Pertussis Toxin Stimulates the Secretion of [Met&lt;sup&gt;5&lt;/sup&gt;]-Enkephalin and the Expression of Proenkephalin A mRNA in Bovine Adrenal Medullary Chromaffin Cells

Suh, Hong‐Won; Hudson, Pearlie M.; McMillian, Michael; Hong, Jau-Shyong

doi:10.1159/000109331

Cited by 9 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In most of these cases, the lack of inhibition can in retrospect be accounted for by the use of iso-H7, rather than authentic H7 (76,77), or very low concentrations of authentic H7 (78,79). In almost every study to date, authentic H7 used at concentrations between 50 and 100 M has been found to block gene induction.…”

Section: Discussionmentioning

confidence: 99%

Protein Kinase Inhibitor H7 Blocks the Induction of Immediate-Early Genes zif268 and c-fosby a Mechanism Unrelated to Inhibition of Protein Kinase C but Possibly Related to Inhibition of Phosphorylation of RNA Polymerase II

Kumahara

Ebihara²,

Saffen

1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

1-(5-Isoquinolinesulfonyl)-2-methylpiperazine (H7)has often been used in combination with protein kinase inhibitor (N-(2-guanidinoethyl)-5-isoquinolinesulfonamide) (HA1004) to assess the contribution of protein kinase C (PKC) to cellular processes, including the induction of gene expression. This use of H7 and HA1004 is based upon the fact that H7 inhibits PKC more potently than HA1004 in in vitro assays. Thus, although both compounds are broad spectrum protein kinase inhibitors, inhibition by H7, but not by HA1004, has often been interpreted as evidence for the involvement of PKC in the cellular process under study. Here we describe experiments that show that this interpretation is not correct with regard to the induction of two immediate-early genes, zif268 and c-fos, in PC12D cells. In these studies we confirmed that H7, but not HA1004, potently blocks the induction of zif268 and c-fos mRNA by nerve growth factor, carbachol, phorbol ester, Ca 2؉ ionophore, or forskolin. Surprisingly, however, H7 has no effect on the ability of these agents to activate mitogen-activated protein kinase ( In this study, we show that pretreating PC12D cells with H7, but not with HA1004, significantly reduces levels of phosphorylated RNA polymerase II in vivo. These results suggest that H7 blocks gene expression by inhibiting the phosphorylation of RNA polymerase II, a step required for progression from transcription initiation to mRNA chain elongation.The immediate-early genes zif268 (also termed NGFI-A, egr-1, krox24, TIS8; reviewed in Ref. 1) and c-fos (2) encode transcription factors that have been proposed to function as "third messengers" in intracellular signal transduction cascades that convert information conveyed by extracellular stimuli into genomic responses that underlie growth, differentiation, and long term changes in the behavior of cells (3, 4). We have previously shown that NGF 1 (1) and the carbachol (carbamylcholine) cause the rapid induction of zif268 mRNA in PC12D cells (5). Induction of zif268 mRNA by NGF is mediated by the high affinity NGF receptor, TrkA, which activates the Ras/MAPK cascade (6). Induction by carbachol is mediated by the m1 subtype of muscarinic acetylcholine receptor, which activates phospholipase C to produce the second messengers inositol 1,4,5-trisphosphate and diacylglycerol (5). Increased intracellular levels of inositol 1,4,5-trisphosphate trigger the release of Ca 2ϩ from internal stores, which in turn opens "capacitative influx" Ca 2ϩ channels in the cell membrane, resulting in a sustained influx of extracellular Ca 2ϩ .2 Increased levels of diacylglycerol activate PKC. Both the sustained increase in intracellular Ca 2ϩ and the activation of PKC contribute to the induction of zif268 mRNA (5), at least in part by activating the MAPK cascade (81). Activation of the MAPK cascade is therefore a common element in the intracellular signaling events leading to gene expression that are initiated by NGF and carbachol in PC12D cells.In the course of investigating the involvement of PKC in t...

show abstract

Section: Discussionmentioning

confidence: 99%

Protein Kinase Inhibitor H7 Blocks the Induction of Immediate-Early Genes zif268 and c-fosby a Mechanism Unrelated to Inhibition of Protein Kinase C but Possibly Related to Inhibition of Phosphorylation of RNA Polymerase II

Kumahara

Ebihara²,

Saffen

1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…The release of AM and PAMP by dbcAMP occurs along the same lines as the release of methionine‐enkephalin and catecholamines evoked by 8‐Br‐cAMP, another membrane permeable analogue of cAMP, or by forskolin, an activator of adenylyl cyclase [32–34]. In addition, changes in ir‐AM, ir‐PAMP and chromogranin B by dbcAMP were attenuated by H89, strongly suggesting that the cAMP‐dependent protein kinase pathway is involved in the gradual release of these peptides from chromaffin granules.…”

Section: Discussionmentioning

confidence: 97%

“…Adrenal medulla and pheochromocytoma contain various biologically active peptides other than AM and PAMP, the synthesis of which is regulated by various intracellular signals. The regulation of AM and PAMP, as well as that of the corresponding mRNA, seem to be unique in comparison with other peptides because elevation of cAMP increased the expression of mRNAs encoding the soluble proteins enkephalin [33,34], chromogranin B, neuropeptide Y and a neuroendocrine‐specific gene product, VGF [39].…”

Section: Discussionmentioning

confidence: 99%

Cyclic AMP‐dependent synthesis and release of adrenomedullin and proadrenomedullin N‐terminal 20 peptide in cultured bovine adrenal chromaffin cells

Kobayashi¹,

Yamamoto²,

Kïtamura³

et al. 1999

European Journal of Biochemistry

View full text Add to dashboard Cite

Adrenomedullin and proadrenomedullin N-terminal 20 peptide are peptides with multiple physiological functions and are most abundant in adrenal medulla. We studied whether the cAMP-dependent pathway is involved in the regulation of synthesis and release of adrenomedullin and proadrenomedullin N-terminal 20 peptide in cultured bovine adrenal chromaffin cells. Exposure of the cells to dibutyryl cAMP (dbcAMP) increased a progressive accumulation of immunoreactive-adrenomedullin and immunoreactive-proadrenomedullin N-terminal 20 peptide in the extracellular medium, while reciprocally decreasing their cellular content in a time-dependent manner. The decrease of levels of both peptides in the cells was much greater in extent than the increase of the peptides in the medium. H89, an inhibitor of cAMP-dependent protein kinase attenuated these changes, induced by dbcAMP. The resulting changes by dbcAMP and H89 were similar to those of chromogranin B, a marker peptide of chromaffin granule. Northern blot analysis showed that the mRNA encoding these peptides, detected as a band of 1.6 kb, was decreased by the treatment with dbcAMP. The effect of dbcAMP on mRNA was attenuated by H89, and was reversible as the decreased mRNA level caused by dbcAMP could be returned to control levels by culturing cells after removal of dbcAMP. These results suggest that the cAMP-dependent protein kinase pathway stimulates the release of adrenomedullin and proadrenomedullin N-terminal 20 peptide, whereas it lowers synthesis of these peptides via the reduction of their transcript level. The AM gene also produces another biologically active peptide, proadrenomedullin N-terminal 20 peptide (PAMP) [10±13]. The C-terminal of PAMP is amidated similarly to AM, but its amino acid sequence differs from that of AM. Although PAMP has hypotensive action [12], the mechanism of action of PAMP is different from that of AM, and has not yet been well defined. Several mechanisms have been proposed for the hypotensive action of PAMP depending on vascular beds and species, including: reduction of vascular tone by suppressing norepinephrine release from sympathetic nerve in rat mesenteric arteries [14], dilatation of the hindlimb vascular bed by a direct cAMP-dependent mechanism in cat [15], and dilatation by a tone-dependent mechanism in rat hindlimb vascular bed [16].The immunoreactivity and mRNA of AM and PAMP are most abundant in the adrenal medulla [11,17±20]. However, the intracellular regulatory mechanisms of the synthesis and release of the both peptides are not known. cAMP is a second messenger involved in the regulation of a wide variety of cell functions. The cAMP level in adrenal chromaffin cells is regulated by neurotransmitters and hormones such as acetylcholine [21], dopamine [22], vasoactive intestinal polypeptide [23] and pituitary adenylate cyclase-activating peptide [24]. Therefore, in this paper, we studied whether the cAMP-dependent pathway was involved in the synthesis and release of AM and PAMP in bovine adrenal chromaffin cells.

show abstract

“…For example, the treatment of chromaffin cells with 12-O-tetradecanoylphorbol 13-acetate (a PKC activator), forskolin (an adenyl cyclase activator), or 8-bromo-cyclic AMP (a cyclic AMP analogue) increases the secretion of ME as well as the expression of proENK mRNA (Eiden et al ., 1984 ;Quach et al ., 1984 ;Inturrisi et al ., 1988 ;Kley, 1988 ;Farin et al ., 1990 ;Sub et al ., 1993) . In addition, treatments with calcium channel blockers or a calmodulin antagonist effectively inhibit the increases of both ME secretion and the expression of the proENK gene (Kley et al ., 1987 ;Stachowiak et al ., 1991 ;Suh et al, 1992aSuh et al, , 1993 . Our studies as well as those from other laboratories have demonstrated that third messengers such as AP-1 transcription factors play a role in the regulation of the proENK gene (Sonnenberg et al ., 1989 ;Mar et al ., 1992 ;Suh et al, 1993) .…”

Section: Introductionmentioning

confidence: 99%

Expression of the Proenkephalin A Gene and [Met⁵]‐Enkephalin Secretion Induced by Arachidonic Acid in Bovine Adrenal Medullary Chromaffin Cells: Involvement of Second Messengers

Suh

Hudson

Hong

1995

Journal of Neurochemistry

Self Cite

View full text Add to dashboard Cite

We have previously reported that arachidonic acid (AA) increases the long‐term secretion of [Met5]‐enkephalin (ME) and the expression of proenkephalin A (proENK) mRNA in bovine adrenal medullary chromaffin (BAMC) cells. To characterize the underlying signal transductional mechanisms for the AA‐induced responses, the interactions of AA with several second messenger systems were studied. Long‐term (24‐h) treatment with AA (100 µM) increased both the secretion of ME and the expression of proENK mRNA. Pretreatment of BAMC cells with nimodipine (1 µM), but not with ω‐conotoxin GVIA (1 µM), inhibited the secretion of ME and the expression of proENK mRNA induced by AA. Calmidazolium (1 µM), a calmodulin antagonist, also significantly inhibited AA‐induced responses. However, a protein kinase C (PKC) inhibitor, sphingosine (36 µM), was ineffective in blocking AA‐induced responses. In addition, the down‐regulation of PKC by phorbol 12‐myristate 13‐acetate (0.1 µM) for 48 h did not inhibit the AA‐induced responses. Forskolin (5 µM), an adenyl cyclase activator, alone increased the secretion of ME as well as proENK mRNA levels and, when coincubated with AA, showed an additive effect on the secretion of ME and the levels of proENK mRNA. The results suggest that the Ca2+/calmodulin pathway, but not the protein kinase A or PKC pathway, is partially involved in mediating the AA‐induced increases of the long‐term secretion of ME and the levels of proENK mRNA.

show abstract

Pertussis Toxin Stimulates the Secretion of [Met<sup>5</sup>]-Enkephalin and the Expression of Proenkephalin A mRNA in Bovine Adrenal Medullary Chromaffin Cells

Cited by 9 publications

References 13 publications

Protein Kinase Inhibitor H7 Blocks the Induction of Immediate-Early Genes zif268 and c-fosby a Mechanism Unrelated to Inhibition of Protein Kinase C but Possibly Related to Inhibition of Phosphorylation of RNA Polymerase II

Protein Kinase Inhibitor H7 Blocks the Induction of Immediate-Early Genes zif268 and c-fosby a Mechanism Unrelated to Inhibition of Protein Kinase C but Possibly Related to Inhibition of Phosphorylation of RNA Polymerase II

Cyclic AMP‐dependent synthesis and release of adrenomedullin and proadrenomedullin N‐terminal 20 peptide in cultured bovine adrenal chromaffin cells

Expression of the Proenkephalin A Gene and [Met⁵]‐Enkephalin Secretion Induced by Arachidonic Acid in Bovine Adrenal Medullary Chromaffin Cells: Involvement of Second Messengers

Contact Info

Product

Resources

About

Pertussis Toxin Stimulates the Secretion of [Met<sup>5</sup>]-Enkephalin and the Expression of Proenkephalin A mRNA in Bovine Adrenal Medullary Chromaffin Cells

Cited by 9 publications

References 13 publications

Protein Kinase Inhibitor H7 Blocks the Induction of Immediate-Early Genes zif268 and c-fosby a Mechanism Unrelated to Inhibition of Protein Kinase C but Possibly Related to Inhibition of Phosphorylation of RNA Polymerase II

Protein Kinase Inhibitor H7 Blocks the Induction of Immediate-Early Genes zif268 and c-fosby a Mechanism Unrelated to Inhibition of Protein Kinase C but Possibly Related to Inhibition of Phosphorylation of RNA Polymerase II

Cyclic AMP‐dependent synthesis and release of adrenomedullin and proadrenomedullin N‐terminal 20 peptide in cultured bovine adrenal chromaffin cells

Expression of the Proenkephalin A Gene and [Met5]‐Enkephalin Secretion Induced by Arachidonic Acid in Bovine Adrenal Medullary Chromaffin Cells: Involvement of Second Messengers

Contact Info

Product

Resources

About

Expression of the Proenkephalin A Gene and [Met⁵]‐Enkephalin Secretion Induced by Arachidonic Acid in Bovine Adrenal Medullary Chromaffin Cells: Involvement of Second Messengers