Project description:Periosteum deficiency affects bone regeneration, especially in the case of the bone disorder congenital pseudarthrosis of the tibia (CPT). We investigated a new mouse model of CPT caused by Nf1 inactivation in boundary cap-derivatives, the Prss56Cre; R26tdTom; Nf1fl/fl model. To investigate altered healing in this CPT model, we generated a dataset of the injured periosteum and fracture callus at day-7 post fracture from Prss56Cre; R26tdTom; Nf1fl/fl mice.
Project description:Expression data from purified human long bone fracture callus Skeletal Stem Cells (SSCs) and Osteogenic Progenitor (hOPs) and Chondrogenic Progenitor (hCPs) cells
Project description:Skeletal stem/progenitor cells are critical for fracture repair by providing osteochondro precursors in the callus, which is impaired in aging. However, the molecular signatures of callus skeletan progenitor cells during aging is not known. We performed single-cell RNA sequencing on CD45-CD31-Ter119- skeletan progenitor cells isolated from young and aged mouse calluses.
Project description:Genome-wide comparative gene expression analysis of callus tissue of osteoporotic mice (Col1a1-Krm2 and Lrp5-/-) and wild-type were performed to identify candidate genes that might be responsible for the impaired fracture healing observed in Col1a1-Krm2 and Lrp5-/- mice. To investigate bone healing in osteoporosis, we performed fracture healing studies in wild-type mice (C57BL/6 genetic background) and the low bone mass strains Col1a1-Krm2 and Lrp5-/- (Schulze et al., 2010; Kato et al., 2002). Osteotomy was set in femora of female mice and stabilized by a semi-rigid fixator to allow fast bone healing (RM-CM-6ntgen et al., 2010). 21 days post surgery we analyzed the fracture calli by biochemical/histological methods, as well as micro-computed tomography, and observed impaired fracture healing in Col1a1-Krm2 and Lrp5-/- mice in comparison to wild-type. To identify genes that may be responsible for the impaired healing in osteoporotic mice, we performed microarray analysis of three independent callus samples of each genotype. The callus tissue was taken 10 days after surgery, because extensive bone formation took place at this point.
Project description:Gene expression profiling of purified stem and progenitor cell types from femoral fracture calluses of patients hemiarthroplasty or open reduction internal fixation procedures. We used microarrays to detail the global program of gene expression of stem and progenitor cells responsible for skeletal repair.
Project description:Fracture healing is a process that involves many cell populations. In this study we characterized gene expression in a subset of cells involved in fracture healing. αSMACreERT2 mice crossed with Ai9 reporter mice that express tdTomato fluorescent protein after Cre-mediated activation were used as an experimental model. αSMA-expressing cells were labeled by tamoxifen administration, then periosteal cells from the tibia were isolated two days later (controls), or tibial fractures were performed and periosteum/soft callus tissue was collected after 2 and 6 days. The tdTomato positive cell population was isolated by flow cytometry, and subjected to microarray analysis. Histology and cell surface marker analysis indicates that αSMACreERT2 labels a mainly mesenchymal population in the periosteum that expands after fracture, and contributes to both osteogenic and chondrogenic elements of the fracture callus. We were therefore able to examine gene expression in a defined population during the early stages of fracture healing. Total RNA was obtained from the tomato positive cells within the periosteal compartment of fractures from αSMACreERT2/Ai9 mice. Control animals were given 2 doses of tamoxifen, and periosteum was collected and labeled cells sorted (8-9 sex-matched mice per group). Fractures were performed after the second dose of tamoxifen, and tomato positive cells from periosteum/callus tissue were isolated 2 and 6 days after fracture (4-8 animals per sample pooled). 3 replicates for each sample are included.
Project description:Gene expression profiling of purified stem and progenitor cell types from stabilized bicortical femoral fracture calluses one week after injury induction. We used microarrays to detail the global program of gene expression of stem and progenitor cells responsible for skeletal repair.
Project description:Age-related delays in fracture healing are prevalent and contribute to morbidity and mortality in elderly populations. Clinical and preclinical studies demonstrate that aging is associated with slower and less complete fracture repair characterized by delayed cartilage and bone formation, impaired matrix resorption, and an increased risk of delayed union or nonunion. Matrix Assisted Laser Desorption Ionization Mass Spectrometry Imaging (MALDI MSI) enables spatially resolved, in situ molecular analysis of proteins directly from murine fracture tissue sections. We applied collagenase type III (MMP 13) mediated proteolytic digestion to formalin fixed, paraffin embedded (FFPE) tibia fracture callus sections harvested 10 days post tibial fracture from young (3 month old) and aged (18 month old) mice to perform spatially resolved proteomic profiling. MALDI MSI revealed pronounced age dependent differences in extracellular matrix protein composition and remodeling within the fracture callus. We identified up regulation of canonical bone and matrix proteins, including Col1a1 and Col1a2 specifically in the young fracture callus demonstrating advancement into harden callus formation. Conversely, Col2a1 and other soft callus proteins were only seen in the aged callus tissues. Further, protein indicators of tissue state, such as fibronectin (up regulated) and calreticulin (down regulated) were selectively regulated aged tissues, demonstrating a failure for aged tissues to fully progress into harden calluses. Spatial proteomic patterns demonstrated a marked delay in progression from cartilaginous to osseous callus in aged mice, consistent with impaired matrix remodeling during fracture repair. Together, these findings establish MALDI MSI based spatial proteomics as a powerful approach to elucidate age related alterations in fracture healing and to identify molecular regulators of impaired skeletal regeneration.