First GreenNanoBone Study Reveals that Modifying Rhamnogalacturonan-I (RG-I)

First GreenNanoBone Study Reveals that Modifying Rhamnogalacturonan-I (RG-I) derived from Potato Pectin Improves Binding Affinity to Galectin-3

Background

Bone possesses the intrinsic capacity for regeneration as part of the repair process in response to injury, as well as during skeletal development or continuous remodelling during adult life. Recent research has shown that nanoparticles such as RG-I can promote bone regeneration.

RG-I derived from potato pectin can modulate inflammation and promote bone regeneration by modulating the action of the galactoside-binding galectin-3. Galectin-3 plays multiple roles in tissue repair, inflammation, and bone metabolism.

Mesenchymal stem cells (MSCs) play a vital role in bone regeneration. These are multipotent stem cells with the capability to support osteogenesis by differentiating into cells like osteoblasts. Galectin-3 helps maintain Mesenchymal Stem Cells (MSC) viability and proliferation and influences their differentiation into osteoblasts, the cells that build new bone.

First GreenNanoBone publication

In this study, the GreenNanoBone team wanted to understand the binding affinity of RG-I to galectin-3, and whether a modified version with reduced arabinose sugars increases its functionality.

RG-I is a complex polysaccharide found in plant cell walls, particularly in pectin. Its structure includes a backbone of rhamnose and galacturonic acid units, with side chains made of sugars like arabinose and galactose. Removing arabinose changes the structure of RG-I and can affect how it interacts with proteins like galectin-3. Results

The study found that both forms of RG-I can bind galectin-3, but with notable differences in strength:

  • RG-I exhibited a binding affinity of 8.66 × 10⁻⁶ M to galectin-3.
  • The arabinose-deficient RG-I (PA) form showed approximately tenfold stronger binding compared to the unmodified PU, suggesting that its galactose-rich structure is crucial for galectin-3 interaction.

Additionally, the team studied how the modified RG-I affects gene activity in human Mesenchymal Stem Cells (taken from bone marrow of elderly patients). Gene expression changes were found in 42 genes, including LGALS3, the gene that encodes the protein galectin-3.

Conclusions

These findings suggest that structural modification of potato pectin enhances its interaction with galectin-3 and triggers gene expression patterns in MSCs associated with inflammation control and tissue repair. By fine-tuning galectin-3 activity, the PA-modified RG-I could be a powerful biomaterial component for bone regeneration and immune modulation in regenerative medicine.

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