Project description:Embryonically established osteoclast precursors expressing tdTomato reporter gene were analyzed by single cell RNA-sequencing. Data showed that hematopoietic stem cell independent yolk-sac erythromyeloid progenitors produced embryonic osteoclast precursors.
Project description:Comparison of gene expression of the osteoclast precursor myeloid blast seeded on plastic and on bone, primed with M-CSF for 4 days and culture with M-CSF and RANKL for 1 day. Osteoclasts and macrophages share progenitors that must receive decisive lineage signals driving them into their respective differentiation routes. Macrophage colony stimulation factor M-CSF is a common factor; bone is likely the stimulus for osteoclast differentiation. To elucidate the effect of both, shared mouse bone marrow precursor myeloid blast was pre-cultured with M-CSF on plastic and on bone. M-CSF priming prior to stimulation with M-CSF and osteoclast differentiation factor RANKL resulted in a complete loss of osteoclastogenic potential without bone. This coincided with a steeply decreased expression of osteoclast genes TRACP and DC-STAMP, but an increased expression of the macrophage markers F4/80 and CD11b. Compellingly, M-CSF priming on bone accelerated the osteoclastogenic potential: M-CSF primed cells that had received only one day M-CSF and RANKL and were grown on bone already expressed an array of genes that are associated with osteoclast differentiation and these cells differentiated into osteoclasts within 2 days. This implies that adhesion to bone dictates the fate of osteoclast precursors. Common macrophage-osteoclast precursors may become insensitive to differentiate into osteoclasts and regain osteoclastogenesis when bound to bone or when in the vicinity of bone. Two conditions: Osteoclast precursors on plastic and on bone, n=4, dye swap
Project description:Bone destruction in inflammatory osteolytic diseases including periodontitis is related to excessive activity of osteoclasts (OC), which originate from precursor cells of the myeloid lineage, termed osteoclast precursors (OCP). In contrast to ample knowledge that we currently have on mature OC, little is known about OCP and their regulation during bacterial infection. Therefore, this study aimed to identify and characterize OCP following chronic infection with a periodontal bacteria Porphyromonas gingivalis (Pg). We used a micro-osmotic pump to continually release Pg subcutaneously in a murine model. Two weeks after Pg infection, the frequency of CD11b+c-fms+Ly6Chi population is significantly elevated within the bone marrow, spleen and peripheral blood. In vitro and in vivo studies identified these cells as the OCP-containing population and Pg infection significantly enhanced the osteoclastogenic activity of these cells. Furthermore, mRNA sequencing analysis indicated a unique gene and pathway profile in CD11b+c-fms+Ly6Chi population following Pg infection, with changes in genes and pathways related to OC differentiation, cell proliferation and apoptosis, inflammatory response, phagocytosis and immunity, as well as antigen processing and presentation. Moreover, using IL-6 knockout mice, we found that IL-6 is important for Pg-induced accumulation of CD11b+c-fms+Ly6Chi population from the bone marrow and periphery. Our results provide new insights into the characterization and regulation of OCP following a chronic bacterial infection. This knowledge is relevant to the understanding of the pathogenesis of bacteria-induced bone loss, and to the identification of potential therapeutic targets of bone loss diseases.
Project description:Osteoclasts are derived from the monocyte/macrophage lineage, but little is known about osteoclast precursors in circulation. Bone marrow cells were subdivided into three populations; RANKhighFmslow, RANKhighFmshigh and RANKlowFmshigh. GeneChip analysis confirmed that the expression levels of monocyte-macrophage markers such as Emr1 (F4/80), Itgam (CD11b) and Csf1 (c-Fms) were lower in the RANKhighFmslow than RANKlowFmshigh population. In contrast, cells in the RANKhighFmslow population expressed higher levels of osteoclast markers such as Car ll (carbonic anhydrase ll), Mmp9 (matrix metalloproteinase 9), Acp5 (acid phosphatase 5) and Tfrc (transferrin receptor). These results suggest that RANKhighFmslow cells express few of the phenotypes of monocytes, and their differentiation into osteoclasts occurs at a slightly more advanced stage than that of the RANKlowFmshigh population. RANKhighFmslow cells and RANKlowFmshigh cells were isolated from bone marrow in ddY mice by FACS (Fluorescent activated cell sorting). Differential expression levels of mRNA were determined by GeneChip analysis.
Project description:Balanced osteoclast differentiation is crucial in maintaining skeleton health through life. Receptor activator of nuclear factor kappa-Β (RANK) is indispensable for OCs normal development in vivo and for the in vitro fusion of circulating progenitor cells into OCs. Many cytokines enhance RANK and RANK-ligand (RANK-L)-mediated differentiation of myeloid cells into OCs. In particular, tumor necrosis factor (TNF) is recognized as a potent activator and is associated with in vivo bone destruction in the context of OC dysregulation in inflammatory arthritis. Paradoxically, infiltration of monocytes into TNF rich inflammatory sites does not lead to a preponderance of osteoclasts but rather macrophages. Recent in vivo murine studies have shown how circulating myeloid precursors play a crucial role in post-natal OC differentiation and skeletal health. However, little is known about such pathways in humans. Herein we demonstrate that, unexpectedly TNF can act as a critical homeostatic regulator of human CD14+ monocyte differentiation into osteoclast by inhibiting osteoclastogenesis to favour macrophage development. In contrast, a distinct, previously unidentified human CD11c+ myeloid pre-osteoclast population is exempt from this negative regulation. In healthy humans, to control cell fate and specifically overcome OC differentiation, TNF drives epigenetic modification of the RANK promoter via a TNFR1-IKK-dependent pathway. In contrast in rheumatoid arthritis, patient-derived monocytes exhibit an altered epigenetic state that results in dysregulated TNF-mediated osteoclast homeostasis providing a pathologic consequence of failure of this pathway.
Project description:Comparison of gene expression of the osteoclast precursor myeloid blast seeded on plastic and on bone, primed with M-CSF for 4 days and culture with M-CSF and RANKL for 1 day. Osteoclasts and macrophages share progenitors that must receive decisive lineage signals driving them into their respective differentiation routes. Macrophage colony stimulation factor M-CSF is a common factor; bone is likely the stimulus for osteoclast differentiation. To elucidate the effect of both, shared mouse bone marrow precursor myeloid blast was pre-cultured with M-CSF on plastic and on bone. M-CSF priming prior to stimulation with M-CSF and osteoclast differentiation factor RANKL resulted in a complete loss of osteoclastogenic potential without bone. This coincided with a steeply decreased expression of osteoclast genes TRACP and DC-STAMP, but an increased expression of the macrophage markers F4/80 and CD11b. Compellingly, M-CSF priming on bone accelerated the osteoclastogenic potential: M-CSF primed cells that had received only one day M-CSF and RANKL and were grown on bone already expressed an array of genes that are associated with osteoclast differentiation and these cells differentiated into osteoclasts within 2 days. This implies that adhesion to bone dictates the fate of osteoclast precursors. Common macrophage-osteoclast precursors may become insensitive to differentiate into osteoclasts and regain osteoclastogenesis when bound to bone or when in the vicinity of bone.
Project description:Osteoclasts are derived from the monocyte/macrophage lineage, but little is known about osteoclast precursors in circulation. Bone marrow cells were subdivided into three populations; RANKhighFmslow, RANKhighFmshigh and RANKlowFmshigh. GeneChip analysis confirmed that the expression levels of monocyte-macrophage markers such as Emr1 (F4/80), Itgam (CD11b) and Csf1 (c-Fms) were lower in the RANKhighFmslow than RANKlowFmshigh population. In contrast, cells in the RANKhighFmslow population expressed higher levels of osteoclast markers such as Car ll (carbonic anhydrase ll), Mmp9 (matrix metalloproteinase 9), Acp5 (acid phosphatase 5) and Tfrc (transferrin receptor). These results suggest that RANKhighFmslow cells express few of the phenotypes of monocytes, and their differentiation into osteoclasts occurs at a slightly more advanced stage than that of the RANKlowFmshigh population.
Project description:Supplemental data for the article: Characterization of functional reprogramming during osteoclast development using quantitative proteomics and mRNA profiling Eunkyung An, Manikandan Narayanan, and Aleksandra Nita-Lazar* *corresponding author: Cellular Networks Proteomics Unit Laboratory of Systems Biology National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda, Maryland, 20892, USA Tel. +1 301-451-4394 Fax: +1 301-480-5170 E-mail: nitalazarau@niaid.nih.gov This dataset includes: 1. Raw LC-MS(/MS) spectra (*.raw), and 2. The output from data analyses using IP2 (Intergrated Proteomics Application, San Diego, CA) searched against the UniProt_mouse_01-18-2011 set of protein sequences (normal + reversed). Note that the version of IP2 that was used could only analyze two SILAC channels at a time, so two analyses were performed (light-medium, light-heavy) (the current version can analyze 3-plex SILAC all together in one analysis). Also, IP2 was run using two criteria (1 or 2 peptides per protein). Lanes D and E were lanes of an SDS-PAGE gel, and each was 3-plex SILAC: Lane D: Light (Osteoclast Precursor), Medium (Mature Osteoclast), Heavy (Intermediate Osteoclast) Lane E: Light (Osteoclast Precursor), Medium (Intermediate Osteoclast), Heavy (Mature Osteoclast)