A Bifunctional Katp Channel Activator and Redox Mimetic for BPD

描述（由申请人提供）：Radikal Therapeutics正在开发一种用于新生儿早产的新型小分子疗法（R-801），该疗法可触发内源性细胞保护性防御，从而阻断肺部炎症和急性肺损伤（ALI）。R-801是由2个具有组织保护特性的共价融合形成的：1)来自pinacidil的mito-K+-ATP通道激活域，以及2)作为广谱氧化还原分解催化剂的吡咯烷基氮氧化物域（羟甲基proxyl，“HMP”）。R-801比经典的K+-ATP通道打开剂（如pinacidil）更有效，并且没有肌层K+-ATP通道激活的经典副作用（高血糖、心室颤动、低血压）。我们的主要假设是R-801可以预防新生儿呼吸窘迫综合征向支气管肺发育不良（BPD）的发展。在Cl2吸入引起的小鼠次halous氧化还原肺损伤模型中，R-801复苏可减轻组织损伤，减少中性粒细胞（PMN）浸润，阻断NF-kB的核易位，减少抗炎细胞质蛋白IkB¿的降解（p<0.01）。R-801不激活肌层K+-ATP通道，其在大鼠中不能诱导低血压、高血糖或心室颤动。我们现在试图建立R-801在新生儿大鼠BPD高氧模型中减弱肺血管和肺泡结构的变化。RTX将与Abman实验室（科罗拉多大学）合作，开展一项前瞻性剂量递增研究，将2天大的大鼠幼鼠置于高氧环境中10天，诱导肺损伤。假对照组（无高氧，无R-801）将与药物对照组（R-801，无高氧）、R-801（3、10、30 mg/kg qd）和载体对照组（D5W）进行比较，腹腔（IP）给药3周，该模型系统的特征是进行性肺纤维化、肺动脉高压（PAH）和低肺泡化。尸检时采集的肺组织将分析肺血管结构和生长、肺泡形成、脂质过氧化（丙二醛）、谷胱甘肽（GSH/GSSG比率）、过氧亚硝酸盐形成（3-硝基酪氨酸）、聚（adp核糖）形成、纤维化（胶原蛋白的Mason三色染色）、R- 801水平和促炎基因的蛋白表达，包括eotaxin、G-CSF、GM-CSF、IFN-？、IL-1¿、IL-2、il - 4、IL-3、IL-5、IL-6、IL-7、IL-9、IL-10、IL-12 （p40）、IL-12 （p70）、IL-13、IL-15、IL-17、IP-10、KC、LIF、LIX、MCP-1、M-CSF、MIG、MIP-1¿、MIP-1¿、MIP-2、RANTES、TNF-¿和VEGF。还将分析心脏是否存在多环芳烃（如右心室肥厚）。进展到2期NIH SBIR将需要R-801治疗的剂量依赖性证明（在p<0.05双尾）相对于载体对照：>肺泡密度增加30%，>肺纤维化减少30%，肺小动脉平滑肌肥大，右心室质量，PMN浸润，脂质过氧化，过氧亚硝酸盐和聚（adp -核糖）形成，促炎基因表达和氧化谷胱甘肽。

DESCRIPTION (provided by applicant): Radikal Therapeutics is developing a novel small molecule therapy (R-801) for neonatal prematurity that triggers an endogenous cytoprotective defense and thereby blocks pulmonary inflammation and acute lung injury (ALI). R-801 is formed from the covalent fusion of 2 moieties with demonstrated tissue protective properties: 1) a mito-K+-ATP channel activating domain derived from pinacidil, and 2) a pyrrolidine nitroxide domain (hydroxymethylproxyl, "HMP") that acts as a broad-spectrum redox decomposition catalyst. R-801 is more potent than classic K+-ATP channel openers (e.g. pinacidil) and is free of the classic side-effects of sarcolemmal K+-ATP channel activation (hyperglycemia, ventricular fibrillation, hypotension). Our overarching hypothesis is that R-801 will prophylactically block th progression of neonatal respiratory distress syndrome to bronchopulmonary dysplasia (BPD). In a murine model of hypohalous redox lung injury induced by Cl2 inhalation, R-801 resuscitation reduced histologic injury, diminished neutrophil (PMN) infiltration, blocked nuclear translocation of NF-kB, and diminished the degradation of the anti-inflammatory cytoplasmic protein IkB¿ (p<0.01). R-801 does not activate the sarcolemmal K+-ATP channel, as shown by its failure in rats to induce hypotension, hyperglycemia, or ventricular fibrillation. We now seek to establish that R-801 attenuates changes of pulmonary vascular and alveolar structure in a hyperoxic model of BPD in neonatal rats. In conjunction with the Abman laboratory (University of Colorado), RTX will carry out a prospective dose-escalation study wherein lung injury is induced by subjecting 2-day old rat pups to hyperoxia for 10 days. A sham control (no hyperoxia, no R-801) will be compared to a drug control (R-801, no hyperoxia), R-801 (3, 10, 30 mg/kg qd), and vehicle control (D5W) administered by an intraperitoneal (IP) route for 3 weeks, a period characterized in this model system by progressive lung fibrosis, pulmonary arterial hypertension (PAH), and hypoalveolarization. Lung tissue taken at necropsy will be analyzed for pulmonary vascular structure and growth, alveolarization, lipid peroxidation (malondialdehyde), glutathione (GSH/GSSG ratio), peroxynitrite formation (3-nitrotyrosine), poly(ADP-ribose) formation, fibrosis (Mason Trichrome staining for collagen), R- 801 levels, and the protein expression of pro-inflammatory genes, including eotaxin, G-CSF, GM-CSF, IFN-?, IL-1¿, IL-2, IL4, IL-3, IL-5, IL-6, IL-7, IL-9, IL-10, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17, IP-10, KC, LIF, LIX, MCP-1, M-CSF, MIG, MIP-1¿, MIP-1¿, MIP-2, RANTES, TNF-¿, and VEGF. The heart will also be analyzed for evidence of PAH (as evidenced by right ventricular hypertrophy). Progression to the Phase 2 NIH SBIR will require that treatment with R-801 dose-dependently demonstrates (at p<0.05 2-tailed) relative to the vehicle control: > 30% increase in alveolar density, and > 30% reductions in pulmonary fibrosis, pulmonary arteriolar smooth muscle hypertrophy, right ventricular mass, PMN infiltration, lipid peroxidation, peroxynitrite and poly(ADP-ribose) formation, pro-inflammatory gene expression, and oxidized glutathione.