Publications by authors named "Donald Salter"

68 Publications

Ubiquitin-protein ligase Ubr5 cooperates with hedgehog signalling to promote skeletal tissue homeostasis.

PLoS Genet 2021 Apr 5;17(4):e1009275. Epub 2021 Apr 5.

Edinburgh CRUK Cancer Research Centre, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom.

Mammalian Hedgehog (HH) signalling pathway plays an essential role in tissue homeostasis and its deregulation is linked to rheumatological disorders. UBR5 is the mammalian homologue of the E3 ubiquitin-protein ligase Hyd, a negative regulator of the Hh-pathway in Drosophila. To investigate a possible role of UBR5 in regulation of the musculoskeletal system through modulation of mammalian HH signaling, we created a mouse model for specific loss of Ubr5 function in limb bud mesenchyme. Our findings revealed a role for UBR5 in maintaining cartilage homeostasis and suppressing metaplasia. Ubr5 loss of function resulted in progressive and dramatic articular cartilage degradation, enlarged, abnormally shaped sesamoid bones and extensive heterotopic tissue metaplasia linked to calcification of tendons and ossification of synovium. Genetic suppression of smoothened (Smo), a key mediator of HH signalling, dramatically enhanced the Ubr5 mutant phenotype. Analysis of HH signalling in both mouse and cell model systems revealed that loss of Ubr5 stimulated canonical HH-signalling while also increasing PKA activity. In addition, human osteoarthritic samples revealed similar correlations between UBR5 expression, canonical HH signalling and PKA activity markers. Our studies identified a crucial function for the Ubr5 gene in the maintenance of skeletal tissue homeostasis and an unexpected mode of regulation of the HH signalling pathway.
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http://dx.doi.org/10.1371/journal.pgen.1009275DOI Listing
April 2021

Chondrocytes from osteoarthritic cartilage of obese patients show altered adiponectin receptors expression and response to adiponectin.

J Orthop Res 2021 Jan 23. Epub 2021 Jan 23.

Bone Research Group, Center for Genomics and Experimental Medicine, The University of Edinburgh, Edinburgh, UK.

Obesity and osteoarthritis (OA) are well-known comorbidities and their precise molecular interactions are still unidentified. Adiponectin, a major adipokine, known to have an anti-inflammatory effect in atherosclerosis or Type 2 Diabetes Mellitus (T2DM), has also been postulated to be pro-inflammatory in OA. This dual role of adiponectin is still not explained. The precise mechanism by which adiponectin affects cartilage and chondrocytes remains to be elucidated. In the present observational study chondrocytes from 30 patients with OA (18 females and 12 males) undergoing total knee replacement (TKR) were isolated. Expression of adiponectin receptors 1 and 2 (ADIPOR1 and ADIPOR2) was examined both at gene and protein levels in chondrocytes. The difference in adiponectin receptor expression between lean and obese patients with OA and the role of adiponectin in regulating pro-inflammatory genes (MCP-1, IL-6, and VCAM-1, MMP-1, MMP-2, and TIMP-1) has been investigated. We found that ADIPOR1 represented the most abundant adiponectin receptor in primary OA chondrocytes. ADIPOR1 and ADIPOR2 genes and ADIPOR1 protein were differently expressed in OA chondrocytes obtained from obese compared with lean patients with OA. Adiponectin induced gene expression of MCP-1, IL-6, and MMP-1 in all OA patients' chondrocytes. In contrast, VCAM-1 and MMP-2 were differently regulated by adiponectin depending on the patient's body mass index. This study suggests that adiponectin and ADIPOR1 may have important roles in the pathogenesis of cartilage degeneration in OA of obese subjects.
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http://dx.doi.org/10.1002/jor.24993DOI Listing
January 2021

High phosphate induces skeletal muscle atrophy and suppresses myogenic differentiation by increasing oxidative stress and activating Nrf2 signaling.

Aging (Albany NY) 2020 11 2;12(21):21446-21468. Epub 2020 Nov 2.

Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.

Skeletal muscle wasting represents both a common phenotype of aging and a feature of pathological conditions such as chronic kidney disease (CKD). Although both clinical data and genetic experiments in mice suggest that hyperphosphatemia accelerates muscle wasting, the underlying mechanism remains unclear. Here, we showed that inorganic phosphate (Pi) dose-dependently decreases myotube size, fusion index, and myogenin expression in mouse C2C12 skeletal muscle cells. These changes were accompanied by increases in reactive oxygen species (ROS) production and Nrf2 and p62 expression, and reductions in mitochondrial membrane potential (MMP) and Keap1 expression. Inhibition of Pi entry, cytosolic ROS production, or Nrf2 activation reversed the effects of high Pi on Nrf2, p62, and myogenin expression. Overexpression of Nrf2 respectively increased and decreased the promoter activity of -Luc and -Luc reporters. Analysis of nuclear extracts from gastrocnemius muscles from mice fed a high-Pi (2% Pi) diet showed increased Nrf2 phosphorylation in sham-operated and 5/6 nephrectomized (CKD) mice, and both increased p62 phosphorylation and decreased myogenin expression in CKD mice. These data suggest that high Pi suppresses myogenic differentiation and promotes muscle atrophy through oxidative stress-mediated protein degradation and both canonical (ROS-mediated) and non-canonical (p62-mediated) activation of Nrf2 signaling.
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http://dx.doi.org/10.18632/aging.103896DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695395PMC
November 2020

Development of mouse models of angiosarcoma driven by p53.

Dis Model Mech 2019 07 9;12(7). Epub 2019 Jul 9.

Edinburgh Cancer Research UK Centre, Institute of Genetics & Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XR, UK

Angiosarcomas are a rare group of tumours which have poor prognosis and limited treatment options. The development of new therapies has been hampered by a lack of good preclinical models. Here, we describe the development of an autochthonous mouse model of angiosarcoma driven by loss of p53 in VE-cadherin-expressing endothelial cells. Using to drive recombination in adult endothelial cells, mice developed angiosarcomas with 100% penetrance upon homozygous deletion of with a median lifespan of 325 days. In contrast, expression of the R172H mutant p53 resulted in formation of thymic lymphomas with a more rapid onset (median lifespan 151 days). We also used -expressing mice, allowing us to target predominantly pericytes, as these have been reported as the cell of origin for a number of soft tissue sarcomas. also results in low levels of recombination in venous blood endothelial cells in multiple tissues during development. Upon deletion of in -expressing mice ( mice), 65% developed lymphomas and 21% developed pleomorphic undifferentiated soft tissue sarcomas. None developed angiosarcomas. In contrast, 75% of mice developed angiosarcomas, with 60% of these mice also developing lymphomas. The median lifespan of the mice was 151 days. Re-implantation of angiosarcoma tumour fragments from mice provided a more consistent and rapid model of angiosarcoma than the two spontaneous models. The ability to passage tumour fragments through the mouse provides a novel model which is amenable to preclinical studies and will help the development of potential new therapies for angiosarcoma.
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http://dx.doi.org/10.1242/dmm.038612DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679377PMC
July 2019

Desmoplastic Fibroma: A Rare Pathological Midshaft Femoral Fracture Treated With Resection, Acute Shortening, and Re-lengthening: A Case Report.

JBJS Case Connect 2019 Apr-Jun;9(2):e0022

Department of Surgery, Orthopaedics, Royal Infirmary Edinburgh, Edinburgh, Scotland.

Case: We report a rare case of desmoplastic fibroma (DF) of the midshaft femur presenting as a pathological fracture. This rare benign bone tumor was treated with an acute en bloc excision and femoral shortening over an intramedullary nail. Once union of the acute shortening had been achieved, further surgery was undertaken to lengthen the femur with the use of Intramedullary Skeletal Kinetic Distractors. At 3 years after fracture, our patient had achieved equal leg lengths, had normal knee function, and was disease free.

Conclusions: DF resulting in pathological fracture of the midshaft femur is extremely rare and has not been reported to occur in the femoral diaphysis. This location is important as preservation of the joint above and below is preferable and en bloc excision is recommended. Restoration of bone stock after en bloc excision is difficult and recurrence needs to be monitored.
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http://dx.doi.org/10.2106/JBJS.CC.18.00022DOI Listing
June 2020

Involvement of ADAM12 in Chondrocyte Differentiation by Regulation of TGF-β1-Induced IGF-1 and RUNX-2 Expressions.

Calcif Tissue Int 2019 07 16;105(1):97-106. Epub 2019 Apr 16.

Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.

A disintegrin and metalloproteinase 12 (ADAM12) is known to be involved in chondrocyte proliferation and maturation; however, the mechanisms are not fully understood. In this study, expression and localization of ADAM12 during chondrocyte differentiation were examined in the mouse growth plate by immunohistochemistry. Adam12 expression during ATDC5 chondrogenic differentiation was examined by real-time PCR and compared with the expression pattern of type X collagen. The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system was used to generate Adam12-knockout (KO) ATDC5 cells. Adam12-KO and Adam12 overexpressing cells were used for analyses of ADAM12 expression with or without TGF-β1 stimulation. ADAM12 was identified predominantly in chondrocytes of the proliferative zone in mouse growth plates by immunohistochemistry. Adam12 was upregulated prior to Col10a1 during chondrogenic differentiation in wild-type ATDC5 cells. In Adam12-KO ATDC5 cells, following initiation of chondrogenic differentiation, we observed a reduction in Igf-1 expression along with an upregulation of hypertrophy-associated Runx2, Col10a1, and type X collagen protein expressions. In ATDC5 wild-type cells, stimulation with TGF-β1 upregulated the expressions of Adam12 and Igf-1 and downregulated the expression of Runx2. In contrast, in Adam12-KO ATDC5 cells, these TGF-β1-induced changes were suppressed. Adam12 overexpression resulted in an upregulation of Igf-1 and downregulation of Runx2 expression in ATDC5 cells. The findings suggest that ADAM12 has important role in the regulation of chondrocyte differentiation, potentially by regulation of TGF-β1-dependent signaling and that targeting of ADAM12 may have a role in management of abnormal chondrocyte differentiation.
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http://dx.doi.org/10.1007/s00223-019-00549-6DOI Listing
July 2019

Immunohistochemistry for small-cell carcinoma: a potential diagnostic pitfall.

Histopathology 2019 04 28;74(5):792-794. Epub 2019 Jan 28.

Department of Pathology, Royal Infirmary of Edinburgh and University of Edinburgh Medical School, Edinburgh, UK.

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http://dx.doi.org/10.1111/his.13789DOI Listing
April 2019

The Potential of Intrinsically Magnetic Mesenchymal Stem Cells for Tissue Engineering.

Int J Mol Sci 2018 Oct 14;19(10). Epub 2018 Oct 14.

Centre for Genomics and Experimental Medicine, MRC IGMM, University of Edinburgh, Edinburgh EH4 2XU, UK.

The magnetization of mesenchymal stem cells (MSC) has the potential to aid tissue engineering approaches by allowing tracking, targeting, and local retention of cells at the site of tissue damage. Commonly used methods for magnetizing cells include optimizing uptake and retention of superparamagnetic iron oxide nanoparticles (SPIONs). These appear to have minimal detrimental effects on the use of MSC function as assessed by in vitro assays. The cellular content of magnetic nanoparticles (MNPs) will, however, decrease with cell proliferation and the longer-term effects on MSC function are not entirely clear. An alternative approach to magnetizing MSCs involves genetic modification by transfection with one or more genes derived from AMB-1, a magnetotactic bacterium that synthesizes single-magnetic domain crystals which are incorporated into magnetosomes. MSCs with either or and genes are followed by bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by magnetic resonance (MR) and which have no deleterious effects on MSC proliferation, migration, or differentiation. The stable transfection of magnetosome-associated genes in MSCs promotes assimilation of magnetic nanoparticle synthesis into mammalian cells with the potential to allow MR-based cell tracking and, through external or internal magnetic targeting approaches, enhanced site-specific retention of cells for tissue engineering.
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http://dx.doi.org/10.3390/ijms19103159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6214112PMC
October 2018

Disappearing hemipelvis: Low grade osteosarcoma, an unusual and poorly described variant of Paget's Sarcoma.

J Orthop 2018 Jun 7;15(2):571-577. Epub 2018 May 7.

Department of Surgery, Orthopaedics, Royal Infirmary Edinburgh, United Kingdom.

Paget's sarcomatous transformation is a rare and potentially fatal complication of Paget's disease. Histologically, it is typically described as a high-grade and extremely aggressive malignancy. We present an unusual radiographic series from a patient diagnosed with a low-grade Paget's osteosarcoma, a very rare and poorly described variant of the disease.
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http://dx.doi.org/10.1016/j.jor.2018.05.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5990377PMC
June 2018

Dexamethasone Down-regulates Osteocalcin in Bone Cells through Leptin Pathway.

Int J Med Sci 2018 8;15(5):507-516. Epub 2018 Mar 8.

Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC.

Glucocorticoid therapy, especially at higher doses, is associated with significant adverse side effects including osteoporosis. Leptin, secreted from adipose tissue, has diverse effects on bone tissue regulation. As glucocorticoids stimulate leptin synthesis and secretion directly in adipose tissue we hypothesised that dexamethasone (DEX) induced osteoporosis may, in part, be mediated by an osteoblast dependent leptin-leptin receptor pathway. Human bone cells expressed leptin and leptin receptors (Ob-Ra and Ob-Rb). DEX increased leptin, Ob-Ra and Ob-Rb expression in a dose-dependent manner while decreasing expression of osteocalcin. In the presence of leptin, Cbfa1 and osteonectin expression showed no significant change, whereas osteocalcin expression was decreased. Recombinant human quadruple antagonist leptin suppressed DEX-induced osteocalcin downregulation. The signaling pathway involved up-regulation of JAK2. In conclusion, upregulation of leptin and Ob-Rb in human bone cells by DEX is associated with down-regulation of osteocalcin expression. The down regulation of osteocalcin by DEX was partially through a leptin autocrine/paracrine loop. Adverse effects of DEX on the skeleton may be modified by targeting leptin signaling pathways.
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http://dx.doi.org/10.7150/ijms.21881DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5859774PMC
August 2018

Kindlin-1 Promotes Pulmonary Breast Cancer Metastasis.

Cancer Res 2018 03 12;78(6):1484-1496. Epub 2018 Jan 12.

Cancer Research UK Edinburgh Centre, University of Edinburgh, Edinburgh, United Kingdom.

In breast cancer, increased expression of the cytoskeletal adaptor protein Kindlin-1 has been linked to increased risks of lung metastasis, but the functional basis is unknown. Here, we show that in a mouse model of polyomavirus middle T antigen-induced mammary tumorigenesis, loss of Kindlin-1 reduced early pulmonary arrest and later development of lung metastasis. This phenotype relied on the ability of Kindlin-1 to bind and activate β integrin heterodimers. Kindlin-1 loss reduced α4 integrin-mediated adhesion of mammary tumor cells to the adhesion molecule VCAM-1 on endothelial cells. Treating mice with an anti-VCAM-1 blocking antibody prevented early pulmonary arrest. Kindlin-1 loss also resulted in reduced secretion of several factors linked to metastatic spread, including the lung metastasis regulator tenascin-C, showing that Kindlin-1 regulated metastatic dissemination by an additional mechanism in the tumor microenvironment. Overall, our results show that Kindlin-1 contributes functionally to early pulmonary metastasis of breast cancer. These findings provide a mechanistic proof in mice that Kindin-1, an integrin-binding adaptor protein, is a critical mediator of early lung metastasis of breast cancer. .
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http://dx.doi.org/10.1158/0008-5472.CAN-17-1518DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5857359PMC
March 2018

Cellular pharmacodynamic effects of Pycnogenol® in patients with severe osteoarthritis: a randomized controlled pilot study.

BMC Complement Altern Med 2017 Dec 16;17(1):537. Epub 2017 Dec 16.

Department of Orthopedics, Universität Würzburg, Orthopedic Center for Musculoskeletal Research, Brettreichstraße 11, 97074, Würzburg, Germany.

Background: The standardized maritime pine bark extract (Pycnogenol®) has previously shown symptom alleviating effects in patients suffering from moderate forms of knee osteoarthritis (OA). The cellular mechanisms for this positive impact are so far unknown. The purpose of the present randomized pilot controlled study was to span the knowledge gap between the reported clinical effects of Pycnogenol® and its in vivo mechanism of action in OA patients.

Methods: Thirty three patients with severe OA scheduled for a knee arthroplasty either received 100 mg of Pycnogenol® twice daily or no treatment (control group) three weeks before surgery. Cartilage, synovial fluid and serum samples were collected during surgical intervention. Relative gene expression of cartilage homeostasis markers were analyzed in the patients' chondrocytes. Inflammatory and cartilage metabolism mediators were investigated in serum and synovial fluid samples.

Results: The oral intake of Pycnogenol® downregulated the gene expression of various cartilage degradation markers in the patients' chondrocytes, the decrease of MMP3, MMP13 and the pro-inflammatory cytokine IL1B were statistically significant (p ≤ 0.05). Additionally, protein concentrations of ADAMTS-5 in serum were reduced significantly (p ≤ 0.05) after three weeks intake of the pine bark extract.

Conclusions: This is the first report about positive cellular effects of a dietary supplement on key catabolic and inflammatory markers in patients with severe OA. The results provide a rational basis for understanding previously reported clinical effects of Pycnogenol® on symptom scores of patients suffering from OA.

Trial Registration: ISRCTN10754119 . Retrospectively registered 08/10/2015.
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http://dx.doi.org/10.1186/s12906-017-2044-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5732384PMC
December 2017

Reply.

Arthritis Rheumatol 2018 01 28;70(1):147-148. Epub 2017 Nov 28.

University of Edinburgh, Edinburgh, UK.

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http://dx.doi.org/10.1002/art.40306DOI Listing
January 2018

Macrophage 11β-HSD-1 deficiency promotes inflammatory angiogenesis.

J Endocrinol 2017 Sep 4;234(3):291-299. Epub 2017 Jul 4.

University/BHF Centre for Cardiovascular ScienceThe Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK

11β-Hydroxysteroid dehydrogenase-1 (11β-HSD1) predominantly converts inert glucocorticoids into active forms, thereby contributing to intracellular glucocorticoid levels. 11β-HSD1 is dynamically regulated during inflammation, including in macrophages where it regulates phagocytic capacity. The resolution of inflammation in some disease models including inflammatory arthritis is impaired by 11β-HSD1 deficiency or inhibition. However, 11β-HSD1 deficiency/inhibition also promotes angiogenesis, which is beneficial in mouse models of surgical wound healing, myocardial infarction or obesity. The cell types responsible for the anti-inflammatory and anti-angiogenic roles of 11β-HSD1 have not been characterised. Here, we generated mice with mediated deletion of to investigate whether 11β-HSD1 deficiency in myeloid phagocytes is pro-angiogenic and/or affects the resolution of inflammation. Resolution of inflammatory K/BxN-induced arthritis was impaired in mice to a similar extent as in mice globally deficient in 11β-HSD1. This was associated with >2-fold elevation in levels of the endothelial marker mRNA, suggesting increased angiogenesis in joints of mice following arthritis. A pro-angiogenic phenotype was confirmed by measuring angiogenesis in subcutaneously implanted polyurethane sponges, in which mice showed 20% greater vessel density than their littermate controls, associated with higher expression of Thus, 11β-HSD1 deficiency in myeloid phagocytes promotes angiogenesis. Targeting 11β-HSD1 in macrophages may be beneficial in tissue repair.
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http://dx.doi.org/10.1530/JOE-17-0223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5574305PMC
September 2017

Regional Differences Between Perisynovial and Infrapatellar Adipose Tissue Depots and Their Response to Class II and Class III Obesity in Patients With Osteoarthritis.

Arthritis Rheumatol 2017 07 10;69(7):1396-1406. Epub 2017 Jun 10.

University of Edinburgh, Edinburgh, UK.

Objective: Obesity is associated with an increased risk of developing osteoarthritis (OA), which is postulated to be secondary to adipose tissue-dependent inflammation. Periarticular adipose tissue depots are present in synovial joints, but the association of this tissue with OA has not been extensively explored. The aim of this study was to investigate differences in local adipose tissue depots in knees with OA and characterize the changes related to class II and class III obesity in patients with end-stage knee OA.

Methods: Synovium and the infrapatellar fat pad (IPFP) were collected during total knee replacement from 69 patients with end-stage OA. Histologic changes, changes in gene and protein expression of adiponectin, peroxisome proliferator-activated receptor γ (PPARγ), and Toll-like receptor 4 (TLR-4), and immune cell infiltration into the adipose tissue were investigated.

Results: IPFP and synovium adipose tissue depots differed significantly and were influenced by the patient's body mass index. Compared to adipocytes from the IPFP and synovium of lean patients, adipocytes from the IPFP of obese patients were significantly larger and the synovium of obese patients displayed marked fibrosis, increased macrophage infiltration, and higher levels of TLR4 gene expression. The adipose-related markers PPARγ in the IPFP and adiponectin and PPARγ in the synovium were expressed at lower levels in obese patients compared to lean patients. Furthermore, there were increased numbers of CD45+ hematopoietic cells, CD45+CD14+ total macrophages, and CD14+CD206+ M2-type macrophages in both the IPFP and synovial tissue of obese patients.

Conclusion: These differences suggest that IPFP and synovium may contain 2 different white adipose tissue depots and support the theory of inflammation-induced OA in patients with class II or III obesity. These findings warrant further investigation as a potentially reversible, or at least suppressible, cause of OA in obese patients.
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http://dx.doi.org/10.1002/art.40102DOI Listing
July 2017

Adult-onset idiopathic chondrolysis of the hip.

Skeletal Radiol 2017 May 13;46(5):687-691. Epub 2017 Feb 13.

Department of Pathology, Royal Infirmary of Edinburgh, NHS Lothian, Edinburgh, UK.

We report the case of a 23-year-old man diagnosed with adult-onset idiopathic chondrolysis of the hip. Chondrolysis of the hip is a disorder most frequently seen in children who have suffered with slipped capital femoral epiphyses. Idiopathic chondrolysis of the hip is extremely rare and to our knowledge, its onset has never been documented in adults aged over 20. With reference to the available medical literature, we summarise the current clinical management of this unusual but important cause of young adult hip pain.
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http://dx.doi.org/10.1007/s00256-017-2589-6DOI Listing
May 2017

Biosynthesis of magnetic nanoparticles by human mesenchymal stem cells following transfection with the magnetotactic bacterial gene mms6.

Sci Rep 2017 01 4;7:39755. Epub 2017 Jan 4.

University of Edinburgh, Centre for Genomics and Experimental Medicine, MRC IGMM, Edinburgh, EH4 2XU, UK.

The use of stem cells to support tissue repair is facilitated by loading of the therapeutic cells with magnetic nanoparticles (MNPs) enabling magnetic tracking and targeting. Current methods for magnetizing cells use artificial MNPs and have disadvantages of variable uptake, cellular cytotoxicity and loss of nanoparticles on cell division. Here we demonstrate a transgenic approach to magnetize human mesenchymal stem cells (MSCs). MSCs are genetically modified by transfection with the mms6 gene derived from Magnetospirillum magneticum AMB-1, a magnetotactic bacterium that synthesises single-magnetic domain crystals which are incorporated into magnetosomes. Following transfection of MSCs with the mms6 gene there is bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by MR and which have no deleterious effects on cell proliferation, migration or differentiation. The assimilation of magnetic nanoparticle synthesis into mammalian cells creates a real and compelling, cytocompatible, alternative to exogenous administration of MNPs.
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http://dx.doi.org/10.1038/srep39755DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5209691PMC
January 2017

PTPN22 Is a Critical Regulator of Fcγ Receptor-Mediated Neutrophil Activation.

J Immunol 2016 12 2;197(12):4771-4779. Epub 2016 Nov 2.

Medical Research Council/University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom;

Neutrophils act as a first line of defense against bacterial and fungal infections, but they are also important effectors of acute and chronic inflammation. Genome-wide association studies have established that the gene encoding the protein tyrosine phosphatase nonreceptor 22 (PTPN22) makes an important contribution to susceptibility to autoimmune disease, notably rheumatoid arthritis. Although PTPN22 is most highly expressed in neutrophils, its function in these cells remains poorly characterized. We show in this article that neutrophil effector functions, including adhesion, production of reactive oxygen species, and degranulation induced by immobilized immune complexes, were reduced in Ptpn22 neutrophils. Tyrosine phosphorylation of Lyn and Syk was altered in Ptpn22 neutrophils. On stimulation with immobilized immune complexes, Ptpn22 neutrophils manifested reduced activation of key signaling intermediates. Ptpn22 mice were protected from immune complex-mediated arthritis, induced by the transfer of arthritogenic serum. In contrast, in vivo neutrophil recruitment following thioglycollate-induced peritonitis and in vitro chemotaxis were not affected by lack of PTPN22. Our data suggest an important role for PTPN22-dependent dephosphorylation events, which are required to enable full FcγR-induced activation, pointing to an important role for this molecule in neutrophil function.
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http://dx.doi.org/10.4049/jimmunol.1600604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5136470PMC
December 2016

Intranodal Palisaded Myofibroblastoma Masquerading as N2 Non-Small Cell Lung Carcinoma.

Ann Thorac Surg 2016 Jul;102(1):e47-8

Department of Cardiothoracic Surgery, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom.

Intranodal palisaded myofibroblastoma is a rare and benign tumor that usually presents in the inguinal region. We report the case of a 68-year-old woman with a right paratracheal mass and right upper lobe non-small cell lung carcinoma initially staged as T1b N2 M0. After mediastinal staging, the right paratracheal mass was found to be an intranodal palisaded myofibroblastoma, which had caused erroneous upstaging of the lung carcinoma to N2 disease. This had the potential of leading to suboptimal treatment of the primary lung carcinoma if formal mediastinal staging had not been performed. To the best of our knowledge, this is the first report in the English literature of an intranodal palisaded myofibroblastoma occurring concurrently with lung cancer. This case highlights the importance of mediastinal staging in lung cancer. Mediastinoscopy remains the gold standard.
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http://dx.doi.org/10.1016/j.athoracsur.2015.11.060DOI Listing
July 2016

Functional roles of CSPG4/NG2 in chondrosarcoma.

Int J Exp Pathol 2016 04 12;97(2):178-86. Epub 2016 Jun 12.

Centre for Genomic and Experimental Medicine, MRC IGMM, University of Edinburgh, Edinburgh, UK.

CSPG4/NG2 is a multifunctional transmembrane protein with limited distribution in adult tissues including articular cartilage. The purpose of this study was to investigate the possible roles of CSPG4/NG2 in chondrosarcomas and to establish whether this molecule may have potential for targeted therapy. Stable knock-down of CSPG4/NG2 in the JJ012 chondrosarcoma cell line by shRNA resulted in decreased cell proliferation and migration as well as a decrease in gene expression of the MMP (matrix metalloproteinase) 3 protease and ADAMTS4 (aggrecanase). Chondrosarcoma cells in which CSPG4/NG2 was knocked down were more sensitive to doxorubicin than wild-type cells. The results indicate that CSPG4/NG2 has roles in regulating chondrosarcoma cell function in relation to growth, spread and resistance to chemotherapy and that anti-CSPG4/NG2 therapies may have potential in the treatment of surgically unresectable chondrosarcoma.
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http://dx.doi.org/10.1111/iep.12189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926050PMC
April 2016

Mapping Chondrocyte Viability, Matrix Glycosaminoglycan, and Water Content on the Surface of a Bovine Metatarsophalangeal Joint.

Cartilage 2016 Apr 8;7(2):193-203. Epub 2015 Nov 8.

Department of Orthopaedic and Trauma Surgery, The University of Edinburgh, Edinburgh, UK.

Objective: The purpose of this study was to determine if there were variations in chondrocyte viability, matrix glycosaminoglycan (GAG), and water content between different areas of the articular surface of a bovine metatarsophalangeal joint, a common and reliable source of articular cartilage for experimental study, which may compromise the validity of using multiple samples from different sites within the joint.

Methods: Nine fresh cadaveric bovine metatarsophalangeal joints were obtained. From each joint, 16 osteochondral explants were taken from 4 facets, yielding a total of 144 cartilage specimens for evaluation of chondrocyte viability, matrix GAG, and water content. A less invasive method for harvesting osteochondral explants and for processing the biopsy for the assessment of chondrocyte viability was developed, which maintained maximal viability within each cartilage explant.

Results: There was no significant difference between the 16 biopsy sites from the different areas of the joint surface with respect to chondrocyte viability, matrix GAG and water content. Pooled data of all samples from each joint established the baseline values of chondrocyte viability to be 89.4% ± 3.8%, 94.4% ± 2.2%, and 77.9% ± 7.8%, in the superficial quarter, central half, and deep quarter (with regard to depth from the articular surface), respectively. The matrix GAG content of bovine articular cartilage was 6.06 ± 0.41 μg/mg cartilage, and the cartilage water content was 72.4% ± 1.5%. There were also no significant differences of these 3 variables between the different joints.

Conclusion: It is thus reasonable to compare biopsies obtained from different sites, as a biopsy from one site would be considered representative of the whole joint.
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http://dx.doi.org/10.1177/1947603515613848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4797237PMC
April 2016

Sympathetic Nervous System Control of Carbon Tetrachloride-Induced Oxidative Stress in Liver through α-Adrenergic Signaling.

Oxid Med Cell Longev 2016 21;2016:3190617. Epub 2015 Dec 21.

Graduate Institute of Medical Sciences, National Defense Medical Center and Department of Pathology, Tri-Service General Hospital, 325 Section 2, Cheng-gong Road, Neihu, Taipei 114, Taiwan; Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, No. 386, Dazhong 1st Road, Zuoying District, Kaohsiung 81362, Taiwan.

In addition to being the primary organ involved in redox cycling, the liver is one of the most highly innervated tissues in mammals. The interaction between hepatocytes and sympathetic, parasympathetic, and peptidergic nerve fibers through a variety of neurotransmitters and signaling pathways is recognized as being important in the regulation of hepatocyte function, liver regeneration, and hepatic fibrosis. However, less is known regarding the role of the sympathetic nervous system (SNS) in modulating the hepatic response to oxidative stress. Our aim was to investigate the role of the SNS in healthy and oxidatively stressed liver parenchyma. Mice treated with 6-hydroxydopamine hydrobromide were used to realize chemical sympathectomy. Carbon tetrachloride (CCl4) injection was used to induce oxidative liver injury. Sympathectomized animals were protected from CCl4 induced hepatic lipid peroxidation-mediated cytotoxicity and genotoxicity as assessed by 4-hydroxy-2-nonenal levels, morphological features of cell damage, and DNA oxidative damage. Furthermore, sympathectomy modulated hepatic inflammatory response induced by CCl4-mediated lipid peroxidation. CCl4 induced lipid peroxidation and hepatotoxicity were suppressed by administration of an α-adrenergic antagonist. We conclude that the SNS provides a permissive microenvironment for hepatic oxidative stress indicating the possibility that targeting the hepatic α-adrenergic signaling could be a viable strategy for improving outcomes in patients with acute hepatic injury.
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http://dx.doi.org/10.1155/2016/3190617DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699022PMC
October 2016

Magnetic forces and magnetized biomaterials provide dynamic flux information during bone regeneration.

J Mater Sci Mater Med 2016 Mar 12;27(3):51. Epub 2016 Jan 12.

Laboratorio di NanoBiotechnologie (NABI), Istituto Ortopedico Rizzoli, via di Barbiano 1/10, 40136, Bologna, Italy.

The fascinating prospect to direct tissue regeneration by magnetic activation has been recently explored. In this study we investigate the possibility to boost bone regeneration in an experimental defect in rabbit femoral condyle by combining static magnetic fields and magnetic biomaterials. NdFeB permanent magnets are implanted close to biomimetic collagen/hydroxyapatite resorbable scaffolds magnetized according to two different protocols . Permanent magnet only or non-magnetic scaffolds are used as controls. Bone tissue regeneration is evaluated at 12 weeks from surgery from a histological, histomorphometric and biomechanical point of view. The reorganization of the magnetized collagen fibers under the effect of the static magnetic field generated by the permanent magnet produces a highly-peculiar bone pattern, with highly-interconnected trabeculae orthogonally oriented with respect to the magnetic field lines. In contrast, only partial defect healing is achieved within the control groups. We ascribe the peculiar bone regeneration to the transfer of micro-environmental information, mediated by collagen fibrils magnetized by magnetic nanoparticles, under the effect of the static magnetic field. These results open new perspectives on the possibility to improve implant fixation and control the morphology and maturity of regenerated bone providing "in site" forces by synergically combining static magnetic fields and biomaterials.
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http://dx.doi.org/10.1007/s10856-015-5659-0DOI Listing
March 2016

Platelet-Rich Plasma Attenuates 30-kDa Fibronectin Fragment-Induced Chemokine and Matrix Metalloproteinase Expression by Meniscocytes and Articular Chondrocytes.

Am J Sports Med 2015 Oct 25;43(10):2481-9. Epub 2015 Aug 25.

Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan

Background: Proteolytic fragments of fibronectin have catabolic effects on cartilage and menisci. Platelet-rich plasma (PRP) is increasingly being used to treat a range of joint conditions, but it is unknown whether PRP influences fibronectin fragment (FN-f) procatabolic activity.

Hypotheses: The procatabolic activity of FN-f on meniscocytes and articular chondrocytes is attenuated by cotreatment with PRP.

Study Design: Controlled laboratory study.

Methods: Human meniscocytes were treated with FN-f (30 kDa) with or without PRP coincubation, and gene expression was analyzed by complementary DNA microarray analysis. Validation of altered expression of known and novel chemokine and protease genes was undertaken by real-time polymerase chain reaction (RT-PCR) in articular chondrocytes and meniscocytes. Chemokine release was assayed by enzyme-linked immunosorbent assay, and intracellular pathway signaling was evaluated by Western immunoblotting.

Results: Microarray analysis and RT-PCR showed increased expression of matrix metalloproteinase (MMP)1, MMP2, MMP3, MMP9, MMP13, interleukin (IL)-6, IL-8 (CXCL8), CCL5, CCL20, and CXCL10 chemokines in meniscocytes after treatment with FN-f. Upregulation of these genes was significantly attenuated by PRP. Similar results were seen with articular chondrocytes, although no changes in MMP2 or MMP9 levels were identified. PRP-induced suppression of gene expression was associated with activation of Akt and p44/p42.

Conclusion: PRP treatment attenuates the 30-kDa FN-f-induced expression of a range of proinflammatory chemokines and MMPs, including IL-8, IL-6, CCL20, CCL5, CXCL10, MMP1, MMP3, and MMP13, by both meniscocytes and articular chondrocytes.

Clinical Relevance: These observations provide support for the use and further trials of PRP in management of cartilage and meniscal injuries.
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http://dx.doi.org/10.1177/0363546515597489DOI Listing
October 2015

Gene-gene interactions between TGF-β/Smad3 signalling pathway polymorphisms affect susceptibility to knee osteoarthritis.

BMJ Open 2015 Jun 11;5(6):e007931. Epub 2015 Jun 11.

Division of Rheumatology/Immunology/Allergy, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.

Objective: Transforming growth factor/Smad family member 3 (TGF)-β/Smad3 signalling is essential for maintaining articular cartilage. A relationship between the genetic variants of TGF-β itself, TGF-β signalling and binding molecules, and osteoarthritis (OA) has been reported. Although variants of candidate genes have become prime targets for genetic analysis, their detailed interplay has not been documented. Our goal was to establish whether single nucleotide polymorphisms (SNPs) of TGF-β1, TGF-βRI, Smad3 and tissue inhibitor of metalloproteinases 3 (TIMP3), and their interactions, are associated with knee OA.

Design: We performed a case-control association study and genotyped 518 knee patients with OA and 468 healthy controls. All participants were genotyped for TGF-β1 (rs1800469C/T), TGF-βRI (rs1590A/G), Smad3 (rs12901499A/G and rs6494629T/C), and TIMP3 (rs715572G/A and rs1962223G/C) polymorphisms by polymerase chain reaction-restriction fragment length polymorphism analysis. Multifactor dimensionality reduction (MDR) was used to identify gene-gene interactions.

Results: Significant associations were observed for TIMP3 rs715572G/A polymorphisms in knee patients with OA and healthy individuals. The GA heterozygote in TIMP3 (rs715572G/A) was significantly associated with OA (p=0.007). Patient stratification using the Kellgren-Lawrence grading scale showed significant differences in TIMP3 rs715572G/A genotypes between grade 4 knee OA and controls. By MDR analysis, a two-locus model (Smad3 rs6494629T/C and TIMP3 rs715572G/A) of gene-gene interaction was the best for predicting knee OA risk, and its maximum testing accuracy was 57.55% and maximum cross-validation consistency was 10/10.

Conclusions: TIMP3 rs715572G/A is a candidate protective gene for severe knee OA. Gene-gene interactions between Smad3 rs6494629T/C and TIMP3 rs715572G/A polymorphisms may play more important protective roles in knee OA.
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http://dx.doi.org/10.1136/bmjopen-2015-007931DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466616PMC
June 2015

Role of the sympathetic nervous system in carbon tetrachloride-induced hepatotoxicity and systemic inflammation.

PLoS One 2015 23;10(3):e0121365. Epub 2015 Mar 23.

Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, R.O.C; Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, R.O.C; Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, R.O.C.

Carbon tetrachloride (CCl4) is widely used as an animal model of hepatotoxicity and the mechanisms have been arduously studied, however, the contribution of the sympathetic nervous system (SNS) in CCl4-induced acute hepatotoxicity remains controversial. It is also known that either CCl4 or SNS can affect systemic inflammatory responses. The aim of this study was to establish the effect of chemical sympathectomy with 6-hydroxydopamine (6-OHDA) in a mouse model of CCl4-induced acute hepatotoxicity and systemic inflammatory response. Mice exposed to CCl4 or vehicle were pretreated with 6-OHDA or saline. The serum levels of aminotransferases and alkaline phosphatase in the CCl4-poisoning mice with sympathetic denervation were significantly lower than those without sympathetic denervation. With sympathetic denervation, hepatocellular necrosis and fat infiltration induced by CCl4 were greatly decreased. Sympathetic denervation significantly attenuated CCl4-induced lipid peroxidation in liver and serum. Acute CCl4 intoxication showed increased expression of inflammatory cytokines/chemokines [eotaxin-2/CCL24, Fas ligand, interleukin (IL)-1α, IL-6, IL-12p40p70, monocyte chemoattractant protein-1 (MCP-1/CCL2), and tumor necrosis factor-α (TNF-α)], as well as decreased expression of granulocyte colony-stimulating factor and keratinocyte-derived chemokine. The overexpressed levels of IL-1α, IL-6, IL-12p40p70, MCP-1/CCL2, and TNF-α were attenuated by sympathetic denervation. Pretreatment with dexamethasone significantly reduced CCl4-induced hepatic injury. Collectively, this study demonstrates that the SNS plays an important role in CCl4-induced acute hepatotoxicity and systemic inflammation and the effect may be connected with chemical- or drug-induced hepatotoxicity and circulating immune response.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0121365PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4370606PMC
February 2016

Targeted sequencing of the Paget's disease associated 14q32 locus identifies several missense coding variants in RIN3 that predispose to Paget's disease of bone.

Hum Mol Genet 2015 Jun 20;24(11):3286-95. Epub 2015 Feb 20.

Rheumatology and Bone Disease Section, Centre for Genomic & Experimental Medicine

Paget's disease of bone (PDB) is a common disorder with a strong genetic component characterized by increased but disorganized bone remodelling. Previous genome-wide association studies identified a locus on chromosome 14q32 tagged by rs10498635 which was significantly associated with susceptibility to PDB in several European populations. Here we conducted fine-mapping and targeted sequencing of the candidate locus to identify possible functional variants. Imputation in 741 PDB patients and 2699 controls confirmed that the association was confined to a 60 kb region in the RIN3 gene and conditional analysis adjusting for rs10498635 identified no new independent signals. Sequencing of the RIN3 gene identified a common missense variant (p.R279C) that was strongly associated with the disease (OR = 0.64; P = 1.4 × 10(-9)), and was in strong linkage disequilibrium with rs10498635. A further 13 rare missense variants were identified, seven of which were novel and detected only in PDB cases. When combined, these rare variants were over-represented in cases compared with controls (OR = 3.72; P = 8.9 × 10(-10)). Most rare variants were located in a region that encodes a proline-rich, intrinsically disordered domain of the protein and many were predicted to be pathogenic. RIN3 was expressed in bone tissue and its expression level was ∼10-fold higher in osteoclasts compared with osteoblasts. We conclude that susceptibility to PDB at the 14q32 locus is mediated by a combination of common and rare coding variants in RIN3 and suggest that RIN3 may contribute to PDB susceptibility by affecting osteoclast function.
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http://dx.doi.org/10.1093/hmg/ddv068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4424954PMC
June 2015

Nerve growth factor increases MMP9 activity in annulus fibrosus cells by upregulating lipocalin 2 expression.

Eur Spine J 2015 Sep 21;24(9):1959-68. Epub 2014 Nov 21.

Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan, Republic of China.

Purpose: Nerve growth factor (NGF) expression and activity is important in chronic lower back pain but may also act as a pro-catabolic factor in the pathogenesis of intervertebral disc (IVD) degeneration. Lipocalin 2 (Lcn2) expression in IVD was upregulated by NGF stimulation in our previous study. The current study was undertaken to identify potential mechanisms of the latter effect including potential interactions between Lcn2 and matrix metalloproteinase 9 (MMP9).

Methods: Rat annulus fibrosus (AF) cells were stimulated by NGF and subjected to microarray analysis, subsequent real-time PCR, western immunoblotting, and immunofluorescence. Cells were treated with NGF in the absence or presence of the NGF inhibitor Ro 08-2750. Zymography and functional MMP9 assays were used to determine MMP9 activity, whilst the dimethyl-methylene blue assay was used to quantify the release of glycosaminoglycans (GAGs) reflecting catabolic effects following NGF treatment. Immunoprecipitation with immunoblotting was used to identify interactions between MMP9 and Lcn2.

Results: Increased expression of Lcn2 gene and protein following NGF stimulation was confirmed by microarray analysis, real-time PCR, western blot and immunofluorescence. Zymography showed that NGF enhanced 125-kDa gelatinase activity, identified as a Lcn2/MMP9 complex by immunoprecipitation and immunoblotting. Functional assays showed increased MMP9 activity and GAG release in the presence of NGF. The effects of NGF were neutralized by the presence of Ro 08-2750.

Conclusions: NGF upregulates Lcn2 expression and increases MMP9 activity in AF cells; processes which are likely to potentiate degeneration of AF tissue in vivo. Anti-NGF treatment may have benefit for management of pain relief and slowing down progression of AF tissue degeneration.
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http://dx.doi.org/10.1007/s00586-014-3675-2DOI Listing
September 2015

Nerve growth factor promotes expression of novel genes in intervertebral disc cells that regulate tissue degradation: Laboratory investigation.

J Neurosurg Spine 2014 Oct 25;21(4):653-61. Epub 2014 Jul 25.

Graduate Institute of Medical Science, National Defense Medical Center, and.

Object: Increased neurotrophin activity in degenerative intervertebral discs (IVDs) is one potential cause of chronic low-back pain (LBP). The aim of the study was to assess if nerve growth factor (NGF) might alter gene expression of IVD cells and contribute to disc degeneration by enhancing expression or activity of factors that cause breakdown of IVD matrix.

Methods: Rat-tail IVD cells were stimulated by NGF and subjected to microarray analysis. Real-time polymerase chain reaction, Western blotting, and immunocytochemistry of rat and human IVD cells and tissues treated with NGF in vitro in the absence or presence of the NGF inhibitor Ro 08-2750 were used to confirm findings of the microarray studies. Phosphorylation of mitogen-activated protein kinase (MAPK) was used to identify cell signaling pathways involved in NGF stimulation in the absence or presence of Ro 08-2750.

Results: Microarray analysis demonstrated increased expression of chitinase 3-like 1 (Chi3l1), lipocalin 2 (Lcn2), and matrix metalloproteinase-3 (Mmp3) following NGF stimulation of rat IVD cells in vitro. Increased gene expression was confirmed by real-time polymerase chain reaction with a relative increase in the Mmp/Timp ratio. Increased expression of Chi3l1, Lcn2, and Mmp3 following NGF stimulation was also demonstrated in rat cells and human tissue in vitro. Effects of NGF on protein expression were blocked by an NGF inhibitor and appear to function through the extracellular-regulation kinase 1/2 (ERK1/2) MAPK pathway.

Conclusions: Nerve growth factor has potential effects on matrix turnover activity and influences the catabolic/anabolic balance of IVD cells in an adverse way that may potentiate IVD degeneration. Anti-NGF treatment might be beneficial to ameliorate progressive tissue breakdown in IVD degeneration and may lead to pain relief.
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http://dx.doi.org/10.3171/2014.6.SPINE13756DOI Listing
October 2014

Thiazide-sensitive Na+ -Cl- cotransporter (NCC) gene inactivation results in increased duodenal Ca2+ absorption, enhanced osteoblast differentiation and elevated bone mineral density.

J Bone Miner Res 2015 Jan;30(1):116-27

Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.

Inactivation of the thiazide-sensitive sodium chloride cotransporter (NCC) due to genetic mutations in Gitelman's syndrome (GS) or pharmacological inhibition with thiazide diuretics causes hypocalciuria and increased bone mineral density (BMD) with unclear extrarenal calcium (Ca(2+) ) regulation. We investigated intestinal Ca(2+) absorption and bone Ca(2+) metabolism in nonsense Ncc Ser707X (S707X) homozygous knockin mice (Ncc(S707X/S707X) mice). Compared to wild-type and heterozygous knockin littermates, Ncc(S707X/S707X) mice had increased intestinal absorption of (45) Ca(2+) and expression of the active Ca(2+) transport machinery (transient receptor potential vanilloid 6, calbindin-D9K , and plasma membrane Ca(2+) ATPase isoform 1b). Ncc(S707X/S707X) mice had also significantly increased Ca(2+) content accompanied by greater mineral apposition rate (MAR) in their femurs and higher trabecular bone volume, cortical bone thickness, and BMD determined by μCT. Their osteoblast differentiation markers, such as bone alkaline phosphatase, procollagen I, osteocalcin, and osterix, were also significantly increased while osteoclast activity was unaffected. Analysis of marrow-derived bone cells, either treated with thiazide or directly cultured from Ncc S707X knockin mice, showed that the differentiation of osteoblasts was associated with increased phosphorylation of mechanical stress-induced focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In conclusion, NCC inhibition stimulates duodenal Ca(2+) absorption as well as osteoblast differentiation and bone Ca(2+) storage, possibly through a FAK/ERK dependent mechanism.
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http://dx.doi.org/10.1002/jbmr.2306DOI Listing
January 2015