Adrenergic differentiation potential in PC12 cells: influence of sodium butyrate and dexamethasone

Ebert, Steven N.; Lindley, Steven E.; Bengoechea, Tasha; Bain, Deborah L.; Wong, Dona L.

doi:10.1016/s0169-328x(97)00032-6

Cited by 26 publications

(25 citation statements)

References 27 publications

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“…1A). As previously reported by us and by others (9,(15)(16)(17), SB (C4) treatment of PC12 cells caused a 4-fold increase in ppEnk mRNA expression when compared with the untreated control group (p Ͻ 0.05). In contrast, SCFAs having shorter carbon 848 chains, such as acetate (C2; the most common SCFA present in either the gut or the bloodstream), did not affect ppEnk or TH mRNA levels (Fig.…”

Section: Resultssupporting

confidence: 83%

Stereospecific Regulation of Tyrosine Hydroxylase and Proenkephalin Genes by Short-Chain Fatty Acids in Rat PC12 Cells

et al. 2004

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Circulating short-chain fatty acids (SCFAs) are primarily derived from bacterial fermentation of carbohydrates in the colon where they function as physiologic modulators of epithelial cell maturation. Butyrate has been shown to induce tyrosine hydroxylase, the rate-limiting enzyme of catecholamine synthesis, and enkephalin neuropeptide gene transcription, suggesting a role in perinatal sympathoadrenal stress-adaptation. We sought to determine whether there were SCFA structural requirements for this effect. Nine biologically relevant SCFAs and butyrate derivatives were tested in an in vitro model (PC12, rat pheochromocytoma cells) for their ability to regulate neurotransmitter-related gene expression. Our results revealed that among all the studied SCFAs, only propionate and butyrate increased tyrosine hydroxylase and proenkephalin mRNA levels. The functional activity was selective to the carbon atom chain length and associated with the presence of an ethyl moiety in the carbon atom backbone chain. Modifications or absence of this domain affected the gene induction response, suggesting a receptor-mediated mechanism(s). Moreover, propionate, butyrate, and the drug 4-phenylbutyrate were each shown to regulate transmitter genes via at least three independent mechanisms: histone hyperacetylation, cAMP signaling, or peroxisome proliferator-activated receptor gamma-mediated pathways. Thus, the biologic impact of SCFAs on catecholaminergic and opioid systems depend on the activation of SCFA-specific, dose-specific, and gene-specific molecular mechanisms. We speculate that 1) circulating levels of SCFAs may influence sympathoadrenal transmitter biosynthesis and hence whole animal stress-adaptive responsiveness after birth, and 2) the adverse effects of antibiotics on delayed acquisition of postnatal gut flora may affect this apparent evolutionary advantage of gut colonization. Sympathoadrenal transmitter systems mature to adult capacity a week or more after birth in response to progressive cholinergic innervation, exposure to growth factors, and hormonal influences from both the hypothalamic-pituitary-adrenal cortical and thyroid hormonal systems (1-6). Although the importance of these conventional control mechanisms is well established, the evolutionary significance of other exogenous stimuli can be considered in a broader view of environmentally derived signal-transduction. For example, the delayed period of adrenal transmitter accumulation after birth coincides with the time taken to establish full enteral feedings, colonization of the intestine, and attendant production of SCFA (7). Moreover, in the rat (as well as in humans), this time frame is far longer than the capacity of the chromaffin cell to rapidly induce biosynthesis of either catecholamines or enkephalins, which can occur in a matter of hours (8)

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Section: Resultssupporting

confidence: 83%

Stereospecific Regulation of Tyrosine Hydroxylase and Proenkephalin Genes by Short-Chain Fatty Acids in Rat PC12 Cells

et al. 2004

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“…Consistent with this role, a functional GRE was identified at Ϫ513 bp in the upstream sequences of the rat PNMT gene when it was first cloned (Ross et al, 1990). At best, however, only weak glucocorticoid responses are elicited through this GRE based on changes in PNMT promoter-reporter gene expression and PNMT mRNA expression in vitro Ebert et al, 1997). Two additional glucocorticoid response elements have now been identified distal to the original GRE.…”

Section: Discussionmentioning

confidence: 89%

“…Glucocorticoids are important regulators of PNMT gene expression, influencing adrenergic differentiation (Bohn et al, 1981;Teitelman et al, 1982;Bohn, 1983;Michelson and Anderson, 1992;Wong et al, 1992a;Schmid et al, 1995;Ebert et al, 1997) and the induction of PNMT in response to acute and chronic stress (Sabban et al, 1995;Sabban et al, 1998;Serova et al, 1998). Consistent with this role, a functional GRE was identified at Ϫ513 bp in the upstream sequences of the rat PNMT gene when it was first cloned (Ross et al, 1990).…”

Section: Discussionmentioning

confidence: 91%

Glucocorticoid Responsiveness of the Rat PhenylethanolamineN-Methyltransferase Gene

Tai

Claycomb²,

Her³

et al. 2002

Mol Pharmacol

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Two newly identified, overlapping (1 bp) glucocorticoid response elements (GREs) at Ϫ759 and Ϫ773 bp in the promoter of the rat phenylethanolamine N-methyltransferase (PNMT; EC 2.1.1.28) gene are primarily responsible for its glucocorticoid sensitivity, rather than the originally identified Ϫ533-bp GRE. A dose-dependent increase in PNMT promoter activity was observed in RS1 cells transfected with a wild-type PNMT promoter-luciferase reporter gene construct and treated with dexamethasone (maximum activation at 0.1 M). The type II glucocorticoid receptor antagonist RU38486 (10 M) fully inhibited dexamethasone (1 M) activation of the PNMT promoter, consistent with classical glucocorticoid receptors mediating corticosteroid-stimulated transcriptional activity. Relative IC 50 values from gel mobility shift competition assays showed that the Ϫ759-bp GRE has a 2-fold greater affinity for the glucocorticoid receptor than the Ϫ773-bp GRE. Site-directed mutation of the Ϫ533-, Ϫ759-, and Ϫ773-bp GREs alone or in tandem demonstrated that the Ϫ759-bp GRE was also functionally more important, but both the Ϫ759-and Ϫ773-bp GREs are required for maximum glucocorticoid responses. Moreover, the Ϫ533-bp GRE, rather than increasing glucocorticoid sensitivity of the promoter, may limit corticosteroid responsiveness mediated via the Ϫ759-and Ϫ773-bp GREs. Finally, the glucocorticoid receptor bound to the Ϫ759-and Ϫ773-bp GREs interacts cooperatively with Egr-1 and/or AP-2 to stimulate PNMT promoter activity in RS1 cells treated with dexamethasone. In contrast, glucocorticoid receptors bound to the Ϫ533-bp GRE only seem to participate in synergistic activation of the PNMT promoter through interaction with activator protein 2.Glucocorticoids are critical regulators of phenylethanolamine N-methyltransferase (PNMT; EC 2.1.1.28), the final enzyme in epinephrine biosynthesis, exerting both transcriptional and post-transcriptional influences. In vivo studies in rats have shown that depletion of corticosteroids by hypophysectomy decreases PNMT mRNA and enzyme expression (Evinger et al

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“…In the presence of nerve growth factor (NGF), the cells gradually exit the mitotic cycle and begin to differentiate, developing axonal projections, electrical excitability, and the characteristics of two distinct phenotypes, cholinergic, and catecholaminergic neurons (Fujita et al, 1989;Song et al, 1998;Teng and Greene, 1994). These specific phenotypes are highly targeted by DEX treatment in vivo (Ebert et al, 1997;Hu et al, 1996;Kreider et al, 2005aKreider et al, , b, 2006Reznikov et al, 2004;Slotkin et al, 1991;Zahalka et al, 1993). Accordingly, the PC12 model is particularly appropriate to evaluate the mechanisms underlying the effects of DEX on neural cell replication and differentiation into defined phenotypes.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies of glucocorticoids in this model have typically used excessive concentrations and have not focused on specific neurodevelopmental stages (Berse and Blusztajn, 1997;Ebert et al, 1997;Hagerty et al, 2001;Lucas and Thoenen, 1977;Schubert et al, 1980;Unsicker et al, 1978). Accordingly, the present study utilized DEX concentrations as low as 0.01 mM and up to 10 mM.…”

Section: Introductionmentioning

confidence: 99%

Adverse Neurodevelopmental Effects of Dexamethasone Modeled in PC12 Cells: Identifying the Critical Stages and Concentration Thresholds for the Targeting of Cell Acquisition, Differentiation and Viability

Jameson

Seidler

Qiao

et al. 2005

Neuropsychopharmacol

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The use of dexamethasone (DEX) to prevent respiratory distress in preterm infants is suspected to produce neurobehavioral deficits. We used PC12 cells to model the effects of DEX on different stages of neuronal development, utilizing exposures from 24 h up to 11 days and concentrations from 0.01 to 10 mM, simulating subtherapeutic, therapeutic, and high-dose regimens. In undifferentiated cells, even at the lowest concentration, DEX inhibited DNA synthesis and produced a progressive deficit in the number of cells as evaluated by DNA content, whereas cell growth (evaluated by the total protein to DNA ratio) and cell viability (Trypan blue exclusion) were promoted. When cell differentiation was initiated with nerve growth factor, the simultaneous inclusion of DEX still produced a progressive deficit in cell numbers and promoted cell growth and viability while retarding the development of neuritic projections as monitored by the membrane/total protein ratio. Again, even 0.01 mM DEX was effective. We next assessed effects at mid-differentiation by introducing nerve growth factor for 4 days followed by coexposure to DEX. Although effects on cell number, growth, and neurite extension were still detectable, the outcomes were generally less notable. DEX also shifted the fate of PC12 cells away from the cholinergic phenotype and toward the adrenergic phenotype, with the maximum effect achieved at the outset of differentiation. Our results indicate that DEX directly disrupts neuronal cell replication, differentiation, and phenotype at concentrations below those required for the therapy of preterm infants, providing a mechanistic link between glucocorticoid use and neurodevelopmental sequelae.

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Adrenergic differentiation potential in PC12 cells: influence of sodium butyrate and dexamethasone

Cited by 26 publications

References 27 publications

Stereospecific Regulation of Tyrosine Hydroxylase and Proenkephalin Genes by Short-Chain Fatty Acids in Rat PC12 Cells

Stereospecific Regulation of Tyrosine Hydroxylase and Proenkephalin Genes by Short-Chain Fatty Acids in Rat PC12 Cells

Glucocorticoid Responsiveness of the Rat PhenylethanolamineN-Methyltransferase Gene

Adverse Neurodevelopmental Effects of Dexamethasone Modeled in PC12 Cells: Identifying the Critical Stages and Concentration Thresholds for the Targeting of Cell Acquisition, Differentiation and Viability

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