Improvement of the skeletal phenotype in a mouse model of diastrophic dysplasia after postnatal treatment with N-acetylcysteine

Inactivation of the tumor suppressor p53 (encoded by the Trp53 gene) is relevant for development and growth of different cancers, including osteosarcoma, a primary bone tumor mostly affecting children and young adolescents. We have previously shown that deficiency of the ribosomal S6 kinase 2 (Rsk2) limits osteosarcoma growth in a transgenic mouse model overexpressing the proto-oncogene c-Fos. Our initial aim for the present study was to address the question, if Rsk2 deficiency would also influence osteosarcoma growth in another mouse model. For that purpose, we took advantage of Trp53fl/fl mice, which were crossed with Runx2Cre transgenic mice in order to inactivate p53 specifically in osteoblast lineage cells. However, since we unexpectedly identified Runx2Cre-mediated recombination also in the thymus, the majority of 6-month-old Trp53fl/fl;Runx2-Cre (thereafter termed Trp53Cre) animals displayed thymic lymphomas, similar to what has been described for Trp53-deficient mice. Since we did not detect osteosarcoma formation at that age, we could not follow our initial aim, but we studied the skeletal phenotype of Trp53Cre mice, with or without additional Rsk2 deficiency. Here we unexpectedly observed that Trp53Cre mice display a unique accumulation of trabecular bone in the midshaft region of the femur and the humerus, consistent with its previously established role as a negative regulator of osteoblastogenesis. Since this local bone mass increase in Trp53Cre mice was significantly reduced by Rsk2 deficiency, we isolated bone marrow cells from the different groups of mice and analyzed their behavior ex vivo. Here we observed a remarkable increase of colony formation, osteogenic differentiation and proliferation in Trp53Cre cultures, which was unaffected by Rsk2 deficiency. Our data thereby confirm a critical and tumorigenesis-independent function of p53 as a key regulator of mesenchymal cell differentiation.

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Characterization of Skeletal Phenotype and Associated Mechanisms With Chronic Intestinal Inflammation in the Winnie Mouse Model of Spontaneous Chronic Colitis

Inflammatory Bowel Diseases ◽

10.1093/ibd/izab174 ◽

2021 ◽

Author(s):

Ahmed Al Saedi ◽

Shilpa Sharma ◽

Ebrahim Bani Hassan ◽

Lulu Chen ◽

Ali Ghasem-Zadeh ◽

...

Keyword(s):

Bone Loss ◽

Mouse Model ◽

Bone Formation ◽

Intestinal Inflammation ◽

Bone Microarchitecture ◽

Mineral Apposition Rate ◽

Serotonin Level ◽

Chronic Colitis ◽

Skeletal Phenotype ◽

Chronic Intestinal Inflammation

Abstract Background Osteoporosis is a common extraintestinal manifestation of inflammatory bowel disease (IBD). However, studies have been scarce, mainly because of the lack of an appropriate animal model of colitis-associated bone loss. In this study, we aimed to decipher skeletal manifestations in the Winnie mouse model of spontaneous chronic colitis, which carries a MUC2 gene mutation and closely replicates ulcerative colitis. In our study, Winnie mice, prior to the colitis onset at 6 weeks old and progression at 14 and 24 weeks old, were compared with age-matched C57BL/6 controls. We studied several possible mechanisms involved in colitis-associated bone loss. Methods We assessed for bone quality (eg, microcomputed tomography [micro-CT], static and dynamic histomorphometry, 3-point bending, and ex vivo bone marrow analysis) and associated mechanisms (eg, electrochemical recordings for gut-derived serotonin levels, real-time polymerase chain reaction [qRT-PCR], double immunofluorescence microscopy, intestinal inflammation levels by lipocalin-2 assay, serum levels of calcium, phosphorus, and vitamin D) from Winnie (6–24 weeks) and age-matched C57BL6 mice. Results Deterioration in trabecular and cortical bone microarchitecture, reductions in bone formation, mineral apposition rate, bone volume/total volume, osteoid volume/bone surface, and bone strength were observed in Winnie mice compared with controls. Decreased osteoblast and increased osteoclast numbers were prominent in Winnie mice compared with controls. Upregulation of 5-HTR1B gene and increased association of FOXO1 with ATF4 complex were identified as associated mechanisms concomitant to overt inflammation and high levels of gut-derived serotonin in 14-week and 24-week Winnie mice. Conclusions Skeletal phenotype of the Winnie mouse model of spontaneous chronic colitis closely represents manifestations of IBD-associated osteoporosis/osteopenia. The onset and progression of intestinal inflammation are associated with increased gut-derived serotonin level, increased bone resorption, and decreased bone formation.

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Dietary phosphate supplement does not rescue skeletal phenotype in a mouse model for craniometaphyseal dysplasia

Journal of Negative Results in BioMedicine ◽

10.1186/s12952-016-0061-0 ◽

2016 ◽

Vol 15 (1) ◽

Cited By ~ 1

Author(s):

Yaling Liu ◽

Eliane H. Dutra ◽

Ernst J. Reichenberger ◽

I-Ping Chen

Keyword(s):

Mouse Model ◽

Skeletal Phenotype ◽

Dietary Phosphate ◽

Craniometaphyseal Dysplasia

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The skeletal effect of post-natal treatment with N-acetylcysteine in a diastrophic dysplasia mouse model

Bone Reports ◽

10.1016/j.bonr.2021.101008 ◽

2021 ◽

Vol 14 ◽

pp. 101008

Author(s):

Chiara Gramegna Tota ◽

Chiara Paganini ◽

Luca Monti ◽

Giulia Quattrini ◽

Antonella Forlino ◽

...

Keyword(s):

Mouse Model ◽

Diastrophic Dysplasia ◽

Skeletal Effect

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A Humanized Mouse Model of Hereditary 1,25-Dihydroxyvitamin D–Resistant Rickets Without Alopecia

Endocrinology ◽

10.1210/en.2014-1417 ◽

2014 ◽

Vol 155 (11) ◽

pp. 4137-4148 ◽

Cited By ~ 18

Author(s):

Seong Min Lee ◽

Joseph J. Goellner ◽

Charles A. O'Brien ◽

J. Wesley Pike

Keyword(s):

Mouse Model ◽

Artificial Chromosome ◽

Null Mouse ◽

Humanized Mouse ◽

Humanized Mouse Model ◽

Vdr Gene ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

Skeletal Phenotype ◽

Resistant Rickets

Abstract The syndrome of hereditary 1,25-dihydroxyvitamin D–resistant rickets (HVDRR) is a genetic disease of altered mineral homeostasis due to mutations in the vitamin D receptor (VDR) gene. It is frequently, but not always, accompanied by the presence of alopecia. Mouse models that recapitulate this syndrome have been prepared through genetic deletion of the Vdr gene and are characterized by the presence of rickets and alopecia. Subsequent studies have revealed that VDR expression in hair follicle keratinocytes protects against alopecia and that this activity is independent of the protein's ability to bind 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. In the present study, we introduced into VDR-null mice a human VDR (hVDR) bacterial artificial chromosome minigene containing a mutation that converts leucine to serine at amino acid 233 in the hVDR protein, which prevents 1,25(OH)2D3 binding. We then assessed whether this transgene recreated features of the HVDRR syndrome without alopecia. RT-PCR and Western blot analysis in one strain showed an appropriate level of mutant hVDR expression in all tissues examined including skin. The hVDR-L233S mutant failed to rescue the aberrant systemic and skeletal phenotype characteristic of the VDR null mouse due to the inability of the mutant receptor to activate transcription after treatment with 1,25(OH)2D3. Importantly, however, neither alopecia nor the dermal cysts characteristic of VDR-null mice were observed in the skin of these hVDR-L233S mutant mice. This study confirms that we have created a humanized mouse model of HVDRR without alopecia that will be useful in defining additional features of this syndrome and in identifying potential novel functions of the unoccupied VDR.

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Skeletal Phenotype and Mechanisms of Bone Loss in Winnie Mice as a Model for Inflammatory Bowel Disease

10.1101/2020.09.28.317495 ◽

2020 ◽

Author(s):

Ahmed Al Saedi ◽

Shilpa Sharma ◽

Ebrahim Bani Hassan ◽

Lulu Chen ◽

Ali Ghasem-Zadeh ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Bone Loss ◽

Mouse Model ◽

Bone Formation ◽

Intestinal Inflammation ◽

Molecular Pathways ◽

List Type ◽

Skeletal Phenotype ◽

Inflammatory Bowel ◽

First Time

AbstractObjectiveWe aimed to investigate the skeletal phenotype of Winnie mouse model of spontaneous chronic colitis, which carries a mutation in the Muc2 gene and closely replicates IBD symptoms and pathophysiology. These mice have a high level of gut-derived serotonin (GDS), a potent osteoblastogenesis inhibitor. We explored the underlying mechanisms of bone loss associated with chronic intestinal inflammation.DesignWinnie male and female mice prior to colitis onset (6 weeks old) and progression (14 and 24 weeks) were compared to age- and sex-matched C57BL/6 controls. We assessed bone quality (static and dynamic histomorphometry, micro-CT, 3-point bending), intestinal inflammation (lipocalin-2), GDS levels, serum levels of calcium, phosphorus and vitamin D, ex vivo bone marrow analysis and molecular mechanisms inhibiting osteoblastogenesis.ResultsSignificant deterioration in trabecular and cortical microarchitecture, reductions in bone formation, mineral apposition rate, bone volume, osteoid volume and bone strength were observed in Winnie mice compared to C57BL/6 controls. Decreased osteoblast and increased osteoclast numbers were prominent in Winnie mice. We report for the first time that elevated GDS cross-talks with molecular pathways to inhibit bone formation in Winnie mice. Increased expression of 5-HTR1B and FOXO1 mRNAs, dissociation of FOXO1/CREB1 complex and association of FOXO1 with ATF4, promoting the transcriptional activity of FOXO1, results in suppression of osteoblast proliferation in Winnie mice compared to controls.ConclusionThese findings open avenues for the development of targeted therapies for IBD-related bone loss.Significance of this studyWhat is already known on this subject?- Osteoporosis is a common extraintestinal manifestation of inflammatory bowel disease (IBD).- Currently available treatments are not effective for IBD-associated bone loss.- The mechanisms of bone loss are poorly understood. A major limitation has been the lack of an appropriate animal model for IBD-associated bone loss.What are the new findings?- We report for the first-time the skeletal phenotype in Winnie mouse model of IBD- This study presents a novel mechanism of IBD-associated bone loss, involving elevated gut-derived serotonin crosstalk with molecular pathways inhibiting bone formation.How might it impact on clinical practice in the foreseeable future- These findings open avenues for the development of targeted therapies for IBD-related bone loss.

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Application of high-resolution landmark-free morphometrics to a mouse model of Down Syndrome reveals a tightly localised cranial phenotype

10.1101/711259 ◽

2019 ◽

Author(s):

Nicolas Toussaint ◽

Yushi Redhead ◽

Wei Liu ◽

Elizabeth M. C. Fisher ◽

Benedikt Hallgrimsson ◽

...

Keyword(s):

Down Syndrome ◽

High Resolution ◽

Mouse Model ◽

Anatomical Landmarks ◽

Human Phenotype ◽

Shape Comparison ◽

User Training ◽

Skeletal Phenotype ◽

Mutant Phenotypes

AbstractCharacterising phenotypes often requires quantification of anatomical shapes. Quantitative shape comparison (morphometrics) traditionally uses anatomical landmarks and is therefore limited by the number of landmarks and operator accuracy when landmarks are located manually. Here we apply a landmark-free method to characterise the craniofacial skeletal phenotype of the Dp1Tyb mouse model of Down syndrome (DS), validating it against a landmark-based approach. We identify cranial dysmorphologies in Dp1Tyb mice, especially smaller size and brachycephaly (front-back shortening) homologous to the human phenotype. The landmark-free phenotyping was less labour-intensive and required less user training than the landmark-based method. It also enabled mapping of local differences as planar expansion or shrinkage. This higher resolution and local mapping pinpointed reductions in interior mid-snout structures and occipital bones in this DS model that were not as apparent using a traditional landmark-based method. This approach could make morphometrics widely-accessible beyond traditional niches in zoology and palaeontology, especially in characterising mutant phenotypes.

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Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

Journal of Visualized Experiments ◽

10.3791/61390 ◽

2020 ◽

Author(s):

Yiling Yang ◽

Qianye Chen ◽

Siru Zhou ◽

Xinyi Gong ◽

Hongyuan Xu ◽

...

Keyword(s):

Mouse Model ◽

Phenotype Analysis ◽

Skeletal Phenotype

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