Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Parkinson's disease is characterized by bradykinesia, rigidity and a resting tremor and the underlying basis for those symptoms is the loss of dopaminergic cells in the nigrostriatal system. Similar to PD, an age-related decrease locomotor activity and the expression of tyrosine hydroxylase immunoreactivity has been observed in rhesus monkeys, but the reason for this decrease in dopaminergic function remains to be elucidated. Trophic factors such as glial cell line derived neurotrophic factor (GDNF) and neurturin sustain the dopaminergic phenotype in midbrain neurons and act through a common receptor tyrosine kinase (RET). Examination of RET expression by immunohistochemistry was performed on sections of tissue containing the substantia nigra pars compacta of young, middle, and old aged rhesus monkeys. Stereological estimates of the number and cellular area of RET-immunoreactive cells found no change with age. Estimation of changes in RET protein using fluorescence intensity measurement was also similar across age groups. The results indicate that the mechanisms of GDNF and neurturin signaling remain intact with age, and therefore these trophic factors may be able to enhance the dopaminergic function of neurons in the nigrostriatal system, when administered to individuals of any age.
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PMID:RET expression does not change with age in the substantia nigra pars compacta of rhesus monkeys. 1595 Mar 22

Parkinson's disease is the second most common age-related neurodegenerative disorder, typified by the progressive loss of substantia nigra pars compacta dopamine neurons and the consequent decrease in the neurotransmitter dopamine. Patients exhibit a range of clinical symptoms, with the most common affecting motor function and including resting tremor, rigidity, akinesia, bradykinesia and postural instability. Current pharmacological interventions are palliative and largely aimed at increasing dopamine levels through increased production and/or inhibition of metabolism of this key neurotransmitter. The gold standard for treatment of both familial and sporadic Parkinson's disease is the peripheral administration of the dopamine precursor, levodopa. However, many patients gradually develop levodopa-induced dyskinesias and motor fluctuations. In addition, dopamine enhancement therapies are most useful when a portion of the nigrostriatal pathway is intact. Consequently, as the number of substantia nigra dopamine neurons and striatal projections decrease, these treatments become less efficacious. Current translational research is focused on the development of novel disease-modifying therapies, including those utilizing gene therapeutic approaches. Herein we present an overview of current gene therapy clinical trials for Parkinson's disease. Employing either recombinant adeno-associated virus type 2 (rAAV2) or lentivirus vectors, these clinical trials are focused on three overarching approaches: augmentation of dopamine levels via increased neurotransmitter production; modulation of the neuronal phenotype; and neuroprotection. The first two therapies discussed in this article focus on increasing dopamine production via direct delivery of genes involved in neurotransmitter synthesis (amino acid decarboxylase, tyrosine hydroxylase and GTP [guanosine triphosphate] cyclohydrolase 1). In an attempt to bypass the degenerating nigrostriatal pathway, a third clinical trial utilizes rAAV2 to deliver glutamic acid decarboxylase to the subthalamic nucleus, converting a subset of excitatory neurons to GABA-producing cells. In contrast, the final clinical trial is aimed at protecting the degenerating nigrostriatum by striatal delivery of rAAV2 harbouring the neuroprotective gene, neurturin. Based on preclinical studies, this gene therapeutic approach is posited to slow disease progression by enhancing neuronal survival. In addition, we discuss the outcome of each clinical trial and discuss the potential rationale for the marginal yet incremental clinical advancements that have thus far been realized for Parkinson's disease gene therapy.
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PMID:Gene therapy in Parkinson's disease: rationale and current status. 2015 94