Project description:we investigated mechanisms underlying RANKL inhibition with the monoclonal antibody denosumab on FD tissue, and its likely indirect effects on osteoprogenitors, by evaluating human FD tissue pre and post-treatment and in murine in vivo pre-clinical models. Results from this study demonstrate that, beyond its expected anti-osteoclastic effects, denosumab reduces FD lesion activity by decreasing FD cell proliferation and increasing osteogenic maturation, leading to increased bone formation within lesions
Project description:we investigated mechanisms underlying RANKL inhibition with the monoclonal antibody denosumab on FD tissue, and its likely indirect effects on osteoprogenitors, by evaluating human FD tissue pre and post-treatment and in murine in vivo pre-clinical models.Results from this study demonstrate that, beyond its expected anti-osteoclastic effects, denosumab reduces FD lesion activity by decreasing FD cell proliferation and increasing osteogenic maturation, leading to increased bone formation within lesions
Project description:Fibrous dysplasia (FD) and cemento-ossifying fibroma (COF) are benign fibrous-osseous lesions of the maxillofacial bones that exhibit numerous similarities in their clinicopathological aspects. However, due to differences in their clinical evolution and treatment, it is essential to diagnose these diseases with accuracy. The differences in the pathogeneses of FD and COF are largely unknown and currently there is no biomarker available for their differential diagnosis. Nonetheless, there are few studies comparing these lesions and predominantly comprised of immunohistochemical investigations of traditional bone biomarkers. Therefore, the present study aimed to quantitatively compare the proteomic and phosphoproteomic profiles of cemento-ossifying fibroma and fibrous dysplasia to shed light onto the mechanisms involved in their molecular pathogenesis and identify potential differential diagnosis biomarkers.
Project description:Fibrous dysplasia (FD) is a rare bone disorder characterized by the replacement of normal bone with benign fibro-osseous tissue. Developments in our understanding of the pathophysiology and treatment options are impeded by the lack of suitable research models. In this study, we developed an in vitro organotypic model capable of recapitulating key intrinsic and phenotypic properties of FD. Transcriptomic profiling of individual cells isolated from patient lesional tissues revealed extensive intralesional molecular and cellular heterogeneity, indicative of pathogenic fibrotic processes.
Project description:Purpose: Among the diverse cytokines involved in osteoclast differentiation, IL-3 has been shown to inhibit RANKL-induced osteoclastogenesis. However, the mechanism underlying IL-3-mediated inhibition of osteoclast differentiation is not fully understood. In the present study, we demonstrate that IL-3 activation of STAT5 inhibits RANKL-induced osteoclastogenesis through the induction of Id genes. Methods: To investigate the effect of STAT5 on osteoclast differentiation and IL-3-mediated inhibition of osteoclast differentiation, bone marrow derived macrophages isolated from STAT5 wild-type (Stat5fl/fl) or STAT5 cKO (STAT5;MX1-Cre) were differentiated to osteoclast in the presence of M-CSF and RANKL with or without IL-3; and bone marrow derived macrophges from STAT5 wild-type and STAT5 cKO were overexpressed with PMX-FIG (control) or STAT5A1*6 (constitutively active form of STAT5A) and differentiated to osteoclast. To analyze bone phenotype, femurs and tibiae of 16 week-old STAT5 wild-type and STAT5 cKO were subjected to micro CT analysis and histomorphometry, respectively. Results: Overexpression of STAT5 inhibited RANKL-induced osteoclastogenesis. However, RANKL did not regulate either expression or activation of STAT5 during osteoclast differentiation. STAT5 deficiency prevented IL-3-mediated inhibition of osteoclastogenesis, suggesting that STAT5 plays an important role in IL-3-mediated inhibition of osteoclast differentiation. In addition, IL-3-induced STAT5 activation upregulated expression of the Id1 and Id2 genes, which are negative regulators of osteoclastogenesis. Overexpression of ID1 or ID2 in STAT5-deficient cells reversed osteoclast development recovered from IL-3-mediated inhibition. Moreover, micro-computed tomography and histomorphometric analysis revealed that STAT5 conditional knockout mice showed reduced bone mass, with an increased number of osteoclasts. Furthermore, IL-3 inhibited RANKL-induced osteoclast differentiation less effectively in STAT5 conditional knockout mice than in wild-type mice in a RANKL injection model. Conclusion: Taken together, our results suggest that STAT5 is a key transcription factor for IL-3-mediated inhibition of RANKL-induced osteoclastogenesis through Id gene expression. Examination of 4 different combination of osteoclast differentiation condition of bone marrow derived macrophages.
Project description:Stable atherosclerotic plaques are characterized by a thick extracellular matrix (ECM)-rich fibrous cap populated by protective ACTA2+ myofibroblast (MF)-like cells, assumed to be almost exclusively derived from smooth muscle cells (SMC). Herein, we show that in murine and human lesions, ~20-40% of ACTA2+ fibrous caps cells, respectively, are derived from non-SMC sources, including endothelial cells (EC) or macrophages that have undergone Endothelial-to-Mesenchymal (EndoMT) or Macrophage-to-Mesenchymal (MMT) transitions. In addition, weshow that SMC-specific knockout of the platelet-derived growth factor receptor beta (PDGFRB) in Apoe-/- mice fed a Western diet (WD) for 18 weeks results in brachiocephalic artery (BCA) lesions nearly devoid of SMC. While absence of SMCs does not affect lesion size, remodeling, or ACTA2+ fibrous cap cell content, prolonged WD feeding results in reduced indices of stability, indicating that EndoMT and MMT-derived MFs cannot compensate indefinitely for loss of SMC-derived MFs. Using RNA-seq analysis of the BCA region and in vitro models, we demonstrate that SMC to MF transitions (SMC-MFT) is induced by PDGF and TFGβ and is dependent on aerobic glycolysis, while EndoMT is induced by IL1β and TGFβ. Together, we provide the first quantitative evidence that the ACTA2+ fibrous cap originates from a tapestry of cell types, which transition to an MF state through distinct signaling pathways that are either dependent on or associated with extensive metabolic reprogramming.