KLF10, CD4+ T cells, and transplant arteriopathy

移植相关动脉病(TAA)是移植失败和受者死亡的主要原因。 他们在心脏移植后存活超过一年，尽管在免疫抑制方面取得了进展。其中之一 导致TAA的早期事件是外膜周围炎性细胞的浸润和激活，包括T细胞 细胞和巨噬细胞，随后形成弥漫的、同心的新生内膜，在其中平滑 肌肉细胞和白细胞堆积。T细胞效应器和T调节细胞在 调节同种异体移植物炎症平衡。有趣的是，与年龄相关的T细胞反应性减弱 有丝分裂原信号与同种异体移植物存活率的提高有关。事实上，流行病学研究表明， 年龄较大的受者比较年轻的受者减少了同种异体移植排斥反应的发生率。因此，确定因素 减少T细胞的激活可能会潜在地影响心脏移植的急性和慢性排斥反应。 Kruppel样因子是细胞生长、分化和激活的转录调节因子。我们确定了一个 KLF10是这个家族的成员，它在T细胞中高表达，并随着年龄的增长而增加。我们 研究发现，转化生长因子-β1反应因子KLF10调节T细胞效应器和T细胞的关键方面 调节细胞的功能。我们的初步研究发现KLF10在与年龄相关的T减少中扮演新的角色 TAA中的细胞激活。主要组织相容性复合体II类(MHC II)不匹配的同种异体心脏移植显示 当移植到野生型(WT)或KLF10-/-小鼠的年轻受者体内时，TAA和存活率相似。在……里面 相比之下，老年KLF10-/-受者的同种异体移植发展为加速的TAA，并增加了周围组织的蓄积。 外膜T细胞和巨噬细胞，促炎标志物(如干扰素-γ、肿瘤坏死因子-α、白介素6、 和MCP-1)，并降低存活率。老年KLF10-/-CD4+T细胞表现为Th1增强而T细胞减少 调节细胞(Treg)功能与CTLA-4表达减少有关，CTLA-4是一个免疫抑制分子 随着年龄的增长，T细胞的反应性。最后，同种异体心脏移植到年轻的KLF10-/-宿主 接受较老的KLF10-/-T细胞(与较年轻的KLF10-/-T细胞相比)显示TAA增加。机械学研究 证明KLF10是由microRNA miR-340靶向的，该microRNA与KLF10反向表达 增龄调节转化生长因子-β1/CTLA-4信号转导。这些观察结果为我们的中央 假设KLF10在衰老和TAA时是T细胞反应性的关键调节因子。在Aim1，我们 将探索KLF10在老年和年轻T细胞效应器中表达的上游调控机制。在Aim2， 我们将确定老年CD4-KLF10缺陷患者Th1和Treg细胞功能受损的分子基础 对TAA至关重要的小鼠。在Aim3中，我们将探索KLF10表达变化对T细胞反应性的影响 以及使用年轻和老年T细胞特异性KLF10-KO小鼠和抗miR-340疗法的实验性TAA。这个 这些研究的结果将为KLF10在T细胞生物学、衰老和 可作为调节T细胞反应性和TAA的新治疗策略的基础。

Transplant-associated arteriopathy (TAA) constitutes the major cause of graft failure and death in recipients who survive more than one year after cardiac transplantation, despite advances in immunosuppression. One of the early events leading to TAA is infiltration and activation of peri-adventitial inflammatory cells, including T cells and macrophages, which is followed by the formation of a diffuse, concentric neointima in which smooth muscle cells and leukocytes accumulate. Both T cell effectors and T regulatory cells play key roles in regulating the balance of allograft inflammation. Interestingly, age-related diminution of T cell responsiveness to mitogen signals have been linked to improved allograft survival. Indeed, epidemiological studies indicate that older recipients have reduced allograft rejection rates than younger recipients. As such, identification of factors that reduce activation of T cells could potentially impact both acute and chronic cardiac allograft rejection. Kruppel-like factors are transcriptional regulators of cell growth, differentiation, and activation. We identified a member of this family, KLF10, whose expression is highly expressed in T cells and increases with age. We identified that the TGF-b1-responsive factor, KLF10, regulates key aspects of both T cell effector and T regulatory cell function. Our preliminary studies uncover a novel role for KLF10 in age-related diminution of T cell activation in TAA. Major histocompatibility complex class II (MHC II)-mismatched cardiac allografts showed similar TAA and survival when transplanted into young recipients of either wild-type (WT) or KLF10-/- mice. In contrast, allografts in older KLF10-/- recipients developed accelerated TAA with increased accumulation of peri- adventitial T cells and macrophages, increased levels of pro-inflammatory markers (e.g. IFN-γ, TNF-a, IL-6, and MCP-1), and reduced survival. Older KLF10-/- CD4+ T cells exhibited enhanced Th1 and decreased T regulatory cell (Treg) function with reduced expression of CTLA-4, an immunosuppressive molecule implicated in T cell responsiveness with aging. Finally, cardiac allografts transplanted into younger KLF10-/- hosts receiving older KLF10-/- T cells (vs. younger KLF10-/- T cells) showed increased TAA. Mechanistic studies demonstrate that KLF10 is targeted by a microRNA, miR-340, that is inversely expressed with KLF10 with increasing age to regulate TGF-b1/CTLA-4 signaling. These observations provide the foundation for our central hypothesis that KLF10 serves as a critical regulator of T cell responsiveness with aging and TAA. In Aim1, we will explore the upstream mechanisms regulating KLF10 expression in old and young T cell effectors. In Aim2, we will determine the molecular basis for impaired Th1 and Treg cell function in older CD4-KLF10-deficient mice critical for TAA. In Aim3, we will explore the effect of altered KLF10 expression on T cell responsiveness and experimental TAA using young and old, T cell-specific KLF10-KO mice and anti-miR-340 therapeutics. The results of these studies will provide considerable insights regarding KLF10 function in T cell biology, aging, and may serve as the basis for novel therapeutic strategies to modulate T cell responsiveness and TAA.