Hdac3 deletion in myeloid progenitor cells enhances bone healing in females and limits osteoclast fusion via Pmepa1
Ontology highlight
ABSTRACT:
SUBMITTER: Molstad D
PROVIDER: S-EPMC7733476 | biostudies-literature | 2020 Jan
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Fracture healing, in which osteoclasts and osteoblasts play important roles, has drawn much clinical attention. Osteoclast deficiency or decreased osteoblast activity will impair fracture healing. TRPV1 is a member of the Ca2+ permeable cation channel subfamily, and pharmacological inhibition of TRPV1 prevents ovariectomy-induced bone loss, which makes TRPV1 a potential target for osteoporosis. However, whether long term TRPV1 inhibition or TRPV1 deletion will affect the fracture healing process is unclear. In this study, we found that the wild-type mice showed a well-remodeled fracture callus, whereas TRPV1 knockout mice still had an obvious fracture gap with unresorbed soft-callus 4 weeks post-fracture. The number of osteoclasts was reduced in the TRPV1 knockout fracture callus, and osteoclast formation and resorption activity were also impaired in vitro. TRPV1 deletion decreased the calcium oscillation frequency and peak cytoplasmic concentration in osteoclast precursors, subsequently reducing the expression and nuclear translocation of NFATc1 and downregulating DC-stamp, cathepsin K, and ATP6V. In addition, TRPV1 deletion caused reduced mRNA and protein expression of Runx2 and ALP in bone marrow stromal cells (BMSCs) and reduced calcium deposition in vitro. Our results suggest that TRPV1 deletion impairs fracture healing, and inhibited osteoclastogenesis and osteogenesis.
| S-EPMC5320507 | biostudies-literature
Project description:We previously established that global deletion of the enhancer of trithorax and polycomb (ETP) gene, Asxl2, prevents weight gain. Because proinflammatory macrophages recruited to adipose tissue are central to the metabolic complications of obesity, we explored the role of ASXL2 in myeloid lineage cells. Unexpectedly, mice without Asxl2 only in myeloid cells (Asxl2ΔLysM) were completely resistant to diet-induced weight gain and metabolically normal despite increased food intake, comparable activity, and equivalent fecal fat. Asxl2ΔLysM mice resisted HFD-induced adipose tissue macrophage infiltration and inflammatory cytokine gene expression. Energy expenditure and brown adipose tissue metabolism in Asxl2ΔLysM mice were protected from the suppressive effects of HFD, a phenomenon associated with relatively increased catecholamines likely due to their suppressed degradation by macrophages. White adipose tissue of HFD-fed Asxl2ΔLysM mice also exhibited none of the pathological remodeling extant in their control counterparts. Suppression of macrophage Asxl2 expression, via nanoparticle-based siRNA delivery, prevented HFD-induced obesity. Thus, ASXL2 controlled the response of macrophages to dietary factors to regulate metabolic homeostasis, suggesting modulation of the cells' inflammatory phenotype may impact obesity and its complications.
| S-EPMC7190927 | biostudies-literature
Project description:ObjectiveSympathetic nervous system and immune cell interactions play key roles in the regulation of metabolism. For example, recent convergent studies have shown that macrophages regulate obesity through brown adipose tissue (BAT) activation and beiging of white adipose tissue (WAT) via effects upon local catecholamine availability. However, these studies have raised issues about the underlying mechanisms involved including questions regarding the production of catecholamines by macrophages, the role of macrophage polarization state and the underlying intracellular signaling pathways in macrophages that might mediate these effects.MethodsTo address such issues we generated mice lacking Irs2, which mediates the effects of insulin and interleukin 4, specifically in LyzM expressing cells (Irs2LyzM-/- mice).ResultsThese animals displayed obesity resistance and preservation of glucose homeostasis on high fat diet feeding due to increased energy expenditure via enhanced BAT activity and WAT beiging. Macrophages per se did not produce catecholamines but Irs2LyzM-/- mice displayed increased sympathetic nerve density and catecholamine availability in adipose tissue. Irs2-deficient macrophages displayed an anti-inflammatory transcriptional profile and alterations in genes involved in scavenging catecholamines and supporting increased sympathetic innervation.ConclusionsOur studies identify a critical macrophage signaling pathway involved in the regulation of adipose tissue sympathetic nerve function that, in turn, mediates key neuroimmune effects upon systemic metabolism. The insights gained may open therapeutic opportunities for the treatment of obesity.
| S-EPMC6358539 | biostudies-literature
Project description:Osteoclasts are specialized multinucleated cells with the unique capacity to resorb bone. Despite insight into the various steps of the interaction of osteoclast precursors leading to osteoclast formation, surprisingly little is known about what happens with the multinucleated cell itself after it has been formed. Is fusion limited to the short period of its formation, or do osteoclasts have the capacity to change their size and number of nuclei at a later stage? To visualize these processes we analyzed osteoclasts generated in vitro with M-CSF and RANKL from mouse bone marrow and native osteoclasts isolated from rabbit bones by live cell microscopy. We show that osteoclasts fuse not only with mononuclear cells but also with other multinucleated cells. The most intriguing finding was fission of the osteoclasts. Osteoclasts were shown to have the capacity to generate functional multinucleated compartments as well as compartments that contained apoptotic nuclei. These compartments were separated from each other, each giving rise to a novel functional osteoclast or to a compartment that contained apoptotic nuclei. Our findings suggest that osteoclasts have the capacity to regulate their own population in number and function, probably to adapt quickly to changing situations.
| S-EPMC3349023 | biostudies-literature
Project description:Hematopoietic stem cells (HSCs) have the capacity to self-renew and continuously differentiate into all blood cell lineages throughout life. At each branching point during differentiation, interactions with the environment are key in the generation of daughter cells with distinct fates. Here, we examined the role of the cell adhesion molecule JAM-C, a protein known to mediate cellular polarity during spermatogenesis, in hematopoiesis. We show that murine JAM-C is highly expressed on HSCs in the bone marrow (BM). Expression correlates with self-renewal, the highest being on long-term repopulating HSCs, and decreases with differentiation, which is maintained longest among myeloid committed progenitors. Inclusion of JAM-C as a sole marker on lineage-negative BM cells yields HSC enrichments and long-term multilineage reconstitution when transferred to lethally irradiated mice. Analysis of Jam-C-deficient mice showed that two-thirds die within 48 hours after birth. In the surviving animals, loss of Jam-C leads to an increase in myeloid progenitors and granulocytes in the BM. Stem cells and myeloid cells from fetal liver are normal in number and homing to the BM. These results provide evidence that JAM-C defines HSCs in the BM and that JAM-C plays a role in controlling myeloid progenitor generation in the BM.
| S-EPMC2651011 | biostudies-literature
Project description: Not available
| S-EPMC5664403 | biostudies-literature
Project description:The molecular control of osteoclast formation is still not clearly elucidated. Here, we show that a process of cell recognition mediated by Siglec15-TLR2 binding is indispensable and occurs prior to cell fusion in RANKL-mediated osteoclastogenesis. Siglec15 has been shown to regulate osteoclastic bone resorption. However, the receptor for Siglec15 has not been identified, and the signaling mechanism involving Siglec15 in osteoclast function remains unclear. We found that Siglec15 bound sialylated TLR2 as its receptor and that the binding of sialylated TLR2 to Siglec15 in macrophages committed to the osteoclast-lineage initiated cell fusion for osteoclast formation, in which sialic acid was transferred by the sialyltransferase ST3Gal1. Interestingly, the expression of Siglec15 in macrophages was activated by M-CSF, whereas ST3Gal1 expression was induced by RANKL. Both Siglec15-specific deletion in macrophages and intrafemoral injection of sialidase abrogated cell recognition and reduced subsequent cell fusion for the formation of osteoclasts, resulting in increased bone formation in mice. Thus, our results reveal that cell recognition mediated by the binding of sialylated TLR2 to Siglec15 initiates cell fusion for osteoclast formation.
| S-EPMC8888621 | biostudies-literature
Project description:Histone deacetylase 3 (HDAC3) contributes to the regulation of gene expression, chromatin structure, and genomic stability. Because HDAC3 associates with oncoproteins that drive leukemia and lymphoma, we engineered a conditional deletion allele in mice to explore the physiological roles of Hdac3 in hematopoiesis. We used the Vav-Cre transgenic allele to trigger recombination, which yielded a dramatic loss of lymphoid cells, hypocellular bone marrow, and mild anemia. Phenotypic and functional analysis suggested that Hdac3 was required for the formation of the earliest lymphoid progenitor cells in the marrow, but that the marrow contained 3-5 times more multipotent progenitor cells. Hdac3(-/-) stem cells were severely compromised in competitive bone marrow transplantation. In vitro, Hdac3(-/-) stem and progenitor cells failed to proliferate, and most cells remained undifferentiated. Moreover, one-third of the Hdac3(-/-) stem and progenitor cells were in S phase 2 hours after BrdU labeling in vivo, suggesting that these cells were impaired in transit through the S phase. DNA fiber-labeling experiments indicated that Hdac3 was required for efficient DNA replication in hematopoietic stem and progenitor cells. Thus, Hdac3 is required for the passage of hematopoietic stem/progenitor cells through the S phase, for stem cell functions, and for lymphopoiesis.
| S-EPMC3696547 | biostudies-literature
Project description:The CD98 heavy chain (CD98hc) regulates virus-induced cell fusion and monocyte fusion, and is involved in amino acid transportation. Here, we examined the role that CD98hc plays in the formation of osteoclasts using CD98hcflox/floxLysM-cre peritoneal macrophages (CD98hc-defect macrophages). Peritoneal macrophages were stimulated with co-cultured with osteoblasts in the presence of 1,25(OH)2 vitamin D3, and thereafter stained with tartrate-resistant acid phosphatase staining solution. The multinucleated osteoclast formation was severely impaired in the peritoneal macrophages isolated from the CD98hc-defect mice compared with those from wild-type mice. CD98hc mediates integrin signaling and amino acid transport through the CD98 light chain (CD98lc). In integrin signaling, suppression of the M-CSF-RANKL-induced phosphorylation of ERK, Akt, JNK and p130Cas were observed at the triggering phase in the CD98h-defect peritoneal macrophages. Moreover, we showed that the general control non-derepressible (GCN) pathway, which was activated by amino acid starvation, was induced by the CD98hc-defect peritoneal macrophages stimulated with RANKL. These results indicate that CD98 plays two important roles in osteoclast formation through integrin signaling and amino acid transport.
| S-EPMC5600448 | biostudies-literature
Project description:Osteoclasts are multinucleated giant cells. Fusion is an essential element in the formation of osteoclasts. However, the exact cellular events and mechanisms remain largely unknown because of limited and insufficient methods for observing fusion process. In this work, a fluorescence reporter strategy was established to monitor osteoclast fusion. After fusing with cells expressing Cre recombinase, those cells with double fluorescence switch its expression from red to green fluorescent protein. The effect of RANKL and PTH on osteoclast fusion were both quantitatively and visually detected utilizing this strategy. Furthermore, a combination of this strategy with a technique of fluorescence-activated cell sorting revealed two different populations of fused osteoclasts, tdTomato+ GFP+ cells (TG cells) and GFP+ cells (G cells). The results argue for the potential of combining this technique with other bio-technologies to gain more information about osteoclast fusion. Overall, these data demonstrated that this visual fluorescence switch strategy is useful for further analysis of osteoclast fusion mechanisms.
| S-EPMC6033910 | biostudies-literature