Mitochondria-targeted antioxidant effects of S(-) and R(+) pramipexole

Journal of Neurochemistry, 2005

We have investigated the ability of pramipexole, a dopamine agonist used in the symptomatic treatment of Parkinson's disease (PD), to protect against cell death induced by 1-methyl-4-phenylpyridinium (MPP + ) and rotenone in dopaminergic and non-dopaminergic cells. Pre-incubation with either the active (-)-or inactive (+)-enantiomer forms of pramipexole (10 lM) decreased cell death in response to MPP + and rotenone in dopaminergic SHSY-5Y cells and in non-dopaminergic JK cells. The protective effect was not prevented by dopamine receptor blockade using sulpiride or clozapine. Protection occurred at concentrations at which pramipexole did not demonstrate antioxidant activity, as shown by the failure to maintain aconitase activity. However, pramipexole reduced caspase-3 activation, decreased the release of cytochrome c and prevented the fall in the mitochondrial membrane potential induced by MPP + and rotenone. This suggests that pramipexole has anti-apoptotic actions. The results extend the evidence for the neuroprotective effects of pramipexole and indicate that this is not dependent on dopamine receptor occupation or antioxidant activity. Further evaluation is required to determine whether the neuroprotective action of pramipexole is translated to a disease-modifying effect in PD patients.

The FASEB Journal, 2006

The dopamine-D2-agonist pramipexole (PPX) was tested for blocking mitochondrial permeability transition (PT) in order to give a possible explanation for its neuroprotective effect seen in PPX-treated Parkinson's disease patients. Patch-clamp techniques for studying singlechannel currents in the inner mitochondrial membrane and large-amplitude swelling of energized mitochondria were used to study PPX action on the permeability transition pore (PTP), a key player in the mitochondrial route of the apoptotic cascade. Identity of the PTP was proven by measuring the concentration-response relation for cyclosporin A-blockade (IC 50 =26 nM). PPX inhibits the PTP reversibly with an IC 50 of 500 nM, which is close to the values determined earlier as plasma concentrations after PPX medication in patients. Interaction of PPX with the PTP is further supported by demonstrating that it abolished Ca 2+-triggered swelling in functionally intact mitochondria. Blockade of the PTP by PPX was attenuated by increasing concentrations of inorganic phosphate and by acidification. We suggest that PPX could exert part of its neuroprotective effect by inhibition of the PTP and thus, probably, blocking of the mitochondrial pathway of the apoptosis cascade.

Antioxidants, 2021

Neurotransmitter depletion and mitochondrial dysfunction are among the multiple pathological events that lead to neurodegeneration. Following our previous studies related with the development of multitarget mitochondriotropic antioxidants, this study aims to evaluate whether the π-system extension on the chemical scaffolds of AntiOXCIN2 and AntiOXCIN3 affects their bioactivity and safety profiles. After the synthesis of four triphenylphosphonium (TPP+) conjugates (compounds 2–5), we evaluated their antioxidant properties and their effect on neurotransmitter-metabolizing enzymes. All compounds were potent equine butyrylcholinesterase (eqBChE) and moderate electric eel acetylcholinesterase (eeAChE) inhibitors, with catechols 4 and 5 presenting lower IC50 values than AntiOXCIN2 and AntiOXCIN3, respectively. However, differences in the inhibition potency and selectivity of compounds 2–5 towards non-human and human cholinesterases (ChEs) were observed. Co-crystallization studies with com...

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 2006

Mitochondria play an important role in controlling the life and death of a cell. Consequently, mitochondrial dysfunction leads to a range of human diseases such as ischemia -reperfusion injury, sepsis, and diabetes. Although the molecular mechanisms responsible for mitochondriamediated disease processes are not fully elucidated yet, the oxidative stress appears to be critical. Accordingly, strategies are being developed for the targeted delivery of antioxidants to mitochondria. In this review, we shall briefly discuss cellular reactive oxygen species metabolism and its role in pathophysiology; the currently existing antioxidants and possible reasons why they are not effective in ameliorating oxidative stressmediated diseases; and recent developments in mitochondrially targeted antioxidants and their future promise for disease treatment.

Experimental Neurology, 2004

Anti-parkinsonian agents possessing both D 2 and D 3 receptor agonist properties are neuroprotective against 1-methyl-4-phenylpyridinium (MPP +) toxicity in a variety of in vitro models. The mechanisms underlying protection by these D 2 /D 3 receptor agonists remain poorly defined. To test if the D 3 receptor preferring agonists S32504 and pramipexole act through D 2 or D 3 receptors and via brain-derived neurotrophic factor (BDNF)-dependent pathways, we utilized a terminally differentiated neuroblastoma SH-SY5Y cell line exhibiting a dopaminergic phenotype. The cytotoxic effects of MPP + (LD 50 of 100 AM) were stereospecifically antagonized by S32504 (EC 50 = 2.0 AM) and, less potently, by pramipexole (EC 50 = 64.3 AM), but not by their inactive stereoisomers, R(+) pramipexole and S32601, respectively. Neuroprotective effects afforded by EC 50 doses of S32504 and pramipexole were antagonized by the selective D 3 antagonists S33084, U99194A, and SB269652, and by the D 2 /D 3 antagonist raclopride. However, the preferential D 2 receptor antagonist LY741626 was ineffective as was the D1 antagonist SCH23390. BDNF (1 nM) potently protected against MPP +-induced neurotoxicity. Antibody directed against BDNF concentration-dependently blocked both the neuroprotective effects of BDNF and those of pramipexole and S32504 against MPP +. The protection afforded by BDNF was blocked by the P3K-AKT pathway inhibitor LY249002 and less so by the MEK/MAPKK pathway inhibitor PD98059. LY249002, but not PD98059, blocked the neuroprotective effects of pramipexole and S32504 against MPP + toxicity. In conclusion, S32504 and, less potently, pramipexole show robust, stereospecific, and long-lasting neuroprotective effects against MPP + toxicity that involve D 3 receptors. Their actions also reflect downstream recruitment of BDNF and via a PK3-AKT pathway.

Bioorganic & Medicinal Chemistry, 2013

Two new aza analogues of the neuroprotective agent idebenone have been synthesized and characterized. Their antioxidant activity, and ability to augment ATP levels have been evaluated in several different cell lines having suboptimal mitochondrial function. Both compounds were found to be good ROS scavengers, and to protect the cells from oxidative stress induced by glutathione depletion. The compounds were more effective than idebenone in neurodegenerative disease cells. These novel pyrimidinol derivatives were also shown to augment ATP levels in coenzyme Q 10-deficient human lymphocytes. The more lipophilic side chains attached to the pyrimidinol redox core in these compounds resulted in less inhibition of the electron transport chain and improved antioxidant activity.

Neuroscience Letters, 2000

Pramipexole has been showed to protect cultured dopaminergic (DAergic) cells against free radical-induced cytotoxicity. To test if pramipexole is protective against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated nigral DAergic injury in vivo and if such protection is related to inhibition of lipid peroxidation, DAergic function and lipid peroxidation were determined in MPTP-treated C57BL/6 mice. We reported that MPTP administration induced a 38.1% increase of lipid peroxidation product thiobarbituric acid reactive substance (TBARS) in nigra, a 46.7% decrease of tyrosine hydroxylase -positive nigral DAergic neurons and a 59.4% reduction of striatal DA levels. However, pramipexole treatment signi®cantly inhibited the TBARS production by 76%, and attenuated the MPTP-induced decreases in nigral DAergic neurons and striatal DA levels by about 50%. This study suggests that pramipexole can inhibit free radicalmediated lipid peroxidation and protect MPTP-induced nigral injury. q

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 2013

Parkinson's disease (PD) is a neurodegenerative disorder for which available treatments provide symptom relief but do not stop disease progression. Mitochondria, and in particular mitochondrial dynamics, have been postulated as plausible pharmacological targets. Mitochondria-targeted antioxidants have been developed to prevent mitochondrial oxidative damage, and to alter the involvement of reactive oxygen species (ROS) in signaling pathways. In this study, we have dissected the effect of MitoQ, which is produced by covalent attachment of ubiquinone to a triphenylphosphonium lipophilic cation by a ten carbon alkyl chain. MitoQ was tested in an in vitro PD model which involves addition of 6-hydroxydopamine (6-OHDA) to SH-SY5Y cell cultures. At sublethal concentrations of 50 μM, 6-OHDA did not induce increases in protein carbonyl, mitochondrial lipid peroxidation or mitochondrial DNA damage. However, after 3 h of treatment, 6-OHDA disrupts the mitochondrial morphology and activates the machinery of mitochondrial fission, but not fusion. Addition of 6-OHDA did not increase the levels of fission 1, mitofusins 1 and 2 or optic atrophy 1 proteins, but does lead to the translocation of dynamin related protein 1 from the cytosol to the mitochondria. Pre-treatment with MitoQ (50 nM, 30 min) results in the inhibition of the mitochondrial translocation of Drp1. Furthermore, MitoQ also inhibited the translocation of the pro-apoptotic protein Bax to the mitochondria. These findings provide mechanistic evidence for a role for redox events contributing to mitochondrial fission and suggest the potential of mitochondria-targeted therapeutics in diseases that involve mitochondrial fragmentation due to oxidative stress.

Brain research, 2012

Cellular stress or injury can result in mitochondrial dysfunction, which has been linked to many chronic neurological disorders including amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Stressed and dysfunctional mitochondria exhibit an increase in large conductance mitochondrial membrane currents and a decrease in bioenergetic efficiency. Inefficient energy production puts cells, and particularly neurons, at risk of death when energy demands exceed cellular energy production. Here we show that the candidate ALS drug dexpramipexole (DEX; KNS-760704; ((6R)-4,5,6,7-tetrahydro-N6-propyl-2,6-benzothiazole-diamine) and cyclosporine A (CSA) inhibited increases in ion conductance in whole rat brain-derived mitochondria induced by calcium or treatment with a proteasome inhibitor, although only CSA inhibited calcium-induced permeability transition in liver-derived mitochondria. In several cell lines, including cortical neurons in culture, DEX significantly decreased oxygen consumption while maintaining or increasing production of adenosine triphosphate (ATP). DEX also normalized the metabolic profile of injured cells and was protective against the cytotoxic effects of proteasome inhibition. These data indicate that DEX increases the efficiency of oxidative phosphorylation, possibly by inhibition of a CSA-sensitive mitochondrial conductance.► Improvement of bioenergetic efficiency may ameliorate mitochondrial damage. ► Mitochondrial damage is a hallmark of chronic neurodegenerative disorders, including ALS. ► Dexpramipexole (DEX) is a drug undergoing clinical trials in ALS. ► DEX inhibited stress- or injury-induced neuronal mitochondrial conductance. ► DEX reduced oxygen consumption while maintaining or increasing ATP levels.

Oxidative Medicine and Cellular Longevity, 2015

Mitochondria are cytoplasmic organelles that regulate both metabolic and apoptotic signaling pathways; their most highlighted functions include cellular energy generation in the form of adenosine triphosphate (ATP), regulation of cellular calcium homeostasis, balance between ROS production and detoxification, mediation of apoptosis cell death, and synthesis and metabolism of various key molecules. Consistent evidence suggests that mitochondrial failure is associated with early events in the pathogenesis of ageing-related neurodegenerative disorders including Parkinson’s disease and Alzheimer’s disease. Mitochondria-targeted protective compounds that prevent or minimize mitochondrial dysfunction constitute potential therapeutic strategies in the prevention and treatment of these central nervous system diseases. This paper provides an overview of the involvement of mitochondrial dysfunction in Parkinson’s and Alzheimer’s diseases, with particular attention toin vitroandin vivostudies ...