tacrolimus and 3-nitropropionic-acid

Huntington's disease (HD) is a genetic neurodegenerative disorder characterized by striatal neurodegeneration, involving apoptosis. FK506, an inhibitor of calcineurin (or protein phosphatase 3, formerly known as protein phosphatase 2B), has shown neuroprotective effects in several cellular and animal models of HD. In the present study, we show the protective effects of FK506 in two striatal HD models, primary rat striatal neurons treated with 3-nitropropionic acid (3-NP) and immortalized striatal STHdh cells derived from HD knock-in mice expressing normal (STHdh(7/7)) or full-length mutant huntingtin (FL-mHtt) with 111 glutamines (STHdh(111/111)), under basal conditions and after exposure to 3-NP or staurosporine (STS). In rat striatal neurons, FK506 abolished 3-NP-induced increase in caspase-3 activation, DNA fragmentation/condensation and necrosis. Nevertheless, in STHdh(111/111) cells under basal conditions, FK506 did not prevent, in a significant manner, the release of cytochrome c and apoptosis inducing factor (AIF) from mitochondria, or alter Bax/Bcl-2 ratio, but significantly reverted caspase-3 activation. In STHdh(111/111) cells treated with 0.3mM 3-NP or 25 nM STS, linked to high necrosis, exposure to FK506 exerted no significant effects on caspase-3 activation. However, treatment of STHdh(111/111) cells exposed to 10nM STS with FK506 effectively prevented cell death by apoptosis and moderate necrosis. The results suggest that FK506 may be neuroprotective against apoptosis and necrosis under mild cell death stimulus in the presence of FLmHtt.

Topics: Animals; Apoptosis; Blotting, Western; Caspase 3; Cell Death; Cell Line; Corpus Striatum; Cytosol; DNA Fragmentation; Humans; Huntingtin Protein; Huntington Disease; Immunosuppressive Agents; Mice; Mice, Transgenic; Mitochondria; Necrosis; Nerve Tissue Proteins; Neurons; Neuroprotective Agents; Nitro Compounds; Nuclear Proteins; Propionates; Staurosporine; Subcellular Fractions; Tacrolimus

FK-506 is an immunosuppressant being widely used for allograft rejection cases in the present clinical scenario. Recently, the neuroprotective effect of FK-506 has also been reported against a number of neurodegenerative diseases in rodents. This study was designed to explore the possible protective effect of FK-506 and its interaction with nitric-oxide modulators against 3-nitropropionic acid (3-NP)-induced behavioural, biochemical, neurochemical, and mitochondrial alterations in striatum, cortex, and hippocampus regions of the brain. Systemic administration of 3-nitropropionic acid produces Huntington-like symptoms in rats. 3-NP (10 mg/kg) treatment for 14 days impaired locomotor activity, grip strength, and body weight. 3-NP treatment significantly raised malondialdehyde, nitrite concentration, depleted antioxidant enzymes (SOD and catalase), and levels of bioamines (dopamine and norepinephrine) in striatum, cortex, and hippocampus areas of rat brain. Significant alterations in mitochondrial enzyme complexes (I, II, and IV) activities and mitochondrial redox activity have also been altered significantly by 3-NP. Pretreatment with FK-506 (0.5, 1, and 2 mg/kg) significantly reversed these behavioral, biochemical, and cellular alterations. L-arginine treatment with a subeffective dose FK-506 (1 mg/kg) reversed the protective effect of FK-506. However, L-NAME pretreatment with FK-506 (1 mg/kg) potentiated the protective effect of FK-506. The present study shows that FK-506 attenuates 3-NP-induced neurotoxicity and nitric-oxide modulation might be involved in its protective action.

Topics: Animals; Behavior, Animal; Body Weight; Brain; Brain Chemistry; Disease Models, Animal; Huntington Disease; Male; Mitochondria; Motor Activity; Neuroprotective Agents; Nitric Oxide; Nitro Compounds; Oxidative Stress; Propionates; Rats; Rats, Wistar; Tacrolimus

Cyclosporine and FK506, a well-known immunosuppressant drugs that are presently being used for prevention of allograft rejection. Recently, several studies suggest their therapeutic potential in the treatment of neurodegenerative diseases. Therefore, present study was conducted to explore their therapeutic potential against 3-nitropropionic acid induced cognitive dysfunctions and biochemical alterations in striatum, cortex and hippocampal regions of brain. Further, attempt has also been made to investigate their possible interaction with nitric oxide modulators.3-Nitropropionic acid (10 mg/kg) for 14 days treatment significantly impaired cognitive task as evidenced by Morris water as well as plus maze performance tasks. 3-Nitropropionic acid treatment significantly disturbed glutathione redox ratio and different levels of glutathione (as indicated by alterations in total glutathione, reduced glutathione, oxidized glutathione, glutathione-S-transferase levels). Acetylcholinesterase enzyme activity was also significantly disturbed by 3-NP treatment. Further, FK-506 (0.5, 1 and 2 mg/kg, p.o.) and cyclosporine (2.5, 5 and 10 mg/kg, p.o.) treatment significantly improved cognitive functions both in Morris water maze and plus maze tasks. Beside these drug treatment significantly attenuated oxidative stress as evidenced by restoring different glutathione levels and acetylcholinesterase activity as compared to control (3-NP treated) animals. Further sub effective doses of cyclosporine (5 mg/kg) and FK-506 (1 mg/kg) effect was potentated by l-NAME and reversed by l-arginine pretreatment. The effects were significant as compared to their effect per se.Study highlights the therapeutic potential of these drugs in the treatment of Huntington's disease. Study further suggest that nitric oxide modulation in involved in the neuroprotective effect of these drugs against 3-NP neurotoxicity.

Topics: Acetylcholinesterase; Analysis of Variance; Animals; Arginine; Behavior, Animal; Brain; Cognition Disorders; Cyclosporine; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Inhibitors; Glutathione; Glutathione Transferase; Male; Maze Learning; Neuroprotective Agents; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitro Compounds; Oxidative Stress; Propionates; Rats; Rats, Wistar; Tacrolimus; Time Factors

Changes in mitochondrial integrity, reactive oxygen species release and Ca2+ handling are proposed to be involved in the pathogenesis of many neurological disorders including methylmalonic acidaemia and Huntington's disease, which exhibit partial mitochondrial respiratory inhibition. In this report, we studied the mechanisms by which the respiratory chain complex II inhibitors malonate, methylmalonate and 3-nitropropionate affect rat brain mitochondrial function and neuronal survival. All three compounds, at concentrations which inhibit respiration by 50%, induced mitochondrial inner membrane permeabilization when in the presence of micromolar Ca2+ concentrations. ADP, cyclosporin A and catalase prevented or delayed this effect, indicating it is mediated by reactive oxygen species and mitochondrial permeability transition (PT). PT induced by malonate was also present in mitochondria isolated from liver and kidney, but required more significant respiratory inhibition. In brain, PT promoted by complex II inhibition was stimulated by increasing Ca2+ cycling and absent when mitochondria were pre-loaded with Ca2+ or when Ca2+ uptake was prevented. In addition to isolated mitochondria, we determined the effect of methylmalonate on cultured PC12 cells and freshly prepared rat brain slices. Methylmalonate promoted cell death in striatal slices and PC12 cells, in a manner attenuated by cyclosporin A and bongkrekate, and unrelated to impairment of energy metabolism. We propose that under conditions in which mitochondrial complex II is partially inhibited in the CNS, neuronal cell death involves the induction of PT.

Topics: Animals; Antimycin A; Bongkrekic Acid; Brain; Calcimycin; Calcium; Catalase; Cell Survival; Cyclosporins; Dose-Response Relationship, Drug; Drug Interactions; Electron Transport Complex II; Enzyme Inhibitors; Female; In Vitro Techniques; Ionophores; Malonates; Membrane Potentials; Methylmalonic Acid; Mitochondria; NADP; Neurons; Nitro Compounds; Oxygen Consumption; PC12 Cells; Permeability; Propionates; Rats; Rotenone; Tacrolimus; Tetrazolium Salts; Thiazoles; Uncoupling Agents

The mitochondrial toxin 3-nitropropionic acid (3-NP) has been largely used to study neurodegenerative disorders in which bioenergetic defects are implicated. In the present study, we analyzed the molecular pathways involved in FK506 neuroprotection against cell death induced by 3-NP, using cultured cortical neurons. 3-NP induced cytochrome c release and increased caspases -2, -3, -8, and -9-like activities, although, calpain activity was not significantly affected. FK506 decreased cytochrome c release and caspase-3-like activity induced by 3-NP, without changing the activities of other caspases. FK-506 also decreased the number of apoptotic neurons, determined by Hoechst. Under these conditions, FK506 alone significantly reduced calcineurin activity by about 50%. Our results also showed a decrease in mitochondrial Bax and an increase in mitochondrial Bcl-2 levels upon exposure to FK506 and 3-NP. However, no significant changes occurred in total Bcl-2 and Bax levels. Altogether, the results suggest that FK506 neuroprotection against 3-NP-induced apoptosis is associated with the redistribution of Bcl-2 and Bax in the mitochondrial membrane.

Topics: Animals; Apoptosis; Caspases; Cell Death; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Embryo, Mammalian; Mitochondria; Nerve Degeneration; Neurotoxins; Nitro Compounds; Propionates; Rats; Rats, Wistar; Tacrolimus

Kynurenic acid (KYNA), the only known endogenous glutamate antagonist, is produced in the brain by kynurenine aminotransferases (KATs) I and II. Mitochondrial toxins, 1-methyl-4-phenylpyridinium (MPP +) and 3-nitropropionic acid (3-NPA), were previously shown to reduce KYNA synthesis via interference with KAT I and II. Data presented here demonstrate that immunophilin ligand, FK506 (10-130 microM), but not CsA (1-50 microM), or ryanodine receptor blocker, dantrolene (1-100 microM), enhances the formation of KYNA in cortical slices. FK506, but not CsA or dantrolene, abolished the inhibition of KYNA synthesis evoked by MPP+ and 3-NPA. None of studied compounds influenced the activity of KAT I and KAT II. FK506 is the first among currently used drugs that might stimulate KYNA synthesis. This effect does not seem to arise from the interference with KATs or calcineurin activity.

Topics: 1-Methyl-4-phenylpyridinium; Animals; Cerebral Cortex; Convulsants; Cyclosporine; Dantrolene; Drug Interactions; Excitatory Amino Acid Antagonists; Herbicides; Immunosuppressive Agents; Kynurenic Acid; Male; Mitochondria; Muscle Relaxants, Central; Nitro Compounds; Organ Culture Techniques; Propionates; Rats; Rats, Wistar; Tacrolimus

Systemically administered 3-nitropropionic acid (3-NPA) that inhibits the mitochondrial oxidative phosphorylation induces selective lesions in the striatum. To investigate the nature of these selective lesions, we administered 3-NPA (20 mg/kg, s.c. daily for 2 or 3 days) to Wistar rats and investigated the behavioral disturbance, striatal lesions and their variations after modulating the activity of nitric oxide synthase (NOS). On the second or third day of 3-NPA administration, half the animals manifested behavioral disturbances (paddling, rolling, tremor, abnormal gait, and recumbence). A strong extravasation of immunoglobulin G (IgG) and a decrease in immunoreaction for glial fibrillary acidic protein (GFAP) were detected, and iNOS-like (iNOS-L) immunoreactive small cells appeared in the lateral and central striatum especially around the vessels. A week later, lesions lacking GFAP-immunoreaction were detected in the striatum in survived animals. Pretreatment with N-nitro-L-arginine methyl ester (L-NAME) along with each injection of 3-NPA did not improve the behavioral disturbances nor the survival rate, but attenuated the extravasation of IgG and iNOS-L immunoreaction. Pretreatment with aminoguanidine or FK506 improved the behavioral symptoms and survival rate. Extravasation of IgG and expression of iNOS-L immunoreactivity were attenuated, and the striatal lesion was reduced. Data indicate the involvement of NO in the high vulnerability of the striatum, and that iNOS, one of inflammatory markers, is induced following exposure to 3-NPA.

Topics: Animals; Antihypertensive Agents; Astrocytes; Behavior, Animal; Cell Death; Dyspnea; Enzyme Inhibitors; Glial Fibrillary Acidic Protein; Guanidines; Immunohistochemistry; Immunosuppressive Agents; Injections, Subcutaneous; Male; Neostriatum; Neuritis; Neurotoxins; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Nitro Compounds; Propionates; Rats; Rats, Wistar; Tacrolimus