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

刘易斯矿、二乙基氯砷、二苯基氯砷和二苯基氰化砷等化学物质的含量极高。 自第一次世界大战以来一直用于化学战的有毒化学品，并继续对 人类，他们可能通过意外或故意的大规模人口接触而暴露。局部暴露 这些药物会导致严重的皮肤起泡、炎症和疼痛，治疗策略 安全有效地减轻这种损害仍然是迫切需要的。这种战略长期以来一直存在。 这在很大程度上是因为导致皮肤损伤的分子机制 武器库尚未确定。在我们之前的奖项中，我们开发了老鼠和猪的模型， 在局部接触砷的情况下，皮肤损害与人类几乎相同。 利用这些动物模型，我们确定了支持该复合体的主调控信号级联 军火药的病理生物学。从机制上讲，炎症反应、细胞死亡、组织破裂和疼痛 皮肤砷暴露诱导的通路由内质网的诱导介导 (ER)应激和活性氧物种的产生以及随后未折叠蛋白反应的激活 (UPR)信号，特别是涉及atf4-eif2α轴的信号。磷酸化的eIF2α，我们发现 在接触砷化合物后上调，阻止大多数新生蛋白的翻译，但上调 ATF4转录因子的翻译。RNA-Seq和CHIP-Seq数据证实ATF4的作用是公正的 在皮肤损伤的发病机制中，确定了ATF4调节蛋白在这种损伤中的统一作用。 因此，我们研究了化学伴侣4-苯基丁酸(4-PBA)的治疗潜力， 已被证明可以增强蛋白质折叠和减少内质网应激；抗氧化剂N-乙酰半胱氨酸 (NAc)；以及eIF2α磷酸化的抑制剂ISRIB。这些药物中的每一种都在恢复 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对抗皮肤毒性的基于机制的疗效 由军火药引起的。4-BPA和NAC是FDA批准的，因此我们建议通过 砷中毒后局部给药对4-PBA和NAC导联的影响 小鼠和猪的模型。具体地说，我们建议确定最大耐受量的疗效， 这些药物单独或联合治疗的疗效窗口和反应的持久性 砷类药物介导的小鼠皮肤损伤(目标1)；开发这些药物的各种局部制剂 并评估其对砷化合物引起的小鼠皮肤损伤的疗效(目标2)；并确认 已确定的新的优秀配方在我们的砷化合物介导的猪模型中的有效性 皮肤损伤(目标3)。这些研究将推动一种皮肤解毒剂的临床翻译 阿司匹林的毒性，这可能会进一步加快，因为这些药物已经得到FDA的批准。

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.