Dataset Information

Obesity/type 2 diabetes increases inflammation, periosteal reactive bone formation, and osteolysis during Staphylococcus aureus implant-associated bone infection.

ABSTRACT: Obese and type 2 diabetic (T2D) patients have a fivefold increased rate of infection following placement of an indwelling orthopaedic device. Though implant infections are associated with inflammation, periosteal reactive bone formation, and osteolysis, the effect of obesity/T2D on these complicating factors has not been studied. To address this question, C57BL/6J mice were fed a high fat diet (60% Kcal from fat) to induce obesity/T2D, or a control diet (10% Kcal from fat) for 3 months, and challenged with a transtibial pin coated with a bioluminescent USA300 strain of S. aureus. In the resulting infected bone, obesity/T2D was associated with increased S. aureus proliferation and colony forming units. RNA sequencing of the infected tibiae on days 7 and 14 revealed an increase in 635 genes in obese/T2D mice relative to controls. Pathways associated with ossification, angiogenesis, and immunity were enriched. MicroCT and histology on days 21 and 35 demonstrated significant increased periosteal reactive bone formation in infected obese/T2D mice versus infected controls (p?

SUBMITTER: Farnsworth CW

PROVIDER: S-EPMC5995608 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Obesity/type 2 diabetes increases inflammation, periosteal reactive bone formation, and osteolysis during Staphylococcus aureus implant-associated bone infection.

Farnsworth Christopher W CW Schott Eric M EM Benvie Abigail M AM Zukoski Jacob J Kates Stephen L SL Schwarz Edward M EM Gill Steven R SR Zuscik Michael J MJ Mooney Robert A RA

Journal of orthopaedic research : official publication of the Orthopaedic Research Society 20180103 6

Obese and type 2 diabetic (T2D) patients have a fivefold increased rate of infection following placement of an indwelling orthopaedic device. Though implant infections are associated with inflammation, periosteal reactive bone formation, and osteolysis, the effect of obesity/T2D on these complicating factors has not been studied. To address this question, C57BL/6J mice were fed a high fat diet (60% Kcal from fat) to induce obesity/T2D, or a control diet (10% Kcal from fat) for 3 months, and chal ...[more]

PMID: 29227579

Similar Datasets

Project description:This study aimed to delineate the cell heterogeneity in the bone-implant interface and investigate the fibroblast responses to implant-associated S. aureus infection. Single-cell RNA sequencing of human periprosthetic tissues from patients with periprosthetic joint infection (PJI, n = 3) and patients with aseptic loosening (AL, n = 2) was performed. Cell type identities and gene expression profiles were analyzed to depict the single-cell landscape in the periprosthetic environment. In addition, 11 publicly available human scRNA-seq datasets were downloaded from GSE datasets and integrated with the in-house sequencing data to identify disease-specific fibroblast subtypes. Furthermore, fibroblast pseudotime trajectory analysis and Single-cell regulatory network inference and clustering (SCENIC) analysis were combined to identify transcription regulators responsible for fibroblast differentiation. Immunofluorescence was performed on the sequenced samples to validate the protein expression of the differentially expressed transcription regulators. Eight major cell types were identified in the human bone-implant interface by analyzing 36,466 cells. Meta-analysis of fibroblasts scRNA-seq data found fibroblasts in the bone-implant interface express a high level of CTHRC1. We also found fibroblasts could differentiate into pro-inflammatory and matrix-producing phenotypes, each primarily presented in the PJI and AL groups, respectively. Furthermore, NPAS2 and TFEC which are activated in PJI samples were suggested to induce pro-inflammatory polarization in fibroblasts, whereas HMX1, SOX5, SOX9, ZIC1, ETS2, and FOXO1 are matrix-producing regulators. Meanwhile, we conducted a CMap analysis and identified forskolin as a potential regulator for fibroblast differentiation toward matrix-producing phenotypes. In this study, we discovered the existence of CTHRC1+ fibroblast in the bone-implant interface. Moreover, we revealed a bipolar mode of fibroblast differentiation and put forward the hypothesis that infection could modulate fibroblast toward a pro-inflammatory phenotype through NPAS2 and TFEC.

Project description:BackgroundOsteomyelitis is a severe and often debilitating disease characterized by inflammatory destruction of bone. Despite treatment, chronic infection often develops which is associated with increased rates of treatment failure, delayed osseous-union, and extremity amputation. Within affected bone, bacteria exist as biofilms, however the impact of biofilms on osteoblasts during disease are unknown. Herein, we evaluated the effect of S. aureus biofilms on osteoblast viability, osteogenic potential, and the expression of the pro-osteoclast factor, receptor activator of NF-kB ligand (RANK-L).MethodsOsteoblasts were exposed to biofilm conditioned media (BCM) from clinical wound isolates of Staphylococcus aureus under normal growth and osteogenic conditions to assess cellular viability and osteoblast differentiation, respectively. Cell viability was evaluated using a live/dead assay and by quantifying total cellular DNA at days 0, 1, 3, 5, and 7. Apoptosis following treatment with BCM was measured by flow-cytometry using the annexin V-FITC/PI apoptosis kit. Osteogenic differentiation was assessed by measuring alkaline phosphatase activity and intracellular accumulation of calcium and osteocalcin for up to 21 days following exposure to BCM. Expression of genes involved in osteogenic differentiation and osteoclast regulation, were also evaluated by quantitative real-time PCR.ResultsBCM from clinical strains of S. aureus reduced osteoblast viability which was accompanied by an increase in apoptosis. Osteogenic differentiation was significantly inhibited following treatment with BCM as indicated by decreased alkaline phosphatase activity, decreased intracellular accumulation of calcium and inorganic phosphate, as well as reduced expression of transcription factors and genes involved in bone mineralization in viable cells. Importantly, exposure of osteoblasts to BCM resulted in up-regulated expression of RANK-L and increase in the RANK-L/OPG ratio compared to the untreated controls.ConclusionsTogether these studies suggest that soluble factors produced by S. aureus biofilms may contribute to bone loss during chronic osteomyelitis simultaneously by: (1) reducing osteoblast viability and osteogenic potential thereby limiting new bone growth and (2) promoting bone resorption through increased expression of RANK-L by osteoblasts. To our knowledge these are the first studies to demonstrate the impact of staphylococcal biofilms on osteoblast function, and provide an enhanced understanding of the pathogenic role of staphylococcal biofilms during osteomyelitis.

Dataset Information

Obesity/type 2 diabetes increases inflammation, periosteal reactive bone formation, and osteolysis during Staphylococcus aureus implant-associated bone infection.

Publications

Obesity/type 2 diabetes increases inflammation, periosteal reactive bone formation, and osteolysis during Staphylococcus aureus implant-associated bone infection.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets