Related Experiment Video

Updated: Jun 3, 2026

Polyelectrolyte Complex for Heparin Binding Domain Osteogenic Growth Factor Delivery
12:27

Polyelectrolyte Complex for Heparin Binding Domain Osteogenic Growth Factor Delivery

Published on: August 22, 2016

The heparin-binding domain of IGFBP-2 has insulin-like growth factor binding-independent biologic activity in the

Masanobu Kawai1, Anne C Breggia, Victoria E DeMambro

  • 1Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, Maine 04074, USA.

The Journal of Biological Chemistry
|March 5, 2011
PubMed

Insights

The heparin-binding domain (HBD) peptide of Insulin-like growth factor-binding protein 2 (IGFBP-2) promotes bone growth. This peptide therapy rescues low bone mass in mice by enhancing osteoblast activity and bone formation.

Area of Science:

  • Skeletal biology and endocrinology
  • Bone metabolism research
  • Growth factor signaling pathways

Background:

  • Insulin-like growth factor-binding protein 2 (IGFBP-2) is crucial for skeletal development.
  • IGFBP-2 deficiency in mice leads to low bone mass, reduced osteoblasts, and impaired bone formation.
  • PTEN expression is elevated in IGFBP-2 deficient mice.

Purpose of the Study:

  • To investigate the role of IGFBP-2's heparin-binding domain (HBD) in bone mass acquisition.
  • To determine if a synthesized HBD peptide can restore skeletal parameters in IGFBP-2 deficient mice.
  • To elucidate the molecular mechanisms by which IGFBP-2 influences bone metabolism.

Main Methods:

  • Synthesis of an IGFBP-2 HBD peptide.
  • In vitro studies using Igfbp2(-/-) bone marrow stromal cells and osteoblasts.
  • Ex vivo analysis of metacarpal periosteal expansion.
  • In vivo administration of HBD peptide to Igfbp2(-/-) mice.
  • Assessment of bone mass, osteoblast number, adipogenesis, and bone resorption.
  • Analysis of PTEN, Akt, and β-catenin signaling pathways.

Main Results:

  • The HBD peptide rescued the mineralization defect in Igfbp2(-/-) cells in vitro.
  • Ex vivo treatment stimulated periosteal expansion.
  • In vivo administration of the HBD peptide increased osteoblast numbers, restored trabecular bone mass, and reduced bone resorption in Igfbp2(-/-) mice.
  • HBD peptide treatment suppressed marrow adipogenesis.
  • Skeletal rescue involved reduced PTEN expression, enhanced Akt phosphorylation, and increased β-catenin signaling.

Conclusions:

  • The HBD peptide of IGFBP-2 exhibits anabolic activity on bone.
  • The peptide functions by activating IGF-I/Akt and β-catenin signaling pathways.
  • IGFBP-2 plays a direct role in stimulating bone growth and acquisition, beyond its carrier function.

More Related Videos

Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach10:23

Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach

Published on: August 26, 2013

Related Concept Videos

Insulin: The Receptor and Signaling Pathways01:28

Insulin: The Receptor and Signaling Pathways

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
Hormones and Bone Tissue01:17

Hormones and Bone Tissue

The endocrine system produces and secretes hormones, which interact with the skeletal system. These hormones control bone growth, maintain bone once it is formed, and remodel it.
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
Role of Hematopoietic Growth Factors01:28

Role of Hematopoietic Growth Factors

Hematopoietic growth factors are molecules that regulate the differentiation rate of hematopoietic stem cells (HSCs). Erythropoietin (EPO), primarily produced by the kidneys, plays a crucial role in erythrocyte production. When oxygen levels in the blood are low, EPO is released into the bloodstream, reaching the bone marrow, where it stimulates HSCs to differentiate and mature into erythrocytes, which are vital for oxygen transport.
Thrombopoietin (TPO), mainly released by the liver,...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
Insulin Secretory Vesicles01:05

Insulin Secretory Vesicles

Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
Phosphoinositides and PIPs01:42

Phosphoinositides and PIPs

Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...