Molecular mechanisms of squamous metaplasia in dry eye

描述：鳞状化生发生在严重的眼表疾病中(例如，Stevens-Johnson综合征(SJS)、眼瘢痕性类天疱疮(OCP)和干燥综合征(SS))，这些疾病是当今眼科护理人员面临的一些最具挑战性的临床病例。根据定义，鳞状化生是一种表型变化，即上皮细胞开始合成特殊的鳞状细胞特异性蛋白，如富含脯氨酸的小蛋白1B(SPRR1B)，形成角化的包膜(角质化)。虽然SPRR1B的表达是皮肤等外部鳞状组织的正常特征，但在眼表等粘膜组织中存在时，它是一种病理迹象。人们对触发鳞状化生的分子机制知之甚少，抑制它的努力到目前为止还没有成功。有趣的是，鳞状化生的存在与眼表的促炎活性广泛相关，但从浸润性细胞释放的促炎细胞因子实际上促进鳞状化生的可能性从未被研究过。在此基础上，我们建议检验炎症介质是病理性角化的关键调节因子的假说。我们的初步数据支持这种可能性，并确认IL-1β是这一过程中的关键参与者。在特定的目标1中，我们将验证SPRR1B作为人类鳞状化生的临床标志物的使用。与加州大学旧金山分校Sjogren的国际合作临床联盟(SICCA)小组合作，使用从SS患者身上收集的印象细胞学和泪液样本，SPRR1B的表达将与眼表炎症介质的水平相关。在特定的目标2中，我们将研究IL-1β在缺乏自身免疫调节(AIRE)基因的SS小鼠模型中作为鳞状化生的主要诱导者的作用。在竞争性抑制和基因消融IL-1信号之后，将对AIRE缺陷小鼠的鳞状化生进行评估。然后，我们将尝试通过局部应用IL-1β来重建鳞状细胞表型。在具体目标3中，我们将使用SPRR1B来确定介导IL-1β诱导鳞状上皮化生的基因元件。这将包括传统的荧光素酶报告分析和凝胶迁移率改变分析，以确定SPRR1B启动子和结合的转录因子上的IL-1β反应元件。这种翻译和分子方法的结合将提高我们对鳞状化生发病机制的理解，并将为开发新的治疗方法来预防人类患者的病理性角化提供可能性。

DESCRIPTION: Squamous metaplasia occurs in severe ocular surfaces diseases (e.g., Stevens-Johnson syndrome (SJS), ocular cicatricial pemphigoid (OCP) and Sjogren's syndrome (SS)) that present some of the most challenging clinical cases facing eye care providers today. By definition, squamous metaplasia is a phenotypic change whereby epithelial cells initiate synthesis of specialized, squamous cell-specific proteins like small proline- rich protein 1B (SPRR1B) to form the cornified envelope (keratinization). While SPRR1B expression is a normal feature of external squamous tissues like the skin, it is a sign of pathology when present in mucosal tissues such as the ocular surface. Very little is known about the molecular mechanisms triggering squamous metaplasia and efforts to inhibit it have so far been unsuccessful. Interestingly, the presence of squamous metaplasia has been extensively correlated with proinflammatory activity of the ocular surface, but the possibility that proinflammatory cytokines released from infiltrating cells actually contribute to squamous metaplasia has never been examined. Based on this, we propose to examine the hypothesis that inflammatory mediators are key regulators of pathological keratinization. Our preliminary data support this possibility and identify IL-1beta as a key participant in this process. In Specific Aim 1, we will validate the use of SPRR1B as a clinical marker for squamous metaplasia in human subjects. SPRR1B expression will be correlated with the levels of inflammatory mediators at the ocular surface using impression cytology and tear samples collected from human patients with SS in collaboration with the Sjogren's International Collaborative Clinical Alliance (SICCA) group at UCSF. In Specific Aim 2, we will examine the role of IL-1beta as a major inducer of squamous metaplasia in a murine model of SS that is lacking the autoimmune regulator (AIRE) gene. Squamous metaplasia in AIRE-deficient mice will be assessed following competitive inhibition and genetic ablation of IL-1 signaling. We will then attempt to reestablish the squamous phenotype through topical application of IL-1beta. In Specific Aim 3, we will use SPRR1B to define gene elements mediating the induction of squamous metaplasia by IL-1beta. This will include traditional luciferase reporter assays and electrophoretic mobility shift assays to identify IL-1beta -response elements on the SPRR1B promoter and bound transcription factors. This combination of translational and molecular approaches will improve our understanding of the pathogenesis of squamous metaplasia and will open the possibility of developing novel treatments to prevent pathological keratinization in human patients.