scholarly journals Growth hormone stimulates osteoprotegerin expression and secretion in human osteoblast-like cells

2007 ◽  
Vol 192 (3) ◽  
pp. 639-645 ◽  
Author(s):  
E Mrak ◽  
I Villa ◽  
R Lanzi ◽  
M Losa ◽  
F Guidobono ◽  
...  
Keyword(s):  
Janus Kinase ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Osteoblast ◽  
Rt Pcr ◽  
Concentration Dependent Manner ◽  
Gh Receptor ◽  
Igf I ◽  
Intracellular Pathway ◽  
Stimulation Of

It is presently thought that osteoprotegerin (OPG) is a cytokine involved in the regulation of osteoblast/osteoclast crosstalk and maintenance of bone mass. Recent studies showed that GH replacement therapy in GH-deficient patients was able to induce a significant increase of OPG in the plasma, as well as in the cortical and the trabecular bone. In order to determine whether GH could directly modulate OPG secretion, the effect of GH on human osteoblast-like cells (hOB) in primary culture was studied. After detecting the presence of the mRNA for the GH receptor (GHR) by RT-PCR, hOB were exposed to increasing concentrations of GH, from 0.1 to 25 ng/ml, for 24 h. The results showed that GH exposure was able to stimulate OPG secretion in a concentration-dependent manner. In addition, the OPG mRNA levels were increased, indicating that the hormone has a stimulatory effect on gene expression. The stimulatory effect on OPG expression and production was prevented by exposing the cells to tyrphostin AG490 (10 μM), an inhibitor of Janus kinase 2, which is one of the kinases involved in the intracellular pathway activated by the binding of GH to its receptor. Similar results were obtained when the cells were exposed to a receptor antagonist of GH, pegvisomant at 50 nM. GH exposure neither induced an increase in IGF-I expression nor secretion in hOB. These results suggest that the stimulation of OPG production induced by GH in hOB is specific and receptor mediated and further support the view that GH is able to modulate bone remodeling by directly influencing osteoblast–osteoclast crosstalk.

Expression of proteinase-activated receptor 2 on human primary gastrointestinal myofibroblasts and stimulation of prostaglandin synthesis

2005 ◽  
Vol 83 (7) ◽  
pp. 605-616 ◽  
Author(s):  
Michelle L Seymour ◽  
David G Binion ◽  
Steven J Compton ◽  
Morley D Hollenberg ◽  
Wallace K MacNaughton
Keyword(s):  
Small Intestine ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Rt Pcr ◽  
Concentration Dependent Manner ◽  
Cell Functions ◽  
Cox 2 ◽  
Colonic Cells ◽  
Cox 1 ◽  
Stimulation Of

It is known that subepithelial myofibroblast-derived prostaglandin (PG)E2 can regulate intestinal epithelial cell functions, and that proteinase-activated receptor-2 (PAR2) is abundantly expressed in the gastrointestinal tract. Since PAR2 activation has previously been associated with stimulation of PGE2 synthesis, we hypothesized that PAR2 expressed on primary human gastrointestinal myofibroblasts regulates PGE2 synthesis via cyclooxygenase (COX)-1 and (or) COX-2, and associated PGE synthases. Primary human myofibroblasts were isolated from the resection tissue of the esophagus, small intestine, and colon. Expression of functional PAR2 was determined by RT-PCR and by calcium mobilization in Fura-2/AM-loaded cells. Trypsin and the selective PAR2-activating peptide (PAR2-AP) SLIGRL-NH2 stimulated PGE2 synthesis in a concentration-dependent manner, as measured by enzyme immunoassay. Selective COX inhibition showed PAR2-induced PGE2 synthesis to be COX-1 dependent in esophageal myofibroblasts and both COX-1 and COX-2 dependent in colonic cells, consistent with the distribution of COX-1 and COX-2 expression. Although both cytosolic and microsomal PGE synthases were expressed in cells from all tissues, microsomal PGE synthases were expressed at highest levels in the colonic myofibroblasts. Activation of PAR2 on gastrointestinal myofibroblasts stimulates PGE2 synthesis via different pathways in the colon than in the esophagus and small intestine. Key words: Proteinase-activated receptor, myofibroblast, cyclooxygenase, PGE synthase, prostaglandin E2, esophagus, small intestine, colon.

Cortisol decreases IGF-I mRNA levels in human osteoblast-like cells

1996 ◽  
Vol 149 (3) ◽  
pp. 397-403 ◽  
Author(s):  
D Swolin ◽  
C Brantsing ◽  
G Matejka ◽  
C Ohlsson
Keyword(s):  
Inhibitory Effect ◽  
Human Muscle ◽  
Mrna Levels ◽  
Human Osteoblast ◽  
Rt Pcr ◽  
Rnase Protection ◽  
Mrna Transcripts ◽  
Igf I ◽  
Males And Females ◽  
Pcr Assays

Abstract Excess levels of glucocorticoids are known to cause osteoporosis. It is speculated that the effect of glucocorticoids could be mediated via regulation of IGF-I. The aims of the present study were to detect and quantify the expression of IGF-I and/or IGF-II mRNA transcripts in human osteoblast-like cells and to investigate whether glucocorticoids regulate the expression of IGF-I mRNA transcripts in human osteoblast-like cells. Cultures of human osteoblast-like cells from trabecular bone were established. The IGF-IA and IGF-IB transcripts were detected in human osteoblast-like cells from seven out of nine patients while the IGF-II transcript was detected in human osteoblast-like cells from eight out of nine patients, as determined by RT-PCR assays. Human osteoblast-like cells, as well as human muscle tissue, expressed approximately 1/10 of the IGF-I mRNA levels found in liver, as determined by RNase protection solution hybridization assay. The IGF-I mRNA levels did not decrease with age in the human osteoblast-like cells and no difference was seen between males and females. However, cortisol (10−6 mol/l) decreased IGF-I mRNA levels. In summary, the present study has shown that human osteoblast-like cells express IGF-I and IGF-II mRNA transcripts and that cortisol down-regulates the IGF-I mRNA levels, indicating that some of the inhibitory effect of glucocorticoids on bone formation in humans is mediated via a reduced autocrine/paracrine expression of IGF-I. Journal of Endocrinology (1996) 149, 397–403

scholarly journals Cortisol increases growth hormone-receptor expression in human osteoblast-like cells

1998 ◽  
Vol 156 (1) ◽  
pp. 99-105 ◽  
Author(s):  
D Swolin-Eide ◽  
A Nilsson ◽  
C Ohlsson
Keyword(s):  
Growth Hormone ◽  
Control Culture ◽  
Receptor Expression ◽  
Serum Starvation ◽  
Maximal Effect ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Osteoblast ◽  
Receptor Mrna ◽  
Gh Receptor

It is well known that high levels of glucocorticoids cause osteoporosis and that physiologic levels of growth hormone (GH) are required for normal bone remodeling. It has been suggested that glucocorticoids regulate GH-responses via the regulation of GH-receptor expression. The aim of the present study was to investigate whether cortisol plays a role in the regulation of GH-receptor expression in cultured human osteoblasts. The effect of serum starvation and cortisol on GH-receptor expression was tested in human osteoblast (hOB)-like cells. Serum starvation for 24 h resulted in an increase in GH-receptor mRNA levels (90 +/- 1% over control culture). Cortisol increased GH-receptor mRNA levels in a dose-dependent manner with a maximal effect at 10(-6)M. The stimulating effect of cortisol on GH-receptor mRNA levels was time-dependent, reaching a peak 12 h after the addition of cortisol (126 +/- 29% over control culture) and remaining up to 12 h later. The increase in GH-receptor mRNA levels was accompanied by an increase in 125I-GH binding which reached a maximum at 24 h (196 +/- 87% over control culture). In conclusion, glucocorticoids increase GH-receptor expression in hOB-like cells. Further studies are needed to clarify whether glucocorticoid-induced regulation of the GH-receptor is important in human bone physiology.

scholarly journals Dexamethasone administration attenuates the inhibitory effect of lipopolysaccharide on IGF-I and IGF-binding protein-3 in adult rats

2005 ◽  
Vol 185 (3) ◽  
pp. 467-476 ◽  
Author(s):  
Teresa Priego ◽  
Miriam Granado ◽  
Ana Isabel Martín ◽  
Asunción López-Calderón ◽  
María Angeles Villanúa
Keyword(s):  
Gene Expression ◽  
Inhibitory Effect ◽  
Mrna Levels ◽  
Serum Concentrations ◽  
Gh Receptor ◽  
Its Gene ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

The aim of this study was to investigate whether glucocorticoid administration had a beneficial effect on serum concentrations of insulin-like growth factor I (IGF-I) and on IGF-binding protein 3 (IGFBP-3) in rats injected with lipopolysaccharide (LPS). Adult male rats were injected with LPS or saline and pretreated with dexamethasone or saline. Dexamethasone administration decreased growth hormone (GH) receptor and IGF-I mRNA levels in the liver of control rats. LPS decreased GH receptor and IGF-I gene expression in the liver of saline-treated rats but not in the liver of dexamethasone-pretreated rats. In the kidney, GH receptor mRNA levels were not modified by dexamethasone or LPS treatment. However, LPS decreased renal IGF-I gene expression and dexamethasone pretreatment prevented this decrease. Serum concentrations of IGF-I were decreased by LPS, and dexamethasone pretreatment attenuated this effect. The gene expression of IGFBP-3 in the liver and kidney and its circulating levels were decreased by LPS. In control rats dexamethasone increased circulating IGFBP-3 and its gene expression in the liver, and decreased the proteolysis of this protein. Dexamethasone pretreatment attenuated the LPS-induced decrease in IGFBP-3 gene expression in the liver and prevented the LPS-induced decrease in IGFBP-3 gene expression in the kidney. Moreover, dexamethasone pretreatment attenuated the LPS-induced decrease in serum concentrations of IGFBP-3 and decreased the LPS-induced IGFBP-3 proteolysis in serum. In conclusion, dexamethasone pretreatment partially attenuates the inhibitory effect of LPS on serum IGF-I by blocking the decrease of its gene expression in the kidney as well as by attenuating the decrease in serum concentrations of IGFBP-3.

scholarly journals IGF-I regulates pro-opiomelanocortin and GH gene expression in the mouse pituitary gland

2003 ◽  
Vol 178 (1) ◽  
pp. 71-82 ◽  
Author(s):  
J Honda ◽  
Y Manabe ◽  
R Matsumura ◽  
S Takeuchi ◽  
S Takahashi
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Northern Blotting ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Gh Treatment ◽  
Gh Receptor ◽  
Pomc Mrna ◽  
Igf I ◽  
Mouse Pituitary

IGF-I is expressed in somatotrophs, and IGF-I receptors are expressed in most somatotrophs and some corticotrophs in the mouse pituitary gland. Our recent study demonstrated that IGF-I stimulates the proliferation of corticotrophs in the mouse pituitary. These results suggested that somatotrophs regulate corticotrophic functions as well as somatotrophic functions by the mediation of IGF-I molecules. The present study aimed to clarify factors regulating pituitary IGF-I expression and also the roles exerted by IGF-I within the mouse anterior pituitary gland. Mouse anterior pituitary cells were isolated and cultured under serum-free conditions. GH (0.5 or 1 microg/ml), ACTH (10(-8) or 10(-7) M), GH-releasing hormone (GHRH; 10(-8) or 10(-7) M), dexamethasone (DEX; 10(-8) or 10(-7) M) and estradiol-17beta (e2; 10(-11) or 10(-9) M) were given for 24 h. IGF-I mRNA levels were measured using competitive RT-PCR, and GH and pro-opiomelanocortin (POMC) mRNA levels were measured using Northern blotting analysis. GH treatment significantly increased IGF-I mRNA levels (1.5- or 2.1-fold). ACTH treatment did not alter GH and IGF-I mRNA levels. IGF-I treatment decreased GH mRNA levels (0.7- or 0.5-fold), but increased POMC mRNA levels (1.8-fold). GH treatment (4 or 8 microg/ml) for 4 days increased POMC mRNA levels. GHRH treatment increased GH mRNA levels (1.3-fold), but not IGF-I mRNA levels. DEX treatment significantly decreased IGF-I mRNA levels (0.8-fold). e2 treatment did not affect IGF-I mRNA levels. GH receptor mRNA, probably with GH-binding protein mRNA, was detected in somatotrophs, and some mammotrophs and gonadotrophs by in situ hybridization using GH receptor cDNA as a probe. These results suggested that IGF-I expression in somatotrophs is regulated by pituitary GH, and that IGF-I suppresses GH expression and stimulates POMC expression at the transcription level. Pituitary IGF-I produced in somatotrophs is probably involved in the regulation of somatotroph and corticotroph functions.

Endothelium and mechanical responses of isolated monkey pulmonary veins to histamine

1990 ◽  
Vol 259 (4) ◽  
pp. H1032-H1037 ◽  
Author(s):  
T. Matsuki ◽  
T. Ohhashi
Keyword(s):  
Pulmonary Veins ◽  
Dependent Manner ◽  
High Concentration ◽  
Concentration Dependent Manner ◽  
Mechanical Responses ◽  
Relaxing Factor ◽  
Prostaglandin F2 Alpha ◽  
H2 Receptors ◽  
Endothelium Derived Relaxing Factor ◽  
Stimulation Of

Ring strips of monkey pulmonary veins precontracted with a high concentration of prostaglandin F2 alpha (PGF2 alpha) relaxed in a concentration-dependent manner in response to histamine. Treatment with mepyramine and/or famotidine attenuated the relaxation. 2-Pyridylethylamine (2PEA) and dimaprit caused relaxations in the precontracted preparations, which were inhibited by pretreatment with mepyramine and famotidine, respectively. Removal of endothelium reversed the histamine- and 2PEA-induced relaxations to dose-related contractions. On the other hand, the removal had no effect on the dimaprit-induced relaxations, which were significantly reduced by pretreatment with famotidine. Histamine-induced relaxations in the precontracted strips with endothelium in the presence and absence of famotidine were suppressed or abolished by treatment with methylene blue or hemoglobin but were unaffected by aspirin. It may be concluded that histamine-induced relaxation in monkey pulmonary veins precontracted with PGF2 alpha is mediated by H2-receptors in smooth muscle and H1-receptors in endothelium. Also, stimulation of the endothelial H1-receptors liberates an endothelium-derived relaxing factor.

scholarly journals Regulation of angiopoietin-like protein 4/fasting-induced adipose factor (Angptl4/FIAF) expression in mouse white adipose tissue and 3T3-L1 adipocytes

2008 ◽  
Vol 100 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Sarah Dutton ◽  
Paul Trayhurn
Keyword(s):  
Skeletal Muscle ◽  
Cell Culture ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Culture Medium ◽  
Mrna Level ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Before And After ◽  
Stimulation Of

Angiopoietin-like protein 4 (Angptl4)/FIAF (fasting-induced adipose factor) was first identified as a target for PPAR and to be strongly induced in white adipose tissue (WAT) by fasting. Here we have examined the regulation of the expression and release of this adipokine in mouse WAT and in 3T3-L1 adipocytes. Angptl4/FIAF expression was measured by RT-PCR and real-time PCR; plasma Angptl4/FIAF and release of the protein in cell culture was determined by western blotting. The Angptl4/FIAF gene was expressed in each of the major WAT depots of mice, the mRNA level in WAT being similar to the liver and much higher (>50-fold) than skeletal muscle. Fasting mice (18 h) resulted in a substantial increase in Angptl4/FIAF mRNA in liver and muscle (9·5- and 21-fold, respectively); however, there was no effect of fasting on Angptl4/FIAF mRNA in WAT and the plasma level of Angptl4/FIAF was unchanged. The Angptl4/FIAF gene was expressed in 3T3-L1 adipocytes before and after differentiation, the level increasing post-differentiation; Angptl4/FIAF was released into the culture medium. Insulin, leptin, dexamethasone, noradrenaline, TNFα and several IL (IL-1β, IL-6, IL-10, IL-18) had little effect on Angptl4/FIAF mRNA levels in 3T3-L1 adipocytes. However, a major stimulation of Angptl4/FIAF expression was observed with rosiglitazone and the inflammatory prostaglandins PGD2 and PGJ2. Angptl4/FIAF does not act as an adipose tissue signal of nutritional status, but is markedly induced by fasting in liver and skeletal muscle.

Regulation of porcine insulin-like growth factor I and growth hormone receptor mRNA expression by energy status

1994 ◽  
Vol 266 (5) ◽  
pp. E776-E785 ◽  
Author(s):  
P. A. Weller ◽  
M. J. Dauncey ◽  
P. C. Bates ◽  
J. M. Brameld ◽  
P. J. Buttery ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Growth Rates ◽  
Mrna Levels ◽  
Energy Status ◽  
Factor I ◽  
Receptor Mrna ◽  
Gh Receptor ◽  
Igf I ◽  
Class 1

Regulation of insulin-like growth factor I (IGF-I) and growth hormone (GH) receptor mRNA in liver and muscle by energy status was assessed in 2-mo-old pigs by altering thermoregulatory demand and energy intake over a 5-wk period to produce a range of plasma IGF-I concentrations from 3.5 +/- 0.7 to 28.9 +/- 6.2 nmol/l. These values were related directly to growth rates (0.06 +/- 0.02 to 0.44 +/- 0.01 kg/day) and total hepatic IGF-I mRNA levels. Increased growth rates were accompanied by an increase in hepatic class 1 and class 2 IGF-I mRNA levels and an increase in the ratio of class 2 to class 1 IGF-I mRNA in liver, suggesting a distinct role for class 2 expression in the endocrine growth response. High levels of class 1 transcripts and a virtual absence of class 2 transcripts characterized all muscle tissues examined, and there was no correlation with plasma IGF-I levels. This suggests that growth promotion in response to increased energy status is regulated via endocrine hepatic IGF-I rather than via a paracrine response. The levels of GH receptor mRNA were positively correlated with overall growth rate (P < 0.005) in liver and negatively correlated (P < 0.05) in muscle, indicating distinct tissue-specific effects of energy status.

scholarly journals Transcriptional Response of Multidrug-Resistant Klebsiella pneumoniae Clinical Isolates to Ciprofloxacin Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Roman Farooq Alvi ◽  
Bilal Aslam ◽  
Muhammad Hidayat Rasool ◽  
Saima Muzammil ◽  
Abu Baker Siddique ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Stress Responses ◽  
Genetic Resistance ◽  
Transcriptional Response ◽  
Multidrug Resistant ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Isolation And Identification ◽  
Concentration Dependent Manner ◽  
High Level

Background. The term “persisters” refers to a small bacterial population that persists during treatment with high antibiotic concentration or dose in the absence of genetic resistance. The present study was designed to investigate the transcriptional response in indigenous Klebsiella pneumoniae under the ciprofloxacin stress. Methods. Isolation and identification of K. pneumoniae were carried out through standard microbiological protocols. The characterization of quinolone resistance was performed by estimating the quinolone susceptibility testing, MIC estimation, and detecting the QRDR and PMQR. Transcriptional response of the isolates to ciprofloxacin was determined using qPCR. Results. Among 34 isolates, 23 (67%) were resistant to ciprofloxacin. Both QRDR (gyrA and gyrB) and PMQR (qnrA, qnrB, and qnrS) were detected in the isolates, and all were found resistant to ciprofloxacin. The mRNA levels of both mutS and euTu under the influence of ciprofloxacin were significantly increased. On ciprofloxacin exposure, the mRNA levels of the DNA damage response element (mutS) were raised in a time-dependent fashion. K. pneumoniae showed high-level resistance to ciprofloxacin in the presence of mutations in QRDR and PMQR genes. Conclusion. The transcriptional response revealed the upregulation of DNA repair and protein folding elements (mutS and euTu) in ciprofloxacin stress and delayed cell division. The ciprofloxacin was found to trigger various stress responses in a time- and concentration-dependent manner.

Physiological concentrations of insulin and T3 stimulate 3T3-L1 adipocyte acyl-CoA synthetase gene transcription

1996 ◽  
Vol 270 (5) ◽  
pp. E873-E881 ◽  
Author(s):  
M. S. Kansara ◽  
A. K. Mehra ◽  
J. Von Hagen ◽  
E. Kabotyansky ◽  
P. J. Smith
Keyword(s):  
Gene Transcription ◽  
Fold Increase ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Long Chain Fatty Acids ◽  
Reciprocal Regulation ◽  
Stearoyl Coa Desaturase ◽  
Dose Dependent ◽  
Long Chain ◽  
Stimulation Of

Acyl-CoAsynthetase (ACS) is a key gene for cellular utilization of long-chain fatty acids. We characterized its regulation by physiological concentrations of insulin that acutely regulate metabolism. Our results demonstrate that subnanomolar insulin rapidly and maximally stimulates ACS gene transcription in the absence of protein synthesis; 0.5 nM insulin produced a 2.3 +/- 0.1-fold increase in ACS mRNA levels and induced ACS gene transcription 2.4 +/- 0.3-fold. The insulin sensitivity of ACS was compared with lipoprotein lipase (LPL) and stearoyl-CoA desaturase-1 (SCD-1), which were both less sensitive to insulin. Physiological triiodothyronine (10 nm) also induced ACS mRNA 2.4 +/- 0.1-fold and gene transcription 2.8 +/- 0.3-fold and coordinately induced LPL and SCD-1 mRNA and gene transcription. Because insulin and adenosine 3',5'-cyclic monophosphate often regulate genes involved in lipid and carbohydrate metabolism in a reciprocal manner, we evaluated effects of 1-methyl-3-isobutylxanthine (MIX).ACS mRNA levels were strongly downregulated by MIX in a dose-dependent manner, and ACS gene transcription inhibited in a coordinate manner with LPL and SCD-1. These data demonstrate a uniquely sensitive pattern of stimulation of ACS gene transcription by insulin with reciprocal regulation by MIX, and they suggest a significant role for ACS as a tightly regulated “gatekeeper” gene participating in the control of adipocyte metabolism.

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