Isolation of a 18 000-Da molecular weight form of parathyroid hormone-related protein from the rat Walker carcinosarcoma 256

Miguel, Fernando de; Esbrit, Pedro

doi:10.1016/0304-3835(92)90248-t

Cited by 12 publications

(7 citation statements)

References 14 publications

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“…Using the anti-PTHrP antiserum C6, we found a band of approximately 18 kD, consistent with the presence of the entire PTHrP molecule (28) (Figure 2A), and a band of approximately 90 kD with the anti-PTH1R antibody VII in these cells (Figure 2A). Similar results were found in VSMC extracts (Figure 2A).…”

Section: Rat Mesangial Cells and Mct Cells Express Pthrp And The Pth1rsupporting

confidence: 72%

Angiotensin II Increases Parathyroid Hormone-Related Protein (PTHrP) and the Type 1 PTH/PTHrP Receptor in the Kidney

Lorenzo¹,

Ruíz-Ortega²,

Esbrit³

et al. 2002

Journal of the American Society of Nephrology

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ABSTRACT. Angiotensin II (AngII) participates in the pathogenesis of kidney damage. Parathyroid hormone (PTH)–related protein (PTHrP), a vasodilator and mitogenic agent, is upregulated during renal injury. The aim of this study was to investigate the potential relation between AngII and PTHrP system in the kidney. Different methods were used to find that both rat mesangial and mouse tubuloepithelial cells express PTHrP and the type 1 PTH/PTHrP receptor (PTH1R). In these cells, AngII increased PTHrP mRNA and protein production. In contrast, PTH1R mRNA was increased in mesangial cells and downregulated in tubular cells, but its protein levels were unmodified in both cells. AT1 antagonist, but not AT2, abolished AngII effects on PTHrP/PTH1R. The in vivo effect of AngII was further investigated by systemic infusion (a low dose of 50 ng/kg per min) into normal rats. In controls, PTHrP immunostaining was mainly detected in renal tubules. In AngII-infused rats, PTHrP staining increased in renal tubules and appeared in the glomerulus and the renal vessels. After AngII infusion, PTHR1 staining was markedly increased in all these renal structures at day 3 but remained elevated only in tubules at day 7. The AT1 antagonist, but not the AT2, significantly diminished AngII-induced PTHrP and PTHR1 overexpression in the renal tissue, associated with a decrease in tubular damage and fibrosis. The results indicate that AngII regulates renal PTHrP/PTH1R system via AT1 receptors. These findings demonstrate that PTHrP upregulation occurs in association with the mechanisms of AngII-induced kidney injury.

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Section: Rat Mesangial Cells and Mct Cells Express Pthrp And The Pth1rsupporting

confidence: 72%

Angiotensin II Increases Parathyroid Hormone-Related Protein (PTHrP) and the Type 1 PTH/PTHrP Receptor in the Kidney

Lorenzo¹,

Ruíz-Ortega²,

Esbrit³

et al. 2002

Journal of the American Society of Nephrology

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“…Thus, both PTH and PTHrP increase calcium reabsorption in the distal tubule, while inhibiting phosphate and bicarbonate reabsorption, and stimulating 1·-hydroxylase activity in the proximal tubule [1,3,23]. In fact, some of these PTH-like features of PTHrP allowed its initial characterization and isolation from tumors associated with hypercalcemia [1,3,24].…”

Section: Physiology Of Pthrp In the Renal Tubulementioning

confidence: 99%

Parathyroid Hormone-Related Protein as a Renal Regulating Factor

et al. 2001

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Parathyroid hormone (PTH) and PTH-related protein (PTHrP) produce similar biological effects through the PTH/PTHrP receptor. Less is known about the physiological role of PTHrP, which was first identified as the agent of the humoral hypercalcemia of malignancy. Despite the widespread production of PTHrP in healthy individuals, the concentration of the protein is below the detectable limit of current assays, suggesting that PTHrP normally functions locally in an autocrine or paracrine manner. Thus, some differences in their biological activities have been described and they may be related to the presence of different receptors. In this regard, a second receptor that binds selectively to PTH has also been found. Recent studies have demonstrated the expression of both PTH/PTHrP receptor and protein in the renal glomeruli. Moreover, there are convincing data that support a direct role of PTH and PTHrP in modulating renal blood flow and glomerular filtration rate. This multifunctional protein, PTHrP, also has a proliferative effect on both glomerular mesangial cells and tubular epithelial cells. Increases in the expression of PTHrP have been observed in several experimental models of nephropathies, suggesting that PTHrP upregulation is a common event associated with the mechanism of renal injury and repair.

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“…A fresh tumor sample (1.2 g) was extracted with 0.2 M HCl/8 M urea/0.1 M cysteine and then with 0.1 M NaCl/20% ethanol/10 mM acetic acid (de Miguel and Esbrit 1992). Aliquots of tumor extract were run on a 15% sodium dodecylsulfate-polyacrylamide gel and then electrophoretically transferred onto nitrocellulose membrane filters.…”

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confidence: 99%

Immunohistochemical Detection of Parathyroid Hormone-related Protein in Human Astrocytomas

Miguel¹,

Sarasa²,

López–Ferro³

et al. 1998

J Histochem Cytochem.

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P arathyroid hormone-related protein (PTHrP) was initially isolated from tumors associated with humoral hypercalcemia of malignancy and has since been identified in many normal tissues, in which it appears to act as an auto/paracrine growth/differentiation factor (Philbrick et al. 1996).Neurons from different subregions of the rat brain, including the cerebellum and the hippocampus, express PTHrP and PTH/PTHrP receptors (Weir et al. 1990;Ureña et al. 1993). In the rat, PTHrP has also been detected in the meninges but not in astrocytes that have PTH/PTHrP receptors (Struckhoff and Turzynski 1995). We evaluated the presence of PTHrP in human astrocytomas, using immunohistochemistry and Western immunoblot analysis.Four low-grade astrocytomas and five high-grade astrocytomas (Daumas-Duport et al. 1988) were studied. Fresh tumor samples were fixed overnight in 10% buffered formalin and embedded in paraffin before sectioning. The histological features were evaluated on hematoxylin-and eosin-stained tumor sections. Cytologically, the constituent tumor cells varied in size and in histological appearance. They consisted of small cells with hyperchromatic nuclei and larger cells with glassy cytoplasm and the morphological appearance of astrocytes.Immunostainings were performed with anti-PTHrP antisera C6 and C13, recognizing the C-and N-terminal region of PTHrP, respectively (Albar et al. 1996), and MIB 1 monoclonal specific antibody (Immunotech; Marseille, France), recognizing the Ki-67 proliferation marker, at 1:100 dilution, by the avidin-biotinperoxidase complex method. Paraffin-embedded tissue sections (5 m) were mounted on glass slides pretreated with 1 g/liter poly-l -lysine hydrobromide (Sigma; St Louis, MO). After heating at 60 Њ C for 12-24 hr, tissue samples were deparaffinized with xylene and rehydrated through a series of graded ethanols. Endogenous peroxidase activity was blocked with 3% hydrogen peroxide for 5 min. Then the tissue sections for PTHrP staining were treated with 0.1% trypsin for 5 min and then blocked with 10% nonspecific porcine serum for 10 min. Tissue samples for MIB 1 staining, in 10 mM sodium citrate buffer, pH 6, were boiled for 2 min under pressure. Incubations were carried out in a humidified chamber for 2 hr at room temperature (RT). Positive staining was developed with 3,3 Ј -diaminobenzidine (Sigma) for 10 min. As negative controls, some tumor sections were incubated with saline buffer instead of the primary antiserum.Positive immunostaining for PTHrP was found in all nine astrocytomas with antisera C6 and C13. With either antiserum, the staining was diffuse in the cytoplasm of neoplastic cells and was prominent in the larger cells with a more astrocytic appearance ( Figures 1A and 1B). These cells were abundant in the five high-grade astrocytomas, whose proliferative activity, expressed as percentage of MIB 1-positive nuclear area was (mean Ϯ SD) 17 Ϯ 5%, greater than 5 Ϯ 3% in the four low-grade cases. Adjacent non-neoplastic cortex in the tissue samples did not stain for PTHrP. ...

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Isolation of a 18 000-Da molecular weight form of parathyroid hormone-related protein from the rat Walker carcinosarcoma 256

Cited by 12 publications

References 14 publications

Angiotensin II Increases Parathyroid Hormone-Related Protein (PTHrP) and the Type 1 PTH/PTHrP Receptor in the Kidney

Angiotensin II Increases Parathyroid Hormone-Related Protein (PTHrP) and the Type 1 PTH/PTHrP Receptor in the Kidney

Parathyroid Hormone-Related Protein as a Renal Regulating Factor

Immunohistochemical Detection of Parathyroid Hormone-related Protein in Human Astrocytomas

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