ABSTRACT
INTRODUCTION: Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most prevalent cause of familial and sporadic Parkinson's disease (PD). Because most pathogenic LRRK2 mutations result in enhanced kinase activity, it suggests that LRRK2 inhibitors may serve as a potential treatment for PD. To evaluate whether LRRK2 inhibitors are effective therapies for PD, it is crucial to know whether LRRK2 inhibitors will affect dopaminergic (DAergic) neurotransmission. However, to date, there is no study to investigate the impact of LRRK2 inhibitors on DAergic neurotransmission. AIMS: To address this gap in knowledge, we examined the effects of three types of LRRK2 inhibitors (LRRK2-IN-1, GSK2578215A, and GNE-7915) on dopamine (DA) release in the dorsal striatum using fast-scan cyclic voltammetry and DA neuron firing in the substantia nigra pars compacta (SNpc) using patch clamp in mouse brain slices. RESULTS: We found that LRRK2-IN-1 at a concentration higher than 1 µM causes off-target effects and decreases DA release, whereas GSK2578215A and GNE-7915 do not. All three inhibitors at 1 µM have no effect on DA release and DA neuron firing rate. We have further assessed the effects of the inhibitors in two preclinical LRRK2 mouse models (i.e., BAC transgenic hG2019S and hR1441G) and demonstrated that GNE-7915 enhances DA release and synaptic vesicle mobilization/recycling. CONCLUSION: GNE-7915 can be validated for further therapeutic development for PD.
Subject(s)
Corpus Striatum/cytology , Dopamine/metabolism , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Parkinson Disease/pathology , Substantia Nigra/cytology , Aminopyridines/pharmacology , Animals , Benzamides/pharmacology , Benzodiazepinones/pharmacology , Biophysical Phenomena/drug effects , Biophysical Phenomena/genetics , Corpus Striatum/drug effects , Disease Models, Animal , Dose-Response Relationship, Drug , Electric Stimulation , In Vitro Techniques , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics , Male , Mice , Mice, Transgenic , Morpholines/pharmacology , Mutation/genetics , Parkinson Disease/drug therapy , Parkinson Disease/genetics , Patch-Clamp Techniques , Pyrimidines/pharmacology , Substantia Nigra/drug effectsABSTRACT
OBJECTIVE: To investigate the significance of pathological changes in murine lung by a single intramuscular injection of chemokine-like factor 1 (CKLF1). METHODS: A total of 120 gender-matched BALB/c mice were randomly and evenly divided into treatment group and control group (60 in each). One hundred nanomilligram of pcDNA3.1-CKLF1-Myc-His, CKLF1-expressing plasmid, in 100 microl of pyrogen-free saline was injected into the anterior tibial muscle of mice followed by the delivery of electric pulses. Mice in the control group received 100 microg of pcDNA3.1-Myc-His in 100 microl of pyrogen-free saline. At the end of week 1, 4 and 8 respectively after injection of CKLF1, 20 mice were sacrificed in every group and the cellular profiles in bronchoalveolar lavage fluid (BALF) and the pulmonary pathological changes were observed. RESULTS: At the end of week 1 and 4 respectively after CKLF1 injection, the neutrophils [(35.0 +/- 5.2)% and (22.9 +/- 2.2)% respectively] and lymphocytes [(34.5 +/- 2.8)% and (22.0 +/- 2.0)% respectively] in BALF of the treatment group were higher than those of the control group [neutrophils: (6.7 +/- 2.2)% and (7.0 +/- 2.4)% respectively, lymphocytes: (5.9 +/- 1.6)% and (6.1 +/- 2.7)% respectively, all P < 0.01]. Pathological studies demonstrated shedding of bronchiolar epithelium, congestion and edema in interstitial tissue and inflammatory cell infiltration in mice at 1 week after CKLF1 injection. Week 4 after CKLF1 administration, the alveolar wall was shown significantly thickened with proliferation of neutrophils, macrophages and fibroblasts as well as remarked collagen deposition in the interstitium. At the end of week 8 after CKLF1 administration, the remarkable morphological changes of the lung gradually subsided and the structure of the lung returned to normal. CONCLUSIONS: CKLF1 causes injury of inflammation and remodeling in airway in mice. The pulmonary pathological changes induced by a single intramuscular injection of CKLF are reversible.
Subject(s)
Chemokines/genetics , Lung/pathology , Pulmonary Fibrosis/metabolism , Pulmonary Fibrosis/pathology , Animals , Female , Genetic Vectors , Male , Mice , Mice, Inbred BALB C , Plasmids , TransfectionABSTRACT
OBJECTIVE: To study the characteristics of cellular metabolism of mandibular condylar chondrocytes in repairing state of osteoarthrosis and investigate its role in the pathogenesis of the disease. METHODS: Temporomandibular joint osteoarthrosis model of rabbits was created by the partial resection of joint disc and confirmed with histological diagnosis. The chondrocytes were harvested from osteoarthritic condylar cartilage in the repairing state and cultured in vitro under the monolayer culture condition. The cellular expression of cartilaginous matrix protein, collagenase and growth factors between the osteoarthritic chondrocytes and the normal controls were measured with RT-PCR technique to outline the basic feature of the osteoarthritic cells. RESULTS: The cultured cells were confirmed as chondrocytes with their ability of expression of collagen type II and Aggrecan. In the reactive repairing state of osteoarthrosis, the chondrocytes showed the imbalance of expression of ECM proteins, and increased expression of collagenase and endogenous growth factors such as IGF-1 and TGF-beta1. CONCLUSIONS: This study found the active anabolism of the chondrocytes within the osteoarthritic condylar cartilage and the imbalance synthesis of cartilage matrix. These repairing attempts by the osteoarthritic chondrocytes may be impossible to restore the primary homeostasis within the condylar cartilage.
