scholarly journals Hypertrophic Chondrocytes Serve as a Reservoir for Unique Marrow Associated Skeletal Stem and Progenitor Cells, Osteoblasts, and Adipocytes During Skeletal Development

2021 ◽  
Author(s):  
Jason T. Long ◽  
Abigail Leinroth ◽  
Yihan Liao ◽  
Yinshi Ren ◽  
Anthony J. Mirando ◽  
...  

Skeletal stem and progenitor cells (SSPCs) reside within niches localized to the intramedullary bone marrow and periosteal tissues surrounding bones, with most being capable of becoming osteoblasts, chondrocytes, and adipocytes during bone development and/or regeneration. SSPCs within the periosteum can give rise to intramedullary SSPCs, osteoblasts, osteocytes, and adipocytes during bone development; however, whether they are the sole source of these cells remains to be determined. Growth plate chondrocytes contribute to the osteoblast lineage and trabecular bone formation; however, the cellular process used to achieve this is unknown. We utilized hypertrophic chondrocyte genetic reporter mouse models combined with single cell RNA-sequencing, immunofluorescent staining, and bulk RNA-sequencing approaches to determine that hypertrophic chondrocytes undergo a process of dedifferentiation to generate unique bone marrow associated SSPC populations that likely serve as a primary source of osteogenic cells during skeletal development, while also contributing to the adipogenic lineage with age.

Author(s):  
Omika Katoch ◽  
Mrinalini Tiwari ◽  
Namita Kalra ◽  
Paban K. Agrawala

AbstractDiallyl sulphide (DAS), the pungent component of garlic, is known to have several medicinal properties and has recently been shown to have radiomitigative properties. The present study was performed to better understand its mode of action in rendering radiomitigation. Evaluation of the colonogenic ability of hematopoietic progenitor cells (HPCs) on methocult media, proliferation and differentiation of hematopoietic stem cells (HSCs), and transplantation of stem cells were performed. The supporting tissue of HSCs was also evaluated by examining the histology of bone marrow and in vitro colony-forming unit–fibroblast (CFU-F) count. Alterations in the levels of IL-5, IL-6 and COX-2 were studied as a function of radiation or DAS treatment. It was observed that an increase in proliferation and differentiation of hematopoietic stem and progenitor cells occurred by postirradiation DAS administration. It also resulted in increased circulating and bone marrow homing of transplanted stem cells. Enhancement in bone marrow cellularity, CFU-F count, and cytokine IL-5 level were also evident. All those actions of DAS that could possibly add to its radiomitigative potential and can be attributed to its HDAC inhibitory properties, as was observed by the reversal radiation induced increase in histone acetylation.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi104-vi104
Author(s):  
Bayli DiVita Dean ◽  
Tyler Wildes ◽  
Joseph Dean ◽  
David Shin ◽  
Connor Francis ◽  
...  

Abstract INTRODUCTION Bone marrow-derived hematopoietic stem and progenitor cells (HSPCs) give rise to the cellular components of the immune system. Unfortunately, immune reconstitution from HSPCs are negatively impacted by solid cancers, including high-grade gliomas. For example, an expansion of myeloid progenitor cells has been previously described across several cancers that originate outside the CNS. A similar expansion of MDSCs coupled with diminished T cell function has also been described in the peripheral blood of patients with newly-diagnosed GBM. Alterations in both lymphoid and myeloid compartments due to CNS malignancy led us to determine how intracranial gliomas impact HSPCs in both their capacity to reconstitute the immune compartment and in their cell fate determination. This is important to better understand the impact of gliomas on immunity and how we can leverage these findings to better develop cellular immunotherapeutics. METHODS HSPCs were isolated from bone marrow of C57BL/6 mice with orthotopic KR158B glioma, or age-matched naïve mice. Experiments were conducted to compare relative changes in: gene expression (RNA-sequencing), precursor frequencies, cell fate determination, and cellular function of cells derived from HSPCs of glioma-bearing mice. RESULTS RNA-sequencing revealed 700+ genes whose expression was significantly up- or downregulated in HSPCs from glioma-bearing mice, particularly those involved with stemness and metabolic activity. Importantly, HSPCs from glioma-bearing mice expressed upregulation of genes involved in myelopoiesis relative to naïve mice. This was coupled with an expansion of granulocyte macrophage precursors (GMPs), the progenitors to gMDSCs. Next, differentiation assays revealed that HSPCs from glioma-bearing mice had higher propensity of differentiating into MDSC under homeostatic conditions relative to controls both in vitro and in vivo. Furthermore, mice bearing intracranial gliomas possess an expansion of MDSCs which are more suppressive on T cell proliferation and hinders T cell-mediated tumor cell killing relative to MDSCs derived from naïve control mice.


Stem Cells ◽  
1999 ◽  
Vol 17 (6) ◽  
pp. 339-344 ◽  
Author(s):  
John Eugenes Chisi ◽  
Joanna Wdzieczak‐Bakala ◽  
Josiane Thierry ◽  
Cecile V. Briscoe ◽  
Andrew C. Riches

2021 ◽  
Vol 218 (4) ◽  
Author(s):  
Siddharth Krishnan ◽  
Kelly Wemyss ◽  
Ian E. Prise ◽  
Flora A. McClure ◽  
Conor O’Boyle ◽  
...  

Hematopoietic stem cells reside in the bone marrow, where they generate the effector cells that drive immune responses. However, in response to inflammation, some hematopoietic stem and progenitor cells (HSPCs) are recruited to tissue sites and undergo extramedullary hematopoiesis. Contrasting with this paradigm, here we show residence and differentiation of HSPCs in healthy gingiva, a key oral barrier in the absence of overt inflammation. We initially defined a population of gingiva monocytes that could be locally maintained; we subsequently identified not only monocyte progenitors but also diverse HSPCs within the gingiva that could give rise to multiple myeloid lineages. Gingiva HSPCs possessed similar differentiation potentials, reconstitution capabilities, and heterogeneity to bone marrow HSPCs. However, gingival HSPCs responded differently to inflammatory insults, responding to oral but not systemic inflammation. Combined, we highlight a novel pathway of myeloid cell development at a healthy barrier, defining a gingiva-specific HSPC network that supports generation of a proportion of the innate immune cells that police this barrier.


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