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），可触发内源性细胞保护防御，从而阻断肺部炎症和急性肺损伤（ALI）。R-801由2个具有组织保护特性的部分共价融合而成：1）源自吡那地尔的线粒体-K +-ATP通道激活结构域，和2）作为广谱氧化还原分解催化剂的吡咯烷氮氧化物结构域（羟甲基乙酰基，“HMP”）。R-801比经典的K+-ATP通道开放剂（例如吡那地尔）更有效，并且没有肌膜K+-ATP通道激活的经典副作用（高血糖症、心室颤动、低血压）。我们的总体假设是R-801将阻断新生儿呼吸窘迫综合征向支气管肺发育不良（BPD）的进展。在由Cl 2吸入诱导的低盐氧化还原肺损伤的小鼠模型中，R-801复苏减少了组织学损伤，减少了中性粒细胞（PMN）浸润，阻断了NF-kB的核转位，并减少了抗炎细胞质蛋白IkB的降解（p<0.01）。R-801不激活肌膜K+-ATP通道，如其在大鼠中未能诱导低血压、高血糖症或心室颤动所示。我们现在试图建立R-801减轻新生大鼠BPD高氧模型中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，进行一项前瞻性剂量递增研究，其中通过使2天大的大鼠幼崽接受10天高氧诱导肺损伤。将假对照（无高氧，无R-801）与通过腹膜内（IP）途径施用3周的药物对照（R-801，无高氧）、R-801（3、10、30 mg/kg qd）和媒介物对照（D5 W）进行比较，在该模型系统中，该时期的特征在于进行性肺纤维化、肺动脉高压（PAH）和肺泡发育不良。将分析尸检时采集的肺组织的肺血管结构和生长、肺泡化、脂质过氧化（丙二醛）、谷胱甘肽（GSH/GSSG比值）、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Mason三色染色）、R- 801水平和促炎基因的蛋白表达，包括嗜酸性粒细胞趋化因子、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、MIP-1、MIP-1、MIP-2、RANTES、TNF-1和VEGF。还将分析心脏的PAH证据（如右心室肥大所证明）。进展到II期NIH SBIR将需要R-801剂量依赖性治疗证明（p<0.05双尾）：肺泡密度增加> 30%，肺纤维化、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型谷胱甘肽。

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.