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Development of severe skeletal defects in induced SHP-2-deficient adult mice: a model of skeletal malformation in humans with SHP-2 mutations.

Bauler TJ, Kamiya N, Lapinski PE, Langewisch E, Mishina Y, Wilkinson JE, Feng GS, King PD - Dis Model Mech (2010)

Bottom Line: Induced deletion of SHP-2 resulted in impaired hematopoiesis, weight loss and lethality.Skeletal malformations were associated with alterations in cartilage and a marked increase in trabecular bone mass.The model is predicted to be of further use in understanding how SHP-2 regulates skeletal morphogenesis, which could lead to the development of novel therapies for the treatment of skeletal malformations in human patients with SHP-2 mutations.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA.

ABSTRACT
SHP-2 (encoded by PTPN11) is a ubiquitously expressed protein tyrosine phosphatase required for signal transduction by multiple different cell surface receptors. Humans with germline SHP-2 mutations develop Noonan syndrome or LEOPARD syndrome, which are characterized by cardiovascular, neurological and skeletal abnormalities. To study how SHP-2 regulates tissue homeostasis in normal adults, we used a conditional SHP-2 mouse mutant in which loss of expression of SHP-2 was induced in multiple tissues in response to drug administration. Induced deletion of SHP-2 resulted in impaired hematopoiesis, weight loss and lethality. Most strikingly, induced SHP-2-deficient mice developed severe skeletal abnormalities, including kyphoses and scolioses of the spine. Skeletal malformations were associated with alterations in cartilage and a marked increase in trabecular bone mass. Osteoclasts were essentially absent from the bones of SHP-2-deficient mice, thus accounting for the osteopetrotic phenotype. Studies in vitro revealed that osteoclastogenesis that was stimulated by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa B ligand (RANKL) was defective in SHP-2-deficient mice. At least in part, this was explained by a requirement for SHP-2 in M-CSF-induced activation of the pro-survival protein kinase AKT in hematopoietic precursor cells. These findings illustrate an essential role for SHP-2 in skeletal growth and remodeling in adults, and reveal some of the cellular and molecular mechanisms involved. The model is predicted to be of further use in understanding how SHP-2 regulates skeletal morphogenesis, which could lead to the development of novel therapies for the treatment of skeletal malformations in human patients with SHP-2 mutations.

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Spinal curvature and increased bone mineral content in induced SHP-2-deficient mice. (A) Gross morphology of moribund ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice. Note lateral spinal curvature (dotted line) and hump (arrowhead) in the ptpn11fl/fl ert2-cre mouse. (B) X-rays of tamoxifen-injected moribund ptpn11fl/fl ert2-cre mice showing kyphosis (top left) and scoliosis (top right), compared with the indicated littermate controls. Note also increased radiodensity of vertebral bodies of spines, metaphyses of femur (bottom left) and humerus (middle right), and entire rib bones (bottom right) of the ptpn11fl/fl ert2-cre mice (all indicated with arrowheads). In A and B, mice were treated with tamoxifen 5 weeks previously, at 6–8 weeks of age. (C) μCT images of the isosurfaces of spines of ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice injected with tamoxifen 5 weeks previously, at 7 weeks of age. Images show scoliosis with rotated vertebral bodies. (D) Mean bone mineral content ± 1 s.e.m. of individual thoracic (T) and lumbar (L) vertebrae from ptpn11fl/fl ert2-cre mice and littermate controls determined by μCT scanning (n=4 for each mouse strain). All mice were treated with tamoxifen 5 weeks previously, at 7 weeks of age. Statistical significance was determined by paired Student’s t-test. *P<0.05.
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f4-0040228: Spinal curvature and increased bone mineral content in induced SHP-2-deficient mice. (A) Gross morphology of moribund ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice. Note lateral spinal curvature (dotted line) and hump (arrowhead) in the ptpn11fl/fl ert2-cre mouse. (B) X-rays of tamoxifen-injected moribund ptpn11fl/fl ert2-cre mice showing kyphosis (top left) and scoliosis (top right), compared with the indicated littermate controls. Note also increased radiodensity of vertebral bodies of spines, metaphyses of femur (bottom left) and humerus (middle right), and entire rib bones (bottom right) of the ptpn11fl/fl ert2-cre mice (all indicated with arrowheads). In A and B, mice were treated with tamoxifen 5 weeks previously, at 6–8 weeks of age. (C) μCT images of the isosurfaces of spines of ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice injected with tamoxifen 5 weeks previously, at 7 weeks of age. Images show scoliosis with rotated vertebral bodies. (D) Mean bone mineral content ± 1 s.e.m. of individual thoracic (T) and lumbar (L) vertebrae from ptpn11fl/fl ert2-cre mice and littermate controls determined by μCT scanning (n=4 for each mouse strain). All mice were treated with tamoxifen 5 weeks previously, at 7 weeks of age. Statistical significance was determined by paired Student’s t-test. *P<0.05.

Mentions: One of the most striking features of tamoxifen-injected ptpn11fl/fl ert2-cre mice is the development of skeletal abnormalities. Visual inspection of live and deceased mice revealed pronounced kyphosis and scoliosis (Fig. 4A). These skeletal abnormalities were apparent as soon as 2 weeks after tamoxifen injection and were observed in all mice to greater or lesser degrees prior to euthanasia or natural death. Kyphosis and scoliosis were confirmed by X-ray analysis of spines (Fig. 4B). Furthermore, curvature of humeri was detected (Fig. 4B). X-ray analysis also revealed an increased radiodensity of all vertebral bodies in the spine of ptpn11fl/fl ert2-cre mice. In addition, increased radiodensity was apparent in metaphyses of humeri and femora and in all rib bones of ptpn11fl/fl ert2-cre mice (Fig. 4B). These findings suggest that bone malformations and osteopetrosis affect the entire skeleton of ptpn11fl/fl ert2-cre mice.


Development of severe skeletal defects in induced SHP-2-deficient adult mice: a model of skeletal malformation in humans with SHP-2 mutations.

Bauler TJ, Kamiya N, Lapinski PE, Langewisch E, Mishina Y, Wilkinson JE, Feng GS, King PD - Dis Model Mech (2010)

Spinal curvature and increased bone mineral content in induced SHP-2-deficient mice. (A) Gross morphology of moribund ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice. Note lateral spinal curvature (dotted line) and hump (arrowhead) in the ptpn11fl/fl ert2-cre mouse. (B) X-rays of tamoxifen-injected moribund ptpn11fl/fl ert2-cre mice showing kyphosis (top left) and scoliosis (top right), compared with the indicated littermate controls. Note also increased radiodensity of vertebral bodies of spines, metaphyses of femur (bottom left) and humerus (middle right), and entire rib bones (bottom right) of the ptpn11fl/fl ert2-cre mice (all indicated with arrowheads). In A and B, mice were treated with tamoxifen 5 weeks previously, at 6–8 weeks of age. (C) μCT images of the isosurfaces of spines of ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice injected with tamoxifen 5 weeks previously, at 7 weeks of age. Images show scoliosis with rotated vertebral bodies. (D) Mean bone mineral content ± 1 s.e.m. of individual thoracic (T) and lumbar (L) vertebrae from ptpn11fl/fl ert2-cre mice and littermate controls determined by μCT scanning (n=4 for each mouse strain). All mice were treated with tamoxifen 5 weeks previously, at 7 weeks of age. Statistical significance was determined by paired Student’s t-test. *P<0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3046097&req=5

f4-0040228: Spinal curvature and increased bone mineral content in induced SHP-2-deficient mice. (A) Gross morphology of moribund ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice. Note lateral spinal curvature (dotted line) and hump (arrowhead) in the ptpn11fl/fl ert2-cre mouse. (B) X-rays of tamoxifen-injected moribund ptpn11fl/fl ert2-cre mice showing kyphosis (top left) and scoliosis (top right), compared with the indicated littermate controls. Note also increased radiodensity of vertebral bodies of spines, metaphyses of femur (bottom left) and humerus (middle right), and entire rib bones (bottom right) of the ptpn11fl/fl ert2-cre mice (all indicated with arrowheads). In A and B, mice were treated with tamoxifen 5 weeks previously, at 6–8 weeks of age. (C) μCT images of the isosurfaces of spines of ptpn11fl/fl ert2-cre mice and ptpn11fl/fl littermate control mice injected with tamoxifen 5 weeks previously, at 7 weeks of age. Images show scoliosis with rotated vertebral bodies. (D) Mean bone mineral content ± 1 s.e.m. of individual thoracic (T) and lumbar (L) vertebrae from ptpn11fl/fl ert2-cre mice and littermate controls determined by μCT scanning (n=4 for each mouse strain). All mice were treated with tamoxifen 5 weeks previously, at 7 weeks of age. Statistical significance was determined by paired Student’s t-test. *P<0.05.
Mentions: One of the most striking features of tamoxifen-injected ptpn11fl/fl ert2-cre mice is the development of skeletal abnormalities. Visual inspection of live and deceased mice revealed pronounced kyphosis and scoliosis (Fig. 4A). These skeletal abnormalities were apparent as soon as 2 weeks after tamoxifen injection and were observed in all mice to greater or lesser degrees prior to euthanasia or natural death. Kyphosis and scoliosis were confirmed by X-ray analysis of spines (Fig. 4B). Furthermore, curvature of humeri was detected (Fig. 4B). X-ray analysis also revealed an increased radiodensity of all vertebral bodies in the spine of ptpn11fl/fl ert2-cre mice. In addition, increased radiodensity was apparent in metaphyses of humeri and femora and in all rib bones of ptpn11fl/fl ert2-cre mice (Fig. 4B). These findings suggest that bone malformations and osteopetrosis affect the entire skeleton of ptpn11fl/fl ert2-cre mice.

Bottom Line: Induced deletion of SHP-2 resulted in impaired hematopoiesis, weight loss and lethality.Skeletal malformations were associated with alterations in cartilage and a marked increase in trabecular bone mass.The model is predicted to be of further use in understanding how SHP-2 regulates skeletal morphogenesis, which could lead to the development of novel therapies for the treatment of skeletal malformations in human patients with SHP-2 mutations.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA.

ABSTRACT
SHP-2 (encoded by PTPN11) is a ubiquitously expressed protein tyrosine phosphatase required for signal transduction by multiple different cell surface receptors. Humans with germline SHP-2 mutations develop Noonan syndrome or LEOPARD syndrome, which are characterized by cardiovascular, neurological and skeletal abnormalities. To study how SHP-2 regulates tissue homeostasis in normal adults, we used a conditional SHP-2 mouse mutant in which loss of expression of SHP-2 was induced in multiple tissues in response to drug administration. Induced deletion of SHP-2 resulted in impaired hematopoiesis, weight loss and lethality. Most strikingly, induced SHP-2-deficient mice developed severe skeletal abnormalities, including kyphoses and scolioses of the spine. Skeletal malformations were associated with alterations in cartilage and a marked increase in trabecular bone mass. Osteoclasts were essentially absent from the bones of SHP-2-deficient mice, thus accounting for the osteopetrotic phenotype. Studies in vitro revealed that osteoclastogenesis that was stimulated by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa B ligand (RANKL) was defective in SHP-2-deficient mice. At least in part, this was explained by a requirement for SHP-2 in M-CSF-induced activation of the pro-survival protein kinase AKT in hematopoietic precursor cells. These findings illustrate an essential role for SHP-2 in skeletal growth and remodeling in adults, and reveal some of the cellular and molecular mechanisms involved. The model is predicted to be of further use in understanding how SHP-2 regulates skeletal morphogenesis, which could lead to the development of novel therapies for the treatment of skeletal malformations in human patients with SHP-2 mutations.

Show MeSH
Related in: MedlinePlus