Shoei Furukawa

Synthesis and secretion of nerve growth factor by mouse astroglial cells in culture

Astroglial cells cultured from the mouse brain have been found to synthesize and secrete a material(s) with nerve growth factor-like immunoreactivity (NGF-LI) into their culture medium. A material(s) with NGF-LI showed identical properties to those of beta NGF purified from the mouse submaxillary gland in immunoreactivity, molecular weight, isoelectric point, and neurite outgrowth stimulatory activity. These results indicate that astroglial cells cultured from mouse brain are able to synthesize and secrete beta NGF in culture.

Erinacines A, B, and C, strong stimulators of nerve growth factor (NGF)-synthesis, from the mycelia of Hericium erinaceum

Abstract The structures of novel diterpenoids, erinacines A, B, and C, isolated from the cultured mycelia of Hericium erinaceum were determined by interpretation of the spectral data, and chemical and enzymatic reactions. These compounds showed potent stimulating activity of nerve growth factor (NGF)-synthesis.

Dietary n-3 fatty acid deficiency decreases nerve growth factor content in rat hippocampus

Dietary deprivation of alpha-linolenic acid (n-3) through two generations has been shown to lower performance in an operant-type brightness-discrimination learning test in rats. Here, we examined a possible correlation between nerve growth factor (NGF) content and n-3 fatty acid status in the brain. Female rats were fed a semipurified diet supplemented with safflower oil (n-3 fatty acid-deficient) and their offsprings were fed a diet supplemented with either 3% safflower oil (Saf group) or a mixture of 2.4% safflower oil plus 0.6% ethyl eicosapentaenoate (Saf+EPA group) after weaning. The brain docosahexaenoic acid (22:6n-3, DHA) content in the Saf group was less than half of that in the Per group fed a diet supplemented with 3% perilla oil (n-3 fatty acid-sufficient) throughout the duration of the experiment. The DHA level of the Saf+EPA group was restored to the level of the Per group. However, the NGF contents in the hippocampus of the Saf and Saf+EPA groups were half that of the Per group. In the piriform cortex, the NGF content tended to be higher in the Saf and Saf+EPA groups than in the Per group. These results indicate that dietary n-3 fatty acid deficiency and restoration affect NGF levels differently among different brain regions.

Synthesis/secretion of nerve growth factor is associated with cell growth in cultured mouse astroglial cells

Astroglial cells cultured from 8-day-old mouse brain synthesized and secreted nerve growth factor (NGF). An increase in cell density or the withdrawal of serum from the culture medium caused a drastic decrease in the rate of NGF secretion which could be reversed by reculturing at a low cell density or by refeeding with serum-containing culture medium. The cells cultured for two weeks without serum entered the quiescent phase without loss of the activity of an astroglial marker enzyme, glutamine synthetase. These results suggest that NGF secretion by astroglial cells in vitro is regulated in a growth phase-dependent manner. Evidence is also presented to show that NGF secretion is not phase-specific in the cell cycle.

Hericenones C, D and E, stimulators of nerve growth factor (NGF)-synthesis, from the mushroom Hericium erinaceum.

Abstract Novel compounds, hericenones C ( 3 ), D ( 4 ) and ( 5 ) were isolated from the mushroom Hericium erinaceum . These structures were determined by interpretation of the spectral data, and chemical and enzymatic reactions. These compounds have stimulating activity of the synthesis of nerve growth factor (NGF).

Regulation of nerve growth factor synthesis/secretion by catecholamine in cultured mouse astroglial cells

The nerve growth factor (NGF) synthesis/secretion by cultured mouse astroglial cells was modulated by catecholamine. In quiescent cells, epinephrine (EN) and dopamine (DA) markedly increased the NGF content in the conditioned medium (CM). Conversely, EN, DA, and norepinephrine (NE) decreased the NGF content in growing cells. Cholinergic agonists, metacholine and carbamylcholine, slightly increased the NGF content in quiescent cells, but showed no effects on growing cells. Other neurotransmitters tested had no effects on either growing or quiescent cells. These results suggest that catecholamine is one of the molecules responsible for regulation of NGF synthesis/secretion in the mouse brain.

Lipopolysaccharide enhances synthesis of brain‐derived neurotrophic factor in cultured rat microglia

Expression of neurotrophins in pure microglia cultured from embryonic rat brain and the effects of lipopolysaccharide (LPS) on the expression were investigated. In untreated cultures, nerve growth factor (NGF), brain‐derived neurotrophic factor (BDNF), and neurotrophin (NT)‐4/5 mRNAs were detected by use of reverse transcriptase‐polymerase chain reaction but NT‐3 mRNA was not. LPS stimulation caused a marked increase in BDNF mRNA expression in addition to a slight increment of the NT‐4/5 mRNA level; however, the NGF mRNA level was not affected. LPS also increased BDNF‐like immunoreactivity in cultured microglia, an action consistent with an elevation of BDNF mRNA. These results demonstrate that LPS stimulates synthesis of BDNF and probably NT‐4/5, specific ligands for tyrosine kinase receptor TrkB, suggesting that activated microglia, which appear in the damaged brain, participate in neuronal regeneration via production of such neurotrophins. J. Neurosci. Res. 50:1023–1029, 1997. © 1997 Wiley‐Liss, Inc.

N-Propargyl-1 (R)-aminoindan, rasagiline, increases glial cell line-derived neurotrophic factor (GDNF) in neuroblastoma SH-SY5Y cells through activation of NF-κB transcription factor

N-Propargyl-l(R)-aminoindan, rasagiline, an anti-Parkinson drug, was found to increase the protein and mRNA levels of glial cell line-derived neurotrophic factor (GDNF) in human neuroblastoma SH-SY5Y cells, whereas an analogue without a propargyl residue, aminoindan, did not. GDNF is known to protect dopaminergic neurons in animal and cellular models of Parkinsons disease, and the supplement has been tried for the treatment of degenerating dopamine neurons in Parkinsonian patients. In this paper, intracellular mechanism underlying the induction of GDNF was studied. Rasagiline induced phosphorylation of inhibitory subunit (IkappaB) of nuclear factor-kappaB (NF-kappaB), and translocation of active p65 subunit from cytoplasm into nuclei. Activation of NF-kappaB was also quantitatively determined by NF-kappaB p65 transcription assay. Sulfasalazine, an inhibitor of IkappaB kinase, suppressed the activation of NF-kappaB and the increase of GDNF by rasagiline simultaneously, further indicating the involvement of the IkappaB kinase-NF-kappaB pathway. The results on the activation of the transcription factor by rasagiline are discussed in relation to its possible application as a neuroprotective drug to halt declining of neurons in neurodegenerative disorders, such as Parkinsons and Alzheimers diseases.

Diabetic neuropathies in brain are induced by deficiency of BDNF.

Diabetes is known to be one of the risk factors for dementia; however, neuropathic changes in the brain of patients with the disease have not been completely revealed. So in the present study, we investigated the brain function of rats with diabetes induced by streptozotocin (STZ), one of the most commonly used animal models for diabetes. In the diabetic rats, immediately working memory performance was impaired in the Y-maze task and neuronal cytoskeleton proteins such as calbindin, synaptophysin, and syntaxin were reduced. Furthermore, morphological observation by Golgi staining showed a decrease in the number of basal dendrites and abnormality of spine structure. Next, we measured the content of brain-derived neurotrophic factor (BDNF) in the diabetic brain, because BDNF is one of the essential proteins for the maintenance of neuronal functions including synapse function and neuronal transmissions. In the diabetic brains, both protein and mRNA levels of BDNF were severely reduced. These results suggest that, in diabetes, synapse dysfunction is, at least in part, caused by a failure of BDNF synthesis in the brain.

Catecholamines increase nerve growth factor mRNA content in both mouse astroglial cells and fibroblast cells

Previous studies have shown that catecholamines increase the nerve growth factor (NGF) content in medium conditioned by mouse L‐M fibroblast cells and mouse astroglial cells. In this study, the NGF mRNA levels in these cells were measured by Northern blot analysis. In astroglial cells treated with epinephrine (EN), the cellular NGF mRNA level increased prior to accumulation of NGF in the culture medium. 3‐Hydroxytyramine (DA) and norepinephrine (NE) also increased the cellular NGF mRNA content. An increased level of NGF mRNA elicited by EN was also observed in mouse L‐M cells. These results indicate that catecholamines enhance NGF synthesis of L‐M fibroblast cells and astroglial cells by increasing the cellular content of NGF mRNA. The present results also indicate that the effects of catecholamines are not mediated by adrenergic receptors.