Biology subjects

Broz, K. S.

Publications and source records attributed to Broz, K. S..

3 recordsLinked to original sources

bioRxiv2026

Genetic and pharmacologic modulation of RAGE rescues the diabetes-mediated impairments to bone at multiple length scales

The bone matrix is precisely maintained and optimized to resist fractures. However, aging and disease deteriorate the bone matrix and increase fragility. Individuals with type 2 diabetes (T2D) have an elevated risk of bone fracture despite apparently normal bone mass. The chronic hyperglycemia in T2D promotes the formation of advanced glycation end-products (AGEs) in the bone tissue and modify the matrix mechanics. AGEs also bind to its receptor, RAGE, to activate inflammation and alter homeostasis. Using a leptin-receptor deficient mouse model of diabetes, we used a combination of high-resolution methods across multiple scales to evaluate the microarchitectural-, material- and cellular- level changes affected by the modulation of RAGE. To demonstrate the relevance of RAGE, we genetically ablated RAGE (RAGE-null) before the onset of diabetes; and to demonstrate the potency of RAGE as a disease modifying therapy, a RAGE antagonist (FPS-ZM1) was administered after prolonged diabetes. Diabetes impaired bone microstructure, the homeostatic actions of bone cells, the bone matrix nanomechanics, and whole- bone strength. The constitutive ablation of RAGE in diabetic animals prevented AGEs accumulation and the decline of trabecular connectivity; protected against the loss of osteocyte lacunae density and morphology; and maintained the matrix nanomechanics and bone strength. The inhibition of RAGE after the onset of diabetes reversed AGE accumulation and loss of bone volume; rescued osteocyte lacunae density and osteoclast activity; and restored matrix nanomechanics and bone strength. These results suggest that RAGE is a viable therapeutic target for diabetes-mediated impairments of bone quality. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/716153v1_ufig1.gif" ALT="Figure 1000"> View larger version (26K): org.highwire.dtl.DTLVardef@8b4ce4org.highwire.dtl.DTLVardef@1652394org.highwire.dtl.DTLVardef@10301a8org.highwire.dtl.DTLVardef@61c23d_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

The sex-specific effects of RAGE signaling and Type 2 Diabetes on mouse cortical bone mechanics, structure, and material properties

Individuals with type 2 diabetes (T2D) are prone to fracture at numerous skeletal sites despite presenting with a higher bone mineral density (BMD). The accumulation of Advanced Glycation End-products (AGEs) in the bone tissues of patients with T2D could be contributing to this paradox, of increased skeletal fragility with higher BMD. AGEs can impair bone cell homeostasis via the receptor for AGEs (RAGE). To investigate the effects of diabetes, AGE accumulation, and RAGE signaling on mouse cortical bone, we utilized male and female leptin receptor-deficient (db/db) mice from three age groups ranging from 3-14 months of age, which were crossed with animals carrying constitutively RAGE-deficient alleles (RAGE-/-). The morphological, mechanical and material outcomes were measured using microCT, 3-pt bending, and an AGE assay. We observed significant impairments dependent on age and sex to the bone matrix and whole-bone mechanical behavior due to diabetes with some impairments alleviated with the ablation of RAGE. In older female diabetic mice, the removal of RAGE signaling prevented the deficits in bone mechanics, morphology and tissue mineral density (TMD). Male diabetic mice without RAGE signaling exhibited improved material properties. The study demonstrated that some bone impairments associated with T2D are prevented with RAGE ablation and may be partially reversible with the inhibition of RAGE signaling. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=145 HEIGHT=200 SRC="FIGDIR/small/631018v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@75acedorg.highwire.dtl.DTLVardef@1ac01fforg.highwire.dtl.DTLVardef@1b70d34org.highwire.dtl.DTLVardef@c3f3a7_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2024

Single cell RNA sequencing reveals a shift in cell function and maturation of endogenous and infiltrating cell types in response to acute intervertebral disc injury

Intervertebral disc (IVD) degeneration contributes to disabling back pain. Degeneration can be initiated by injury, and progressively leads to irreversible cell loss and loss of IVD function. Attempts to restore IVD function through cell replacement therapies have had limited success due to knowledge gaps in the critical cell populations and molecular crosstalk after injury. Here, we used single cell RNA sequencing to identify the transcriptional changes of endogenous cells of the IVD and infiltrating cell populations following IVD injury. Control and Injured coccygeal IVDs were extracted from 12 week old female C57BL/6J mice 7 days post injury and subjected to single-cell resolution transcriptomic sequencing. Clustering, gene ontology, and pseudotime trajectory analyses determined transcriptomic divergences in the cells of the Injured IVD, flow cytometry identified they types of infiltrating immune cells, and immunofluorescence was utilized to define mesenchymal stem cell (MSC) localization. Clustering analysis revealed 11 distinct cell populations that included IVD, immune, vascular cells, and MSCs. Differential gene expression analysis determined that Outer Annulus Fibrosus, Neutrophils, Saa2-High MSCs, Macrophages, and Krt18+ Nucleus Pulposus (NP) cells were the major drivers of transcriptomic differences between Control and Injured cells. Gene ontology revealed that the most upregulated biological pathways were angiogenesis and T cell-related while wound healing and ECM regulation categories were downregulated. Pseudotime trajectory analyses revealed that IVD injury directed cells towards increased differentiation in all clusters, except for Krt18+ NP cells which remained in a less mature cell state. Saa2-High and Grem1-High MSCs populations drifted towards more differentiated IVD cells profiles with injury and localized distinctly within the IVD. This study revealed novel MSC populations in a heterogeneous landscape of IVD cell populations during injury, and these cells may be leveraged for future IVD repair studies. Lay SummaryThe intervertebral disc (IVD) is a spinal joint that accumulates damage with age but has limited tissue repair capabilities. IVD injuries progress into degeneration, and IVD degeneration is a leading cause of lower back pain. Understanding the cell populations that change and respond to injury will uncover targets to restore IVD function. Mesenchymal stem cells (MSCs) are cells within the IVD that can potentially replenish the cells lost after IVD damage. To better understand how IVD cell populations are affected by tissue damage, we performed single cell RNA sequencing of IVD tissue 7 days post injury and analyzed the differences in gene regulation. We identified diverse cells populations such as IVD, immune cells, vascular cells, and MSCs. We discovered the presence of Saa2 and Grem1 expressing MSCs that become less stem cell-like and express higher levels of IVD gene markers after injury. We also determined that Saa2 and Grem1 have varying gene expression patterns in IVD tissues that becomes attenuated after injury. These MSCs could be targeted for future stem cell therapies to prevent IVD degeneration.

cell biology↗