Pharmacokinetic properties of Ogerin and its regulation of post-ischemia signaling in mice

Ogerin, a positive regulator of GPR68, reduces infarct volume and attenuates blood-brain barrier (BBB) leakage post transient middle cerebral artery occlusion (tMCAO). These data support the potential use of Ogerin for ischemic protection. For therapeutic interventions, tissue distribution, kinetics, and brain penetration are important characteristics for a compound. For these reasons, we performed liquid chromatography-mass spectrometry (LC-MS) analysis of Ogerin in mice. At 3 hours following intraperitoneal (IP) injection, liver exhibited highest level of Ogerin among all major organs assessed. We further analyzed time-dependent changes in Ogerin concentration in serum following intravenous delivery. Brain Ogerin level was ~140 ng/g at 2 hour and ~0.06ng/g at 24 hours. The brain-to-serum ratio of Ogerin was ~0.6 at 5 hr. To determine the effect of Ogerin on signaling, we collected samples 24 hours after tMCAO with or without Ogerin delivered and performed Western blotting. Consistent with the diminished level of Ogerin in brain at 24 hour, tMCAO increased similar changes in phosphorylation of PKA substrates and PKC substrates in vehicle- and Ogerin-treated groups. The pharmacokinetic data suggests that Ogerin is effective mainly during acute hours after injection. This finding generates important insights on the design of effective protocol for Ogerin delivery to potentiate GPR68 function in vivo.