Parathyroid hormone/parathyroid hormone-related protein receptor expression in nude mice with a transplantable canine apocrine adenocarcinoma (CAC-8) and humoral hypercalcaemia of malignancy

1997 ◽  
Vol 153 (1) ◽  
pp. 123-129 ◽  
Author(s):  
A Gröne ◽  
L K McCauley ◽  
C C Capen ◽  
T J Rosol
Keyword(s):  
Parathyroid Hormone ◽  
Nude Mice ◽  
Elevated Serum ◽  
Receptor Expression ◽  
Receptor Protein ◽  
Receptor Mrna ◽  
Tumour Bearing ◽  
Parathyroid Hormone Related Protein ◽  
Significant Difference ◽  
Pthrp Receptor

Abstract The effect of humoral hypercalcaemia of malignancy (HHM) on parathyroid hormone/parathyroid hormonerelated protein (PTH/PTHrP) receptor expression was investigated in nude mice with subcutaneous transplantation of an adenocarcinoma line (CAC-8) which produces PTHrP. Serum calcium and PTHrP concentrations were analysed by colorimetric assay and a two-site IRMA respectively. Mice were hypercalcaemic (3·3 ±0·1 mmol/l) compared with non-tumour-bearing control mice (2·1 ± 0·1 mmol/l) and had elevated serum PTHrP concentrations (30·4 ±3·4 pmol/l) compared with non-tumour-bearing control mice (0·7 ±0·1 pmol/l. Lumbar vertebrae were analysed by histomorphometry. Tumourbearing mice had a significant (P<0·01) increase in resorptive perimeter, increased numbers of osteoclasts/mm endosteum and increased endosteal bone-forming perimeter. Total RNA was isolated from calvarium, humerus and kidney and analysed for PTH/PTHrP receptor expression by Northern blot analysis. There was no significant difference between PTH/PTHrP receptor mRNA expression in the kidneys and humeri of tumourbearing mice compared with non-tumour control mice, but a significant increase in PTH/PTHrP receptor expression in calvaria. Kidneys and vertebral bodies were stained for PTH/PTHrP receptor protein by immunohistochemistry. Renal proximal tubules (especially the basolateral regions) and endosteal osteoblasts of control and tumourbearing mice stained positive for PTH/PTHrP receptor. These results demonstrated that HHM induced by increased serum PTHrP concentrations did not result in down-regulation of PTH/PTHrP receptor mRNA or protein expression in vivo. Journal of Endocrinology (1997) 153, 123–129

Expression of PTHrP, PTH/PTHrP receptor, and Ca(2+)-sensing receptor mRNAs along the rat nephron

1997 ◽  
Vol 272 (6) ◽  
pp. F751-F758 ◽  
Author(s):  
T. Yang ◽  
S. Hassan ◽  
Y. G. Huang ◽  
A. M. Smart ◽  
J. P. Briggs ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Cellular Localization ◽  
Divalent Cations ◽  
Primary Cultures ◽  
Related Protein ◽  
Receptor Mrna ◽  
Parathyroid Hormone Related Protein ◽  
Product Identity ◽  
Collecting Ducts ◽  
Pthrp Receptor

To provide a frame of reference for studies of renal divalent cation and phosphate metabolism, we assessed the cellular localization of kidney calcium receptor (RaKCaR), parathyroid hormone-related protein (PTHrP), and parathyroid hormone/ parathyroid hormone-related protein (PTH/PTHrP) receptor mRNA. The studies used using reverse transcription-polymerase chain reaction (RT-PCR) applied to cDNA prepared from dissected rat nephron segments and from primary cultures of mouse juxtaglomerular granular cells. With species-specific primers, PCR products of expected size were obtained for RaKCaR (967 bp), PTHrP (420 bp), and PTH/PTHrP receptor (817 bp), with product identity being confirmed by restriction digestion. RaKCaR mRNA was found in medullary and cortical thick ascending limbs (MTAL and CTAL, respectively), the macula densa-containing segment, distal convoluted tubules (DCT), and, to a lesser extent, in cortical collecting ducts (CCD). It was not found in glomeruli, proximal convoluted and straight tubules (PCT and PST, respectively), outer and inner medullary collecting ducts (OMCD and IMCD, respectively), or in juxtaglomerular granular cell isolates. PTHrP mRNA was predominantly expressed in glomeruli and at lower levels in PCT and the macula densacontaining segment but was not detectable in CTAL, MTAL, DCT, and CD segments. Presence of PTH/PTHrP receptor mRNA was demonstrated in glomeruli, PCT, PST, CTAL, MTAL, and DCT but not in CD segments. These results suggest that the function of TAL and DCT cells, in addition to being affected by PTH, may be directly altered by extracellular divalent cations through RaKCaR and that PTHrP may act in the glomerulus and proximal tubule as an autocrine or paracrine regulator of hemodynamics and phosphate transport.

Mechanisms of homologous and heterologous desensitization of PTH/PTHrP receptor signaling in LLC-PK1 cells

1997 ◽  
Vol 273 (2) ◽  
pp. E383-E393 ◽  
Author(s):  
J. Guo ◽  
B. Y. Liu ◽  
F. R. Bringhurst
Keyword(s):  
Parathyroid Hormone ◽  
Receptor Expression ◽  
Wild Type ◽  
Single Receptor ◽  
Parathyroid Hormone Related Protein ◽  
Protein Receptor ◽  
Heterologous Desensitization ◽  
Pthrp Receptor ◽  
Mutant Cells ◽  
Homologous Desensitization

Parathyroid hormone (PTH) activates multiple intracellular effectors, including adenylyl cyclase (AC) and phospholipase C (PLC), via a single receptor [PTH/parathyroid hormone-related protein receptor (PTHR)] expressed in bone and kidney. Homologous desensitization of PTHR signaling occurs, but the relative importance of reduced receptor expression vs. impaired receptor-effector coupling in this process remains unclear. It also is not known if AC and PLC responses to PTH are desensitized independently or interdependently. In LLC-PK1 cells that expressed transfected wild-type PTHRs, PTH caused dose- and time-dependent desensitization of both the AC and PLC-responses to PTH without altering PTHR expression. Desensitization of AC was blocked in mutant cells resistant to adenosine 3',5'-cyclic monophosphate but not when cells expressed mutant PTHRs with defective PLC coupling. Desensitization of PLC was unaffected by PKA blockade, partially mimicked by phorbol ester, and not reproduced by agents that selectively activated AC. The finding that homologous PTHR desensitization in LLC-PK1 cells is signal specific suggests that prior exposure of other cells to PTH also may induce discordant regulation of subsequent PTHR signaling, altering the character as well as the intensity of the hormonal response.

scholarly journals Parathyroid hormone-related protein (PTHrP) mRNA splicing and parathyroid hormone/PTHrP receptor mRNA expression in human placenta and fetal membranes

1998 ◽  
Vol 21 (2) ◽  
pp. 225-234 ◽  
Author(s):  
NE Curtis ◽  
RJ Thomas ◽  
MT Gillespie ◽  
RG King ◽  
GE Rice ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Mrna Expression ◽  
Late Pregnancy ◽  
Mrna Splicing ◽  
Fetal Membranes ◽  
Related Protein ◽  
Receptor Mrna ◽  
Parathyroid Hormone Related Protein ◽  
Pthrp Expression ◽  
Pthrp Receptor

During human pregnancy, parathyroid hormone-related protein (PTHrP) and parathyroid hormone (PTH)/PTHrP receptor are produced by the uterus, placenta, fetal membranes (amnion and chorion) and developing fetus. PTHrP alternative 3' mRNA splicing results in transcripts which encode three PTHrP isoforms and have been identified in amnion. Uteroplacental PTHrP expression is greatest in amnion and increases dramatically during late pregnancy. The aims of this study were to determine PTH/PTHrP receptor mRNA expression at preterm and term gestations and to determine 3' alternative splicing patterns in placenta, amnion and choriodecidua at preterm and term gestations. Using semiquantitative reverse transcription-polymerase chain reaction, PTHrP and PTH/PTHrP receptor transcripts were identified in preterm (n=5) and term (n=7) gestational tissues. PTH/PTHrP receptor mRNA expression did not differ between tissue types or change with advancing gestation. In contrast, PTHrP expression in the same tissues increased with advancing gestation and was significantly greater in amnion than in placenta and choriodecidua. Thus PTHrP, although produced predominantly in amnion, may act in amnion and other tissues including placenta, choriodecidua and myometrium. In amnion over placenta, transcripts encoding PTHrP 1-139 and 1-173 were detected in some preterm and all term samples and those encoding PTHrP 1-141 were detected in all samples. Similar results were obtained for reflected amnion. In placenta and choriodecidua, PTHrP 1-139 and 1-173 transcripts were undetectable or of low abundance. PTHrP 1-141 transcripts were detected in some placenta and choriodecidua samples. In summary, transcripts encoding PTHrP 1-141 appeared to be more abundantly expressed than those encoding PTHrP 1-139 or 1-173. However, the up-regulation of PTHrP expression in amnion at term may involve each of the alternative 3' mRNA splicing pathways since transcripts for each isoform appeared to be more consistently expressed at term.

Parathyroid hormone-parathyroid hormone-related peptide receptor expression and function in otosclerosis

1999 ◽  
Vol 277 (6) ◽  
pp. E1005-E1012
Author(s):  
Alexis Bozorg Grayeli ◽  
Olivier Sterkers ◽  
Pierre Roulleau ◽  
Pierre Elbaz ◽  
Evelyne Ferrary ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Bone Turnover ◽  
Bone Cells ◽  
Receptor Expression ◽  
Camp Production ◽  
Receptor Mrna ◽  
And Function ◽  
Pthrp Receptor ◽  
Cells Cultured ◽  
Stimulation Of

The aim of this study was to investigate the possibility that an abnormality related to parathyroid hormone (PTH) action is involved in the increased bone turnover observed in otosclerosis. To do so, expression and function of the PTH-PTH-related peptide (PTHrP) receptor were studied in the involved tissue (stapes) and compared with that in control bone sample obtained from the external auditory canal (EAC) in the same patient in 10 cases of otosclerosis and in 1 case of osteogenesis imperfecta. PTH-PTHrP receptor expression was studied by RT-PCR of RNA prepared from cultured cells in three patients and RNA directly extracted from bone samples in four patients. PTH-PTHrP receptor function was assessed by measuring the stimulation of cAMP production by 0.8, 8, and 80 nM PTH in bone cell cultures in seven cases. Results showed that PTH-PTHrP receptor mRNA expression in the otosclerotic stapes was lower than that in EAC samples ( P < 0.05), whereas it was higher in stapes than that in EAC in the case of osteogenesis imperfecta. cAMP production after PTH stimulation was lower in bone cells cultured from otosclerotic stapes compared with that in cells cultured from EAC (range of increase in stimulation: 0.8–4.5 and 1.5–7 in stapes and EAC bone cells, respectively, P < 0.05). In contrast, the stimulation of cAMP production by forskolin was not significantly different in otosclerotic stapes and EAC bone cells (range of increase in stimulation: 20.7–83.1 and 4.9–99.8 in stapes and EAC, respectively, P > 0.05). These results show a lower stimulation of cAMP production in response to PTH associated with a lower PTH-PTHrP receptor mRNA expression in pathological stapes from patients with otosclerosis compared with that in control EAC samples. This difference supports the hypothesis that an abnormal cellular response to PTH contributes to the abnormal bone turnover in otosclerosis.

Expression of parathyroid hormone-related peptide (PTHrP) and PTH/PTHrP receptor in newborn human calvaria osteoblastic cells

1997 ◽  
Vol 136 (6) ◽  
pp. 640-648 ◽  
Author(s):  
Abderrahim Lomri ◽  
Cindy de Pollak ◽  
Michael Sebag ◽  
David Goltzman ◽  
Richard Kremer ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Parathyroid Hormone ◽  
Culture Media ◽  
Receptor Expression ◽  
Osteoblastic Cells ◽  
Pcr Analysis ◽  
Intracellular Camp ◽  
Related Peptide ◽  
Parathyroid Hormone Related Peptide ◽  
Pthrp Receptor

Abstract We examined the expression of parathyroid hormone-related peptide (PTHrP) and its receptor in normal newborn human calvaria osteoblastic (NHCO) cells. Northern blot analysis showed that NHCO cells express a single 1·6 kb transcript of PTHrP, which was increased within 1 h (2x) and peaked at 6 h (7x) after serum treatment. In the culture media, the release of PTHrP peptide was maximally increased (4x) 24 h after the addition of serum, as determined by immunoradiometric assay. NHCO cells exhibited a cytoplasmic immunostaining for PTHrP in the presence of serum, and most PTHrP-positive cells were alkaline phosphatase-negative, suggesting that PTHrP was expressed in undifferentiated cells. Furthermore, RT-PCR analysis showed that both PTHrP and PTH/PTHrP receptor were expressed in NHCO cells in basal conditions or after stimulation with serum. The maximal PTHrP expression induced by serum suppressed PTH/PTHrP receptor expression, suggesting that PTHrP down-regulated its receptor in NHCO cells. Treatment with 10 nm human PTH(1–34—which binds to PTH/PTHrP receptors, increased intracellular cAMP levels and alkaline phosphatase activity, and decreased cell growth, indicating that ligand binding to PTH/PTHrP receptors regulates NHCO cell proliferation and differentiation. The expression and synthesis of PTHrP and the presence of functional PTH/PTHrP receptors suggest a possible paracrine mechanism of action of PTHrP in normal human calvaria osteoblastic cells. European Journal of Endocrinology 136 640–648

Abstract 309: Sp-3 But not the NF-kB Transcription Factor Causes the Up-regulation of Angiotensin Type 1 Receptor Expression and Contributes to Hypertension in Aging FBN rats.

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Mohammad Saleem ◽  
Mohammad Asghar
Keyword(s):  
Blood Pressure ◽  
Transcription Factors ◽  
At1 Receptor ◽  
Receptor Expression ◽  
Receptor Protein ◽  
Receptor Function ◽  
Receptor Mrna ◽  
Hk2 Cells ◽  
Angiotensin Type

We recently reported that age-associated oxidative stress is causal to higher renal angiotensin Type 1 (AT1) receptor function and hypertension in aged Fisher 344 X Brown Norway (FBN) rats. We became interested in examining the mechanism of higher AT1 receptor function in the aging kidneys. Adult (3-month) and aging (21 month) FBN rats were subjected to conscious blood pressure measurement by telemetry approach. The levels of AT1 receptor mRNA in the kidney cortex was measured by qRT-PCR while nuclear Sp-3 and NF-kB-p65 redox-sensitive transcription factors were determined by western blotting. We found that blood pressure was higher in aged than in adult rats (adult vs. old: 110±1 vs. 130±1 mmHg) which was associated with higher AT1 receptor mRNA levels (adult vs. old: 1.51±0.72 vs. 7.86±1.03 DU), and nuclear levels of both Sp-3 (adult vs. old: 0.56±.01 vs. 1.54±.02 DU) and NF-kB-p65 (adult vs. old: 0.9±.01 vs. 1.5±0.01 DU). To further delineate whether sp-3 or NF-kB-p65 or both transcription factors are responsible for the up-regulation of AT1 receptor, human kidney (HK2) cells were transfected with Sp-3 and NF-kB-p65 plasmids. We found that Sp-3 plasmid but not NF-κB-p65 plasmid transfection caused an increase in the levels of AT1 receptor protein in HK2 cells (control vs. transfected: 135±22 vs. 235±10 DU). Furthermore, Sp-3 siRNA treatment resulted in the reduction of Sp-3 (control vs. transfected: 136±10 vs. 93±21 DU) and AT1 receptor protein levels (control vs. transfected: 270±38 vs. 172±201 DU) in HK2 cells. Our results suggest that sp-3 but not the NF-κB-p65 is involved in the up-regulation of renal AT1 receptor that may be contributing to hypertension in aging FBN rats.

Parathyroid Hormone-Related Protein-Induced Hypercalcemia in SCID Mice Engrafted With Adult T-Cell Leukemia Cells

Blood ◽  
1998 ◽  
Vol 91 (12) ◽  
pp. 4747-4751 ◽  
Author(s):  
Akifumi Takaori-Kondo ◽  
Kazunori Imada ◽  
Itsuo Yamamoto ◽  
Akane Kunitomi ◽  
Yasuharu Numata ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
T Cell ◽  
Scid Mice ◽  
T Cell Leukemia ◽  
Related Protein ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia ◽  
Humoral Hypercalcemia ◽  
Parathyroid Hormone Related Protein ◽  
Significant Difference

Abstract Parathyroid hormone-related protein (PTHrP) is considered to be one of the main causes of hypercalcemia associated with adult T-cell leukemia (ATL). To clarify the role of PTHrP and bone remodeling in the development of hypercalcemia in ATL, we examined the SCID mouse model of ATL that has previously been shown to mimic the disease in humans. Using this model, we found clear elevations in serum levels of calcium and C-terminal PTHrP (C-PTHrP). PTHrP mRNA was highly expressed in ATL cells proliferating in vivo. After the development of hypercalcemia, ATL mice were killed and bone histomorphometric analysis was performed. Bone volume was clearly decreased in the ATL mice. In comparison to control SCID mice, bone formation indices were very low in the ATL mice. Surprisingly, no significant difference was detected between the ATL mice and the control SCID mice in eroded surface/bone surface (ES/BS), a parameter of bone resorption. To our knowledge, the model presented here is the first animal model of ATL with humoral hypercalcemia. This is in contrast to previously reported, well-characterized animal models of human solid tumors associated with humoral hypercalcemia of malignancy (HHM). Furthermore, this model not only provides us with the opportunity to study the mechanisms underlying development of elevated calcium levels in ATL, but also allows us to test new therapeutic agents designed to treat hypercalcemia.

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