# Co-stimulation with equibiaxial strain and pre-osteoblast co-culture differentiates monocytes in a bone model

## TL;DR

This study shows that applying mechanical strain and co-culturing cells can help monocytes and pre-osteoblasts differentiate into immune and bone cells.

## Contribution

The study introduces a bone model using mechanical strain and co-culture to induce cell differentiation.

## Key findings

- Cyclic strain increased CD11B, CD14, IL-6, and IL-8 in U937 cells, indicating monocytic differentiation.
- ALP expression and calcium deposition in ST2 cells showed osteoblastic differentiation.
- Combining strain and co-culture enhanced differentiation in the bone model.

## Abstract

Bone remodeling and immune function are dynamically regulated through cell–cell and cell–matrix interactions by stem and mature cell populations. We investigated the hypothesis that monocytes and pre-osteoblasts respond to cyclic tensile stress and paracrine interactions by differentiating into macrophage-like and osteoblast-like cells. 20% cyclic equibiaxial strain was applied to monocytic U937 and pre-osteoblastic ST2 cells for 72 h. Increased levels of CD11B, CD14, IL-6, and IL-8 in U937 indicated monocytic differentiation. Increased ALP expression and calcium deposition in ST2 indicated differentiation towards osteoblastic lineage. Overall, application of cyclic strain and pre-osteoblastic co-culture induced differentiation in this cyclically strained bone model.