Optimization of Novel Molecular Target-based Drugs for Arsenical Skin Injury

砷化物如路易氏剂、二乙基氯胂、二苯基氯胂和二苯基氰胂是极其有害的。 自第一次世界大战以来一直用于化学战的有毒化学品， 人类，可能通过意外或有意的大规模人群接触而接触。局部暴露 这些药物导致严重的皮肤起泡、炎症和疼痛， 仍然迫切需要安全和有效地减轻这种损害。这样的战略长期以来一直存在 在很大程度上是因为这些导致皮肤损伤的分子机制 没有发现砷化物。在我们之前的奖项中，我们开发了小鼠和猪模型， 在局部砷暴露后，会出现与人类几乎相同的皮肤损伤。 利用这些动物模型，我们确定了一个主要的调节信号级联支持的复杂 砷剂的病理生物学从机制上讲，炎症反应，细胞死亡，组织破坏和疼痛 皮肤砷暴露诱导的途径是通过诱导内质网介导的 (ER)应激和活性氧产生以及随后未折叠蛋白质应答的激活 (UPR)信号转导，特别是涉及ATF 4-eIF 2 α轴的信号转导。磷酸化eIF 2 α，我们发现它是 砷暴露后上调，阻断大多数新生蛋白的翻译，但上调 ATF 4转录因子的翻译。RNA-Seq和CHIP-Seq数据证实了ATF 4的无偏倚作用。 在皮肤损伤的发病机制，并确定了一个统一的作用，ATF 4调节蛋白在这种损伤。 因此，我们研究了化学伴侣4-苯基丁酸（4-PBA）的治疗潜力， 它已被证明可以增强蛋白质折叠并减少ER应激;抗氧化剂N-乙酰半胱氨酸 (NAC)和eIF 2 α磷酸化抑制剂ISRIB。这些药物中的每一种都对恢复 在我们的小鼠模型中，蛋白质翻译和减轻炎症、组织破坏和疼痛。因此我们 已经验证了这些小分子药物针对皮肤毒性的基于机制的功效 由砷引起的。4-BPA和NAC是FDA批准的，因此我们建议通过以下方式推进这些发现： 砷剂暴露后局部给药4-PBA和NAC先导物优化 鼠和猪模型。具体而言，我们建议确定最大耐受剂量的有效性， 这些药物单独和联合治疗的疗效窗口和反应持久性 砷介导的小鼠皮肤损伤（目的1）;开发这些药物的各种局部制剂 并评估其对砷介导的小鼠皮肤损伤的功效（目的2）;并确认 在我们的砷介导的猪模型中， 皮肤损伤（目的3）。这些研究将推动皮肤病解毒剂的临床转化， 砷剂的毒性，这可能会进一步加快，因为这些药物已经被FDA批准。

Arsenicals such as lewisite, diethylchloroarsine, diphenylchlorarsine, and diphenylcyanoarsine are extremely toxic chemicals that have been used in chemical warfare since World War I and continue to remain a threat to humans, who may be exposed through accidental or intentional mass population exposure. Topical exposure to these agents results in severe cutaneous blistering, inflammation and pain, and therapeutic strategies that safely and effectively attenuate this damage remain urgently needed. Such a strategy has long remained elusive in large part because the molecular mechanisms that underlie the cutaneous damage caused by arsenicals had not been identified. With our previous award, we developed murine and porcine models that, upon topical arsenical exposure, develop cutaneous lesions nearly identical to those that occur in humans. Employing these animal models, we identified a master regulatory signaling cascade underpinning the complex pathobiology of arsenicals. Mechanistically, the inflammatory responses, cell death, tissue disruption, and pain pathways induced by cutaneous arsenicals exposure are mediated by the induction of endoplasmic reticulum (ER) stress and reactive oxygen species generation and subsequent activation of unfolded protein response (UPR) signaling, particularly that involving the ATF4-eIF2α axis. Phosphorylated eIF2α, which we found to be upregulated after arsenicals exposure, blocks translation of most nascent proteins but upregulates the translation of the ATF4 transcription factor. RNA-Seq and CHIP-Seq data confirmed an unbiased role of ATF4 in the pathogenesis of the skin lesions and identified a unified role of ATF4-regulated proteins in this injury. Therefore, we investigated the therapeutic potential of the chemical chaperone 4-phenylbutyric acid (4-PBA), which has been shown to enhance protein folding and reduce ER stress; the antioxidant N-acetyl cysteine (NAC); and the inhibitor of eIF2α phosphorylation ISRIB. Each of these drugs was highly effective in restoring protein translation and diminishing inflammation, tissue disruption, and pain in our mouse model. Thus, we have validated the mechanism-based efficacy of these small molecule agents against cutaneous toxicity induced by arsenicals. 4-BPA and NAC are FDA approved, thus we propose to advance these findings through the lead optimization of 4-PBA and NAC delivered by topical administration after arsenicals exposure in our murine and porcine models. Specifically, we propose to determine the efficacy of the maximum tolerated dose, the window of efficacy, and the durability of response for these drugs, alone and in combination, in treating arsenicals-mediated cutaneous injury in mice (Aim 1); to develop various topical formulations of these drugs and assess the efficacy thereof against arsenicals-mediated cutaneous injury in mice (Aim 2); and to confirm the efficacy of the identified novel outstanding formulation in our porcine model of arsenicals-mediated cutaneous injury (Aim 3). These studies will drive the clinical translation of an antidote for the cutaneous toxicity of arsenicals, which may be further expedited as these drugs are already FDA approved.