RANKL interferes with osteoclastogenesis in PEG-fused U937 cells through LGR4.

Area of Science:

• Cell Biology
• Osteoclastogenesis
• Biochemistry

Background:

• Osteoclast differentiation and maturation are critical processes involving cell fusion.
• Understanding the regulation of osteoclast fusion is essential for bone biology research.
• Existing models lack the ability to elucidate the limits and regulation of successive cell fusions.

Purpose of the Study:

• To investigate LGR4 receptor expression in PEG-fused U937 cells.
• To determine the effect of RANKL on osteoclast-like cells generated via PEG fusion.
• To compare osteoclastic activity in PEG-fused, RANKL-treated cells versus non-fused cells.

Main Methods:

• U937 cells were fused using Polyethylene Glycol (PEG).
• LGR4 expression was assessed in fused and non-fused cells.
• Osteoclast-like cells were treated with RANKL, and their activity was measured.
• RANKL-LGR4 interaction was interfered with in PEG-treated cells.

Main Results:

• PEG-mediated fusion of U937 cells promoted LGR4 receptor expression within 24 hours.
• RANKL application inhibited osteoclastic activity, whether applied before or after fusion.
• Interference with RANKL-LGR4 interaction in PEG-fused cells restored and enhanced cell fusion and osteoclastic activity.
• PEG-fused U937 cells exhibited osteoclast markers comparable to classical RANKL-stimulated models.

Conclusions:

• The developed model demonstrates RANKL's fusogenic role early in culture and its modulatory effect on fusion in later stages.
• The study differentiates the role of RANKL before and after cell fusion, highlighting LGR4's involvement.
• This research provides a novel model to understand the regulation of osteoclast fusion and the dual role of RANKL.