Taming IL-33 to Control Inflammation and Fibrosis

炎症和纤维化经常并存，并导致各种疾病 器官和组织。白介素33在炎症和纤维化中的总体作用已经被证实 已经建立，但这种监管的机制还没有完全了解。人们对此的关注有限 对于IL-33的前体-全长IL-33(FLIL33)-它是碱性和诱导表达的，主要存在于 在细胞核中，被认为调节炎症反应、伤口愈合和转录 独立于成熟的IL-33(MIL33)细胞因子的调节。未被研究的FLIL33需要更多 注意，因为它既是MIL33细胞因子的直接来源，也是一个独立的活性因子。 这些IL-33形式在应激下变得病理生理参与，但IL-33缺失的小鼠没有明显的 基础表型，提示IL-33耗竭是一种安全的治疗方法。我们的目标是形成 综合认识IL-33在炎性纤维化疾病中的治疗操作基础 MIL33的蛋白降解成熟和胞外释放，细胞内信号转导和功能， 和FlIL33蛋白库的蛋白水解性。我们收集了与分子控制有关的新数据。 IL-33的亚细胞定位、功能成熟和细胞外释放 在FLIL33分子内的区域，它比目前已知的跨越更多的N-末端 “传感域。”我们推测，这一片段可能以控制IL-33的激活和 细胞外释放。我们还发现，FLIL33的细胞内功能主要集中在Smad3上 以转化生长因子-β非依赖的方式进行磷酸化。我们假设这一过程是由 接头相关蛋白复合体2和靶向这一机制允许消除功能性 细胞内FLIL33的作用。我们最近还报道，Importin 5(IPO5)保护FLIL33不受 蛋白降解，推动了IPO5结合，细胞可穿透的诱骗多肽(S)将诱导 IPO5介导的FLIL33蛋白酶体降解保护作用的丧失。这种前瞻性疗法将会 耗尽FLIL33蛋白池，从而耗尽MIL33的来源，同时衰减 FLIL33的细胞内效应。这个项目的具体目标是：1)准确地绘制出 FLIL33的N-末端区域负责其核质定位，功能 成熟、细胞外释放和细胞内分子伴侣的选择性结合；2)定义 FIL33诱导转化生长因子β配体非依赖的Smad3磷酸化的分子机制 3)开发一种基于细胞通透性诱饵多肽的方法来耗尽细胞内的FLIL33，从而 耗尽MIL33的来源，同时减弱FLIL33的独立作用。评估 这种FLIL33耗竭的体内疗效。实现这些目标将提供对IL-33的新理解 并启动精确、创新的治疗模式的开发。

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.