scholarly journals Regulation of Leydig cell steroidogenesis by extracellular signal-regulated kinase 1/2: role of protein kinase A and protein kinase C signaling

2007 ◽  
Vol 193 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Pulak R Manna ◽  
Youngah Jo ◽  
Douglas M Stocco
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Kinase Inhibitor ◽  
Steroid Synthesis ◽  
Extracellular Signal Regulated Kinase ◽  
Star Protein ◽  
Kinase C ◽  
Extracellular Signal ◽  
Kinase A

The steroidogenic acute regulatory (StAR) protein plays a central role in the regulation of steroid biosynthesis. While steroidogenesis is influenced by many processes, their modes of actions, in a few cases, remain obscure. In this study, we explored the mechanism of action of one such signaling pathway, the extracellular signal-regulated kinase 1/2 (ERK1/2), in regulating StAR expression and steroidogenesis in conjunction with the protein kinase A (PKA) and protein kinase C (PKC) pathways. Using MA-10 mouse Leydig tumor cells, we demonstrate that the activation of PKC and PKA signaling, by phorbol-12-myristate-13-acetate (PMA) and dibutyryl cAMP (dbcAMP)/human chorionic gonadotropin (hCG) respectively, was able to phosphorylate ERK1/2, an event markedly decreased by an upstream kinase inhibitor, U0126. Treatment with PMA enhanced StAR protein expression (associated with a slight increase in progesterone synthesis) but not its phosphorylation (P-StAR), which, in contrast, coordinately increased in response to dbcAMP/hCG. Inhibition of ERK1/2 activity by U0126 decreased PMA-treated StAR expression but increased dbcAMP/hCG-mediated StAR and P-StAR; however, progesterone levels were attenuated. U0126 was found to affect StAR expression and steroidogenesis both at the transcriptional and translational levels. Further studies demonstrated that the effect of U0126 on PMA- and dbcAMP/hCG-mediated StAR expression and steroid synthesis was tightly correlated with the expression of dosage-sensitive sex reversal, adrenal hypoplasia congenita, critical region on the X chromosome, gene 1 (DAX-1) and scavenger receptor class B type 1 (SR-B1). In fact, both DAX-1 and SR-B1 appear to play important roles in hormone-regulated steroidogenesis. These findings clearly demonstrate that the ERK1/2 signaling cascade involved in regulating StAR expression and steroid synthesis is mediated by multiple factors and pathways and is stimulus specific in mouse Leydig cells.

scholarly journals Role of Dosage-Sensitive Sex Reversal, Adrenal Hypoplasia Congenita, Critical Region on the X Chromosome, Gene 1 in Protein Kinase A- and Protein Kinase C-Mediated Regulation of the Steroidogenic Acute Regulatory Protein Expression in Mouse Leydig Tumor Cells: Mechanism of Action

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 187-199 ◽  
Author(s):  
Pulak R. Manna ◽  
Matthew T. Dyson ◽  
Youngah Jo ◽  
Douglas M. Stocco
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Tumor Cells ◽  
Orphan Nuclear Receptor ◽  
Star Protein ◽  
Kinase C ◽  
Leydig Tumor Cells ◽  
Steroidogenic Acute Regulatory ◽  
Kinase A

Dosage-sensitive sex reversal, adrenal hypoplasia congenita, critical region on the X chromosome, gene 1 (DAX-1) is an orphan nuclear receptor that has been demonstrated to be instrumental to the expression of the steroidogenic acute regulatory (StAR) protein that regulates steroid biosynthesis in steroidogenic cells. However, its mechanism of action remains obscure. The present investigation was aimed at exploring the molecular involvement of DAX-1 in protein kinase A (PKA)- and protein kinase C (PKC)-mediated regulation of StAR expression and its concomitant impact on steroid synthesis using MA-10 mouse Leydig tumor cells. We demonstrate that activation of the PKA and PKC pathways, by a cAMP analog dibutyryl (Bu)2cAMP [(Bu)2cAMP] and phorbol 12-myristate 13-acetate (PMA), respectively, markedly decreased DAX-1 expression, an event that was inversely correlated with StAR protein, StAR mRNA, and progesterone levels. Notably, the suppression of DAX-1 requires de novo transcription and translation, suggesting that the effect of DAX-1 in regulating StAR expression is dynamic. Chromatin immunoprecipitation studies revealed the association of DAX-1 with the proximal but not the distal region of the StAR promoter, and both (Bu)2cAMP and PMA decreased in vivo DAX-1-DNA interactions. EMSA and reporter gene analyses demonstrated the functional integrity of this interaction by showing that DAX-1 binds to a DNA hairpin at position −44/−20 bp of the mouse StAR promoter and that the binding of DAX-1 to this region decreases progesterone synthesis by impairing transcription of the StAR gene. In support of this, targeted silencing of endogenous DAX-1 elevated basal, (Bu)2cAMP-, and PMA-stimulated StAR expression and progesterone synthesis. Transrepression of the StAR gene by DAX-1 was tightly associated with expression of the nuclear receptors Nur77 and steroidogenic factor-1, demonstrating these factors negatively modulate the steroidogenic response. These findings provide insight into the molecular events by which DAX-1 influences the PKA and PKC signaling pathways involved in the regulation of the StAR protein and steroidogenesis in mouse Leydig tumor cells. The characterization of protein kinase A- and protein kinase C-mediated steroidogenic acute regulatory (StAR) expression and steroidogenesis suggests that the orphan nuclear receptor DAX-1 is an important regulator of the steroidogenic response in Leydig cells.

The effect of IBMX and prolactin on functional status of cryopreserved bull spermatozoa

2021 ◽  
pp. 52-58
Author(s):  
I. Chistyakova ◽  
V. Denisenko ◽  
T. Kuzmina
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Functional Status ◽  
Protein Kinase A ◽  
Acrosome Reaction ◽  
Kinase Inhibitor ◽  
Kinase C ◽  
Inhibitory Analysis ◽  
Bovine Spermatozoa ◽  
Kinase A

Purpose: investigate the effect of IBMX (activator of protein phosphorylation) and prolactin (PRL) on the functional state of cryopreserved bovine spermatozoa using inhibitory analysis.Materials and methods. Frozen-thawed semen samples from 60 black-and-white bulls was used in the experiments. For capacitation, cells were incubated in Sp-TALP medium supplemented with 6 mg/ml bovine serum albumin and various compounds: an inductor of capacitation (IBMX at concentrations of 1 μM, 10 μM, 50 μM, 100 μM), hormone (PRL at concentrations of 1 ng, 10 ng, 50 ng, 100 ng) and inhibitors of protein kinases C (Ro 31-8220 at a concentration of 10 ng/ml) and protein kinase A (H-89 at a concentration of 10 μM). The incubation was carried out at 38°C in an atmosphere of 5% CO2, 98% humidity for 4 hours. The functional status of the cells was determined by the chlortetracycline test.Results. It was shown that IBMX at all experimental concentrations did not affect the post-ejaculatory maturation (capacitation and acrosome reaction) of spermatozoa, while all concentrations of PRL (1-100 ng/ml) promoted the acrosome reaction in capacitated cells. In the presence of a protein kinase A inhibitor, there was a decrease in number of capacitated and an increase in number of acrosome-reactive spermatozoa under the action of IBMX at a concentration of 100 μM and no changes under the action of a protein kinase C inhibitor. Also, in case of protein kinase C inhibition the PRL-related stimulation of the acrosome reaction was canceled, while the usage of H-89 did not affect the functional status of spermatozoa, mediated by PRL. Thus, the influence of IBMX and PRL on the processes of post-ejaculatory maturation in thawed bovine spermatozoa was studied using the inhibitory analysis.Conclusion. At the capacital stage, all studied IBMX concentrations did not affect the ratio of deconved cells with various functional status. Prode also contributed to the passage of the acrosomous reaction in the rolled spermatozoa after defrosting. Inhibition of protein kinase A when incubating cells with IBMX has mediated the processes of acrosomal exocytosis in ripped cells and did not affect this process under the action of the PRR, while the protein kinase inhibitor C changed the ratio of cells with various functional status in the direction of increasing the percentage of cells at the rate of occasion I did not participate in intracellular action provided IBMX on deconved cells.

scholarly journals Mechanisms of Protein Kinase C Signaling in the Modulation of 3′,5′-Cyclic Adenosine Monophosphate-Mediated Steroidogenesis in Mouse Gonadal Cells

Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3308-3317 ◽  
Author(s):  
Pulak R. Manna ◽  
Ilpo T. Huhtaniemi ◽  
Douglas M. Stocco
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Binding Protein ◽  
Ectopic Expression ◽  
Creb Binding Protein ◽  
Steroid Synthesis ◽  
Kinase C ◽  
Star Gene ◽  
Kinase A

The protein kinase C (PKC) signaling pathway plays integral roles in the expression of the steroidogenic acute regulatory (StAR) protein that regulates steroid biosynthesis in steroidogenic cells. PKC can modulate the activity of cAMP/protein kinase A signaling involved in steroidogenesis; however, its mechanism remains obscure. In the present study, we demonstrate that activation of the PKC pathway, by phorbol 12-myristate 13-acetate (PMA), was capable of potentiating dibutyryl cAMP [(Bu)2cAMP]-stimulated StAR expression, StAR phosphorylation, and progesterone synthesis in both mouse Leydig (MA-10) and granulosa (KK-1) tumor cells. The steroidogenic potential of PMA and (Bu)2cAMP was linked with phosphorylation of ERK 1/2; however, inhibition of the latter demonstrated varying effects on steroidogenesis. Transcriptional activation of the StAR gene by PMA and (Bu)2cAMP was influenced by several factors, its up-regulation being dependent on phosphorylation of the cAMP response element binding protein (CREB). An oligonucleotide probe containing a CREB/activating transcription factor binding region in the StAR promoter was found to bind nuclear proteins in PMA and (Bu)2cAMP-treated MA-10 and KK-1 cells. Chromatin immunoprecipitation studies revealed that the induction of phosphorylated CREB was tightly correlated with in vivo protein-DNA interactions and recruitment of CREB binding protein to the StAR promoter. Ectopic expression of CREB binding protein enhanced CREB-mediated transcription of the StAR gene, an event that was markedly repressed by the adenovirus E1A oncoprotein. Further studies demonstrated that the activation of StAR expression and steroid synthesis by PMA and (Bu)2cAMP was associated with expression of the nuclear receptor Nur77, indicating its essential role in hormone-regulated steroidogenesis. Collectively, these findings provide insight into the mechanisms by which PKC modulates cAMP/protein kinase A responsiveness involved in regulating the steroidogenic response in mouse gonadal cells.

Phosphorylation of NADPH oxidase activator 1 (NOXA1) on serine 282 by MAP kinases and on serine 172 by protein kinase C and protein kinase A prevents NOX1 hyperactivation

2010 ◽  
Vol 24 (6) ◽  
pp. 2077-2092 ◽  
Author(s):  
Yolande Kroviarski ◽  
Maya Debbabi ◽  
Rafik Bachoual ◽  
Axel Pe´rianin ◽  
Marie‐Anne Gougerot‐Pocidalo ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Nadph Oxidase ◽  
Protein Kinase A ◽  
Map Kinases ◽  
Kinase C ◽  
Kinase A

scholarly journals Pituitary adenylate cyclase activating polypeptide as a novel hypophysiotropic factor in fish

2000 ◽  
Vol 78 (3) ◽  
pp. 329-343 ◽  
Author(s):  
Anderson OL Wong ◽  
Wen Sheng Li ◽  
Eric KY Lee ◽  
Mei Yee Leung ◽  
Lai Yin Tse ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Adenylate Cyclase ◽  
Protein Kinase A ◽  
Anterior Pituitary ◽  
Kinase C ◽  
Pituitary Adenylate Cyclase ◽  
Pacap Receptors ◽  
Kinase A

Pituitary adenylate cyclase activating polypeptide (PACAP) is a novel member of the secretin-glucagon peptide family. In mammals, this peptide has been located in a wide range of tissues and is involved in a variety of biological functions. In lower vertebrates, especially fish, increasing evidence suggests that PACAP may function as a hypophysiotropic factor regulating pituitary hormone secretion. PACAP has been identified in the brain-pituitary axis of representative fish species. The molecular structure of fish PACAP is highly homologous to mammalian PACAP. The prepro-PACAP in fish, however, is distinct from that of mammals as it also contains the sequence of fish GHRH. In teleosts, the anterior pituitary is under direct innervation of the hypothalamus and PACAP nerve fibers have been identified in the pars distalis. Using the goldfish as a fish model, mRNA transcripts of PACAP receptors, namely the PAC1 and VPAC1 receptors, have been identified in the pituitary as well as in various brain areas. Consistent with the pituitary expression of PACAP receptors, PACAP analogs are effective in stimulating growth hormone (GH) and gonadotropin (GTH)-II secretion in the goldfish both in vivo and in vitro. The GH-releasing action of PACAP is mediated via pituitary PAC1 receptors coupled to the adenylate cyclase-cAMP-protein kinase A and phospholipase C-IP3-protein kinase C pathways. Subsequent stimulation of Ca2+ entry through voltage-sensitive Ca2+ channels followed by activation of Ca2+-calmodulin protein kinase II is likely the downstream mechanism mediating PACAP-stimulated GH release in goldfish. Although the PACAP receptor subtype(s) and the associated post-receptor signaling events responsible for PACAP-stimulated GTH-II release have not been characterized in goldfish, these findings support the hypothesis that PACAP is produced in the hypothalamus and delivered to the anterior pituitary to regulate GH and GTH-II release in fish.Key words: PACAP, VIP, PAC1 receptor, VPAC1 receptor, VPAC2 receptor, growth hormone, gonadotropin-II, cAMP, protein kinase A, protein kinase C, calcium, pituitary cells, goldfish, and teleost.

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