制的，我们可能就能够恢复激活并开发它们的伤口愈合潜力。这些特定的目标将通过检查糖尿病皮肤中DETC的数量如何下降以及剩余的DETC是否在功能上无反应或无能来测试。无能会影响DETC在正常内稳态和伤口修复过程中的增殖和分泌因子的能力。在2型糖尿病期间，将检测DETC和角质形成细胞之间的相互作用，以确定角质形成细胞是否在抑制DETC中发挥作用。最后，将采取两种方法来恢复糖尿病小鼠的正常DETC激活。首先，DETC将通过用IL-2细胞因子疗法治疗小鼠来恢复DETC的激活。第二种方法包括改善胰岛素反应性，使角质形成细胞正常化，这可能间接恢复DETC功能。明确2型糖尿病对T细胞-上皮细胞相互作用的影响将极大地促进我们对这种情况如何导致免疫功能障碍的了解。这将导致开发新的策略来促进伤口修复和糖尿病的其他并发症。与公共健康相关：皮肤中的T细胞受到受损角质形成细胞的刺激，产生对伤口修复至关重要的生长因子。慢性无法愈合的伤口是糖尿病的一种严重并发症，具有毁灭性的后果。我们研究的目标是确定2型糖尿病如何改变T细胞在上皮细胞中的存活和功能，以及这一过程是否可以通过治疗逆转以促进慢性伤口的愈合。

DESCRIPTION (provided by applicant): Diabetic foot ulcerations are a debilitating complication common to type 1 and 2 diabetes. There is a critical need for studies that identify how diabetes affects cell-cell interactions in epithelial tissues such as the skin, which are very susceptible to damage. Murine skin 34 T cells, also known as dendritic epidermal T cells (DETC), play roles in skin homeostasis and wound repair. The complex cross-talk between the activating keratinocytes and the responding DETC is mediated by receptor expression and growth factor production. Our long-term goal is to determine how diabetes negatively impacts the immune system, with a special focus on epithelial T cell populations. This application will examine how type 2 diabetes alters the survival and function of DETC and whether this can be reversed therapeutically. The working hypothesis is that DETC are chronically stimulated by insulin resistant keratinocytes rendering the DETC apoptotic and eventually anergic. This hypothesis is based on preliminary results, which show that the normal cross-talk between DETC and keratinocytes is altered in diabetic skin. The following specific aims are proposed: (1) determine why DETC are diminished in the skin of mice with type 2 diabetes, (2) identify the contribution of keratinocyte-DETC cross-talk to DETC dysfunction in diabetic mice, and (3) restore DETC numbers and function in diabetic mice. Once we identify how DETC are suppressed in diabetic mouse skin we may be able to restore activation and exploit their wound healing potential. These specific aims will be tested by examining how DETC numbers decline in diabetic skin and whether the remaining DETC are rendered functionally unresponsive or anergic. Anergy would affect the ability of DETC to proliferate and secrete factors during normal homeostasis and wound repair. Cross-talk between DETC and keratinocytes will be examined during type 2 diabetes to identify whether keratinocytes play a role in the suppression of DETC. Finally, two approaches will be taken to restore normal DETC activation in diabetic mice. First, the DETC will be targeted by treating mice with IL-2 cytokine therapy to restore DETC activation. The second approach involves improving insulin responsiveness to allow the keratinocytes to normalize, which may indirectly restore DETC function. Defining the impact of type 2 diabetes on T cell- epithelial cell interactions will greatly advance our knowledge of how this condition may lead to immune dysfunction. This will lead to the development of novel strategies to promote wound repair and other complications of diabetes. PUBLIC HEALTH RELEVANCE: T cells in the skin are stimulated by damaged keratinocytes to produce growth factors important for wound repair. Chronic non-healing wounds are a serious complication of diabetes with devastating consequences. The goal of our research is to determine how type 2 diabetes alters T cell survival and function in the epithelia and whether this process can be reversed therapeutically to promote healing of chronic wounds.