Taming IL-33 to Control Inflammation and Fibrosis

炎症和纤维化通常共同发生，并导致各种各样的疾病。 器官和组织白细胞介素（IL）-33在炎症和纤维化中的总体作用已经被证实。 虽然已经建立，但这种监管的机制尚未得到充分理解。注意力有限 IL-33的转录因子-全长IL-33（FLIL 33）-其是基础和诱导表达的，主要存在于 位于细胞核中，被认为可以调节炎症反应、伤口愈合和转录 独立于成熟IL-33（MIL 33）细胞因子的调节。未充分研究的FLIL 33需要更多 这是因为它既是MIL 33细胞因子的直接来源，也是一种独立的活性因子。 这些IL-33形式在应激下变得病理生理性参与，但IL-33缺失小鼠没有明显的 基础表型，表明IL-33耗竭是一种安全的治疗方法。我们的目标是建立 通过综合理解IL-33在炎性纤维化疾病中的治疗操作的基础 MIL 33的蛋白水解成熟和细胞外释放，FIL 33的细胞内信号传导和功能， 和FLIL 33蛋白库的蛋白水解稳定性。我们积累了新的数据， IL-33的亚细胞定位、功能成熟和细胞外释放， FLIL 33分子内的区域，其比目前已知的FLIL 33分子基本上跨越更多的N-末端。 “感应领域”我们假设该片段可能是控制IL-33激活的靶点， 细胞外释放我们还发现FLIL 33的细胞内功能以Smad 3为中心 在一些实施方案中，TGF-β以非TGF-β依赖性方式磷酸化。我们假设这一过程是由 衔接子相关蛋白复合物2，并且靶向该机制允许功能性的 细胞内FLIL 33的作用。我们最近还报道，输入蛋白5（IPO 5）保护FLIL 33免受 蛋白水解降解，推动了IPO 5结合的细胞可渗透诱饵肽将诱导 IPO 5介导的FLIL 33保护免于蛋白酶体降解的丧失。这种前瞻性治疗将 耗尽FLIL 33蛋白库，从而耗尽MIL 33的来源，同时减弱 FLIL 33的细胞内效应。该项目的具体目标是：1）精确映射 FLIL 33的N-末端区域负责其核相对于细胞质定位，功能性 成熟，细胞外释放和细胞内分子伴侣的选择性结合; 2）定义 负责FLIL 33诱导的TGF-β配体非依赖性Smad 3磷酸化的分子机制; 和3）开发基于细胞可渗透的诱饵肽的方法以耗尽细胞内FLIL 33，从而 耗尽MIL 33的源，同时减弱FLIL 33的独立影响。评价 这种FLIL 33消耗的体内功效。实现这些目标将为IL-33提供新的认识 病理生物学，并启动精确的，创新的治疗方式的发展。

Inflammation and fibrosis often co-occur and contribute to a remarkably broad variety of diseases of every organ and tissue. The overall role of interleukin (IL)-33 in inflammation and fibrosis has already been established, but the mechanisms of such regulation are not fully understood. Limited attention has been paid to the IL-33 precursor—full-length IL-33 (FLIL33)—which is basally and inducibly expressed, resides mostly in the cell nucleus, and is thought to regulate inflammatory responses, wound healing, and transcriptional regulation independently of the mature IL-33 (MIL33) cytokine. The understudied FLIL33 requires more attention, because it is both the immediate source of the MIL33 cytokine and an independently active factor. These IL-33 forms become pathophysiologically engaged under stress, but IL-33-null mice have no noticeable basal phenotype, suggesting that IL-33 depletion is a safe therapeutic approach. Our objective is to form the basis for therapeutic manipulation of IL-33 in inflammatory fibrotic diseases through integrated understanding of proteolytic maturation and extracellular release of MIL33, intracellular signaling and functioning of FLIL33, and proteolytic stability of the FLIL33 protein pool. We amassed new data related to the molecular control of IL-33 subcellular localization, functional maturation, and extracellular release through a previously unknown region within the FLIL33 molecule, which spans substantially more of the N-terminus than the currently known “sensor domain.” We hypothesize that this segment may be targeted to control IL-33 activation and extracellular release. We also discovered that the intracellular function of FLIL33 is centered on Smad3 phosphorylation in a TGF-beta-independent fashion. We hypothesize that this process is mediated by the adaptor-related protein complex 2 and that targeting this mechanism allows for abrogation of the functional effects of intracellular FLIL33. We also recently reported that importin 5 (IPO5) protects FLIL33 from proteolytic degradation, driving the hypothesis that IPO5-binding, cell-permeable decoy peptide(s) will induce the loss of IPO5-mediated protection of FLIL33 from proteasomal degradation. This prospective therapy will deplete the FLIL33 protein pool, thus exhausting the source of MIL33 and simultaneously attenuating the intracellular effects ofFLIL33. The Specific Aims of this project are to: 1) Precisely map the segments in the N-terminal region of FLIL33 that are responsible for its nuclear-versus-cytoplasmic localization, functional maturation, extracellular release, and selective binding of intracellular molecular partners; 2) Define the molecular mechanism responsible for FLIL33-induced, TGF-βligand-independent phosphorylation of Smad3; and 3) Develop a cell-permeable decoy peptide-based approach to deplete intracellular FLIL33, thereby exhausting the source of MIL33 and simultaneously attenuating the independent effects of FLIL33. Evaluate the in vivo efficacy of such FLIL33 depletion. Achieving these goals will offer new understanding of IL-33 pathobiology and initiate the development of precise, innovative therapeutic modalities.