Embryonic and postnatal tendon cells respond differently to interleukin-1β

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Cell Biology

Background:

• Adult tendons heal with scar tissue, impairing function, while embryonic tendons heal without scars.
• Scarring in adult tendons is linked to inflammation-induced imbalances in tissue repair processes.

Purpose of the Study:

• To compare the inflammatory responses of embryonic and adult (postnatal) tendon cells.
• To investigate the molecular mechanisms underlying scarless versus scarred tendon healing.

Main Methods:

• Treated embryonic and postnatal tendon cells with interleukin-1 beta (IL-1β).
• Analyzed gene expression of collagens and matrix metalloproteinases (MMPs).
• Measured inflammatory mediators and signaling pathway activation (NF-κB, p38 MAPK).

Main Results:

• Postnatal tendon cells exhibited higher baseline inflammatory mediator levels than embryonic cells.
• IL-1β treatment upregulated inflammatory mediators and MMPs in both cell types, with a significantly greater response in postnatal cells.
• p38 MAPK pathway activation was markedly higher in postnatal tendon cells following IL-1β stimulation.

Conclusions:

• Adult tendon cells' heightened response to inflammation, involving p38 MAPK signaling, promotes anabolic-catabolic imbalance, leading to scarring.
• Embryonic tendon cells show a less pronounced response to inflammatory stimuli.
• Tendon cells play a crucial role in determining healing outcomes (scarless vs. scarred) by regulating tissue repair processes.