Research reportThe combination of lithium and l-Dopa/Carbidopa reduces MPTP-induced abnormal involuntary movements (AIMs) via calpain-1 inhibition in a mouse model: Relevance for Parkinson׳s disease therapy
Introduction
Parkinson׳s disease (PD) is a progressive movement disorder with a prevalence of 1.8% in individuals of 65 years or older (de Rijk et al., 2000, Bogaerts et al., 2008); its etiology is largely unknown in most cases. Dopamine replacement therapy using levodopa (l-Dopa) has remained the most effective treatment to reduce motor symptoms in PD. Currently most patients taking l-Dopa also receive the DOPA decarboxylase inhibitor, Carbidopa, for higher efficacy and lower side-effects (Celesia and Wanamaker, 1976, Wajsbort et al., 1978). However, chronic l-Dopa treatment results in abnormal involuntary movements (AIMs) including dyskinesia, in approximately 30% patients after 4–6 years of treatment; almost 90% of patients suffer from this complication after 9 years of chronic use (Ahlskog and Muenter, 2001).
Lithium has been the most commonly-used mood-stabilizing drug for the treatment of bipolar disorder. However, its recently discovered neuroprotective and neurotrophic properties have suggested it as a potential repurposed therapeutic for several neurodegenerative conditions (Li et al., 2002, Pies, 2002). Chronic lithium treatment was found to significantly attenuate neurodegeneration in the trigeminal, facial, ambiguus, and hypoglossal nuclei associated with an animal model of amyotrophic lateral sclerosis (ALS) (Ferrucci et al., 2010). In the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication PD mouse model, lithium was reported to prevent MPTP-induced neurotoxicity via regulation of Bcl-2 and Bax (Youdim and Arraf, 2004). Currently, lithium is in widespread “off label” usage for PD. It has been suggested that its co-administration could possibly provide some level of symptomatic relief against l-Dopa-induced dyskinesia (LID) and akinesia associated with “on–off” phenomenon complications following long-term l-Dopa treatment (Smith, 1976, Coffey et al., 1982). Lithium appears to be relatively safe at lower therapeutic dosages, readily penetrates the blood brain barrier, and low cost generic versions are available, making lithium an appealing drug for potential use in PD. Recently we demonstrated that chronic oral lithium administration was sufficient to prevent age-related, pesticide-induced alpha-synuclein aggregation and associated neuronal loss in multiple brain regions in a pan-neuronal human alpha-synuclein A53T mutant over-expressing transgenic line (Kim et al., 2011a).
The potential mechanisms by which lithium may modulate dopamine levels and reduce AIMs are largely unknown. Recent post-mortem studies, however, demonstrated that this could be via inhibition of a pathway involving calpain activation. Calpains have been shown to be elevated in human PD brains and calpain inhibition has been demonstrated to prevent reduction in the number of tyrosine hydroxylase (TH) positive cells in both MPTP and 6-hydroxydopamine (6-OHDA) treated rodent models of PD (Mouatt-Prigent et al., 1996, Crocker et al., 2003, Alvira et al., 2008). The calpain inhibitor MDL28170 was also shown to augment TH levels in the striatum of 6-OHDA lesioned rats, resulting in reductions in AIM frequencies (Chagniel et al., 2012). Here, we demonstrate that low-dose lithium with l-Dopa/Carbidopa reduces MPTP-induced AIMs in a mouse model coinciding with both calpain-1 inhibition and up-regulation of TH expression within both the striatum and the Substantia Nigra pars compacta (SNpc). These results suggest the potential use of lithium in combination with l-Dopa/Carbidopa (Sinemet®), not only as a neuroprotectant, but also for reducing AIMs and alleviating potential side-effects associated with currently available treatments for PD.
Section snippets
In the hindlimb clasping test, the combination of lithium and l-Dopa/Carbidopa reduces MPTP-induced abnormal involuntary movements (AIMs) in MPTP-lesioned mice
Using the hindlimb clasping test, we assessed AIMs after chronic MPTP treatment via analysis of hindlimb clasping severity and average instances of hindlimb clasping in the various experimental paradigms. In the comparison of pre-treatment (black filled bars) and post-treatment conditions (lined bars), we found that only the combination of lithium and l-Dopa/Carbidopa significantly reduced the severity of hindlimb clasping behavior (Fig. 1B, p<0.001), while we detected significant reductions in
Discussion
In this study, we demonstrated that combined lithium (0.127% LiCl in food) and l-Dopa/Carbidopa (IP injection: 100 mg/kg levodopa and 25 mg/kg Carbidopa) therapy significantly reduced MPTP-induced AIMs in mice as indicated by improvements in the hindlimb clasping test (Fig. 2, video data are Supplemented). The combination therapy not only reduces MPTP-induced AIMs but also increases TH expression in both the ST and the brainstem (Farah et al., 2013, Lieu et al., 2014). We found that lithium
MPTP treatment and lithium feeding
All animal protocols were conducted in accordance with the United States Public Health Service Guide for the Care and Use of Laboratory Animals; all procedures were approved by the Buck Institute Animal Care and Use Committee. All efforts were made to minimize animal numbers and distress. C57BL/6J male mice (8 months of age) were obtained from Charles River Laboratory (Wilmington, MA) and intraperitoneally injected with 25 mg/kg 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, Sigma, St.
Acknowledgments
We thank Dr. Alan Hubbard at the University of California, Berkeley for statistical discussion for this paper. This study was supported by NIH-5P20GM103653-02 (YHK) and NIH-RL1 NS062415 (JKA).
References (42)
- et al.
Epigenetic targets of HDAC inhibition in neurodegenerative and psychiatric disorders
Curr. Opin. Pharmacol.
(2008) - et al.
Activation of the calpain/cdk5/p25 pathway in the girus cinguli in Parkinson׳s disease
Parkinsonism Relat. Disord.
(2008) - et al.
The effect of l-dopa and carbidopa treatment on the survival of rat fetal dopamine grafts assessed by tyrosine hydroxylase immunohistochemistry and [3H]mazindol autoradiography
Neuroscience
(1991) - et al.
Striatal inhibition of calpains prevents levodopa-induced neurochemical changes and abnormal involuntary movements in the hemiparkinsonian rat model
Neurobiol. Dis.
(2012) - et al.
Evidence of calpain/cdk5 pathway inhibition by lithium in 3-nitropropionic acid toxicity in vivo and in vitro
Neuropharmacology
(2009) - et al.
Subacute systemic 3-nitropropionic acid intoxication induces a distinct motor disorder in adult C57Bl/6 mice: behavioural and histopathological characterisation
Neuroscience
(2002) - et al.
A systematic study of brainstem motor nuclei in a mouse model of ALS, the effects of lithium
Neurobiol. Dis.
(2010) - et al.
Implication of cyclin-dependent kinase 5 in the neuroprotective properties of lithium
Neuroscience
(2005) - et al.
Downregulation of miR-124 in MPTP-treated mouse model of Parkinson׳s disease and MPP iodide-treated MN9D cells modulates the expression of the calpain/cdk5 pathway proteins
Neuroscience
(2014) - et al.
Inducible dopaminergic glutathione depletion in an alpha-synuclein transgenic mouse model results in age-related olfactory dysfunction
Neuroscience
(2011)