Molecular medicine (Cambridge, Mass.)

IRS2 and FOXO1 may reduce osteoarthritis by controlling cartilage cell recycling and energy use

Updated

Abstract

Essence

In a mouse model, boosting IRS2 signaling suggested protection against cartilage damage by restoring chondrocyte and mitochondrial function.

Evidence

This preclinical study combined OA transcriptomic analyses, primary mouse chondrocyte experiments, and intra-articular Irs2 delivery in DMM mice, where IRS2 overexpression restored AKT/FOXO1 signaling, increased mitophagy, and improved cartilage and subchondral bone measures.

Caveat

The evidence is limited to mouse and cell-model data, so the therapeutic effect remains preclinical rather than proven in humans with osteoarthritis.

Simplified

Key numbers

5.1 × 10
Expression Reduction
Most significant differential expression identified in .
12 patients
Patient Cohort Size
Tibial plateaus obtained from patients undergoing knee replacement.

Key figures

Fig. 1
Control vs : gene expression differences and pathway enrichment in cartilage samples
Highlights reduced expression and key pathway changes in OA cartilage compared to controls
10020_2025_1346_Fig1_HTML
  • Panel A
    Heatmap showing (DEGs) with control samples clustered separately from OA samples; gene expression levels vary from low (blue) to high (red)
  • Panel B
    displaying DEGs with upregulated genes in OA marked in red and downregulated genes in green
  • Panel C
    Boxplot comparing IRS2 expression levels, showing visibly lower IRS2 expression in OA samples than controls
  • Panel D
    analysis identifying five selected genes including IRS2, ARHGDIB, BEST1, SERPING1, and VPS37B
  • Panel E
    highlighting pathways such as PI3K-Akt signaling and ECM-receptor interaction with varying gene counts and significance
Fig. 3
overexpression effects on gene expression, protein levels, proliferation, and apoptosis in mouse treated with IL-1β
Highlights IRS2 overexpression restoring proliferation and reducing apoptosis in chondrocytes impaired by IL-1β treatment
10020_2025_1346_Fig3_HTML
  • Panel A
    Relative mRNA expression levels of Col2, Mmp13, and Acan in four groups of mouse chondrocytes (Con, IL-1β, IL-1β+Ad-C, IL-1β+Ad-Irs2) with significant changes indicated
  • Panels B and C
    Western blot images and quantification of COL2A1, SOX9, MMP13, and IRS2 protein levels in four groups; COL2A1 and SOX9 levels appear higher in IL-1β+Ad-Irs2 compared to IL-1β
  • Panel D
    showing proliferating chondrocytes (green) and nuclei (blue) in four groups; IL-1β+Ad-Irs2 group appears to have more EDU-positive cells than IL-1β and IL-1β+Ad-C groups
  • Panel E
    Quantification of relative EDU-positive cell percentage in four groups, with IL-1β+Ad-Irs2 showing increased proliferation compared to IL-1β and IL-1β+Ad-C
  • Panel F
    measuring proliferation over 72 hours in four groups; IL-1β+Ad-Irs2 group shows increased absorbance (proliferation) compared to IL-1β and IL-1β+Ad-C
  • Panel G
    plots assessing apoptosis in four groups; IL-1β+Ad-Irs2 group appears to have fewer apoptotic cells than IL-1β and IL-1β+Ad-C groups
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Full Text

What this is

  • () is a chronic joint disease affecting over 240 million people globally, causing pain and functional impairments.
  • This research investigates the role of Insulin Receptor Substrate 2 (IRS2) in , focusing on its impact on chondrocyte and mitochondrial function.
  • Findings indicate that reduced IRS2 expression correlates with progression, suggesting IRS2 as a potential therapeutic target.

Essence

  • Reduced IRS2 expression in leads to impaired mitochondrial function and in , contributing to disease progression. Targeting IRS2 may offer a therapeutic strategy for .

Key takeaways

  • IRS2 expression is significantly reduced in cartilage, correlating with increased levels of matrix metalloproteinases and decreased cartilage integrity.
  • Overexpression of IRS2 in restores mitochondrial and improves cell survival, suggesting its role in maintaining chondrocyte homeostasis.
  • Intra-articular injection of adenovirus expressing IRS2 improves cartilage matrix integrity and alleviates bone changes in a mouse model of .

Caveats

  • The study primarily focuses on early changes, necessitating further research to evaluate long-term effects of IRS2 targeting.
  • The findings are based on mouse models and human samples, which may not fully represent the complexity of in all populations.

Definitions

  • Osteoarthritis (OA): A degenerative joint disease characterized by cartilage degradation, bone remodeling, and inflammation, leading to pain and functional impairment.
  • Chondrocytes: Specialized cells found in cartilage responsible for maintaining cartilage structure and function.
  • Autophagy: A cellular process that degrades and recycles cellular components, crucial for maintaining cell health and homeostasis.

Simplified

Funding

Competing interests

0 of 7
authors report competing interests
7 report none
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