Dataset Information

Multimodal single cell profiling of bone fracture microenvironment

ABSTRACT: Age-specific alterations of the adaptive immune system include low-grade chronic inflammation, which contributes to the unfavorable outcome of the bone healing process in the elderly. In this work, we aimed to characterize the effect of immune experience and age on cellular phenotype during the early inflammatory phase after bone fracture by using a mouse model which included young, aged, and immune-aged mice 2- and 5-days post osteotomy. Single-cell proteo-genomics quantified thousands of transcriptomes of cells isolated from three different bone regions (fracture hematoma, proximal and distal bone marrow). The fracture hematoma is a very distinct tissue consisting of coagulated blood caused by rupture of adjacent blood vessels, bone marrow influx and cells attracted from the surrounding tissue. The hematoma matures with the healing process and the adjacent bone marrow (proximal and distal to the fracture gap) supports the healing process.

ORGANISM(S): Mus musculus

PROVIDER: GSE273792 | GEO | 2025/02/25

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:The fracture hematoma that forms between the broken fragments of bone serves as a natural fibrin scaffold. However, there is no data regarding the differences between the micro-architectural and biological properties of hematomas formed in normally healing, delayed healing, and non-healing bone defects. Mimicking these three conditions in the rat femur, we demonstrate clear differences in fibrin clot morphology, which directly affect the gene expression pattern. Specifically, RNA-sequencing reveals that the expression of essential osteogenic genes in normally healing defects are significantly up-regulated, whereas in delayed and non-healing defects they are down-regulated. Surprisingly, there were no substantial differences between delayed and non-healing defects. Most importantly, this study demonstrates that the healing outcome has already been determined at the earliest stage of bone healing. These findings could be used to develop biomaterial scaffolds mimicking the micro-architectural properties of normally healing fracture hematoma as a treatment strategy for bone defects. The hypothesis of this study was that the micro-architectural properties of the initially formed hematoma has a significant effect on the regulation of the biological process at the fracture site, which ultimately determines the outcome of bone healing. Three different healing models were investigated - normally healing, delayed healing, and non-healing defects. The results demonstrated that the intrinsic micro-architectural properties of hematomas between those groups varied distinctly in terms of fiber diameter, porosity, and density of the formed fibrin network. Those differences influenced biological responses, as evidenced by a higher expression of osteogenic genes in normally healing compared to delayed and non-healing defects, and the failed activation of BMP-2 in non-healing defects. More importantly, our results demonstrate healing outcomes are already determined at the initial (hematoma) stage of bone healing.

Project description:Bone fractures, the most common musculoskeletal injuries, heal through three main phases: inflammatory, repair, and remodeling. Around 10% of fracture patients suffer from impaired healing that requires surgical intervention, a huge burden on the healthcare system. The rate of impaired healing increases with metabolic diseases such as obesity-associated hyperglycemia/type 2 diabetes (T2D), an increasing concern given the growing incidence of obesity/T2D. Immune cells play pivotal roles in fracture healing, and obesity/T2D is associated with defective immune-cell functions. However, there is a gap in knowledge regarding the stoichiometry of immune cells that populate the callus and how that population changes during different phases of healing. Here, we used complementary global and single-cell techniques to characterize the repertoire of immune cells in the fracture callus and to identify populations specifically enriched in the fracture callus relative to the unfractured bone or bone marrow. Our analyses identified two clear waves of immune-cell infiltration into the callus: the first wave occurs during the early inflammatory phase of fracture healing, while the second takes place during the late repair/early remodeling phase. Innate immune cells were activated during the early inflammatory phase, but in later phases they returned to homeostatic numbers and activation levels. Of the innate immune cells, distinct subsets of activated dendritic cells were particularly enriched in the inflammatory healing hematoma. In contrast to innate cells, lymphocytes, including B and T cells, were enriched and activated in the callus primarily during the late repair phase. The Diet-Induced Obesity (DIO) mouse, an established model of obesity-associated hyperglycemia and insulin resistance, suffers from multiple healing defects. Our data demonstrate that DIO mice exhibit dysregulated innate immune responses during the inflammatory phase, and defects in all lymphocyte compartments during the late repair phase. Taken together, our data characterize, for the first time, immune populations that are enriched/activated in the callus during two distinct phases of fracture healing and identify defects in the healing-associated immune response in DIO mice, which will facilitate future development of immunomodulatory therapeutics for impaired fracture healing.

Dataset Information

Multimodal single cell profiling of bone fracture microenvironment

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets