Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.14.16.2 (tyrosine hydroxylase)
 14,760 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A phenomenon-in which microglia are activated in axotomized rat facial nucleus suggests that a certain neuronal stimulus triggers the activation of microglia. However, how the microglial characteristics are regulated by this neuronal stimulus has not previously been determined. In this study, therefore, the regulation of microglial properties by neurons was characterized in vitro from a neurotrophic perspective. To evaluate the neurotrophic effects of microglia stimulated with neurons, the effects of conditioned medium (CM) of microglia stimulated with neuronal CM (NCM) were assessed in neuronal cultures. The amounts of tyrosine hydroxylase (TH) in neuronal culture exposed to CM of microglia stimulated with NCM was much more than those in neurons exposed to CM of control microglia, suggesting that neuronal stimulus enhances the production of neurotrophic factors for catecholaminergic neurons in microglia. Therefore, the neurotrophic effects of CM of microglia stimulated with NCM were analyzed in detail. The immunocytochemical and biochemical experiments revealed that the CM of microglia stimulated with NCM enhances the survival/maturation of GABAergic and catecholaminergic neurons. The levels of choline acetyltransferase specific to cholinergic neurons also significantly increased in response to stimulation with the same microglial CM. These results allowed us to investigate the production of neurotrophic factors in the CM of microglia stimulated with NCM. The results indicated that NCM induces nerve growth factor (NGF), and enhances neurotrophin-4/5 (NT-4/5), transforming growth factor beta1 (TGFbeta1), glial cell line-derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), interleukin-3 (IL-3), and IL-10 in microglia. The promoted neurotrophic effects of CM of microglia stimulated with NCM were significantly abrogated by deprivation of neurotrophic factors by means of an immunoprecipitation method. Taken together, neuronal stimulus was found to activate microglia to produce more neurotrophic factors as above, thereby changing microglia into more neurotrophic cells.
 ...
PMID:Neuronal regulation by which microglia enhance the production of neurotrophic factors for GABAergic, catecholaminergic, and cholinergic neurons. 1745 25

Idiopathic Parkinson's disease (PD) is a progressive neurodegenerative disorder, clinically manifested by cardinal motor symptoms including tremor at rest, bradykinesia, and muscle rigidity. Transplantation of dopaminergic (DAergic) neurons is an experimental therapy for PD, however, it is limited by suboptimal integration and low survival of grafts. Pretreatment of donor tissue may offer a strategy to improve properties of transplanted DAergic neurons and thereby clinical outcome. We have previously shown that a combination of neurotrophin-4/5 (NT-4/5) and glial cell line-derived neurotrophic factor (GDNF) demonstrated additive effects on rat ventral mesencephalic (VM) tissue. The present study investigated the effects of NT-4/5 and GDNF as single factors, or in combination on DAergic neurons, in organotypic explant cultures of fetal human ventral mesencephalon. For that purpose, free-floating roller-tube cultures were prepared from VM and the equally sized pieces grown for 1 week in the presence or absence of neurotrophic factors. Both neurotrophic factors increased dopamine content in the culture medium and in the number of tyrosine hydroxylase immunoreactive neurons, most prominently after combined GDNF + NT-4/5 treatment. Culture volumes did not differ between groups while content of lactate dehydrogenase in the culture medium was moderately reduced in all treated groups. In conclusion, we identified that a combination of GDNF and NT-4/5 robustly promoted differentiation and survival of human fetal VM DAergic neurons, an observation with potential promising impact for cell replacement approaches in PD.
 ...
PMID:A Combination of NT-4/5 and GDNF Is Favorable for Cultured Human Nigral Neural Progenitor Cells. 2970 Oct 77

Parkinson's disease (PD) is a neurodegenerative disorder that presents with hallmark clinical symptoms of tremor at rest, bradykinesia, and muscle rigidity. Stem cell therapy has emerged as an experimental treatment for PD. However, optimizing the cell culture condition that allows enhanced survival and differentiation of cells toward the dopaminergic phenotype remains a logistical challenge. Here, we discuss the utility of a combination of neurotrophin-4/5 (NT-4/5) and glial cell line-derived neurotrophic factor (GDNF) in increasing the dopaminergic phenotypic expression of rat ventral mesencephalic (VM) tissue. Using organotypic explant cultures of fetal human ventral mesencephalon, we observed that NT-4/5 and GDNF as single factors, or in combination on DAergic neurons, increased survival and number of tyrosine hydroxylase immunoreactive neurons as well as the dopamine content in the culture medium. The application of specific neurotrophic factors, such as NT-4/5 and GDNF, as cell culture supplements or as adjunctive therapy to cell transplantation may achieve improved functional outcomes when contemplating cell-based regenerative medicine for PD.
 ...
PMID:Neurotrophic factor-based strategies to enhance survival and differentiation of neural progenitor cells toward the dopaminergic phenotype. 3045 Apr 22


<< Previous 1 2