Insulin-like growth factor-II in human fetal adrenals: regulation by ACTH, protein kinase C and growth factors

1993 ◽  
Vol 137 (3) ◽  
pp. 533-542 ◽  
Author(s):  
V. Ilvesmäki ◽  
W. F. Blum ◽  
R. Voutilainen
Keyword(s):  
Gene Expression ◽  
Protein Kinase C ◽  
Growth Factors ◽  
Growth Factor ◽  
Culture Medium ◽  
Mrna Levels ◽  
Mrna Accumulation ◽  
Polypeptide Growth Factors ◽  
Kinase C ◽  
Factor Ii

ABSTRACT Insulin-like growth factor-II (IGF-II) may be one of the most important local growth factors in human fetal adrenals (HFAs), where its mRNA levels are upregulated by ACTH. We have investigated whether protein kinase C (PKC)-dependent mechanisms and various polypeptide growth factors participate in the regulation of IGF-II gene expression in cultured HFA cells, and whether HFA cells secrete IGF-II peptide into the culture medium. ACTH enhanced IGF-II mRNA accumulation dose- and time-dependently, maximally four- to sixfold, and this increase was inhibited dose-dependently (0·01-100 μg/l) by 12-O-tetradecanoyl phorbol-13-acetate (TPA), a PKC activator. TPA decreased basal IGF-II mRNA levels by approximately 55%. Staurosporine, a PKC inhibitor, abolished the inhibitory effects of TPA and induced accumulation of IGF-II mRNA. Dibutyryl cyclic AMP, cholera toxin and forskolin increased IGF-II mRNA accumulation as much as ACTH, and TPA inhibited these stimulations in a similar way. ACTH increased the IGF-II peptide concentration in most experiments, but this increase was modest in comparison with IGF-II mRNA changes. TPA, although it decreased IGF-II mRNA levels, tended to increase IGF-II peptide in the medium. Additions of GH, IGF-I and IGF-II to the cell culture medium also increased IGF-II mRNA accumulation. Transforming growth factor-β1 inhibited IGF-II mRNA accumulation to the same extent as TPA. Epidermal growth factor and basic fibroblast growth factor did not change IGF-II mRNA levels. Our results confirm previous reports that ACTH is an important regulator of IGF-II in human fetal adrenals, and show that IGF-II gene expression is under multifactorial control, which includes the PKC system and polypeptide growth factors. Journal of Endocrinology (1993) 137, 533–542

Glucocorticoids increase insulin-like growth factor-II mRNA accumulation in cultured human phaeochromocytoma cells

1994 ◽  
Vol 142 (1) ◽  
pp. 29-35 ◽  
Author(s):  
J Liu ◽  
A I Kahri ◽  
P Heikkilä ◽  
W F Blum ◽  
R Voutilainen
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Protein Kinase ◽  
Primary Cultures ◽  
Cdna Probe ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Mrna Accumulation ◽  
Cytoplasmic Rna ◽  
Factor Ii

Abstract Human phaeochromocytomas abundantly express insulin-like growth factor-II (IGF-II), but its regulation and biological role in these neoplasms is not known at present. To clarify the regulation of IGF-II gene expression in phaeochromocytomas, we studied the effects of glucocorticoids, nerve growth factor (NGF), and protein kinase A and C regulators in primary cultures of human phaeochromocytoma cells. Cytoplasmic RNA was extracted and analysed by Northern and dot blotting with a 32P-labelled cDNA probe for IGF-II. Dexamethasone treatment (500 ng/ml) for 3 and 7 days resulted in a 260% and 515% increase in the accumulation of IGF-II mRNA respectively. The stimulatory effect of dexamethasone was time-and dose-dependent. The increases in the 6·0 and 2·2 kb species of IGF-II mRNAs were the most apparent. Cortisol (1 μg/ml) increased the amount of IGF-II mRNA by threefold compared with the control. NGF (200 ng/ml), dibutyryl cyclic AMP (1 mm) and 12-O-tetradecanoyl phorbol-13-acetate (a protein kinase C activator; 100 ng/ml) had no significant effect on IGF-II mRNA levels. These data suggest that IGF-II gene expression in human phaeochromocytomas may be regulated by microenvironmental glucocorticoids. Journal of Endocrinology (1994) 142, 29–35

scholarly journals Neuroprotection by Peptide Growth Factors against Anoxia and Nitric Oxide Toxicity Requires Modulation of Protein Kinase C

1995 ◽  
Vol 15 (3) ◽  
pp. 440-449 ◽  
Author(s):  
Kenneth Maiese ◽  
Lauraine Boccone
Keyword(s):  
Nitric Oxide ◽  
Signal Transduction ◽  
Protein Kinase C ◽  
Growth Factors ◽  
Growth Factor ◽  
Protein Kinase ◽  
Neuronal Degeneration ◽  
Kinase C ◽  
Peptide Growth Factors ◽  
Pkc Activation

Basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) are neuroprotective during anoxia and nitric oxide (NO) toxicity. Signal transduction systems that modulate protein kinase C (PKC) also can modulate the toxic effects of anoxia and NO. We therefore examined whether PKC was involved in the protective effects of bFGF and EGF during anoxia and NO toxicity. Down-regulation or inhibition of PKC activity before anoxia or NO exposure prevented hippocampal neuronal degeneration. Yet, this protective effect of inhibition of PKC activity was not present with the coadministration of growth factors. Combined inhibition of PKC activity and application of bFGF or EGF lessened the protective mechanisms of the growth factors. In addition, the protective ability of the growth factors was lost during anoxia and NO exposure with the activation of PKC, suggesting that at least a minimal degree of PKC activation is necessary for growth factor protection. Although modulation of PKC activity may be a necessary prerequisite for protection against anoxia and NO toxicity by bFGF and EGF, only inhibition of PKC activity, rather than application of the growth factors, was protective following exposure to NO. These results suggest that the mechanism of protection by bFGF and EGF during anoxia and NO toxicity appears initially to be dependent on a minimum degree of PKC activation, but that other signal transduction pathways independent of PKC also may mediate protection by peptide growth factors.

Cross-talk between receptors with intrinsic tyrosine kinase activity and α1b-adrenoceptors

2000 ◽  
Vol 350 (2) ◽  
pp. 413-419 ◽  
Author(s):  
Luz DEL CARMEN MEDINA ◽  
José VÁZQUEZ-PRADO ◽  
J. Adolfo GARCÍA-SÁINZ
Keyword(s):  
Protein Kinase C ◽  
Growth Factors ◽  
Growth Factor ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Functional Coupling ◽  
Kinase C ◽  
Epidermal Growth ◽  
Phosphoinositide 3 Kinase ◽  
And Function

The effect of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) on the phosphorylation and function of α1b-adrenoceptors transfected into Rat-1 fibroblasts was studied. EGF and PDGF increased the phosphorylation of these adrenoceptors. The effect of EGF was blocked by tyrphostin AG1478 and that of PDGF was blocked by tyrphostin AG1296, inhibitors of the intrinsic tyrosine kinase activities of the receptors for these growth factors. Wortmannin, an inhibitor of phosphoinositide 3-kinase, blocked the α1b-adrenoceptor phosphorylation induced by EGF but not that induced by PDGF. Inhibition of protein kinase C blocked the adrenoceptor phosphorylation induced by EGF and PDGF. The ability of noradrenaline to increase [35S]guanosine 5´-[γ-thio]triphosphate ([35S]GTP[S]) binding in membrane preparations was used as an index of the functional coupling of the α1b-adrenoceptors and G-proteins. Noradrenaline-stimulated [35S]GTP[S] binding was markedly decreased in membranes from cells pretreated with EGF or PDGF. Our data indicate that: (i) activation of EGF and PDGF receptors induces phosphorylation of α1b-adrenoceptors, (ii) phosphatidylinositol 3-kinase is involved in the EGF response, but does not seem to play a major role in the action of PDGF, (iii) protein kinase C mediates this action of both growth factors and (iv) the phosphorylation of α1b-adrenoceptors induced by EGF and PDGF is associated with adrenoceptor desensitization.

scholarly journals Divergent regulation by growth factors and cytokines of 95 kDa and 72 kDa gelatinases and tissue inhibitors or metalloproteinases-1, -2, and -3 in rabbit aortic smooth muscle cells

1996 ◽  
Vol 315 (1) ◽  
pp. 335-342 ◽  
Author(s):  
Rosalind P. FABUNMI ◽  
Andrew H. BAKER ◽  
Edward J. MURRAY ◽  
Robert F. G. BOOTH ◽  
Andrew C. NEWBY
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Growth Factors ◽  
Growth Factor ◽  
Protein Kinase ◽  
Basement Membrane ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Tissue Inhibitors ◽  
Kinase C

The migration and proliferation of vascular smooth muscle cells (SMCs) during neointima formation in atherosclerosis and angioplasty restenosis is mediated by certain growth factors and cytokines, one action of which may be to promote basement-membrane degradation. To test this hypothesis further, the effects of such growth factors and cytokines on the synthesis of two basement-membrane-degrading metalloproteinases, namely the 72 kDa gelatinase (MMP-2, gelatinase A) and the 95 kDa gelatinase (MMP-9, gelatinase B) and three tissue inhibitors of metalloproteinases (TIMPs) was studied in primary cultured rabbit aortic SMCs. Expression of the 95 kDa gelatinase was increased by phorbol myristate acetate, foetal calf serum, thrombin and interleukin-1α (IL-1α); platelet-derived growth factor (PDGF) BB alone had no effect but acted synergistically with IL-1α. A selective protein kinase C inhibitor, Ro 31-8220, abolished induction of the 95 kDa gelatinase. In contrast, none of the agents tested modulated the synthesis of the 72 kDa gelatinase. We conclude that maximal up-regulation of 95 kDa gelatinase expression requires the concerted action of growth factors and inflammatory cytokines mediated, in part, by a protein kinase C-dependent pathway. TIMP-1 and TIMP-2 were highly expressed, and their synthesis was not affected by growth factors or cytokines. Expression of TIMP-3 mRNAs was, however, increased by PDGF and transforming growth factor β, especially in combination. Divergent regulation of gelatinase and TIMP expression implies that either net synthesis or net degradation of basement membrane can be mediated by appropriate combinations of growth factors and cytokines.

Regulation of parathyroid hormone gene expression and peptide secretion in human parathyroid cells

1994 ◽  
Vol 130 (4) ◽  
pp. 394-401 ◽  
Author(s):  
Jianqi Liu ◽  
Arvi I Kahri ◽  
Anna-Maija Teppo ◽  
Raimo Voutilainen
Keyword(s):  
Gene Expression ◽  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Calcium Level ◽  
Mrna Accumulation ◽  
Kinase C ◽  
High Calcium ◽  
Peptide Secretion

Liu J, Kahri AI, Teppo A-M, Voutilainen R. Regulation of parathyroid hormone gene expression and peptide secretion in human parathyroid cells. Eur J Endocrinol 1994;130:394–401. ISSN 0804–4643 In cell cultures prepared from human parathyroid adenomas, parathyroid hormone (PTH) mRNA expression decreased slowly. During short-term incubations (less than 24), a low calcium concentration (0.5 mmol/l) and protein kinase C activator TPA (12-O-tetradecanoyl phorbol 13-acetate) (160 nmol/l) increased PTH secretion (60%; p <0.05), while a high extracellular calcium concentration (2.5 mmol/l) reduced PTH secretion (60%; p<0.05), The TPA could block the inhibitory effect of a high calcium level on PTH peptide secretion. All these agents had no effect on PTH mRNA accumulation in short-term experiments. In long-term cultures (more than 24 h), a low calcium level increased and a high calcium level reduced both PTH mRNA (85 and 34%; p <0.05) and peptide secretion (140 and 80%; p <0.05), respectively. The TPA reduced PTH mRNA accumulation down to 30% (p<0.05) and PTH secretion down to 14% (p<0.05) in a time- and dose-dependent fashion. The TPA also reversed the stimulatory effect of hypocalcemia on PTH mRNA accumulation and peptide secretion. Protein kinase C inhibitors staurosporine (100 nmol/l) and H-7 (1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride) (50 μmol/l) had similar effects to TPA on PTH gene expression and peptide secretion in long-term cultures. The results support the hypothesis that extracellular calcium regulates PTH mRNA accumulation and PTH secretion via protein kinase C. Raimo Voutilainen, Department of Pathology, PO Box 21 (Haartmaninkatu 3), SF-00014 University of Helsinki, Finland

scholarly journals Thrombin increases clusterin mRNA in glomerular epithelial and mesangial cells.

1997 ◽  
Vol 8 (6) ◽  
pp. 906-914 ◽  
Author(s):  
N J Laping ◽  
B A Olson ◽  
B Short ◽  
C R Albrightson
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Specific Effect ◽  
Receptor Activation ◽  
Thrombin Receptor ◽  
Mrna Levels ◽  
Kinase C

Clusterin, a multifunctional protein with complement blocking activity, and fibrin, a product of thrombin's enzymatic activity, are present in the kidney during acute and chronic renal failure. The role of thrombin in regulating clusterin mRNA in the kidney is not known. The effect of thrombin on clusterin mRNA expression was examined in rat glomerular mesangial and glomerular epithelial cells, and cultured human renal proximal tubular epithelial cells by northern blot. Thrombin (10(-8) M) increased clusterin mRNA levels two- to fourfold in glomerular mesangial, glomerular epithelial, and proximal tubule epithelial cells. This was a specific effect of thrombin receptor activation because peptides corresponding to the tethered ligand of the thrombin receptor were also able to increase clusterin mRNA levels. Epidermal growth factor, insulin-like growth factor-1, and transforming growth factor-beta 1 had little or no effect on clusterin mRNA levels. The protein kinase C inhibitor RO-32-0432 (1 microM) inhibited the thrombin-induced increase in clusterin mRNA, suggesting that thrombin receptor activation may regulate renal clusterin mRNA levels through protein kinase C.

Isoenzyme-selective regulation of SERCA2 gene expression by protein kinase C in neonatal rat ventricular myocytes

2003 ◽  
Vol 285 (1) ◽  
pp. C39-C47 ◽  
Author(s):  
Michael J. Porter ◽  
Maria C. Heidkamp ◽  
Brian T. Scully ◽  
Nehu Patel ◽  
Jody L. Martin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Ventricular Myocytes ◽  
Dominant Negative ◽  
Neonatal Rat ◽  
Mrna Levels ◽  
Rat Ventricular Myocytes ◽  
Kinase C ◽  
Neonatal Rat Ventricular Myocytes

Patients with cardiac hypertrophy and heart failure display abnormally slowed myocardial relaxation, which is associated with downregulation of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2) gene expression. We previously showed that SERCA2 downregulation can be simulated in cultured neonatal rat ventricular myocytes (NRVM) by treatment with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA). However, NRVM express three different PMA-sensitive PKC isoenzymes (PKCα, PKCϵ, and PKCδ), which may be differentially regulated and have specific functions in the cardiomyocyte. Therefore, in this study we used adenoviral vectors encoding wild-type (wt) and kinase-defective, dominant negative (dn) mutant forms of PKCα, PKCϵ, and PKCδ to analyze their individual effects in regulating SERCA2 gene expression in NRVM. Overexpression of wtPKCϵ and wtPKCδ, but not wtPKCα, was sufficient to downregulate SERCA2 mRNA levels, as assessed by Northern blotting and quantitative, real-time RT-PCR (69 ± 7 and 61 ± 9% of control levels for wtPKCϵ and wtPKCδ, respectively; P < 0.05 for each adenovirus; n = 8 experiments). Conversely, overexpression of all three dnPKCs appeared to significantly increase SERCA2 mRNA levels (dnPKCδ > dnPKCϵ > dnPKCα). dnPKCδ overexpression produced the largest increase (2.8 ± 1.0-fold; n = 11 experiments). However, PMA treatment was still sufficient to downregulate SERCA2 mRNA levels despite overexpression of each dominant negative mutant. These data indicate that the novel PKC isoenzymes PKCϵ and PKCδ selectively regulate SERCA2 gene expression in cardiomyocytes but that neither PKC alone is necessary for this effect if the other novel PKC can be activated.

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