Nuclear poly(ADP-ribose) activity is a therapeutic target in amyotrophic lateral sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is a devastating and fatal motor neuron disease. Diagnosis typically occurs in the fifth decade of life and the disease progresses rapidly leading to death within ~ 2–5 years of symptomatic onset. There is no cure, and the few available treatments offer only a modest extension in patient survival. A protein central to ALS is the nuclear RNA/DNA-binding protein, TDP-43. In > 95% of ALS patients, TDP-43 is cleared from the nucleus and forms phosphorylated protein aggregates in the cytoplasm of affected neurons and glia. We recently defined that poly(ADP-ribose) (PAR) activity regulates TDP-43-associated toxicity. PAR is a posttranslational modification that is attached to target proteins by PAR polymerases (PARPs). PARP-1 and PARP-2 are the major enzymes that are active in the nucleus. Here, we uncovered that the motor neurons of the ALS spinal cord were associated with elevated nuclear PAR, suggesting elevated PARP activity. Veliparib, a small-molecule inhibitor of nuclear PARP-1/2, mitigated the formation of cytoplasmic TDP-43 aggregates in mammalian cells. In primary spinal-cord cultures from rat, Veliparib also inhibited TDP-43-associated neuronal death. These studies uncover that PAR activity is misregulated in the ALS spinal cord, and a small-molecular inhibitor of PARP-1/2 activity may have therapeutic potential in the treatment of ALS and related disorders associated with abnormal TDP-43 homeostasis

Kainic acid-induced seizure activity alters the mRNA expression and G-protein activation of the opioid/nociceptin receptors in the rat brain cortex

The opioid/nociceptin receptors are involved in many neurological disorders such as Alzheimer's disease, Parkinson's disease and epilepsy. Kainic acid (KA) is an analog of the excitatory amino acid transmitter glutamate and the systemic administration of KA induces status epilepticus (SE) in rodents. In this study, we examined the alterations in the G-protein activity and the gene expression levels of mu, kappa, delta opioid and nociceptin receptors (MOPr, KOPr, DOPr and NOPr) as well as PNOC, the precursor polypeptide of nociceptin-OFQ (N/OFQ) in KA-induced seizures in the rat brain cortex. KA was used to create seizures with the dose of 10 mg/kg body weight i.p. Following the KA administration, the rats were observed for 3 h to assess seizure activity. Seizures occurred approximately 45 min after the KA injection. Only rats exhibiting full limbic seizures, forelimb clonus with rearing, were used in this study. All animals were decapitated 4 h after the administration of KA. Our [S-35]GTP gamma S binding results showed that there was a significant difference in both the affinity and efficacy particularly one of NOPr stimulation following KA treatment. Slight, but significant increase was observed for MOPr. Moreover PNOC, NOPr and MOPr mRNA levels were increased by KA treatment but there were no significant changes in the levels of DOPr and KOPr mRNAs. These results show that the activities of opioid/nociceptin receptors can be modified by KA-treatment, and MOPr, PNOC and NOPr are the most responsive to KA-induced seizures in the rat brain cortex. (C) 2013 Elsevier B.V. All rights reserved

Nicotinamide treatment reduces the levels of oxidative stress, apoptosis, and PARP-1 activity in Aß(1-42)-induced rat model of Alzheimer's disease

PubMed ID: 24151909The underlying mechanisms of Alzheimer's Disease (AD) are still unclear. It is suggested that poly(ADP-ribose) polymerase-1 (PARP-1) overactivation can cause neuroinflammation and cell death. In this study we searched the effects of nicotinamide (NA), endogenous PARP-1 inhibitor, on oxidative stress, apoptosis, and the regulation of PARP-1 and nuclear factor kappa B (NF-?B) in amyloid beta peptide (1-42) (Aß(1-42))-induced neurodegeneration. Sprague-Dawley rats were divided into four groups as control, Aß(1-42), Aß(1-42) + NA(100 and 500 mg/kg). All groups were stereotaxically injected bilaterally into the hippocampus with Aß(1-42) or saline. After surgery NA administrations were made intraperitoneally (ip) for 7 days. In order to investigate the effects of Aß(1-42) and NA, protein carbonyls, lipid peroxidation, reactive oxygen species (ROS) production, glutathione (GSH) levels, activities of antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), mitochondrial function, mRNA and protein levels of PARP-1, NF-?B, p53, Bax, and Bcl-2 were measured in specific brain regions such as cortex and hippocampus. Aß(1-42) treatment only increased the oxidative stress parameters and caused decline in antioxidant enzyme activities, mitochondrial function, and GSH levels. Also, overexpression of PARP-1, NF-?B, p53, Bax, and the decreased levels of Bcl-2 were observed in Aß(1-42)-treated group. NA treatments against Aß(1-42)-upregulated Bcl-2 and downregulated PARP-1, NF-?B, p53, and Bax levels. NA treatments also decreased the oxidative stress parameters and elevated antioxidant enzyme activities, GSH levels, and mitochondrial function against Aß(1-42) treatment. These data suggest that NA may have a therapeutic potential in neurodegenerative processes due to the decreased levels of oxidative stress, apoptosis, and PARP-1 activity. © 2013 Informa UK, Ltd.Foundation for the National Institutes of Health Scientific Research Foundation of Beijing Normal University: 10/ECZ/011Male Sprague – Dawley rats (200 – 250 g) were used for present study. Animals were obtained from the Experimental Research Center of Ege University and maintained on a 12:12 h light – dark cycle and given continuous access to food and water. All procedures were approved by the Utilization Committee of Ege University (Ref. No: 2010-35) and confirmed by the National Institutes of Health Guide for the Care and Use of Laboratory Animals. All efforts were made to minimize animal suffering and to reduce the number of animals used. -- The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper. This study was supported by the Ege University Scientific Research Foundation (Project No: 10/ECZ/011). E.T. acknowledged a scholarship for postgraduate students obtained from Turkish Scientific and Technological Council (TUBITAK). The authors also acknowledged the Pharmaceutical Sciences Research Centre (FABAL) of Ege University, Faculty of Pharmacy for equipmental support in the determination of protein expressions. -

Nicotinamide treatment reduces the levels of oxidative stress, apoptosis, and PARP-1 activity in A beta (1-42)-induced rat model of Alzheimer's disease

WOS: 000329408800005PubMed ID: 24151909The underlying mechanisms of Alzheimer's Disease (AD) are still unclear. It is suggested that poly(ADP-ribose) polymerase-1(PARP-1) overactivation can cause neuroinflammation and cell death. In this study we searched the effects of nicotinamide(NA), endogenous PARP-1 inhibitor, on oxidative stress, apoptosis, and the regulation of PARP-1 and nuclear factor kappa B(NF-kappa B) in amyloid beta peptide(1-42)(A beta(1-42))-induced neurodegeneration. Sprague-Dawley rats were divided into four groups as control, A beta(1-42), A beta(1-42) + NA(100 and 500 mg/kg). All groups were stereotaxically injected bilaterally into the hippocampus with A beta(1-42) or saline. After surgery NA administrations were made intraperitoneally(ip) for 7 days. In order to investigate the effects of A beta(1-42) and NA, protein carbonyls, lipid peroxidation, reactive oxygen species(ROS) production, glutathione(GSH) levels, activities of antioxidant enzymes(catalase, superoxide dismutase, glutathione peroxidase), mitochondrial function, mRNA and protein levels of PARP-1, NF-kappa B, p53, Bax, and Bcl-2 were measured in specific brain regions such as cortex and hippocampus. A beta(1-42) treatment only increased the oxidative stress parameters and caused decline in antioxidant enzyme activities, mitochondrial function, and GSH levels. Also, overexpression of PARP-1, NF-kappa B, p53, Bax, and the decreased levels of Bcl-2 were observed in A beta(1-42)-treated group. NA treatments against A beta(1-42)-upregulated Bcl-2 and downregulated PARP-1, NF-kappa B, p53, and Bax levels. NA treatments also decreased the oxidative stress parameters and elevated antioxidant enzyme activities, GSH levels, and mitochondrial function against A beta(1-42) treatment. These data suggest that NA may have a therapeutic potential in neurodegenerative processes due to the decreased levels of oxidative stress, apoptosis, and PARP-1 activity.Ege University Scientific Research FoundationEge University [10/ECZ/011]; Turkish Scientifi c and Technological Council (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)This study was supported by the Ege University Scientific Research Foundation (Project No: 10/ECZ/011). E.T. acknowledged a scholarship for postgraduate students obtained from Turkish Scientifi c and Technological Council (TUBITAK). The authors also acknowledged the Pharmaceutical Sciences Research Centre (FABAL) of Ege University, Faculty of Pharmacy for equipmental support in the determination of protein expressions

Ex vivo protective effects of nicotinamide and 3-aminobenzamide on rat synaptosomes treated with Aß(1-42)

PubMed ID: 25111857Alzheimer's disease (AD) is the most common form of dementia and is characterized by the presence of senile plaques and neurofibrillary tangles, along with synaptic loss. The underlying mechanisms of AD are not clarified yet, but oxidative stress and mitochondrial dysfunction are important factors. Overactivation of poly(adenosine diphosphate ribose) polymerase-1 (PARP-1) enzyme has been known to cause neuroinflammation and cell death in neurodegenerative processes. The aim of the present study was to investigate the protective effects of the PARP-1 inhibitors, 3-aminobenzamide (3-AB) and nicotinamide (NA), against amyloid ß peptide (1-42) (Aß(1-42))-induced oxidative damage and mitochondrial reduction capacity on isolated synaptosomes. Rats were injected intraperitoneally with 3-AB (30-100mgkg-1), NA (100-500mgkg-1) or with saline for 7days. Synaptosomes were incubated with 10-30µM Aß(1-42) or saline for 6h at 37°C. Ex vivo Aß(1-42) treatment significantly induced oxidative stress and mitochondrial dysfunction in synaptosomes of the saline group, while synaptosomes of 3-AB and NA groups showed significant decreases in lipid peroxidation, reactive oxygen species production and protein oxidation. Moreover, both NA and 3-AB were able to improve the mitochondrial reduction capacity against Aß(1-42). These data suggest that NA and 3-AB may have protective effects in neurodegenerative processes because of the reduced levels of oxidative stress and the improvement of mitochondrial function. © 2014 John Wiley & Sons, Ltd.

Neuroprotective Effects of Engineered Polymeric Nasal Microspheres Containing Hydroxypropyl-ß-cyclodextrin on ß-Amyloid (1-42)–Induced Toxicity

PubMed ID: 27353207ß-Amyloid (Aß) plaques are the key neurotoxic assemblies in Alzheimer disease. It has been suggested that an interaction occurs between membrane cholesterol and Aß aggregation in the brain. Cyclodextrins can remove cholesterol from cell membranes and change receptor function. This study aimed to investigate the effect of hydroxypropyl-ß-cyclodextrin (HP-CD) polymeric microspheres, based on chitosan or sodium alginate, on the levels of lipid peroxidation, reactive oxygen species production, and mitochondrial function in brain synaptosomes. The effect of microspheres on DNA fragmentation, the expression of Bcl-2, Bax, and Apex1 mRNAs in rat hippocampus after Aß(1-42) peptide-induced neurotoxicity was also evaluated. Comparison with HP-CD raw material was performed. Aß(1-42) treatment significantly decreased the mitochondrial activity of Apex1 and Bcl-2 mRNAs, induced DNA fragmentation, and increased mRNA levels of Bax. Treatment with HP-CD microspheres against Aß(1-42) significantly reduced DNA fragmentation and increased the Bcl-2/Bax mRNA ratio and mitochondrial function. In addition, HP-CD microspheres used against Aß(1-42) decreased the levels of lipid peroxidation and reactive oxygen species production. These results indicate that nasally administered spray-dried HP-CD microspheres are able to provide protection against Aß(1-42)-induced neurotoxicity, due to the suppressed levels of oxidative stress and apoptotic signals in the rat hippocampus. © 2016 American Pharmacists Association ®12/ECZ/037This study was partially supported by Ege University Research Foundation (Project no: 12/ECZ/037 to A.Y). -