ARG2, MAP4K5 and TSTA3 as Diagnostic Markers of Steroid-Induced Osteonecrosis of the Femoral Head and Their Correlation With Immune Infiltration

Exploring the genetic association between immune cells and susceptibility to osteonecrosis using large-scale population data

Objectives

Research shows a close association between aberrant immune reactions in osteonecrotic tissues and immune cell infiltration. However, due to limitations in sample size and dataset comprehensiveness, the causal relationship between them is not fully established. This study aims to determine whether there is a causal relationship using a larger and more diverse dataset.

Methods

We conducted a comprehensive Mendelian Randomization (MR) analysis to investigate the causal relationship between immune cell characteristics and osteonecrosis. Utilizing publicly available genetic data, we explored the causal relationships between 731 immune cell features and 604 cases from the FinnGen Finnish database, as well as 257 cases from the UK Biobank database with osteonecrosis data. The inverse-variance weighted (IVW) method was used for the primary analysis, and we employed sensitivity analyses to assess the robustness of the main results. In addition, considering data from the two databases used in this study, a meta-analysis was conducted on the significant immune cells associated with osteonecrosis (FDR <0.05).

Results

our findings suggested that specific immune cell signatures, such as CD20- % lymphocytes, CD62L-monocytes, and CD33br HLA DR+ CD14-cells were associated with increased odds of osteonecrosis. In contrast, EM CD4+ activated cells and DP (CD4+ CD8+) T cells were associated with decreased odds. Notably, osteonecrosis was associated with a potential decrease in CD45 on immature MDSC cell content.

Conclusion

From a genetic perspective, we demonstrated a close association between immune cells and osteonecrosis. These findings significantly enhance our understanding of the interplay between immune cell infiltration and the risk of osteonecrosis, contributing to the potential design of therapeutic strategies from an immunological standpoint.

HIF-1α in cartilage homeostasis, apoptosis, and glycolysis in mice with steroid-induced osteonecrosis of the femoral head

With the prevalence of coronavirus disease 2019, the administration of glucocorticoids (GCs) has become more widespread. Treatment with high-dose GCs leads to a variety of problems, of which steroid-induced osteonecrosis of the femoral head (SONFH) is the most concerning. Since hypoxia-inducible factor 1α (HIF-1α) is a key factor in cartilage development and homeostasis, it may play an important role in the development of SONFH. In this study, SONFH models were established using methylprednisolone (MPS) in mouse and its proliferating chondrocytes to investigate the role of HIF-1α in cartilage differentiation, extracellular matrix (ECM) homeostasis, apoptosis and glycolysis in SONFH mice. The results showed that MPS successfully induced SONFH in vivo and vitro, and MPS-treated cartilage and chondrocytes demonstrated disturbed ECM homeostasis, significantly increased chondrocyte apoptosis rate and glycolysis level. However, compared with normal mice, not only the expression of genes related to collagens and glycolysis, but also chondrocyte apoptosis did not demonstrate significant differences in mice co-treated with MPS and HIF-1α inhibitor. And the effects observed in HIF-1α activator-treated chondrocytes were similar to those induced by MPS. And HIF-1α degraded collagens in cartilage by upregulating its downstream target genes matrix metalloproteinases. The results of activator/inhibitor of endoplasmic reticulum stress (ERS) pathway revealed that the high apoptosis rate induced by MPS was related to the ERS pathway, which was also affected by HIF-1α. Furthermore, HIF-1α affected glucose metabolism in cartilage by increasing the expression of glycolysis-related genes. In conclusion, HIF-1α plays a vital role in the pathogenesis of SONFH by regulating ECM homeostasis, chondrocyte apoptosis, and glycolysis.

Unraveling the genetic basis of the causal association between inflammatory cytokines and osteonecrosis

Background

Previous studies have reported that the occurrence and development of osteonecrosis is closely associated with immune-inflammatory responses. Mendelian randomization was performed to further assess the causal correlation between 41 inflammatory cytokines and osteonecrosis.

Methods

Two-sample Mendelian randomization utilized genetic variants for osteonecrosis from a large genome-wide association study (GWAS) with 606 cases and 209,575 controls of European ancestry. Another analysis included drug-induced osteonecrosis with 101 cases and 218,691 controls of European ancestry. Inflammatory cytokines were sourced from a GWAS abstract involving 8,293 healthy participants. The causal relationship between exposure and outcome was primarily explored using an inverse variance weighting approach. Multiple sensitivity analyses, including MR-Egger, weighted median, simple model, weighted model, and MR-PRESSO, were concurrently applied to bolster the final results.

Results

The results showed that bFGF, IL-2 and IL2-RA were clinically causally associated with the risk of osteonecrosis (OR=1.942, 95% CI=1.13-3.35, p=0.017; OR=0.688, 95% CI=0.50-0.94, p=0.021; OR=1.386, 95% CI=1.04-1.85, p = 0.026). there was a causal relationship between SCF and drug-related osteonecrosis (OR=3.356, 95% CI=1.09-10.30, p=0.034).

Conclusion

This pioneering Mendelian randomization study is the first to explore the causal link between osteonecrosis and 41 inflammatory cytokines. It conclusively establishes a causal association between osteonecrosis and bFGF, IL-2, and IL-2RA. These findings offer valuable insights into osteonecrosis pathogenesis, paving the way for effective clinical management. The study suggests bFGF, IL-2, and IL-2RA as potential therapeutic targets for osteonecrosis treatment.

[Role and mechanism of macrophage-mediated osteoimmune in osteonecrosis of the femoral head]

Objective

To summarize the research progress on the role of macrophage-mediated osteoimmune in osteonecrosis of the femoral head (ONFH) and its mechanisms.

Methods

Recent studies on the role and mechanism of macrophage-mediated osteoimmune in ONFH at home and abroad were extensively reviewed. The classification and function of macrophages were summarized, the osteoimmune regulation of macrophages on chronic inflammation in ONFH was summarized, and the pathophysiological mechanism of osteonecrosis was expounded from the perspective of osteoimmune, which provided new ideas for the treatment of ONFH.

Results

Macrophages are important immune cells involved in inflammatory response, which can differentiate into classically activated type (M1) and alternatively activated type (M2), and play specific functions to participate in and regulate the physiological and pathological processes of the body. Studies have shown that bone immune imbalance mediated by macrophages can cause local chronic inflammation and lead to the occurrence and development of ONFH. Therefore, regulating macrophage polarization is a potential ONFH treatment strategy. In chronic inflammatory microenvironment, inhibiting macrophage polarization to M1 can promote local inflammatory dissipation and effectively delay the progression of ONFH; regulating macrophage polarization to M2 can build a local osteoimmune microenvironment conducive to bone repair, which is helpful to necrotic tissue regeneration and repair to a certain extent.

Conclusion

At present, it has been confirmed that macrophage-mediated chronic inflammatory immune microenvironment is an important mechanism for the occurrence and development of ONFH. It is necessary to study the subtypes of immune cells in ONFH, the interaction between immune cells and macrophages, and the interaction between various immune cells and macrophages, which is beneficial to the development of potential therapeutic methods for ONFH.

Bioinformatic analysis of related immune cell infiltration and key genes in the progression of osteonecrosis of the femoral head

Objective

Osteonecrosis of the femoral head (ONFH) is a common orthopedic condition that will prompt joint dysfunction, significantly impacting patients' quality of life. However, the specific pathogenic mechanisms underlying this disease remain elusive. The objective of this study is to examine the differentially expressed messenger RNAs (DE mRNAs) and key genes linked to ONFH, concurrently investigating the immune cell infiltration features in ONFH patients through the application of the CIBERSORT algorithm.

Methods

Microarray was applied to scrutinize mRNA expression profiles in both ONFH patients and healthy controls, with data integration sourced from the GEO database. DE mRNAs were screened using the Limma method. The biological functions of DE mRNAs were explored through the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, Gene Ontology (GO) functional analysis, and Gene Set Enrichment Analysis (GSEA). Additionally, support vector machine-recursive feature elimination (SVM-RFE) and the least absolute shrinkage and selection operator (LASSO) were employed to discern diagnostic biomarkers associated with the disease. Receiver operating characteristic (ROC) analysis was utilized to assess the statistical performance of the feature genes. The validation of key genes was performed using qRT-PCR in bone tissues obtained from ONFH patients and healthy controls. Osteogenic differentiation of BMSC was then performed and detected by alkaline phosphatase staining (ALP) and qRT-PCR to verify the correlation between key genes and osteogenic differentiation. Finally, immune cell infiltration analysis was executed to evaluate immune cell dysregulation in ONFH, concurrently exploring the correlation between the infiltration of immune cells and key genes.

Results

After consolidating the datasets, the Limma method revealed 107 DEGs, comprising 76 downregulated and 31 upregulated genes. Enrichment analysis revealed close associations of these DE mRNAs with functions such as cell migration, osteoblast differentiation, cartilage development and extracellular region. Machine learning algorithms further identified APOD, FBXO43 and LRP12 as key genes. ROC curves demonstrated the high diagnostic efficacy of these genes. The results of qRT-PCR showed that the expression levels of key genes were consistent with those of microarray analysis. In addition, the results of in vitro experiments showed that APOD was closely related to osteogenic differentiation of BMSC. Immune infiltration analysis suggested a close correlation between ONFH and imbalances in levels of Neutrophils, Monocytes, Macrophages M2, Dendritic cells activated and Dendritic cells resting.

Conclusion

APOD is closely related to osteogenic differentiation of BMSCs and can be used as a diagnostic marker of ONFH. Immune cell infiltration significantly differs between controls and ONFH patients.

Biomarkers of ulcerative colitis disease activity CXCL1, CYP2R1, LPCAT1, and NEU4 and their relationship to immune infiltrates

The diagnosis and assessment of ulcerative colitis (UC) poses significant challenges, which may result in inadequate treatment and a poor prognosis for patients. This study aims to identify potential activity biomarkers for UC and investigate the role of infiltrating immune cells in the disease. To perform gene set enrichment analysis, we utilized the cluster profiler and ggplot2 packages. Kyoto encyclopedia of genes and genomes was used to analyze degenerate enrichment genes. Significant gene set enrichment was determined using the cluster profiler and ggplot2 packages. Additionally, quantitative PCR (qRT-PCR) was employed to validate the expression of each marker in the ulcerative colitis model. We identified 651 differentially expressed genes (DEGs) and further investigated potential UC activity biomarkers. Our analysis revealed that CXCL1 (AUC = 0.710), CYP2R1 (AUC = 0.863), LPCAT1 (AUC = 0.783), and NEU4 (AUC = 0.833) were promising activity markers for the diagnosis of UC. Using rat DSS model, we validated these markers through qRT-PCR, which showed statistically significant differences between UC and normal colon mucosa. Infiltrating immune cell analysis indicated that M1 macrophages, M2 macrophages, activated dendritic cells (DCs), and neutrophils played crucial roles in the occurrence and progression of UC. Moreover, the activity markers exhibited varying degrees of correlation with activated memory CD4 T cells, M0 macrophages, T follicular helper cells, memory B cells, and activated DCs. The potential diagnostic genes for UC activity, such as CXCL1, CYP2R1, LPCAT1, and NEU4, as well as the infiltration of immune cells, may contribute to the pathogenesis and progression of UC.

Bioinformatics-Based Analysis of Key Genes in Steroid-Induced Osteonecrosis of the Femoral Head That Are Associated with Copper Metabolism

Osteonecrosis of the femoral head (ONFH) is a common disabling disease. Copper has positive effects on cells that regulate bone metabolism. However, the relationship between copper metabolism (CM) and steroid-induced ONFH (SONFH) remains unclear. The GSE123568 dataset was downloaded from the Gene Expression Omnibus. The differentially expressed CM-related SONFH genes (DE-CMR-SONFHGs) were identified via differential analysis and weighted gene coexpression network analysis (WGCNA). Receiver operating characteristic (ROC) analysis was performed for the predictive accuracy of key genes. Targeting drugs and the copper death-related genes (CDRGs) relevant to key genes were investigated. The bioinformatics results were confirmed via quantitative real-time polymerase chain reaction (qRT–PCR) and Western blot (WB) analysis. Two out of 106 DE-CMR-SONFHGs were identified as key genes (PNP and SLC2A1), which had diagnostic value in distinguishing SONFH from control samples and were related to various immune cell infiltrations. Eleven PMP-targeting drugs and five SLC2A1-targeting drugs were identified. The qRT–PCR, as well as WB, results confirmed the downregulation PNP and SLC2A1 and high expression of the CDRGs DLD, PDHB, and MTF1, which are closely related to these two key genes. In conclusion, PNP and SLC2A1 were identified as key genes related to SONFH and may provide insights for SONFH treatment.

Polarization Behavior of Bone Macrophage as Well as Associated Osteoimmunity in Glucocorticoid-Induced Osteonecrosis of the Femoral Head

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is a disabling disease with high mortality in China but the detailed molecular and cellular mechanisms remain to be investigated. Macrophages are considered the key cells in osteoimmunology, and the cross-talk between bone macrophages and other cells in the microenvironment is involved in maintaining bone homeostasis. M1 polarized macrophages launch a chronic inflammatory response and secrete a broad spectrum of cytokines (eg, TNF-α, IL-6 and IL-1β) and chemokines to initiate a chronic inflammatory state in GIONFH. M2 macrophage is the alternatively activated anti-inflammatory type distributed mainly in the perivascular area of the necrotic femoral head. In the development of GIONFH, injured bone vascular endothelial cells and necrotic bone activate the TLR4/NF-κB signal pathway, promote dimerization of PKM2 and subsequently enhance the production of HIF-1, inducing metabolic transformation of macrophage to the M1 phenotype. Considering these findings, putative interventions by local chemokine regulation to correct the imbalance between M1/M2 polarized macrophages by switching macrophages to an M2 phenotype, or inhibiting the adoption of an M1 phenotype appear to be plausible regimens for preventing or intervening GIONFH in the early stage. However, these results were mainly obtained by in vitro tissue or experimental animal model. Further studies to completely elucidate the alterations of the M1/M2 macrophage polarization and functions of macrophages in glucocorticoid-induced osteonecrosis of the femoral head are imperative.

The role of immune cells in modulating chronic inflammation and osteonecrosis

Osteonecrosis occurs when, under continuous stimulation by adverse factors such as glucocorticoids or alcohol, the death of local bone and marrow cells leads to abnormal osteoimmune function. This creates a chronic inflammatory microenvironment, which interferes with bone regeneration and repair. In a variety of bone tissue diseases, innate immune cells and adaptive immune cells interact with bone cells, and their effects on bone metabolic homeostasis have attracted more and more attention, thus developing into a new discipline - osteoimmunology. Immune cells are the most important regulator of inflammation, and osteoimmune disorder may be an important cause of osteonecrosis. Elucidating the chronic inflammatory microenvironment regulated by abnormal osteoimmune may help develop potential treatments for osteonecrosis. This review summarizes the inflammatory regulation of bone immunity in osteonecrosis, explains the pathophysiological mechanism of osteonecrosis from the perspective of osteoimmunology, and provides new ideas for the treatment of osteonecrosis.

Effects of Simvastatin on Cartilage Homeostasis in Steroid-Induced Osteonecrosis of Femoral Head by Inhibiting Glucocorticoid Receptor

Steroid-induced osteonecrosis of femoral head (SONFH) is one of the most common bone disorders in humans. Statin treatment is beneficial in preventing the development of SONFH through anti-inflammation effects and inhibition of the glucocorticoid receptor (GR). However, potential mechanisms of statin action remain to be determined. In this study, pulse methylprednisolone (MP) treatment was used to induce SONFH in broilers, and then MP-treated birds were administrated with simvastatin simultaneously to investigate the changes in cartilage homeostasis. Meanwhile, chondrocytes were isolated, cultured, and treated with MP, simvastatin, or GR inhibitor in vitro. The changes in serum homeostasis factors, cell viability, and expression of GR were analyzed. The results showed that the morbidity of SONFH in the MP-treated group increased significantly compared with the simvastatin-treated and control group. Furthermore, MP treatment induced apoptosis and high-level catabolism and low-level anabolism in vitro and vivo, while simvastatin significantly decreased catabolism and slightly recovered anabolism via inhibiting GR and the hypoxia-inducible factor (HIF) pathway. The GR inhibitor or its siRNA mainly affected the catabolism of cartilage homeostasis in vitro. In conclusion, the occurrence of SONFH in broilers was related to the activation of GR and HIF pathway, and imbalance of cartilage homeostasis. Simvastatin and GR inhibitor maintained cartilage homeostasis via GR and the HIF pathway.

Bioinformatics analysis to obtain critical genes regulated in subcutaneous adipose tissue after bariatric surgery

Bariatric surgery (BS) is a dependable method for managing obesity and metabolic diseases, however, the regulatory processes of lipid metabolism are still not well elucidated. Differentially expressed genes (DEGs) were analysed through three transcriptomic datasets of GSE29409, GSE59034 and GSE72158 from the GEO database regarding subcutaneous adipose tissue (SAT) after BS, and 37 DEGs were identified. The weighted gene co-expression network analysis (WGCNA), last absolute shrinkage and selection operator (LASSO) logistic regression and support vector machine-recursive feature elimination (SVM-RFE) algorithms further screened four key genes involved in the regulation of STMN2, SFRP4, APOE and MXRA5. The GSE53376 dataset was used to further confirm the differential expression of SFRP4, APOE and MXRA5 in the postoperative period. GSEA analysis reveals activation of immune-related regulatory pathways after surgery. Finally, the silencing of MXRA5 was found by experimental methods to affect the expression of PPARγ and CEBPα during the differentiation of preadipocytes, as well as to affect the formation of lipid droplets. In conclusion, SAT immunoregulation was mobilized after BS, while MXRA5 was involved in the regulation of lipid metabolism.

[Research progress of immune cells regulating the occurrence and development of osteonecrosis of the femoral head]

OBJECTIVE

To summarize the characteristics of the occurrence and development of osteonecrosis of the femoral head (ONFH), and to review the important regulatory role of immune cells in the progression of ONFH.

METHODS

The domestic and foreign literature on the immune regulation of ONFH was reviewed, and the relationship between immune cells and the occurrence and development of ONFH was analyzed.

RESULTS

The ONFH region has a chronic inflammatory reaction and an imbalance between osteoblast and osteoclast, while innate immune cells such as macrophages, neutrophils, dendritic cells, and immune effector cells such as T cells and B cells are closely related to the maintenance of bone homeostasis.

CONCLUSION

Immunotherapy targeting the immune cells in the ONFH region and the key factors and proteins in their regulatory pathways may be a feasible method to delay the occurrence, development, and even reverse the pathology of ONFH.

Identification of Inflammation-Related Genes and Exploration of Regulatory Mechanisms in Patients with Osteonecrosis of the Femoral Head

Background

Osteonecrosis of the femoral head (ONFH) is a disabling orthopedic disease, which is impacted by infiltration of immune cells. Thus, the aim of the current research was to determine the inflammation-related biomarkers in ONFH.

Methods

GSE123568 dataset with control and steroid-induced osteonecrosis of the femoral head (SONFH) samples were downloaded from Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were detected by limma R package and weighted gene co-expression network analysis (WGCNA) was used to explore the co-expression genes and modules. We obtained inflammation-related genes (IRGs) from the Molecular Signatures Database (MSigDB). Then, the IRGs associated with SONFH (IRGs-SONFH) were screened out and analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. A protein-protein interaction (PPI) network was established using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and hub genes were identified by the MCODE algorithm. Based on the hub genes, we constructed a lncRNA-miRNA-mRNA network.

Results

We identified 535 DEGs between control and SONFH samples. The WGCNA clearly indicated that the brown module was most significantly associated with SONFH. We identified 25 IRGs-SONFH through WGCNA module genes, DEGs and IRGs. A total of 4 hub genes (CD14, CYBB, NOD2, and TLR1) were identified by Cytoscape. Receiver operating characteristic (ROC) curve analysis determined that the expressions of the four genes could distinguish SONFH from controls as evidenced by the area under the curve (AUC) greater than 0.7. Finally, we constructed a competitive endogenous RNA (ceRNA) network which included 67 lncRNAs, 1 miRNA (hsa-miR-320a), and 1 mRNA (NOD2).

Conclusions

Our study identified 4 hub genes as potential inflammation-related biomarkers of SONFH. Moreover, we proposed a ceRNA network of lncRNAs targeting hsa-miR-320a, hsa-miR-320a, and NOD2 as a potential RNA regulatory pathway that controls disease progression in ONFH.

Global research trends of steroid-induced osteonecrosis of the femoral head: A 30-year bibliometric analysis

OBJECTIVE

To explore the global research trends and hotspots of steroid-induced osteonecrosis of the femoral head (SONFH) through qualitative and quantitative analysis of bibliometrics.

METHODS

All publications on SONFH published from 1992 to 2021 were extracted from the Web of Science Core Collection database. CiteSpace was used for the visualization analysis of major countries, active institutions, productive authors, and the burst of keywords. VOSviewer was used for coupling analysis of countries/regions, institutions, and authors. Microsoft Excel 2017 was used for statistical analysis, drawing bar charts, pie charts, and cumulative area charts. The software of MapInfo was used to draw the distribution map of the publications.

RESULTS

A total of 780 publications were included for analyses. The most productive year was 2020 with 98 records. China was the most influential country with 494 publications, an H-index of 59, and total citations of 16820. The most prolific institution was Shanghai Jiaotong University in China with 53 publications and 998 citations. Clinical Orthopaedics and Related Research (IF = 4.755, 2021) was the most active journal with 26 articles. The hot keywords were "osteonecrosis", "avascular necrosis", "osteogenic differentiation", "proliferation", "PPAR gamma", "apoptosis", "oxidative stress", "genetic polymorphism" and "mesenchymal stem cells". The keywords like "proliferation", "PPAR gamma" and "genome-wide" have emerged in recent years.

CONCLUSION

The number of publications in SONFH has increased significantly in the last three decades. The pathologic mechanism of SONFH gathered most research interests. Genomics and cell molecular biology of SONFH are the research frontiers.