Molecular characterization of two novel isoforms of the human calcitonin receptor

Beaudreuil, J.; Balasubramanian, Sundaravadivel; Chenais, J.; Taboulet, J.; Frenkian, Mélinée; Orcel, Philippe; Jullienne, A.; Horne, William C.; Vernejoul, M. C. De; Cressent, M.

doi:10.1016/j.gene.2004.08.019

Cited by 10 publications

(11 citation statements)

References 38 publications

(72 reference statements)

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“…We have likewise examined the expression of the calcitonin receptor using the same four primer pairs and additionally in pronase- and collagenase-retrieved isolated human chondrocytes pooled from four patients, and were in all instances able to detect calcitonin expression (data not shown). Of concern, multiple splice variants of the calcitonin receptor exists in the same organism, and at least four are recognized in humans, of which one is located in the non-coding region of the receptor [43,44]. Further research is needed to investigate which splices variant or variants as well as their signaling in human articular chondrocytes.…”

Section: Discussionmentioning

confidence: 99%

Investigation of the direct effects of salmon calcitonin on human osteoarthritic chondrocytes

Søndergaard

Madsen

Segovia-Silvestre

et al. 2010

BMC Musculoskelet Disord

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BackgroundCalcitonin has been demonstrated to have chondroprotective effects under pre-clinical settings. It is debated whether this effect is mediated through subchondral-bone, directly on cartilage or both in combination. We investigated possible direct effects of salmon calcitonin on proteoglycans and collagen-type-II synthesis in osteoarthritic (OA) cartilage.MethodsHuman OA cartilage explants were cultured with salmon calcitonin [100 pM-100 nM]. Direct effects of calcitonin on articular cartilage were evaluated by 1) measurement of proteoglycan synthesis by incorporation of radioactive labeled 35SO4 [5 μCi] 2) quantification of collagen-type-II formation by pro-peptides of collagen type II (PIINP) ELISA, 3) QPCR expression of the calcitonin receptor in OA chondrocytes using four individual primer pairs, 4) activation of the cAMP signaling pathway by EIA and, 5) investigations of metabolic activity by AlamarBlue.ResultsQPCR analysis and subsequent sequencing confirmed expression of the calcitonin receptor in human chondrocytes. All doses of salmon calcitonin significantly elevated cAMP levels (P < 0.01 and P < 0.001). Calcitonin significantly and concentration-dependently [100 pM-100 nM] induced proteoglycan synthesis measured by radioactive 35SO4 incorporation, with a 96% maximal induction at 10 nM (P < 0.001) corresponding to an 80% induction of 100 ng/ml IGF, (P < 0.05). In alignment with calcitonin treatments [100 pM-100 nM] resulted in 35% (P < 0.01) increased PIINP levels.ConclusionCalcitonin treatment increased proteoglycan and collagen synthesis in human OA cartilage. In addition to its well-established effect on subchondral bone, calcitonin may prove beneficial to the management of joint diseases through direct effects on chondrocytes.

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Section: Discussionmentioning

confidence: 99%

Investigation of the direct effects of salmon calcitonin on human osteoarthritic chondrocytes

Søndergaard

Madsen

Segovia-Silvestre

et al. 2010

BMC Musculoskelet Disord

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“…Consequently, in the framework of very-well known mechanisms and their models of allosteric regulation the cyclic attractor, formerly described for pure cellular model [25] Menten, n, number of binding cites, is equal to 2.0. B, the Hill (logit) plot of some important in bone regulation molecular ligands: data adopted from [65] for hPHT, from [66] for calcitonin and for RANKL from [67]. =20.0, β 11 =0.01, β 2 =0.3, β 22 =0.1, β 23 =0.01, s=0.1, k 1 =0.0001, k 2 =0.01; a, Hill, K 11.…”

Section: Discussionmentioning

confidence: 99%

“…We tried to find a quantitative confirmation for our suggestions by calculating the Hill constant for data adopted from available literature sources. We calculated an example for the data adopted from [65] for hPTH, from [66] for calcitonin, from [67] for RANKL. Results are shown in Fig.2B.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

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Allosteric control model of bone remodelling containing periodical modes

Moroz¹,

Wimpenny²

2007

Biophysical Chemistry

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To help to understand the modelling process that occurs when a scaffold is implanted it is vital to understand the rather complex bone remodelling process prevalent in native bone.We have formulated a mathematical model that predicts osteoactivity both in scaffolds, as well as in bone in vivo and could set a basis for the more detailed allosteric models. The model is extended towards a bio-cybernetic vision of basic multicellular unit (BMU) action, when some of the regulation loops have been modified to reflect the allosteric control mechanisms, developed by Michaels-Menten, Hill, Koshland-Nemethy-Filmer, Monod-Wyman-Changeux.By implementation of this approach a four-dimensional system was obtained that shows steady cyclic behaviour using a wide range of constants with clear biological meaning. We have observed that a local steady-state appears as a limiting cycle in multidimensional phase space and this is discussed in this paper. Physiological interpretation of this limiting four-dimension cycle possibly related to a conservative-like value has been proposed. Analysis and simulation of the model has shown an analogy between this conservative value, as a kind of substrateenergy regenerative potential of the bone remodelling system with a molecular nature, and to the classical physical value -energy. This dynamic recovery potential is directed against both mechanical and biomechanical damage to the bone. Furthermore, the current model has credibility when compared to the normal bone remodelling process. In the framework of widely recognised Hill mechanisms of allosteric regulation the cyclic attractor, described formerly for a pure cellular model, prevails for different forms of feedback control. This result indicates the viability of the proposed existence of a conservative value (analogous to energy) that characterises the recovery potential of the bone remodelling cycle. Linear stability analysis has been performed in order to determine the robustness of the basic state, however, additional work is required to study a wider range of constants.

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“…A different splice variant lacking both the 16-amino acid insert in the first intracellular domain as well as the first 47 amino acids of the amino-terminus extracellular domain was reported to bind to [ 125 I] sCT with high affinity and responding to human CT with increases in cAMP [26]. The significance of two most recently discovered isoforms [27] is still unknown. A further human CTR variant results from a T-to-C base mutation producing a leucine 447 to proline (L447P) amino acid change.…”

Section: Introductionmentioning

confidence: 99%

Identification of the calcitonin receptor in osteoarthritic chondrocytes

et al. 2011

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BackgroundPreclinical and clinical studies have shown that salmon calcitonin has cartilage protective effects in joint degenerative diseases, such as osteoarthritis (OA). However, the presence of the calcitonin receptor (CTR) in articular cartilage chondrocytes is yet to be identified. In this study, we sought to further investigate the expression of the CTR in naïve human OA articular chondrocytes to gain further confirmation of the existents of the CTR in articular cartilage.MethodsTotal RNA was purified from primary chondrocytes from articular cartilage biopsies from four OA patients undergoing total knee replacement. High quality cDNA was produced using a dedicated reverse transcription polymerase chain reaction (RT-PCR) protocol. From this a nested PCR assay amplifying the full coding region of the CTR mRNA was completed. Western blotting and immunohistochemistry were used to characterize CTR protein on protein level in chondrocytes.ResultsThe full coding transcript of the CTR isoform 2 was identified in all four individuals. DNA sequencing revealed a number of allelic variants of the gene including two potentially novel polymorphisms: a frame shift mutation, +473del, producing a shorter form of the receptor protein, and a single nucleotide polymorphism in the 3' non coding region of the transcript, +1443 C>T. A 53 kDa protein band, consistent with non-glycosylated CTR isoform 2, was detected in chondrocytes with a similar size to that expressed in osteoclasts. Moreover the CTR was identified in the plasma membrane and the chondrocyte lacuna of both primary chondrocytes and OA cartilage section.ConclusionsHuman OA articular cartilage chondrocytes do indeed express the CTR, which makes the articular a pharmacological target of salmon calcitonin. In addition, the results support previous findings suggesting that calcitonin has a direct anabolic effect on articular cartilage.

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Molecular characterization of two novel isoforms of the human calcitonin receptor

Cited by 10 publications

References 38 publications

Investigation of the direct effects of salmon calcitonin on human osteoarthritic chondrocytes

Investigation of the direct effects of salmon calcitonin on human osteoarthritic chondrocytes

Allosteric control model of bone remodelling containing periodical modes

Identification of the calcitonin receptor in osteoarthritic chondrocytes

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