Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have isolated clones for rat collagenase from a rat osteoblastic cell cDNA library. These clones have been sequenced and the amino acids deduced. The calculated molecular weight is 51,352 for the proenzyme and 42,229 for the active enzyme. The deduced amino acid sequence was compared to those previously reported for: 1) human collagenase, 2) rat transin 1 (stromelysin), 3) human stromelysin, and 4) rabbit collagenase. The number of amino acids conserved was 47, 47, 50, and 47%, respectively. We also compared the collagenase mRNA and protein in different rat cells (osteoblast, uterine smooth muscle, synovial fibroblast) and determined that in rat uterine cells the message is slightly larger, although collagenase protein in all three cell types was identical in size. Parathyroid hormone dramatically induces the 2.9-kilobase collagenase mRNA in the rat osteoblastic cells, UMR 106-01. Nuclear run-on studies in UMR 106-01 cells demonstrated a 4-8-fold induction in the rate of synthesis of collagenase mRNA at 2 and 4 after parathyroid hormone treatment, with steady state levels of mRNA increased 100-fold at 4 h. Thus, parathyroid hormone regulation of the collagenase gene in UMR 106-01 cells is in part transcriptional.
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PMID:Rat collagenase. Cloning, amino acid sequence comparison, and parathyroid hormone regulation in osteoblastic cells. 217 15

In this study we show direct inhibitory effects on prostaglandin E2 (PGE2) production by the androgens, testosterone (T) and dihydrotestosterone (DHT), in cultured neonatal mouse calvariae. After 24 h of preculture with or without androgens, bones were treated with bovine (1-34)-parathyroid hormone (PTH) or recombinant human interleukin-1 alpha (IL-1). During preculture androgens decreased PGE2 release only in those experiments in which control PGE2 was high. PTH increased medium PGE2 9-fold at 24 h, and 10(-11) M T inhibited this increase by 50%. Treatment with IL-1 for 24 h increased medium PGE2 19- to 22-fold, and 10(-10) M T and DHT inhibited this increase by 60 and 70%, respectively. T did not significantly affect the PTH-stimulated release of previously incorporated 45Ca or alter the PTH inhibition of incorporation of [3H]proline into collagenase-digestible protein. IL-1 stimulated 45Ca release by 60-80%, and small but significant reductions of 20-30% were seen with T and DHT. This study shows that T and DHT have direct effects on bone at physiologic concentrations, similar to our previous study in which PTH-stimulated PGE2 production in the same culture system was inhibited by physiologic concentrations of 17 beta-estradiol, and suggests that prostaglandins may mediate some of the effects of androgens in vivo.
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PMID:Effects of androgens on parathyroid hormone and interleukin-1-stimulated prostaglandin production in cultured neonatal mouse calvariae. 227 Jul 81

Suspensions of proximal tubules were obtained by collagenase digestion of rat renal cortex followed by centrifugation on a percoll gradient. NAD content in tubules incubated at 37 degrees C was decreased by 40-60% compared with tubules incubated at 4 degrees C. This change occurred within 30 min and was maintained for up to 2 hr. Inhibitors of NAD hydrolysing enzymes prevented the depletion of cellular NAD at 37 degrees C. Acute changes in proximal tubule NAD content at 37 degrees C were not accompanied by changes in phosphate uptake by brush border membrane vesicles subsequently prepared from the same tubules. In contrast, incubation of tubules with parathyroid hormone (10(-6) M) produced the expected inhibition (20%) of brush border membrane transport of phosphate. One implication of these findings is that acute changes in total NAD content of proximal tubules at 37 degrees C may not influence the phosphate transport system in the renal brush border membrane. Other interpretations are discussed.
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PMID:Phosphate transport after acute changes in total NAD content in renal proximal tubules. 232 May 95

We have developed a method that allows us to measure bone resorption and formation simultaneously in the parietal bones from 22-day fetal rat calvaria. Parietal bones labeled with 45Ca, by injection of the mother, were cultured for 72 h with parathyroid hormone (PTH, bovine 1-34, 1.56 nM) or prostaglandin E2 (PGE2, 100 nM), in the presence or absence of indomethacin (Indo, 1 microM) or corticosterone (Cort, 1 microM). Two hours prior to the end of the culture, the bones were pulsed with [3H]-proline or [3H]-thymidine. Resorption was assessed as the percent of 45Ca released into the medium. Incorporation of [3H]-proline into collagenase digestible protein (CDP) and of [3H]-thymidine into DNA (TDR) were measured to assess collagen and DNA synthesis, respectively. Basal %45Ca release was 16 +/- 1% and was significantly decreased by Indo and Cort. Cort decreased TDR and CDP while Indo did not. PTH and PGE2 significantly increased %45Ca release, and this was not blocked by Indo. However, in the presence of Cort, only PTH increased %45Ca release while PGE2 did not. PGE2 increased TDR under all culture conditions while PTH increased TDR only in the presence of Cort. While PTH and PGE2 had the same effects on bone resorption, they had different effects on CDP. PGE2 increased CDP in the presence of Indo or Cort but PTH did not. Thus, this model allows us to study bone resorption, collagen synthesis, and DNA synthesis simultaneously. We have also shown that PTH and PGE2 differ in their sensitivity to inhibition of resorption by Cort and in their effects on bone formation.
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PMID:Simultaneous assessment of bone resorption and formation in cultures of 22-day fetal rat parietal bones: effects of parathyroid hormone and prostaglandin E2. 233 33

We have developed a procedure which allows the isolation of secretion granules from fresh parathyroid glands. Following collagenase digestion of the tissue, the cells were broken with osmotic shock and a crude granule/mitochondrial pellet was obtained by differential centrifugation. Before loading this fraction onto a metrizamide density gradient it was subjected to brief sonication to disrupt the mitochondria. This procedure was necessary in order to achieve separation of the granules from the mitochondria during ultracentrifugation of the gradient. When the fractionated gradient was analysed for PTH by radioimmunoassay, three bands containing parathyroid hormone were found, at densities of 1.0, 1.05 and 1.18. Upon electron microscopic examination of the gradient fractions, granules were found only in those fractions containing hormone. A typical granule appearance was observed for two of the populations, but the third population (density 1.18), consisted of granules without membranes and which appeared less electron dense than those of populations 1 (density of 1.0) and 2 (density of 1.05). Moreover, the lack of a limiting membrane imparted a fuzzy appearance to the population 3 granules. When fresh tissue sections were examined as control samples, granules with and without membranes were also observed. Standard marker enzyme assays further confirmed that populations 2 and 3 were relatively free of other cellular contaminants, but population 1 contained endoplasmic reticulum and lysosomal material. Because the number of granules contained in this population is very small, we have not been successful in achieving further purification of population 1. Based on radioimmunoassay of extracts of each granule population, PTH was concentrated in population 3, while the other two contained lesser amounts. Interestingly, results obtained with a radioimmunoassay for SP-1 revealed a striking difference in the distribution of SP-1 in the three granule populations. This protein, which is also secreted by the parathyroid gland, was concentrated in population 1 and 2. Only very low levels were found in population 3. Thus, the two major secretory products are localized in different granule populations. The isolated granules were stable to pH changes, cycles of freeze/thaw and sonication. The yields of PTH extracted from each of the granule populations by freezing and thawing in buffer or by Triton containing solutions were low. PTH was completely extracted from each population only by using 8 M urea in HCl. Lower concentrations of urea were less effective. These results indicate that the molecular architecture of the granules is highly resistant to disruption.
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PMID:The isolation and partial characterization of bovine parathyroid secretory granules. 233 91

The role of calcium in the parathyroid hormone-mediated increase in 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) production was evaluated using isolated proximal tubules from rats fed a low calcium diet (0.002% Ca) for 14 days. Tubules were prepared by collagenase digestion and centrifugation through Percoll. Tubules from rats fed a low calcium diet produced 1,25-(OH)2D3 at rates 10 times that of tubules from rats fed normal calcium diet (1.2% Ca). In vitro 1,25-(OH)2D3 biosynthesis was highly dependent upon extracellular calcium with inhibition in the absence of medium calcium and maximal production at 0.25 mM medium calcium (0.9 +/- 0.25 versus 15.1 +/- 2.3 nmol/mg protein/5 min, p less than 0.03). Inhibition of 1,25-(OH)2D3 production was partly due to depressed ATP content (0 versus 1.2 mM calcium, 6.8 +/- 0.6 versus 12.7 +/- 0.6 nmol/mg protein, p less than 0.006). EGTA reduced 1,25-(OH)2D3 synthesis and total cell calcium and ATP production. Ruthenium red blocked the inhibitory effects of EGTA on 1,25-(OH)2D3 production. Barium (1.0 mM) inhibited 1,25-(OH)2D3 production (7.2 +/- 0.5 versus 3.4 +/- 0.3, p less than 0.001) without altering ATP production. The calcium ionophore A23187 increased 1,25-(OH)2D3 production in a calcium-dependent manner. It is concluded that parathyroid hormone-mediated increases in 1,25-(OH)2D3 production, as during low calcium diet, require extracellular calcium. Extracellular calcium maintains mitochondrial calcium at optimal concentrations for normal ATP production, a requirement for 25-hydroxyvitamin D3-1-hydroxylase (25-OH-D3-1-hydroxylase) activity. Inhibition of 25-OH-D3-1-hydroxylase activity by barium without an alteration of ATP suggests calcium may also control 1,25-(OH)2D3 production independent of its effects on oxidative phosphorylation, perhaps through a direct interaction with one or more components of the 25-OH-D3-1-hydroxylase.
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PMID:Evidence for calcium-dependent control of 1,25-dihydroxyvitamin D3 production by rat kidney proximal tubules. 242 68

We studied whether alpha-human atrial natriuretic peptide (alpha-hANP) had the capacity to regulate cyclic AMP (cAMP) levels in human glomeruli, since decreased cAMP in the glomerulus may increase the glomerular filtration rate (GFR) through increasing kf (glomerular capillary ultrafiltration coefficient). Human kidneys were obtained at surgery for carcinoma. Normal cortical tissues from these kidneys were used for the study. After incubating the renal cortical slices with 0.1% collagenase, glomeruli were dissected manually under the stereomicroscope. Two glomeruli were incubated (37 degrees C, 2 min) with parathyroid hormone (PTH) and/or alpha-hANP. cAMP was determined by radioimmunoassay. alpha-hANP at a concentration of 5 x 10(-6) M had no effect on glomerular cAMP accumulation in the basal condition. PTH stimulated cAMP formation in a dose-dependent manner. alpha-hANP inhibited significantly the increase in cAMP formation induced by PTH (p less than 0.01). This action of alpha-hANP was dose-dependent, with a maximum of 50% inhibition. PTH is one of the endogenous substances that are known to increase cAMP formation and decrease kf. Thus, it seems likely that alpha-hANP increased GFR through modulating the production of cAMP in human kidney.
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PMID:Inhibitory effect of human atrial natriuretic peptide on cyclic AMP levels in microdissected human glomeruli. 247 46

Mixed bone cell cultures obtained by sequential collagenase-trypsin digestion of newborn chick, rat, and mouse calvaria responded to calcitonin gene-related peptide (CGRP) with a dose-dependent increase in cyclic AMP formation. The amplitude of response to CGRP in each species was less than that to parathyroid hormone (PTH). The CGRP effect was not the result of an action as a weak calcitonin agonist, since in most instances a calcitonin effect was not observed. Only in early digests of mouse calvarial cells were consistent stimulatory effects of calcitonin on cyclic AMP noted, and these were always considerably less in amplitude than those to CGRP. It is concluded that chick, rat, and mouse bones contain cells in osteoblast-rich populations that respond specifically to CGRP with a rise in cyclic AMP.
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PMID:Effects of calcitonin gene-related peptide on cyclic AMP formation in chicken, rat, and mouse bone cells. 254 86

A human osteosarcoma cell line was established from a biopsy specimen from a 13-year-old girl. The osteosarcoma tissue was maintained in athymic nude mice (Balb C nu/nu) by serial transplantation for three years. The tumor was excised from a host mouse and digested with collagenase. The isolated cells were cultured by 98 passages in 14 months, and clones of osteosarcoma cells were obtained by limiting dilution. A clone named human osteosarcoma cell 6 (H-OS-6) that showed the osteoblastic phenotypes of productions of bone morphogenetic protein (BMP) and alkaline phosphatase and a response to human parathyroid hormone (h-PTH 1-34) was selected. The morphology of its chromosomes indicated its human origin. This human osteosarcoma cell line is unique in producing BMP under in vitro conditions.
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PMID:Establishment of a cell line producing bone morphogenetic protein from a human osteosarcoma. 254 99

The clonally derived mouse osteoblast-like cell line MC3T3-E1 was shown to produce latent collagenase (approximately 0.2 units/ml) under stimulation with either heparin or parathyroid hormone in confluent cultures. However, it was found that MC3T3 E1 cultures which were first induced to undergo mineralization by the addition of beta-glycerophosphate and were subsequently stimulated with heparin showed an approximately ten-fold increase in collagenase synthesis. MC3T3-E1 cell collagenase from a small sample of serum-free culture medium was purified 49-fold to a specific activity of 200 units/mg protein with a yield of 14% by heparin-sepharose affinity chromatography and ion-exchange high performance liquid chromatography. This new mineralization-primed cell culture system may be a valuable model for the study of osteoblast collagenase.
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PMID:Mineralization induced by beta-glycerophosphate in cultures leads to a marked increase in collagenase synthesis by mouse osteogenic MC3T3-E1 cells under subsequent stimulation with heparin. 254 74


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