Restoration of reduced nitric oxide bioavailability in Preeclampsia

PROJECT SUMMARY: Our lab in collaboration with Akkadian Therapeutics, Inc. (AKTX), have demonstrated the beneficial effects of the novel catalytic radical scavenger and nitric oxide donor/vasodilator, AKT-1005, in established in vitro and in vivo models of preeclampsia. However, the development of AKT-1005 itself as a drug candidate is limited by poor water solubility, instability and sub-optimal pharmacokinetic (PK) characteristics. To circumvent these issues, we proposes to synthesize, screen and test water-soluble prodrugs of AKT-1005 for solubility, stability, and release of AKT-1005 in vitro and in vivo, in order to select candidates for in vivo efficacy studies using an established rodent model of preeclampsia. Preeclampsia (PE) is a serious life-threatening complication during pregnancy, characterized by high maternal blood pressure, kidney dysfunction, proteinuria, and in severe cases, eclampsia and premature birth. It affects around 5% of pregnancies. While the etiology and pathogenesis of PE are elusive, placental ischemia/ hypoxia due to impaired placental development and subsequent release of anti-angiogenic factors (sFlt1 and sEng) are key components There is also compelling evidence for the involvement of oxidative stress, and concurrent mitochondrial alterations in PE. AKT-1005, is a novel cell-permeable redox-active agent incorporating two chemical active moieties: 1) an organic nitrate that releases nitric oxide in vivo, and 2) a pyrrolidine nitroxide that acts as a degradation catalyst of reactive oxygen species (ROS). We propose that these dual actions of AKT-1005 will (i) efficiently remove ROS responsible for the deleterious effects of oxidative stress in PE, (ii) reduce maternal blood pressure by the direct vasodilator effect of NO on blood vessel walls, and (iii) increase the bioavailability of NO, which is deficient in PE, but not other deleterious reactive nitrogen species (RNS, a side-reaction of NO with ROS). For selected prodrugs, systemic PK of parent prodrug, AKT-1005 and the major metabolite, HMP, will be determined in rodents following IV and IP dosing to the efficacy species (mouse) at doses found efficacious for AKT-1005 in previous studies. Cross-species metabolic comparisons for preferred prodrug(s) using isolated liver microsomes from mouse, rat, dog or human will also be performed. Selected prodrugs with the best attributes from the above will then be compared to AKT-1005 in an established/published murine model of PE. Time-pregnant mice will be subjected to adenovirus-sFLT1 (AdsFLT1), which reliably induces the main features of PE, and treated with prodrug or vehicle control 3 days later. Mice will be evaluated for blood pressure, renal function, histologic damage, 3-nitrotyrosine (3-NT) tissue immunoreactivity, plasma biomarkers (oxidative/nitrosative stress, sFlt-1 and VEGF, and pregnancy outcomes, etc.) The proposed studies will provide a rational foundation for advancement of an AKT-1005 prodrug, through lead optimization, to clinical candidate as a first-line early intervention in high-risk PE pregnancies.