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Jolene J Windle

Publications and source records attributed to Jolene J Windle.

12 recordsLinked to original sources
PubMed2006

Mutation of the sequestosome 1 (p62) gene increases osteoclastogenesis but does not induce Paget disease.

Paget disease is the most exaggerated example of abnormal bone remodeling, with the primary cellular abnormality in the osteoclast. Mutations in the p62 (sequestosome 1) gene occur in one-third of patients with familial Paget disease and in a minority of patients with sporadic Paget disease, with the P392L amino acid substitution being the most commonly observed mutation. However, it is unknown how p62(P392L) mutation contributes to the development of this disease. To determine the effects of p62(P392L) expression on osteoclasts in vitro and in vivo, we introduced either the p62(P392L) or WT p62 gene into normal osteoclast precursors and targeted p62(P392L) expression to the osteoclast lineage in transgenic mice. p62(P392L)-transduced osteoclast precursors were hyperresponsive to receptor activator of NF-kappaB ligand (RANKL) and TNF-alpha and showed increased NF-kappaB signaling but did not demonstrate increased 1,25-(OH)(2)D(3) responsivity, TAF(II)-17 expression, or nuclear number per osteoclast. Mice expressing p62(P392L) developed increased osteoclast numbers and progressive bone loss, but osteoblast numbers were not coordinately increased, as is seen in Paget disease. These results indicate that p62(P392L) expression on osteoclasts is not sufficient to induce the full pagetic phenotype but suggest that p62 mutations cause a predisposition to the development of Paget disease by increasing the sensitivity of osteoclast precursors to osteoclastogenic cytokines.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Alpha9beta1: a novel osteoclast integrin that regulates osteoclast formation and function.

UNLABELLED: We identified a previously unknown integrin, alpha(9)beta(1), on OCLs and their precursors. Antibody to alpha(9) inhibited OCL formation in human marrow cultures, and OCLs from alpha(9) knockout mice had a defect in actin ring reorganization and an impaired bone resorption capacity. INTRODUCTION: Integrins play important roles in osteoclast (OCL) formation and function. Mature OCLs mainly express alpha(v)beta(3) integrin, a heterodimer adhesion receptor that has been implicated in osteoclastic bone resorption. We identified ADAM8, a disintegrin and metalloproteinase, as a novel stimulator of OCL differentiation and showed that the disintegrin domain of ADAM8 mediated its effects on OCL formation. Because the disintegrin domain of ADAM8 does not bind Arg-Gly-Asp (RGD) sequences, we determined which integrin bound ADAM8 and characterized its role in OCL formation and activity. MATERIALS AND METHODS: Chinese hamster ovary cells (CHO) expressing different integrin subunits were tested for their capacity to bind the disintegrin domain of ADAM8. Mouse or human bone marrow cells and purified OCL precursors were tested for alpha(9)beta(1) integrin expression by Western blot, immunocytochemistry, and real-time RT-PCR. A monoclonal antibody to human alpha(9) was used to block alpha(9)beta(1) on OCL precursors stimulated by 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] or RANKL. Vertebrae of 7-day-old alpha(9)(-/-) mice and wildtype (WT) littermates were compared using bone histomorphometry and 3D microCT analysis. RESULTS: Alpha(9) integrin was expressed by mouse and human bone marrow-derived OCLs and their precursors. Importantly, the anti-alpha(9) antibody inhibited human OCL formation stimulated by 1alpha,25(OH)(2)D(3) or RANKL dose-dependently. Furthermore, analysis of OCLs formed in marrow cultures from alpha(9)(-/-) mice showed that the OCLs formed were more contracted and formed significantly less bone resorption pits on dentin slices. Histologic analysis of alpha(9)(-/-) vertebrae showed thickened trabecular regions and retained cartilage within vertebral bodies of alpha(9)(-/-) mice. 3D microCT analysis of alpha(9)(-/-) vertebrae also showed a significant increase in trabecular bone volume/total tissue volume and a tendency for decreased trabecular separation compared with WT mice. CONCLUSIONS: These results support a previously unknown role for alpha(9)beta(1) integrin in OCL formation and function.

ADAM Proteins↗
PubMed2006

Experimental models of Paget's disease.

UNLABELLED: We targeted the MVNP gene to the OCL lineage in transgenic mice. These mice developed abnormal OCLs and bone lesions similar to those found in Paget's patients. These results show that persistent expression of MVNP in OCLs can induce pagetic-like bone lesions in vivo. INTRODUCTION: Paget's disease (PD) is one of the most exaggerated examples of abnormal bone remodeling, with increased bone resorption and excessive new bone formation. However, its etiology is unclear. A viral etiology for PD has been suggested based on the presence of paramyxoviral-like nuclear inclusions, detection of measles virus nucleocapsid (MVNP) mRNA or protein in osteoclasts (OCLs) from PD lesions, and in vitro studies showing that transfection of normal OCL precursors with the MVNP gene results in formation of OCLs that express a pagetic phenotype (increased numbers of OCLs; increased responsivity to 1,25(OH)(2)D(3), RANKL, and TNF-alpha; increased expression of the TAF(II)-17 gene, and increased bone resorption capacity). MATERIALS AND METHODS: We targeted MVNP to cells in the OCL lineage in transgenic mice using the TRACP promoter. RESULTS: Histomorphometric analysis showed that there was a 64% increase in OCL perimeter (p = 6.0002) and 37% increase in osteoblast (OBL) perimeter in MVNP mice. In a mouse that was 14 months of age, there was a 225% increase in OBL perimeter and 149% in OBL perimeter. This was accompanied by increased cancellous bone volume (83%) and trabecular width (47%) and number (25%), with a marked increase in the amount of woven bone. In contrast, cancellous bone volume decreased between 3 and 12 months in wildtype (WT) mice, whereas cancellous bone volume in MVNP mice increased over the same time period. Ex vivo studies showed that the numbers of OCLs formed in marrow cultures from MVNP mice were increased, and the OCLs were hyper-responsive to 1,25(OH)(2)D(3) and had an increased bone resorbing capacity compared with WT cultures. CONCLUSION: These results show that expression of MVNP in OCL in vivo results in a bone phenotype that is characteristic of PD.

Acid Phosphatase↗
PubMed2005

Expression of measles virus nucleocapsid protein in osteoclasts induces Paget's disease-like bone lesions in mice.

UNLABELLED: We targeted the MVNP gene to the OCL lineage in transgenic mice. These mice developed abnormal OCLs and bone lesions similar to those found in Paget's patients. These results show that persistent expression of MVNP in OCLs can induce pagetic-like bone lesions in vivo. INTRODUCTION: Paget's disease (PD) of bone is the second most common bone disease. Both genetic and viral factors have been implicated in its pathogenesis, but their exact roles in vivo are unclear. We previously reported that transfection of normal human osteoclast (OCL) precursors with the measles virus nucleocapsid (MVNP) or measles virus (MV) infection of bone marrow cells from transgenic mice expressing a MV receptor results in formation of pagetic-like OCLs. MATERIALS AND METHODS: Based on these in vitro studies, we determined if the MVNP gene from either an Edmonston-related strain of MV or a MVNP gene sequence derived from a patient with PD (P-MVNP), when targeted to cells in the OCL lineage of transgenic mice with the TRACP promoter (TRACP/MVNP mice), induced changes in bone similar to those found in PD. RESULTS: Bone marrow culture studies and histomorphometric analysis of bones from these mice showed that their OCLs displayed many of the features of pagetic OCLs and that they developed bone lesions that were similar to those in patients with PD. Furthermore, IL-6 seemed to be required for the development of the pagetic phenotype in OCLs from TRACP/MVNP mice. CONCLUSIONS: These results show that persistent expression of the MVNP gene in cells of the OCL lineage can induce pagetic-like bone lesions in vivo.

Animals↗
PubMed2005

Combretastatin A-4 prodrug in the treatment of a murine model of retinoblastoma.

PURPOSE: To evaluate the effect of subconjunctival injections of combretastatin A-4 phosphate (CA-4P) prodrug treatment on tumor vasculature and growth in an animal model of hereditary retinoblastoma. METHODS: Twenty-four, 12-week-old simian virus-40 T-antigen-positive mice received six subconjunctival CA-4P injections at doses of 0.5, 1.0, 1.5, and 2.0 mg delivered at 72-hour intervals to the right eye only. Six control animals received placebo treatment. All animals underwent serial ophthalmic evaluations and were euthanatized at 16 weeks of age, and eyes were obtained for histopathologic examination. Eyes were graded for presence or absence of tumor, delay of tumor growth, and intratumoral vascularity. RESULTS: The use of subconjunctivally injected CA-4P prodrug induced an extensive, dose-dependent decrease in microvessel density and led to significant tumor reduction in treated eyes compared with the placebo control (P <0.001). No evidence of corneal, lenticular, choroidal, or retinal toxicity was observed by histopathologic evaluation. CONCLUSIONS: Subconjunctival delivery of CA-4P is associated with extensive dose-dependent reduction in blood vessel count in this murine model of retinoblastoma. A combination treatment of retinoblastoma incorporating CA-4P may allow enhanced tumor reduction enabling a decrease in standard treatment doses of both chemotherapy and external beam radiotherapy.

Animals↗
PubMed2005

Paget disease of bone.

Paget disease of bone (PD) is characterized by excessive bone resorption in focal areas followed by abundant new bone formation, with eventual replacement of the normal bone marrow by vascular and fibrous tissue. The etiology of PD is not well understood, but one PD-linked gene and several other susceptibility loci have been identified, and paramyxoviral gene products have been detected in pagetic osteoclasts. In this review, the pathophysiology of PD and evidence for both a genetic and a viral etiology for PD will be discussed.

Animals↗
PubMed2003

p53-independent response to cisplatin and oxaliplatin in MMTV-ras mouse salivary tumors.

A transgenic mouse tumor model was used to investigate the role of p53 in tumor response to two different platinum-based chemotherapeutic agents: (a) cisplatin and (b) oxaliplatin, a diaminocyclohexane platine recently introduced into the clinic. MMTV-v-Ha-ras transgenic mice were interbred to p53-deficient mice to generate mice that develop salivary tumors either possessing or lacking p53. Tumor-bearing mice were then treated on either a 9-day schedule to assess overall tumor growth response or on a short-term treatment schedule to assess effects on cell cycle parameters and apoptosis. Both agents induced significant apoptosis and promoted overall tumor regression, regardless of the p53 status of the tumor. This is in contrast to previous studies using this model in which treatment with paclitaxel or doxorubicin promoted tumor growth arrest but not apoptosis. These findings indicate that even in the context of an activated ras gene that potentially mediates suppression of apoptosis, both cisplatin and oxaliplatin are capable of promoting an efficient p53-independent tumor response.

Animals↗
PubMed2002

Split tolerance in a novel transgenic model of autoimmune myasthenia gravis.

Because it is one of the few autoimmune disorders in which the target autoantigen has been definitively identified, myasthenia gravis (MG) provides a unique opportunity for testing basic concepts of immune tolerance. In most MG patients, Abs against the acetylcholine receptors (AChR) at the neuromuscular junction can be readily identified and have been directly shown to cause muscle weakness. T cells have also been implicated and appear to play a role in regulating the pathogenic B cells. A murine MG model, generated by immunizing mice with heterologous AChR from the electric fish Torpedo californica, has been used extensively. In these animals, Abs cross-react with murine AChR; however, the T cells do not. Thus, to study tolerance to AChR, a transgenic mouse model was generated in which the immunodominant Torpedo AChR (T-AChR) alpha subunit is expressed in appropriate tissues. Upon immunization, these mice showed greatly reduced T cell responses to T-AChR and the immunodominant alpha-chain peptide. Limiting dilution assays suggest the likely mechanism of tolerance is deletion or anergy. Despite this tolerance, immunization with intact T-AChR induced anti-AChR Abs, including Abs against the alpha subunit, and the incidence of MG-like symptoms was similar to that of wild-type animals. Furthermore, evidence suggests that this B cell response to the alpha-chain receives help from T cells directed against the other AChR polypeptides (beta, gamma, or delta). This model offers a novel opportunity to elucidate mechanisms of tolerance regulation to muscle AChR and to clarify the role of T cells in MG.

Animals↗
PubMed2002

Lung-specific expression of human mutant p53-273H is associated with a high frequency of lung adenocarcinoma in transgenic mice.

To investigate the tumorigenic potential of mutant p53 when selectively expressed in lung tissue, a transgenic mouse model was developed in which a mutant form of p53 (p53-273H) was placed under the transcriptional control of the lung-specific human surfactant protein C (SP-C) promoter. Two founder mice were identified, and a line of SP-C/p53-273H transgenic mice was established from one of the founders. Human p53-273H protein was detected specifically in lung tissue from transgenic mice. Malignant tumors, which were histologically characterized as adenocarcinomas, were observed in transgenic mice, with the earliest onset documented at 4 months of age. To further evaluate incidence and onset of tumor formation, transgenic mice (n=113) were sacrificed at age intervals ranging from 4-15 months. At 13-15 months of age, transgenic mice were significantly more likely to have lung tumors at necropsy than age-matched non-transgenic littermates (9 out of 39 (23%) versus 2 out of 35 (5.7%), chi(2) test, P=0.036). The SP-C/p53-273H transgenic mice described here thus represent a genetically defined model with which to study the role of p53 mutations in lung tumorigenesis, as well as the potential complementary contributions of other genetic alterations or environmental carcinogens to lung tumor development.

Adenocarcinoma↗
PubMed2002

Differential effects of p21(WAF1/CIP1) deficiency on MMTV-ras and MMTV-myc mammary tumor properties.

p21(WAF1/CIP1) (p21) functions as a cyclin-dependent kinase (CDK) inhibitor and is a key mediator of p53-dependent growth arrest. However, its role in cell cycle regulation is complex, because it also appears to promote CDK activity in certain experimental contexts. Its potential role in tumor suppression was evaluated in MMTV-ras and MMTV-myc transgenic mice that were interbred to p21(WAF1/CIP1) knockout mice (p21-/-). p21 deficiency had differential effects on tumor incidence and age of onset, proliferation, and apoptosis in the presence of these two oncogenes. Tumors arising in MMTV-ras/p21-/- mice displayed higher S-phase fractions and correspondingly increased cyclin D1 and E/CDK activity than MMTV-ras tumors. In contrast, MMTV-myc/p21-/- tumors had lower S-phase fractions and levels of cyclin D1 and E/CDK activity than MMTV-myc tumors. In both tumor types, changes in cyclin D1 and E/CDK activity were paralleled by changes in the corresponding cyclin protein levels. Tumor cell apoptosis was also differentially influenced by p21 deficiency in the two models. MMTV-ras/p21-/- tumors exhibited a significant increase in spontaneous apoptosis as compared with MMTV-ras tumors, whereas p21 deficiency had minimal effect on apoptosis in MMTV-myc tumors. These results indicate that the effects of p21 expression on cellular proliferation are differentially affected by the expression of different oncogenes, and that p21 may play a role in promoting either growth arrest or proliferation, depending on the specific cellular context.

Animals↗
PubMed2002

Cyclin kinase inhibitor p21 potentiates bile acid-induced apoptosis in hepatocytes that is dependent on p53.

Prolonged activation of the mitogen-activated protein kinase (MAPK) pathway enhances expression of the cyclin kinase inhibitor p21 that can promote growth arrest and cell survival in response to cytotoxic insults. Bile acids can also cause prolonged MAPK activation that is cytoprotective against bile acid-induced cell death. Here, we examined the impact of bile acid-induced MAPK signaling and p21 expression on the survival of primary mouse hepatocytes. Deoxycholic acid (DCA) caused prolonged activation of the MAPK pathway that weakly enhanced p21 protein expression. When DCA-induced MAPK activation was blocked using MEK1/2 inhibitors, both hepatocyte viability and expression of p21 were reduced. Surprisingly, constitutive overexpression of p21 in p21+/+ hepatocytes enhanced DCA-induced cell killing. In agreement with these findings, treatment of p21-/- hepatocytes with DCA and MEK1/2 inhibitors also caused less apoptosis than observed in wild-type p21+/+ cells. Expression of p21 in p21-/- hepatocytes did not modify basal levels of apoptosis but restored the apoptotic response of p21-/- cells to those of p21+/+ cells overexpressing p21. These findings suggest that basal expression of p21 plays a facilitating, proapoptotic role in DCA-induced apoptosis. Overexpression of p21 enhanced p53 protein levels. In agreement with a role for p53 in the enhanced apoptotic response, overexpression of p21 did not potentiate apoptosis in p53-/- hepatocytes but, instead, attenuated the death response in these cells. In conclusion, our data suggest that overexpression of p21 can promote apoptosis, leading to elevated sensitivity to proapoptotic stimuli.

Animals↗