# Expression of Kielin/chordin-like protein is regulated by BMP-2 in osteoblasts

## TL;DR

This study shows that BMP-2 increases Kcp expression in osteoblasts, which helps promote bone formation through positive feedback.

## Contribution

The study reveals that Kcp is regulated by BMP-2 and contributes to osteoblast differentiation via SMAD signaling.

## Key findings

- Kcp expression in osteoblasts is increased by BMP-2 in a concentration- and time-dependent manner.
- SMAD signaling is involved in the regulation of BMP-2-induced Kcp expression.
- Kcp partially regulates BMP-2-induced osteoblast differentiation and mineralization.

## Abstract

Bone morphogenetic protein (BMP), an osteoinductive factor, is a cytokine that induces osteoblast differentiation and mineralization, and expected to be applicable for hard tissue reconstruction. Kielin/chordin-like protein (Kcp), a member of the family of cysteine-rich proteins, enhances BMP signaling. The present study found that expression of Kcp in osteoblasts was induced by BMP-2 in a concentration- and time-dependent manner. Up-regulation of Kcp by BMP-2 was inhibited by Dorsomorphin, a SMAD signaling inhibitor. The involvement of up-regulation of Kcp by BMP-2 in induction of osteoblast differentiation by BMP-2 was also examined, which showed that suppression of Kcp expression by si Kcp partially inhibited induction of osteoblast differentiation and mineralization by BMP-2. Together, these results suggest that Kcp induced by BMP-2 functions to provide positive feedback for promotion of osteoblastic differentiation and mineralization by BMP-2 in osteoblasts.

•Kcp expression was induced in osteoblasts by BMP-2 in a concentration- and time-dependent manner.•BMP-2-induced Kcp expression was regulated by SMAD signaling.•Induction of Kcp partially regulated BMP-2-induced osteoblast differentiation.

Kcp expression was induced in osteoblasts by BMP-2 in a concentration- and time-dependent manner.

BMP-2-induced Kcp expression was regulated by SMAD signaling.

Induction of Kcp partially regulated BMP-2-induced osteoblast differentiation.