Browsing by Subject "APX3330"

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    APX3330 Promotes Neurorestorative Effects after Stroke in Type One Diabetic Rats
    (Buck Institute for Age Research, 2018-06-01) Yan, Tao; Venkat, Poornima; Chopp, Michael; Zacharek, Alex; Yu, Peng; Ning, Ruizhuo; Qiao, Xiaoxi; Kelley, Mark R.; Chen, Jieli; Medicine, School of Medicine
    APX3330 is a selective inhibitor of APE1/Ref-1 redox activity. In this study, we investigate the therapeutic effects and underlying mechanisms of APX3330 treatment in type one diabetes mellitus (T1DM) stroke rats. Adult male Wistar rats were induced with T1DM and subjected to transient middle cerebral artery occlusion (MCAo) and treated with either PBS or APX3330 (10mg/kg, oral gavage) starting at 24h after MCAo, and daily for 14 days. Rats were sacrificed at 14 days after MCAo and, blood brain barrier (BBB) permeability, ischemic lesion volume, immunohistochemistry, cell death assay, Western blot, real time PCR, and angiogenic ELISA array were performed. Compared to PBS treatment, APX3330 treatment of stroke in T1DM rats significantly improves neurological functional outcome, decreases lesion volume, and improves BBB integrity as well as decreases total vessel density and VEGF expression, while significantly increases arterial density in the ischemic border zone (IBZ). APX3330 significantly increases myelin density, oligodendrocyte number, oligodendrocyte progenitor cell number, synaptic protein expression, and induces M2 macrophage polarization in the IBZ of T1DM stroke rats. Compared to PBS treatment, APX3330 treatment significantly decreases plasminogen activator inhibitor type-1 (PAI-1), monocyte chemotactic protein-1 and matrix metalloproteinase 9 (MMP9) and receptor for advanced glycation endproducts expression in the ischemic brain of T1DM stroke rats. APX3330 treatment significantly decreases cell death and MMP9 and PAI-1 gene expression in cultured primary cortical neurons subjected to high glucose and oxygen glucose deprivation, compared to untreated control cells. APX3330 treatment increases M2 macrophage polarization and decreases inflammatory factor expression in the ischemic brain as well as promotes neuroprotective and neurorestorative effects after stroke in T1DM rats.
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    Chemically induced partial unfolding of the multifunctional apurinic/apyrimidinic endonuclease 1
    (Wiley, 2025) Rai, Ratan; Dawodu, Olabode I.; Meng, Jingwei; Johnson, Steven M.; Vilseck, Jonah Z.; Kelley, Mark R.; Ziarek, Joshua J.; Georgiadis, Millie M.; Biochemistry and Molecular Biology, School of Medicine
    Apurinic/apyrimidinic endonuclease I (APE1) acts as both an endonuclease and a redox factor to ensure cell survival. The two activities require different conformations of APE1. As an endonuclease, APE1 is fully folded. As a redox factor, APE1 must be partially unfolded to expose the buried residue Cys65, which reduces transcription factors including AP-1, NF-κB, and HIF-1α and thereby enables them to bind DNA. To determine a molecular basis for partial unfolding associated with APE1's redox activity, we characterized specific interactions of a known redox inhibitor APX3330 with APE1 through waterLOGSY and 1H-15N HSQC NMR approaches using ethanol and acetonitrile as co-solvents. We find that APX3330 binds to the endonuclease active site in both co-solvents and to a distant small pocket in acetonitrile. Prolonged exposure of APE1 with APX3330 in acetonitrile resulted in a time-dependent loss of 1H-15N HSQC chemical shifts (~35%), consistent with partial unfolding. Regions that are partially unfolded include adjacent N- and C-terminal beta strands within one of the two sheets comprising the core, which converge within the small binding pocket defined by the CSPs. Removal of APX3330 via dialysis resulted in a slow reappearance of the 1H-15N HSQC chemical shifts suggesting that the effect of APX3330 is reversible. APX3330 significantly decreases the melting temperature of APE1 but has no effect on endonuclease activity using a standard assay in either co-solvent. Our results provide insights on reversible partial unfolding of APE1 relevant for its redox function as well as the mechanism of redox inhibition by APX3330.